Genetic and physiological aspects of mating behavior in Japanese quail (Coturnix coturnix japonica)
by Siegfried Mahn
A thesis submitted to the Graduate Faculty in partial fulfillment of the requirements for the degree of
DOCTOR OF PHILOSOPHY in Genetics
Montana State University
© Copyright by Siegfried Mahn (1968)
Abstract:
In a study involving 419 male and 618 female Japanese quail (Coturnix coturnix japonica) selection
pressure was applied for five generations to increase and decrease mating activity in the males. The
males only were tested and the females were drawn at random from the control group. The high and
low line were clearly separated in the first generation (G-1) and remained significantly different to. the
end of the experiment. Though the difference between the mean scores of the high and low line
remained significantly different in all generations except the G-2, no further progress was made in
widening the difference. The lack of further progress was attributed to one or a combination of factors
such as the use of an inadequate selection index, small number of segregating alleles, small population
size, selection in one sex only and a decrease in the number of families.
The absolute difference between the mean scores of the high and low line remained about the same to
the G-5 but the average scores declined in the last two generations. This decline was attributed to
environmental effect, the increasing number of males not contributing to the score, and a shift in
selection pressure. In the high line, a shift in selection pressure seems to have occurred with the result
that greater emphasis was placed on mating behaviors with lower positive numerical values (picking,
mounting, courting). In the low line, the mating score index consisted to an increasing extent of
displacement activities rather than copulations.
In the fifth generation (G-5), the high and low line differed considerably in their reaction to being
handled. The low group males and females were wilder and more excitable than the high group males
and females. The low line males also became more "timid" as the study progressed.
Courting displays occurred predominantly after copulation. The five generations of selection for
increased and decreased mating activity did not change any of the measure physiological characters
(I131 uptake, BMR, hatchability, post-hatch mortality, body weights, testes weight, anesthetic
out-time, hematocrit, and heart rate). The herit- ability estimates of the non-selected traits followed
those reported in the literature when comparisons were possible. I131_uptake very probably estimated
the level of endogenous PBI rather than the inverse of it.
In the fifth generation, the low line females matured later and laid at a lower rate than the high line
females. Egg weight was significantly positively correlated with rate of production. G E N E T I C AND P H Y S IO L O G IC A L A S P E C T S OF M ATING BEHAVIOR
IN J A P A N E S E Q U A I L ( C o t u r n i x c o t a r n i x i a p o n i c a )
by
S IE G F R IE D MAHN
A t h e s i s s u b m i t t e d to t h e G r a d u a t e F a c u l t y in p a r t i a l
f u l f i l l m e n t of t h e r e q u i r e m e n t s f o r t h e d e g r e e
of
DOCTOR OF PHILOSOPHY
in
G enetics
A pproved:
M ONTANA S T A T E UNIVERSITY
B o zem an , M ontana
A u g u s t , 1968
iii
ACKNOWL EDG E M E N T
T h e w r i t e r w o u l d l i k e t o t h a n k p a r t i c u l a r l y D r . D. W. B l a c k m o r e
and D r. R . L . B lack w ell fo r th e ir continued guidance, in te r e s t, and en ­
c o u r a g e m e n t d u r i n g t h e p r o g r e s s of t h i s s t u d y .
T h a n k s is due D r. B l a c k -
m o r e a ls o fo r m a k in g his l a b o r a t o r y and f a c ilitie s a v a ila b le durin g the
experim ent.
T h e e n c o u r a g e m e n t a n d s u g g e s t i o n s of t h e o t h e r m e m b e r s
of t h e g r a d u a t e c o m m i t t e e , D r . P . H . G r a y , D r . P . D. S k a a r a n d D r . A.
M. E l-N egoum y w ere greatly appreciated.
D r. G . T , D av is d e s e r v e s c r e d i t fo r the s u g g e s tio n to u s e J a p a n e s e
q u ail a f te r an a b o rtiv e a t te m p t w ith G uinea Fow l, and for having obtained
the s u b je c ts fo r the e x p e r im e n t.
D r. H e le n L . - M a y fie ld kindly p ro v id e d the r e s p i r o m e t e r and D r. M.
H ull the e l e c t r o - c a r d i o g r a p h fo r this in v e stig a tio n .
M iss P a r k e r 's efforts
i n o b t a i n i n g l i t e r a t u r e m a t e r i a l s w e n t b e y o n d t h e c a l l of d u t y .
D r . A. E. F l o w e r c o n t r i b u t e d in m a n y d i s c u s s i o n s to th e e x p e r i m e n t .
T h e w r i t e r w i s h e s t o t h a n k a l s o M r . A. F . B e e c k l e r a n d h i s s t a f f f o r
t h e i r h e l p in t h e c a r e a n d m a n a g e m e n t of t h e q u a i l .
T h e h e l p of D r . E . P . S m i t h a n d M r . W. S c h a f f i n t h e s t a t i s t i c a l
a n a l y s e s of t h e d a t a is g r a t e f u l l y a c k n o w l e d g e d .
S p e c i a l a p p r e c i a t i o n g o e s to m y w ife a n d M i s s M . B l a n c h e t t e fo r
iv.
:
t h e i r c o n s c i e n t i o u s t y p i n g of t h e m a n u s c r i p t .
T h i s w o r k i s m a d e p o s s i b l e t h r o u g h t h e f i n a n c i a l a s s i s t a n c e of t h e
D e p a r t m e n t of A n i m a l a n d R a n g e S c i e n c e s of M o n t a n a S t a t e U n i v e r s i t y .
V
TA B LE OF CONTENTS
V i t a .................................................................................................................. ..........................Li
A c k n o w l e d g e m e n t . . .....................................................................' ........................... Lii
T a b l e of C o n t e n t s ............................................................................................................. v
L i s t of T a b l e s ...........................................................................................................
vii
L i s t of F i g u r e s .................................................................................................................x
A b s t r a c t ...................................................................................................................................... x i
I n t r o d u c t i o n ....................................
I
R e v i e w of L i t e r a t u r e ...............................................................................................................2
I.
M a t i n g B e h a v i o r of Q u a i l ............................................................................
3
II.
M a t i n g B e h a v i o r of o t h e r A n i m a l s . . . . . . . . . . . .
4
IIL F a c t o r s and C o n d itio n s A ffecting S e x u al
B e h a v i o r ....................................................................................................................... 13
A . G e n e t i c ....................................................................................................... 13
B.
P h y s i o l o g i c ............................................................................................19
1. H o r m o n e s .............................................................................. 19
2. O t h e r F a c t o r s .
24
C . P s y c h o l o g i c ............................................................................................. 25
D. N e u r o l o g i c . ...............................................................................
28
IV.. M e a s u r e m e n t of S e x u a l B e h a v i o r ............................................................ 30
V . . S e l e c t i o n E x p e r i m e n t s a n d A s s o c i a t e d R e s p o n s e s ........................31
VI.
G e n e tic and o th e r F a c t o r s influencing the
m e a s u r e d u n s e l e c t e d T r a i t s ............................................................................. 36
A . E g g P r o d u c t i o n a n d E g g W e i g h t .............................................. 36
B. ., H a t c h a b i l i t y a n d F e r t i l i t y .........................................................37
C . P o s t - H a t c h M o r t a l i t y .......................................................................38
D. S e x R a t i o ..................................................................................................38
E. Sexual M aturity. . . . . .
38
F . B o d y W e i g h t .............................................................................................39
G . T e s t e s W e i g h t a n d C o l o r ..............................................
39
H . B a s i c M e t a b o l i c R a t e ( B M R ) ........................................................ 40
I.
P r o t e i n - B o u n d Iodine andT h y ro id F u n c tio n . . . .
40
J„
B l o o d G l u c o s e .............................................
42
K. H e m a t o c r i t
..........................................................................................42
L . H e a r t R a t e ............................................................................................... 43
M . R e s p o n s e t o A n e s t h e t i c s .........................................
43
M a t e r i a l s a n d E x p e r i m e n t a l P r o c e d u r e ...............................
. . . .
44
I. E x p e r i m e n t a l A n i m a l s ....................................................................................... 44
vi
II. T e s t i n g E q u i p m e n t f o r B e h a v i o r a l O b s e r v a t i o n s ..................... ..... . 5 1
III. T e s t i n g P r o c e d u r e . ................................................... ..................... ..... . . 51
IV. P h y s i o l o g i c a l T e s t i n g E q u i p m e n t a n d P r o c e d u r e s .......................... 53
V. S t a t i s t i c a l A n a l y s i s ..............................................................................................5 7
R e s u l t s .......................... .. ............................................................................... .............................. 60
I. R e s p o n s e i n t h e S e l e c t e d T r a i t ........................................................ . . 60
II. R e s p o n s e i n t h e u n s e l e c t e d p h y s i o l o g i c a l T r a i t s ......................................66
A . R e s u l t s i n t h e M a l e s . . . ..........................................................66
I.. H a t c h i n g P e r c e n t a g e ..............................
66
2'.. P o s t - H a t c h M o r t a l i t y ..............................................................67
3. S e x R a t i o ....................................................................................... 67
4. S i x W e e k a n d F i n a l B o d y W e i g h t ......................................68
5. T e s t e s W e i g h t ............................................................................. 68
6. B a s i c M e t a b o l i c R a t e ..............................................................68
7. A n e s t h e t i c O u t - T i m e .................................................... . 69
8. I o d i n e ^ ^ - U p t a k e .
69
9. H e m a t o c r i t .................................... ..................................... 6 9
10. H e a r t R a t e
.. . ..........................................
69
11. B l o o d G l u c o s e . . >....................................
70
B . S t a t i s t i c a l R e s u l t s ........................................................................
70
C . R e s u l t s i n t h e F e m a l e s ............................................... .....
71
III. R e s p o n s e s i n t h e u n s e l e c t e d b e h a v i o r a l T r a i t s .
73
A . D i s p l a c e m e n t A c t i v i t i e s ......................................................... ..... . 73
B . OtlxeT) B e h a v i o r s ....................................................................................... 73
T a b l e s ........................................................................................................................................ . 76
D iscussion .
............................................... ........................................................................ 92
I. G e n e t i c C o n s i d e r a t i o n s ....................................................................
92
II. P h e n o t y p i c C o n s i d e r a t i o n s .................................................................................103
A . P h y s i o l o g y of t h e M a l e s . . . . . . . . . . . . . . 103
1. R e l a t i o n s h i p s b e t w e e n s o m e
M e a s u r e m e n t s ..............................................
104
2. I n d i v i d u a l M e a s u r e m e n t s ............................... ..... . . 1 1 2
B . P h y s i o l o g y of t h e F e m a l e s ..............................................................1 1 6
1. E g g P r o d u c t i o n a n d E g g W e i g h t ................................... 1 16
2. S e x u a l M a t u r i t y . ......................................................................117
3. B o d y W e i g h t ................................................................................118
C . B e h a v i o r a l C o n s i d e r a t i o n s .............................................................. . 1 1 8
L ite ra tu re C ited .
......................... ................................................... 130
vii
L I S T :OF T A B L E S
TABLE
I.
N u m b e r of B i r d s I n v o l v e d In t h i s S t u d y ..................... 47
II.
H atching D ates and Age at w hich v ario u s T e s ts
w e r e d o n e .................................................................................. 4 9
III.
M e a n s a n d S t a n d a r d D e v i a t i o n s of M a t i n g S c o r e
D i f f e r e n c e in S c o r e s b e t w e e n H i g h a n d L o w L i n e
and Selection D ifferential.
........................76
IV.
In tr a-G ene ratio n and C um ulative H eritab ility
E s t i m a t e s f o r M a tin g S c o r e in th e H ig h and
L o w L i n e .......................... ................................... ■....................... 76
V.
VI.
C o r r e l a t i o n s a n d R e g r e s s i o n s of T o t a l S c o r e
in M a t i n g T e s t On e a n d M a t i n g T e s t T w o in
G e n e r a t i o n s T w o a n d T h r e e ................................................77
C o r r e l a t i o n s a n d R e g r e s s i o n s of M a t i n g S c o r e
C p m p o n e n t s in M a t i n g T e s t O n e a n d M a t i n g
T e s t T w o in G e n e r a t i o n s T w o a n d T h r e e . . . .
77
VII.
M e a n N u m b e r of P i c k , M o u n t , a n d C o p u l a t i o n
in M a t i n g T e s t On e a n d M a t i n g T e s t T w o in
G e n e r a t i o n s T w o a n d T h r e e ............................................. 78
VIII.
R a t i o s b e t w e e n t h e M e a n N u m b e r of P i c k ,
M o u n t , a n d C o p u l a t i o n in' M a t i n g T e s t On e
a n d M a t i n g T e s t T w o in G e n e r a t i o n s T w o ,
T h r e e a n d F i v e .............................................................................. 78
IX.
C o r r e l a t i o n s b e t w e e n C o m p o n e n t s of M a t i n g
S c o r e in M a t i n g T e s t O n e a n d M a t i n g T e s t
T w o in G e n e r a t i o n s T w o , T h r e e , a n d F i v e .
.
.
79
viii
X.
XI.
XII.
XIII.
X IV .
N u m b e r a n d P e r c e n t a g e s of M a l e s t h a t d i d
n o t M a t e , a n d t h o s e M a l e s w h i c h M a t e d in o n ly
O ne of t h e T w o M a t i n g T e s t s f o r G e n e r a t i o n s
O ne t o F i v e ................................................................................... 63
A v e r a g e C o n v e r t e d L a t e n c i e s t o C o p u l a t i o n of
t h e T e s t e d M a l e s in G e n e r a t i o n s O n e t o F i v e .
.
80
C o r r e l a t i o n s b e t w e e n C o m p o n e n t s of M a t i n g
S c o re and T o ta l S c o re w ith Six W eek and
F i n a l B o d y W e i g h t s in t h e S e l e c t e d a n d C o n ­
t r o l G r o u p s in G e n e r a t i o n s tw o , t h r e e a n d f o u r •
81
P e r c e n t a g e of M a l e s C o u r t i n g b e f o r e o r a f t e r
C o p u la tio n w ith in L i n e s in th e G - 4 and G - 5 - • •
82
. S c o r e s of a l l L o w L i n e M a l e s a n d of t h o s e
P r o d u c i n g O f f s p r i n g w i t h R e s p e c t of D i s p l a c e ­
m e n t A c t i v i t i e s w i t h i n G e n e r a t i o n s .............................
82
XV.
P h en o ty p ic C o r r e la tio n s b etw ee n M ating S c o re
and the U n s e le c te d C h a r a c t e r s w ithin the H igh
and Low Line and P o o led o v er all G en eratio n s
f o r t h e M a l e s p r o d u c i n g O f f s p r i n g . .................................83
XVI.
A v e r a g e H a t c h i n g P e r c e n t a g e s of E g g s S e t
w i t h i n L i n e s a n d G e n e r a t i o n s ................................................ 83
XVII.
XVIII.
XIX..
XX.
D i s p o s i t i o n of a l l E g g s S e t in t h e G - 4 .....................84
P o s t- H a tc h M o rta lity w ithin L in es and G en ­
e r a t i o n s (in p e r c e n t ) ..................................................................... 84
. S e x R a t i o s a n d N u m b e r s of M a l e s a n d F e m a l e s
w i t h i n L i n e s a n d G e n e r a t i o n s .........................
A v e r a g e M ale Six W eek and F in a l Body W eights
w i t h i n L i n e s a n d G e n e r a t i o n s (in g r a m s ) .
84
85
ix
XXI,
XXII,
XXII I,
X XI V ,
A v e r a g e T e s t e s W e i g h t (in g r a m s ) a n d a s P e r
c e n t of B o d y W e i g h t w i t h i n L i n e s a n d G e n e r a t i o n s .
85
E s t i m a t e s of B a s i c M e t a b o l i c R a t e ...................................... 86
A v e r a g e A n e s t h e t i c O u t - t i m e (in m i n u t e s '
w i t h i n L i n e s a n d G e n e r a t i o n s ............................... ■.
.
.
87
131
A v e r a g e C o u n t s ( p e r m i n u t e ) of I
-U ptake
w i t h i n L i n e s a n d G e n e r a t i o n s .................................................... 87
XXV.
A v e r a g e H e m a t o c r i t V a l u e s (in p e r c e n t ) w i t h i n
L i n e s a n d G e n e r a t i o n s ....................................................................87
XXVI,
A v e r a g e - H e a r t R a te s (b e a ts/m in u te ) w ithin '
L i n e s a n d G e n e r a t i o n s ....................................................................88
XXVII,
X XV II I,
XXIX,
XXX.
A v e r a g e B l o o d G l u c o s e (in m g % V w i t h i n L i n e s
in t h e G - 4 ..........................
88
S ire-O ffspring R eg ressio n s and H eritabilities
fo r v a rio u s T r a i t s w ithin the High and Low L in e
a n d P o o l e d f o r a l l G e n e r a t i o n s ..................................................89
S ignificant P hen o ty p ic C o r r e la tio n s betw een
v a rio u s T r a i t s , pooled fo r all s e le c te d M ales
C o r r e l a t i o n s a m o n g M e a s u r e d T r a i t s in t h e F e ­
m a le s, P ooled for all G enerations
.
.
90
91
X
LIST OF FIGU RES
FIGU RE
1.
T h e R e s p i r o m e t e r u s e d in t h i s E x p e r i m e n t .......................... 53
2, „ T a k i n g t h e H e a r t R a t e ......................................................................55
3.
R e s p o n s e of S e l e c t i o n f o r H i g h a n d L o w M a t i n g
Scores
A. M e a n S c o r e s , of a l l M a l e s t e s t e d w i t h i n
the L in e s and G e n e r a t i o n s .
B . M e a n S c o r e s of t h e S e l e c t e d M a l e s w i t h i n
the L in es and G e n e ra tio n s .
C . M e a n S c o r e s of a l l M a l e s t e s t e d w i t h i n
the High and Low L ine a d ju ste d fo r E n ­
v ir o n m e n ta l F lu c tu a tio n s w ith R e g r e s s i o n
L i n e s f i t t e d ............................................................................... 6 1
4,
M i s t r e a t e d F e m a l e s ............................................................................... 74
xi
ABSTRACT
I n a s t u d y i n v o l v i n g 4 1 9 m a l e a n d 618 f e m a l e J a p a n e s e q u a i l
( C o t u r n i x c o t u r n i x j a p o n i c a ) s e l e c t i o n p r e s s u r e w a s a p p l i e d f o r f iv e
g e n e r a t i o n s t o i n c r e a s e a n d d e c r e a s e m a t i n g a c t i v i t y in t h e m a l e s . T h e
m a l e s only w e r e t e s t e d an d th e f e m a l e s w e r e d r a w n a t r a n d o m f r o m
t h e c o n t r o l g r o u p . T h e h i g h a n d l o w l i n e w e r e c l e a r l y s e p a r a t e d in t h e
f i r s t g e n e r a t i o n ( G - I ) a n d r e m a i n e d s i g n i f i c a n t l y d i f f e r e n t to. t h e e n d
of t h e e x p e r i m e n t . T h o u g h t h e d i f f e r e n c e b e t w e e n t h e m e a n s c o r e s of
t h e h i g h a n d l o w l i n e r e m a i n e d s i g n i f i c a n t l y d i f f e r e n t in a l l g e n e r a t i o n s
e x c e p t th e G -Z , no f u r t h e r p r o g r e s s w a s m a d e in w id e n in g th e d if f e r e n c e .
T h e l a c k of f u r t h e r p r o g r e s s w a s a t t r i b u t e d t o o n e o r a c o m b i n a t i o n of
f a c t o r s s u c h a s t h e u s e of a n i n a d e q u a t e s e l e c t i o n i n d e x , s m a l l n u m b e r
of s e g r e g a t i n g a l l e l e s , s m a l l p o p u l a t i o n s i z e , s e l e c t i o n in o n e s e x
o n l y a n d a d e c r e a s e i n t h e n u m b e r of f a m i l i e s .
T h e a b s o l u t e d i f f e r e n c e b e t w e e n t h e m e a n s c o r e s of t h e h i g h a n d l o w
line r e m a i n e d a b o u t th e s a m e to the G - 5 b u t the a v e r a g e s c o r e s d e c l in e d
in th e l a s t tw o g e n e r a t i o n s . T h is d e c l in e w a s a t t r i b u t e d to e n v i r o n m e n t ­
a l e f f e c t , t h e i n c r e a s i n g n u m b e r of m a l e s n o t c o n t r i b u t i n g t o t h e s c o r e ,
an d a shift in s e le c tio n p r e s s u r e . In the high line, a shift in s e le c tio n
p r e s s u r e s e e m s to h a v e o c c u r r e d w ith th e r e s u l t th a t g r e a t e r e m p h a s i s
w a s p l a c e d on m a t i n g b e h a v i o r s w ith l o w e r p o s i t i v e n u m e r i c a l v a lu e s
( p i c k i n g , m o u n t i n g , c o u r t i n g ) . In t h e l o w l i n e , t h e m a t i n g s c o r e i n d e x
c o n s i s t e d to a n i n c r e a s i n g e x t e n t of d i s p l a c e m e n t a c t i v i t i e s r a t h e r t h a n
copulations.
In th e fifth g e n e r a t i o n (G -5), the high an d low lin e d i f f e r e d c o n s i d ­
e r a b l y in t h e i r r e a c t i o n to b eing h a n d le d . T h e low g r o u p m a l e s and f e ­
m a l e s w e r e w ild e r and m o r e e x c ita b le th a n the high g r o u p m a l e s and f e ­
m a l e s . T he low line m a l e s a l s o b e c a m e m o r e " tim id " a s the study
progressed.
C o u r tin g d i s p la y s o c c u r r e d p r e d o m i n a n t l y a f t e r c o p u la tio n . The five
g e n e r a t i o n s of s e l e c t i o n f o r i n c r e a s e d a n d d e c r e a s e d m a t i n g a c t i v i t y d i d
n o t c h a n g e a n y of t h e m e a s u r e p h y s i o l o g i c a l c h a r a c t e r s (I* * u p t a k e ,
BMR, h a tc h a b ility , p o s t-h a tc h m o rta lity , body w eights, te s te s
w eight, a n e s th e tic o u t-tim e , h e m a to c rit, and h e a r t rate ). The h e rit-
Xi i
a b i l i t y e s t i m a t e s of t h e n o n - s e l e c t e d t r a i t s f o l l o w e d t h o s e r e p o r t e d in
the lite r a tu r e w hen c o m p a ris o n s w e re p o ssib le.
uptake v ery
p r o b a b l y e s t i m a t e d t h e l e v e l of e n d o g e n o u s P B I r a t h e r t h a n t h e i n v e r s e
of it.
In the fifth g e n e r a t i o n , th e low lin e f e m a l e s m a t u r e d l a t e r an d la id
at a lo w e r r a t e th a n the high line f e m a le s . Egg w eight w as significantly
p o s i t i v e l y c o r r e l a t e d w i t h r a t e of p r o d u c t i o n .
9
G E N E T IC AND PH Y SIO L O G IC A L A S P E C T S OF M ATING BEHAVIOR
IN J A P A N E S E Q U A I L ( C o t u r n i x c o t u r n i x j a p o n i c a )
INTRODUCTION
A d e q u a t e s e x u a l b e h a v i o r is v e r y i m p o r t a n t in r e p r o d u c t i o n .
It h a s
b e e n o b s e r v e d th a t s o m e b u lls lo s e t h e i r u s e fu ln e s s as s e m e n donors due
t o t h e i r d e c r e a s e d r e s p o n s e t o t e a s e r a n i m a l s ( K e r r u i s h , 1955).
This
p r o b le m could p e rh a p s be o v e rc o m e by s e le c tio n for in c r e a s e d sexual
a c t i v i t y o r s e x u a l d r i v e if. a . g e n e t i c d i f f e r e n c e e x i s t s .
G re a te r sexual
a c t i v i t y in r e s p o n s e t o s e l e c t i o n h a s b e e n o b s e r v e d b y R a s m u s s e n (1952),
W o o d - G u s h a n d O s b o r n e (1956), M a n n i n g (1961, 1963), P a r s o n (1964),
F u l k e r (1966), a n d o t h e r s .
R elativ ely little has b e e n r e p o r te d about
c h a n g e s in a s s o c i a t e d p h y s i o l o g i c a l p a r a m e t e r s a s s e l e c t i o n f o r i n , .
c r e a s e d sexual activity continues.
R e d u c t i o n , i n f e r t i l i t y of s e x u a l l y
h i g h l y a c t i v e m a l e s h a s b e e n i n d i c a t e d b y P a r k e r jA a l (1942), R a s m u s ­
s e n (1952), a n d F o m i n e t a l (1963).
J a p a n e s e q u a i l (C o t u r n i x c o t u r n i x j a p o n i c a ) a r e v e r y s u i t a b l e f o r
s e l e c t i o n s t u d i e s a n d t h e d e t e r m i n a t i o n of p h y s i o l o g i c a l c h a r a c t e r s .
F i n d i n g s o b t a i n e d f r o m s t u d i e s of t h i s b i r d m a y b e a p p l i c a b l e t o o t h e r
b i r d s , p a r t i c u l a r l y d o m e s t i c f o w l.
G enetic c o rre la tio n s betw een s e l ­
e c t e d a n d u n s e l e c t e d c h a r a c t e r s m a y a l s o g i v e a n i n d i c a t i o n of t h e r e ­
s p o n s e s t o e x p e c t w h e n s e l e c t i o n f o r h i g h e r s e x u a l a c t i v i t y is u n d e r t a k e n '
-2-
in l a r g e r d o m e s t i c a n i m a l s .
T h is stu d y w a s u n d e r t a k e n to o b s e r v e p o s s i b l e a s s o c i a t e d c h a n g e s in
c e r t a i n p h y s i o l o g i c a l c h a r a c t e r s w h e n s e l e c t i o n p r e s s u r e is a p p l i e d t o a
b e h a v i o r a l c h a r a c t e r , in th i s c a s e m a t i n g p r o p e n s i t y .
■R E V I E W O F L I T E R A T U R E
J a p a n e s e q u a i l (C o t u r n i x c o t u r n i x j a p o n i c a ) w e r e c h o s e n b e c a u s e t h e y
a re relatively sm all,
r e q u ir e little sp ace; have a s h o rt g e n e ra tio n in­
te r v a l; and h av e enough s e x u a l d i m o r p h i s m fo r easy identification.
C o t u r n i x b e l o n g t o t h e s a m e o r d e r (G a l l i f o r m e s ) a s c h i c k e n s a n d
turkeys.
o ;' '
T h e y b e l o n g i n t h e s a m e f a m i l y (P h a s i a n i d a e l w i t h p a r t r i d g e s
( P e r d i x ) , p h e a s a n t s (P h a s i a n u s ) , a n d b o b w h i t e q u a i l (C o l i n u s ) .
How­
e v e r , C o l i n u s a n d C o t u r n i x a r e c l a s s i f i e d in d i f f e r e n t s u b f a m i l i e s ,
O d o n t o p h o r i n a e a n d P h a s i a n i n a e , r e s p e c t i v e l y ( S t o r e r , I960) c i t e d b y
S a c h s (1966b).
M a i n a r d i (1959) h a s q u e s t i o n e d t h e v a l i d i t y of t h i s d i v ­
ision.
T h e C o t u r n i x of E u r o p e a n d N o r t h A f r i c a a r e c l a s s i f i e d a s C o t u r n i x
C o t u r n i x c o t u r n i x , w h e r e a s t h e A s i a n f o r m is C o t u r n i x c o t u r n i x j a p o n i c a
T h e r e h a s b e e n s o m e q u e s t i o n a s to w h e t h e r th e A s i a n a n d E u r o p e a n
q u a il a r e r e a l l y d i s t i n c t r a c e s o r b e lo n g to a R a s s e n k r e i s (Stanford,
-3-
1957).
C o t u r n i x h a v e a long h i s t o r y a n d w e r e e s t e e m e d a s good food as
e a r l y a s t h e M e r o v i n g i n a t i m e s ( 5 0 0 - 7 5 0 A. D. ) ( Z e u n e r , 1963).
J a p a n e s e q u a i l h a v e b e e n d o m e s t i c a t e d a t l e a s t s i n c e t h e e n d of t h e
sixteenth century.
In ten siv e b reed in g fo r eggs and m e a t w as s ta r te d f r o m
t h e b a s i s of t h o s e d o m e s t i c a t e d , a n d p r o b a b l y a l s o w i l d q u a i l a t t h e t u r n
of t h e t w e n t i e t h c e n t u r y ( S h i m a k u r a , 1940); a p p r o x i m a t e l y 200 g e n e r a t i o n s
have p a s s e d sin ce then.
In the la b o r a t o r y , u n d e r a p p r o p r i a t e conditions,
one can obtain f e r t i l e
e g g s a l l y e a r a r o u n d w i t h s o m e f l u c t u a t i o n in f e r t i l i t y ( B e a c h a n d I n m a n ,
1965).
I n t h e w i l d , t h e q u a i l u s u a l l y r a i s e o n e b r o o d of y o u n g , b u t s o m e
h e n s s i t a s e c o n d , t h o u g h r a r e l y a t h i r d t i m e in o n e s e a s o n ( S t e v e n s , 1961).
I.
M ATING BEHAVIOR OF QUAIL
M ating b e h a v i o r in the w ild has not b e e n d e s c r i b e d w ell.
B annerm an
(1963) w r o t e t h a t m i g r a t i o n o c c u r s i n u n i s e x u a l f l o c k s , t h e m a l e s a r r i v i n g
f i r s t to e s t a b l i s h t e r r i t o r i e s .
The f e m a le s follow and w ithout c o n c e r n fo r
the m a le s e s ta b lis h n e s t s ite s.
W hen a s u ita b le lo c a tio n h a s b e e n found,
t h e f e m a l e c a l l s a n d u s u a l l y t h e m a l e in t h e t e r r i t o r y c l o s e s t t o h e r w i l l
m a te w ith h e r .
C o pulation m a y be p r e c e d e d by s h o r t v e r t i c a l flights and
vocalization.by b o th .m ates.
indicated.
C ourtship,
oth e r than th o se flights was not
-4-
D e s c r i p t i o n s of t h e c o u r t i n g a n d m a t i n g b e h a v i o r of q u a i l in t h e
l a b o r a t o r y h a v e b e e n p r o v i d e d b y B e a c h a n d I n m a n (1965) a n d F a r r i s
(1967).
ulation.
They indicated that courting m a y o ccu r b efo re a n d /o r after co p ­
E i th e r the m a l e o r the fe m a le m a y ta k e the initia tiv e.
The m a le
w i l l o f t e n " s t r u t " d u r i n g t h e a p p r o a c h , i. e. , w a l k s t i f f - l e g g e d a n d u p on
his to e s , th e n e c k ex ten d ed f o r w a r d a l m o s t h o riz o n ta lly w ith the h ead
cocked to w ard s the fem a le.
H is f e a t h e r s a r e e r e c t , and th e wing facing
the f e m a le is m o r e o r l e s s d e p r e s s e d as he c i r c l e s the f e m a le .
m a le 's
The fe ­
a p p r o a c h b e g i n s w i t h p i c k i n g a t t h e m a l e in t h e g e n e r a l f o r w a r d
a r e a of t h e b o d y o r s h e m a y r u b p a s t u n d e r h i s n e c k a n d a g a i n s t h i s
b reast.
T he f e m a l e m a y sh o w l o r d o s i s , b u t th e m a l e is not d e t e r r e d
w h en th is f e a t u r e is a b sen t:
the m a le th e n g r a b s the fe m a le by the
f e a t h e r s o r s k i n of t h e h e a d ox n e c k .
This o rien tatio n gives the c o r r e c t
l i n e - u p a n d h e will, q u i c k l y m o u n t a n d c o p u l a t e .
achieved, the m a le ,
A f t e r c l o a c a l c o n t a c t is
o r b o t h b i r d s , m a y f a l l . D i s m o u n t i n g is m o s t o f t e n
f o l l o w e d w i t h f l u f f i n g of t h e f e a t h e r s b y t h e m a l e , a n d s h a k i n g .
Strutting
m a y also occur a fte r dism ounting.
II.
M ATING BEHAVIOR OF O T H E R ANIMALS
M a t i n g b e h a v i o r h a s b e e n s t u d i e d in m a n y d i f f e r e n t a n i m a l s .
Schein
a n d H a l e (1965), S m i t h (1956), a n d G u h l (1961) i n d i c a t e d t h a t e v e r y s t e p
-5-
in t h e s e q u e n c e of m a t i n g b e h a v i o r i s g o v e r n e d b y s t i m u l i t h a t f i r s t
s e r v e t o b r i n g p o t e n t i a l m a t e s i n p r o x i m i t y of e a c h o t h e r ( b r o a d c a s t
s tim u li) , th e n to e s t a b l i s h m a t i n g p a i r s (id e n tific a tio n s t i m u l i ) , and th e n
t o c o o r d i n a t e t h e s p e c i e s - s p e c i f i c m o t o r p a t t e r n s of e a c h p a r t n e r s o t h a t
f e r t i l i z a t i o n w i l l h a v e a h i g h p r o b a b i l i t y of o c c u r r i n g ( s y n c h r o n i z a t i o n
stim uli).
F o r m a m m a l s , S c h e i n a n d H a l e (1965) s u g g e s t e d t h a t s e q u e n c e s of
s e x u a l r e s p o n s e s o v e r t i m e a r e n o t b a s e d u p o n f l u c t u a t i o n s in s e x d r i v e ,
th resh o ld s o r sexual deprivation.
T h e e n t i r e s e q u e n c e of e v e n t s is
b a s e d on t h e a m o u n t of n o v e l t y in t h e s i t u a t i o n a n d t h e o n l y c e i l i n g on
s e x u a l r e s p o n s e s i s t h a t e s t a b l i s h e d i n t e r m s of t h e o r g a n i s m ' s c a p a c i t y
t o i d e n t i f y n o v e l t y (G oy a n d J a k w a y , . 1962).
B ut n o v e lty is a f e a t u r e
w h i c h e v o k e s a v o i d a n c e in r a t s ( K a g a n a n d B e a c h , 1953).
Flight fro m
n o v e l t y is a u t o m a t i c a n d u n d i s c r i m i n a t i n g , a n d h a s s u r v i v a l v a l u e f o r
w ild r a ts .
In the c o c k ro a c h , novelty w ill.m a in ta in explo ratio n :
children,
l i k e m o n k e y s , w i l l r e a d i l y l e a r n a s i m p l e t a s k w h e n t h e o n l y r e w a r d is
t h e s i g h t of s o m e t h i n g n o v e l ( c . f . H a l e a n d A l m q u i s t , I 9 6 0 ; B a r n e t t ,
1967) .
T h e s o u r c e s of d i s p l a y o r c o u r t s h i p m o v e m e n t s i n c l u d e :
m ovem ents,
2.
D isp lacem en t activities , and 3 .
I.
Intention
R ed irecte d activities
-6-
( H a f e z , 1962).
stim uli.
C o u r t s h i p p a t t e r n s of b i r d s a r e e s s e n t i a l l y i d e n t i f i c a t i o n
U s u a l l y r e c e p t i v e f e m a l e t u r k e y s s o l i c i t in t h e p r e s e n c e of a
d i s p l a y i n g m a l e ; t h e m a l e r e s p o n d s m o s t s t r o n g l y to t h e f e m a l e ' s h e a d .
)
S c h e i n a n d H a l e (1965) s u g g e s t e d t h a t t h e d i f f e r e n c e b e t w e e n c h i c k e n s a n d
t u r k e y s is due to th e f a c t t h a t .t h e l a t t e r a r e m o r e d e l i b e r a t e a n d the f o r ­
m e r a r e m o r e agile.
R o o s t e r s c a n s e e m o r e of t h e h e n d u r i n g t h e c o p ­
u l a t i o n t h a n t h e t u r k e y t o m ( c . f . C a r b a u g h _et al,. 1962).
S o m e s t r a i n s of
t u r k e y s ex ten d t h e i r s e x u a l r e s p o n s e s to h u m a n s and t h e r e b y show le s s
s p e c i f i c i t y of s e x u a l c h o i c e t h a n o t h e r s t r a i n s r e a r e d u n d e r i d e n t i c a l
conditions.
Since the
b e t w e e n s u c h s t r a i n s is i n t e r m e d i a t e i n s p e c ­
ificity, a g e n e tic b a s i s has to be a s s u m e d fo r this d iffe re n c e (Schein and
H a l e , 1959, 1965).
F o r m , p o s t u r e a n d c o l o r t o g e t h e r e l i c i t t h e m a t i n g r e s p o n s e in t h e
B r e w e r ' s B l a c k b i r d (I c t e r i d a e ) , b u t n o n e of t h e f a c t o r s a l o n e w a s s u f ­
ficient.
H o w e l l a n d B a r t h o l o m e w (1952) c o n c l u d e d f r o m t h e r e a c t i o n of
the m a l e s to d u m m i e s f r o m w h ic h d i f f e r e n t p a r t s h a d b e e n r e m o v e d , th a t
t h e t a i l i s p r o b a b l y t h e m o s t i m p o r t a n t f e a t u r e in m a t i n g p o s t u r e .
C o u r ti n g w ith h i s s i n g is done by b o th m a l e a n d f e m a l e r u ffe d g r o u s e
( B o n a s a u m b e l l u s L , ). A l l e n (1934) s u g g e s t e d t h a t t h e s e b i r d s do n o t
-7-
r e c o g n i z e s e x a s s u c h a n d t h a t t h e i n t i m i d a t i o n d i s p l a y i s a m a t t e r of
relative strength.
In t h e i r m a t i n g d is p la y , in c o n t r a s t to m a n y o th e r
b i r d s , t h e i r f e a t h e r s a r e d e p r e s s e d i n s t e a d of r u f f l e d a n d t h e i r t a i l s d r a g
on t h e g r o u n d .
T h e m a le w alks slow ly and upon a p p ro a c h in g a n o th er
b ir d , g en tly p ic k s a t th e b a s e of the b e a k .
D o m in a tio n and f e a r a r e the
i m p o r t a n t p r i n c i p l e s in t h e c o n t r o l of t h e m a t i n g c y c l e a n d i n t h e d e v e l ­
o p m e n t of s e c o n d a r y s e x u a l c h a r a c t e r s .
C o p u la tio n s w ithout p r e l i m i n a r i e s h ave b e e n o b s e r v e d in the Y ellow h a m m e r (E m b e r i z a c i t i r n e l l a ) a n d o t h e r B u n t i n g s .
w hen the m a le ap p ro a c h e s.
T he fem a le solicits
C o p u l a t i o n a t t e m p t s m a y b e b r o k e n off d u e
t o t h e i n c r e a s e of f e a r i n t h e m a l e a s h e c o m e s c l o s e r t o t h e f e m a l e .
T h e m a l e e i t h e r h o v e r s a b o v e th e f e m a l e o r la n d s d i r e c t l y on h e r b a c k .
A fte r a few seco n d s he co p u lates and flies away.
T h e m a l e s of t h e s e
s p e c ie s s o m e tim e s m o u n t f r o m the g ro u n d a fte r c o u rts h ip d isp lay s and
m a k e v io l e n t a t t e m p t s to c o p u la te , d u r in g w h ic h th e y s e i z e th e f e m a l e s
by the n ap e o r b a c k .
T h e c o p u l a t i o n c a l l a n d a c c o m p a n y i n g p o s t u r e s of
t h e C o r n B u n t i n g (E m b e r i z a c a l a n d r a ) s u g g e s t t h a t o r i g i n a l l y i n t h i s
s p e c i e s th e m a l e h a d th e te n d e n c y to a t t a c k a s he a p p r o a c h e d to c o p u la te
( A n d r e w , 1956).
-8-
Z e b r a f i n c h e s (P o e p h i l a g u t t a t a ) a r e s t r o n g l y d i m o r p h i c a n d y e t
f o r m p a i r b o n d s ( M o r r i s , 1954),
C o u rtin g does not ta k e p la c e w ithout
s o n g , alth o u g h t h e r e m a y be song w ithout c o u rtin g .
In c o u r tin g , the
m a l e m o v e s a s to exhibit a ll the m a r k i n g s w hich a r e p a r t i c u l a r l y m a le .
A f te r d is m o u n tin g , bo th b i r d s w ill often p r e e n .
Raping m a y o c c u r when
a f e m a l e c o m e s i n t o t h e t e r r i t o r y of a m a t e d p a i r a n d t h e n t h e n e w f e m a l e
s e e m s to be a s t r o n g e r s e x s t i m u l u s t h a n th e p a i r e d one.
M ale and fem ale sexual re sp o n se s sh a re c e rta in sh o rt t e r m causal
f a c t o r s ( S e w a r d , 1941).
T h e s o l i c i t i n g of t h e m a l e Y e l l o w h a m m e r is a n
e x a m p l e of c o m p r o m i s e b e h a v i o r s i n c e i t e x p r e s s e s t h e s e x u a l t e n d e n c y ,
bu t, b e in g a s t a t i o n a r y d is p la y , p e r m i t s th e m a l e to a v o id th e f e m a l e
a n d s o i s c o m p a t i b l e w i t h s t r o n g f e a r of h e r ( A n d r e w , 1956).
D a r w i n (1874) s t a t e d t h a t w h e n m a l e s h a v e h a r e m s , t h e y a r e m u c h
l a r g e r t h a n t h e f e m a l e s , b u t t h e y a r e of a b o u t e q u a l s i z e w h e n m o n o g a ­
mous.
B i r d s w i t h g r e a t e r c o l o r d i m o r p h i s m t e n d to b e p o l y g a m o u s .
He
q u o t e s A u d u b o n a s w r i t i n g t h a t '-When s e v e r a l m a l e s of t h e V i r g i n i a n G o a t ­
s u c k e r (C a p r i m u l g u s v i r g i n i a n u s ) c o u r t , i n a h i g h l y e n t e r t a i n i n g m a n n e r ,
t h e f e m a l e , a n d no s o o n e r h a s s h e m a d e h e r c h o i c e , t h a n h e r a p p r o v e d
g iv e s c h a s e to a l l i n t r u d e r s , an d d r i v e s t h e m b e y o n d his dom inions. "
- 9—
D a r w i n c o n s i d e r e d t h a t f e m a l e s of t h e p e a f o w l ( P a v o c r i s t a t u s ) a n d t h e
w i l d t u r k e y (M e l e a g r i s g a l l o p a y o ) m a k e t h e c h o i c e of a m a t e b y f i g h t i n g ,
o r e v e n c o u r t i n g th e m a l e to g a in h is p o s s e s s i o n .
E l a b o r a t e p o s t - c o i t a l d i s p l a y s h a v e b e e n a t t r i b u t e d to th e E u r o p e a n
A v o c e t fR e c u r v i r o s t r a a v o s e t t a I .
b y M a r l e r a n d H a m i l t o n (1966) w h i c h
m a y t r i g g e r ovulation. ' T he m a l e and fe m a le s t a r t co p u latio n by picking
a t t h e i r f e a t h e r s o r t h e w a t e r ( t h e y u s u a l l y m a t e in s h a l l o w w a t e r ) a n d
m a k e s i m i l a r m o v e m e n t s w h e n on l a n d .
P r e e n i n g by the m a t e s alw ays
p r e c e d e s c o p u la tio n , b u t not a ll p r e e n i n g s l e a d to c o p u la tio n .
E xcitem ent
s e e m s to b e i m p o r t a n t a s th e A v o c e ts f r e q u e n t ly m a t e a f t e r a fight o r
other d isturbance.
T h e r e is no r a p in g .
A fter copulation, the b ird s m a y
hold e a c h o t h e r 's b ill and ru n to g e th e r f o r a s h o r t d is ta n c e .
M akking
(193 6) d i s a g r e e d w i t h D o m m a n d D a v i s (1948) t h a t s e x r e c o g n i t i o n is b y
b e h a v i o r o n l y a s h e o b s e r v e d no w r o n g p a i r i n g s .
T h e r e a r a p p r o a c h of t h e m a l e t o w a r d t h e f e m a l e g i v e s t h e b e s t
o r i e n t a t i o n f o r m o u n t i n g in t h e W h i t e L e g h o r n fo w l (G u h l, 1961).
W altzes
and w in g -flu tte r w e r e m o s t c o m m o n w hen the potential m a te s w e re u n a c ­
quainted.
T h e s e b e h a v io r s a r e a s s o c i a t e d w ith se x d riv e and should be
co n sid ered disp lacem en t activities.
If a W h i t e L e g h o r n m a l e h a s a h i g h
-10-
s e x d r i v e , he m a y a p p r o a c h a fe m a le and m o u n t and t r e a d b e f o r e the f e ­
m a l e c r o u c h e s (G u h l , 1951).
H i n d e (1954), M o r r i s (1954), A n d r e w (1956), W o o d - G u s h (1956) c o n ­
s i d e r e d t h a t a l l c o u r t s h i p b e h a v i o r s a r e a r e s u l t of t h e t e n d e n c i e s to
a t ta c k ,- f le e , and behave sexually to w ard s the m a te .
In th e G re e n fin c h
(C h l o r i s c h l o r i s c h l o r i s ) , t h e m o s t f r e q u e n t f o r m of r e d i r e c t e d a c t i v i t y
w a s b i l l - w i p i n g ; a n d H i n d e (1953) s u g g e s t e d t h a t t h e m a l e ' s s o l i c i t i n g
a f t e r c o p u l a tio n in v o lv e s th e t h w a r t e d te n d e n c y to flee,
T id b ittin g is done in a c o n flic t s i t u a t i o n by B r o w n L e g h o r n and is
m o r e f r e q u e n t w h e n t h e m a l e i s m o l t i n g o r h i s s e x u a l a c t i v i t y is l o w f o r
s o m e o t h e r r e a s o n ( W o o d - G u s h , 1956).
H e a lso in d ic a te d th a t the d i s ­
p l a y of t h e c o c k i n c l u d e s a t l e a s t t w o g r o u p s of b e h a v i o r s , d e p e n d i n g on
the o v e rt f e m a le re a c tio n .
entices and pacifies h e r.
F i r s t , he i n t i m i d a t e s the f e m a l e , an d th e n he
To b eh av e sexually, th e r e f o r e , m u s t involve
f i r s t a s u p p r e s s i o n of a g g r e s s i v e n e s s a n d l a t e r t h e t e n d e n c y t o f l e e .
G r e a t e r s e x u a l a c t iv it y an d c o u r ti n g w a s o b s e r v e d in m a l e c h ic k e n s
of d i f f e r e n t b r e e d s t h a t h a d b e e n r a i s e d i n a l l m a l e f l o c k s o r m a i n t a i n e d
i n i n d i v i d u a l c a g e s ( P a r k e r _et a l , 1940; W o o d - G u s h , 1956; S i e g e l a n d
S i e g e l , 1964).
-li­
l t h a s b e e n p r o p o s e d ( Y o u n g , 1957) t h a t p a t t e r n s of s e x u a l b e h a v i o r
h a v e a s o m a t i c b a s i s a n d t h a t t h e c h a r a c t e r of t h e b e h a v i o r d i s p l a y e d d e ­
p e n d s on t h e c h a r a c t e r of t h e s o m a o r t h e s u b s t r a t e o n w h i c h t h e h o r ­
m o n e s act.
In g u in e a p i g s , c o n t a c t w ith o t h e r a n i m a l s is i m p o r t a n t ,
if
n o t n e c e s s a r y f o r t h e d e v e l o p m e n t o r o r g a n i z a t i o n of t h e c o m p l e t e p a t ­
t e r n of s e x u a l b e h a v i o r ( V a l e n s t e i n a n d G o y , 1957).
The genetic b a c k ­
g ro u n d m a y im p o s e lim ita tio n s w hich n e ith e r the e x p e r ie n tia l fa c to r, n o r
a n y a c t i o n of g o n a d a l h o r m o n e s c a n o v e r c o m e .
It is r a r e f o r a m a l e
g u i n e a p i g t o b e i n t e r e s t e d in a f e m a l e a f t e r h a v i n g a c h i e v e d e j a c u l a t i o n ,
and only in a b o u t one p e r c e n t . o f th e t i m e , a s e c o n d e j a c u l a t i o n is a c h ­
i e v e d (Y ou n g a n d G r u n t , 1951).
L i k e t h e c a g e d r o o s t e r s of P a r k e t _et a l (1940) a n d G u h l (1961), i s o l a t e d
g u in e a pig m a l e s e n g a g e in m o r e s e x u a l l y e x p l o r a t o r y b e h a v i o r su c h as
sniffing and licking.
It is not is o la tio n p e r se th a t p r e v e n t s a m a le f r o m
d is p la y in g th e full s e x u a l p a t t e r n a s long a s th e b e h a v i o r a l s k ills had b e e n
a c q u i r e d p r e v i o u s l y ( V a l e n s t e i n a n d G o y , 1957).
V a l e n s t e i n e t a l (1955)
e x p l a in e d th e s u s t a i n e d e x p l o r a t o r y b e h a v i o r on th e b a s i s t h a t the s e x u a l
b e h a v i o r of t h e i s o l a t e d m a l e s h a d n o t b e e n o r g a n i z e d i n t o a n e f f e c t i v e
p a t t e r n , w h ic h th e s o c i a l a n i m a l s h ad a c h a n c e to d e v e lo p .
Experience
-12-
w ith th e b r o a d e n v i r o n m e n t is m o r e i m p o r t a n t th a n w ith s p e c i e s - m a t e s
to f a c i l i t a t e c o p u l a t i o n i n t h e p l a t y f i s h (X y p h o p h o r u s m a c u l a t u s ) (Shaw,
1962 ) .
V is u a l stim u li a r e the m o s t im p o r ta n t cues influencing c o u rtsh ip
b e h a v i o r i n t h e f r u i t fl y , D r o s o p h i l a s u b o b s c u r a .
M ating does not take
p l a c e in t h e d a r k , a n d i n c o n t r a s t t o o t h e r m a l e s of t h e o b s c u r a g r o u p ,
m a l e s w i l l a t t e m p t t o m a t e w i t h w a x m o d e l s , p r o v i d e d t h e y a r e m o v e d in
a n a p p r o p r i a t e m a n n e r ( S m i t h , 1956).
te n d s his p r o b o s c i s and d a n c e s .
m a le does not resp o n d positively.
m ounts.
m ent.
A s th e m a l e a p p r o a c h e s , he e x ­
T h e s e q u e n c e m a y e n d t h e r e if t h e f e ­
If s h e d o e s , t h e m a l e t h e n c i r c l e s a n d
The co u rtsh ip m ay be a ritu alized escape or avoidance m o v e ­
D i s c o u r a g e m e n t of m a l e s m a y c o m e a b o u t b y i n s e m i n a t e d f e m a l e s
o r by fe m a le s k ep t w ith o th e r m a le s .
m e n t is only t e m p o r a r y .
In th e T a t t e r c a s e , the d i s c o u r a g e ­
M a l e s i n b r e d f o r 18 g e n e r a t i o n s h a d g r e a t e r '
difficulty to c o m p le te c o u r ts h i p th a n o u tb re d m a l e s .
If t h e y w e r e .
t h w a r t e d a few t i m e s , th e y a t t e m p t e d to a p p r o a c h th e f e m a l e f r o m th e
s id e o r f r o m b e h in d to m a t e d ire c tly , w h ich w a s n e v e r o b s e r v e d in the
outbred m a le s .
S m i t h (1956) c o n s i d e r e d t h i s a s d e s p e r a t i o n r a t h e r t h a n
discouragem ent.
the o u tb red m a le s .
T h e in b r e d s w e r e c o n s i d e r e d p h y s i c a l l y n o t a s fit as
-13-
F o r m o s t c l a s s e s of v e r t e b r a t e s ,
it is g e n e r a l l y a g r e e d th a t both
s e x e s a c t i v e l y c o o p e r a t e in c o u r t s h i p a n d t h a t m a l e a d o r n m e n t , posturing,
and so u n d s a r e e s s e n t i a l to th e c o u r ts h i p p a t te r n .
E v a n s (1938) c o r r o b o ­
r a t e d t h e s e fin d in g s in h is o b s e r v a t i o n s on th e l i z a r d s , A n o lis c a r o l i n e n s i s a n d A. s a g r a i .
H o w e v e r , N o b l e a n d B r a d l e y (1933) r e p o r t e d t h a t
f e m a le liz a r d s n e v e r show in t e r e s t in the c o u rts h ip o r copulation, and
w h i l e t h e y m a y b e q u i e t e d b y t h e a c t i o n s of t h e c o u r t i n g m a l e , they, n e v e r
ta k e an activ e p a r t in facilitatin g copulation.
The la tte r authors consid­
e r e d , i n c o n t r a s t t o E v a n s , t h a t t h e b r i g h t c o l o r e d d e w l a p of A n o l l s
e v o l v e d a s a f r i g h t e n i n g d e v i c e , a n d n o t a t a l l t o s t i m u l a t e t h e f e m a l e to
m ate.
III.
F A C T O R S AND CONDITIONS A F F E C T I N G SE X U A L BEHAVIOR
A.
GEN ETIC
T h at b e h a v io r is u n d er genetic c o n tro l has b een w ell esta b lish e d
f r o m th e following o b s e r v a tio n s :
behavior,
2.
I.
M utations at c e rta in loci can change
D i f f e r e n t i n b r e d s t r a i n s d i f f e r in m o r p h o l o g i c a l and b e h a v ­
ioral ch ara cters,
3.
O ne c a n s u c c e s s f u l l y s e l e c t in t h e p o s i t i v e a n d
n e g a t i v e d i r e c t i o n f o r a b e h a v i o r a l t r a i t ( C a s p a r i , 1958).
B u t no b e h a v ­
i o r i s i n h e r i t e d ; its c a p a c i t y is d e v e l o p e d th r o u g h g r o w th a n d m a t u r a t i o n
a n d i s o r g a n i z e d b y h e r e d i t a r y f a c t o r s a n d l e a r n i n g ( H a f e z , 1962).
-14-
S i r F r a n c i s G a l l o n b e g a n in 1869 t o s t u d y t h e i n h e r i t a n c e of m e n t a l
c a p a c i t i e s in t w i n s ( B r o a d h u r s t , I 9 6 0 ) .
T y ro n called beh av io r genetics
t h e b a s i c s c i e n c e of i n d i v i d u a l d i f f e r e n c e s .
The relation betw een behav­
i o r a l v a r i a t i o n a n d r e l e v a n t g e n e tic v a r i a t i o n is n e v e r c o n s ta n t .
Behav­
i o r s m u s t b e m e a s u r e d in s p e c if i c p o p u la tio n s a n d u n d e r s p e c if i c c o n d i­
t i o n s , a s t h e y v a r y w i t h b o t h ( H a r c h , 1965).
R a s m u s s e n (1952), S i e g e l a n d S i e g e l (1964), W o o d - G u s h (1956), G u h l
(1951), a n d M a n n i n g (1961,. 1963) h a v e b e e n a b l e t o s u c c e s s f u l l y s e l e c t f o r
i n c r e a s e d a n d d e c r e a s e d s e x u a l b e h a v i o r in d i f f e r e n t o r g a n i s m s .
ever,
How­
in g e n e r a l , t h e r e s e e m s t o h a v e b e e n a l a g p e r i o d b e f o r e t h e l i n e s
d i v e r g e d ( c . f . M a t h e r , , I960).
L o r e n z (1958) s h o w e d t h a t h y b r i d i z a t i o n of tw o s p e c i e s of d u c k s v a r y ­
ing in w i l d n e s s m a y l e a d t o t h e s u p p r e s s i o n of s o m e p a r e n t a l t r a i t s in
c o u r t s h i p b e h a v i o r , o r t o t h e e x p o s u r e of s o m e p a t t e r n s n o t s e e n i n
either parent.
G e n e t i c d i f f e r e n c e s b e t w e e n s t r a i n s of g u i n e a p i g s a r e r e s p o n s i b l e
f o r d i f f e r e n c e s i n t h e a g e a t w h i c h o r g a n i z a t i o n of s e x u a l b e h a v i o r m a y
t a k e p l a c e , a n d f o r t h e a m o u n t of s e x u a l e x c i t e m e n t e x h i b i t e d d u r i p g
tests.
T h e s e g e n e tic d if f e r e n c e s a r e not o v e r c o m e by the a d m i n i s t r a t i o n
-15-
of l a r g e q u a n t i t i e s of e x o g e n o u s a n d r o g e n ( V a l e n s t e i n e t a l , 1955).
I n b r e e d i n g D r o s o p h i l a s u b o b s c u r a f o r 18 g e n e r a t i o n s r e s u l t e d in a
r e d u c t i o n of m a l e f e r t i l i t y .
T h e s e m a l e s w e r e a l s o found to b e d e fic ie n t
in t h e q u a l i t y a n d q u a n t i t y of s p e r m p r o d u c e d c o m p a r e d t o o u t b r e d m a l e s .
E n v i r o n m e n t a l an d e x p e r i e n t i a l f a c t o r s s e e m to c o n t r i b u t e to th is d i f f e r ­
e n c e ( S m i t h , 1956).
F a c t o r s w h i c h a r e of e v o l u t i o n a r y a n d r e p r o d u c t i v e s i g n i f i c a n c e ( s i z e ,
viability, fe rtility , e tc .) a r e g en e ra lly in h e rite d polygenically; th e ir
f i n a l e x p r e s s i o n d e p e n d s o n t h e a c t i o n a n d i n t e r a c t i o n of m a n y g e n e s on
w h i c h t h e e f f e c t s of t h e e n v i r o n m e n t a r e s u p e r i m p o s e d .
S i n c e in p o l y ­
genic b lo c k s t h e r e a r e s e v e r a l o r m a n y g e n e s, m u ta tio n s affecting c h a r ­
a c t e r s d e te r m in e d by th e s e blocks w ill be rela tiv e ly freq u en t; th e re fo re ,
p o ly g e n ic c h a r a c t e r s m a y b e c o n s i d e r e d to b e not v e r y s t a b l e in p o p u la ­
t i o n s ( C a s p a r i , 1958).
W h e n s e a r c h i n g f o r g e n e t i c b a s e s of s e x b e h a v i o r , it i s i m p o r t a n t
to r e a l i z e t h a t t h e r e a r e in d iv id u a l d i f f e r e n c e s , and th a t th e p e r f o r m a n c e
of t h e i n d i v i d u a l v a r i e s f r o m t e s t t o t e s t .
T h a t t h e l i m i t s of t h e p h e n o ­
t y p i c e x p r e s s i o n of e l e m e n t s in s e x u a l b e h a v i o r a r e s e t b y t h e g e n o m e is
s t r o n g l y s u g g e s t e d b y t h e c o n s i s t e n c y of i n d i v i d u a l d i f f e r e n c e s f o u n d in
g e n e t i c a l l y h e t e r o g e n e o u s p o p u l a t i o n s ( B e a c h , 1942).
The h ered itary
- 16-
n a t u r e of l i b i d o h a s b e e n e s t a b l i s h e d in f e m a l e s h e e p ( H a f e z , 1951, 1952),
a n d b u l l s ( F r a z e r , 1957, I 96 0) .
H y b r i d s o b t a i n e d i n t h e l a b o r a t o r y b e t w e e n t w o s u b s p e c i e s of D r o s o ­
p h il a p a u l i s t o r u m p o s s e s s a g e n e tic c o n s t i t u t i o n w h ic h is so d i s c o r d a n t
t h a t t h e h y b r i d f e m a l e s r e p e l t h e c o u r t s h i p of a l l m a l e s .
The hybrid
m a l e s w i l l c o u r t b u t a r e r e j e c t e d b y a l m o s t a l l f e m a l e s ( E h r m a n , I96 0) .
A b a l a n c i n g m e c h a n i s m w a s f o u n d b y S h e p p a r d (1953).
In th e m o th
P a n a x i a d o m in u la .in d iv id u als c a r r y i n g th e g ene " m e d i o n e g r a " m a t e p r e ­
fe re n tia lly w ith p a r t n e r s not c a r r y in g th is gene.
C ro s se s betw een th re e
S o u t h A m e r i c a n s p e c i e s of D r o s o p h i l a p a u l i s t o r u m r e s u l t e d i n t h e p r o ­
duction
of f e r t i l e f e m a l e a n d s t e r i l e m a l e h y b r i d s , w h i c h w a s f o u n d to
d e p e n d o n t h e g e n o t y p e of t h e m o t h e r ( E h r m a n , I9 60 ).
I n d i v i d u a l g e n e s h a v e b e e n s h o w n t o a f f e c t m a t i n g b e h a v i o r in D r o s o phila m e l a n o g a s t e r .
R e e d a n d R e e d (1950) s h o w e d t h a t t h e p r e s e n c e of
t h e g e n e w ( w h i t e ey e) d e c r e a s e d m a t i n g f r e q u e n c y b y 25%.
Rendel
(1951) f o u n d t h a t t h e g e n e _e (ebon y) r e d u c e d t h e m a t i n g a c t i v i t y of h o m o ­
z y g o u s m a l e s i n t h e l i g h t , w h e r e a s in t h e d a r k t h e y w e r e e q u a l to, o r
b e t t e r than, the v e s tig ia l c o n tro l m a l e s .
B a s t o c k '1956) f o u n d t h a t y
( y e ll o w ) r e d u c e d t h e e f f e c t i v e n e s s of m a t i n g in t h a t t h e s e m a l e s a r e
slo w e r and le s s activ e than the c o n tro ls.
F e m a le s c a r r y in g the d o m in ­
- 17-
a n t _y b e c a m e m o r e r e c e p t i v e a f t e r s e v e n g e n e r a t i o n s of s e l e c t i o n , w h i c h
m a y have b e e n a s e c o n d a r y ad a p ta tio n to c o m p e n s a te fo r the deficient
c o u r t s h i p of t h e m a l e s .
C r a w f o r d a n d S m y t h C96D f o u n d t h a t F a y o u m i
fowl f e m a le s w ith Colum bian p a t t e r n h ave a h ig h e r s o c ia l ra n k .a n d show
g r e a t e r s e x u a l r e s p o n s e th an th o se w ith b a r r e d p a tte rn .
F u l l e r (1967)
f o u n d t h a t C 5 7 B L / 6 J m i c e h o m o z y g o u s c_c ( a lb i n o ) s i r e d s m a l l e r l i t t e r s
t h a n t h e p i g m e n t e d (C e o r C O m a l e s .
T h e p r i m a r y d e f e c t of t h e cc
a n i m a l s is a d i m i n u t i o n of t y r o s i n a s e a n d d o p a o x i d a s e in t h e s k i n .
Dopa
is t h e p r e c u r s o r of n o r e p i n e p h r i n e a n d it is c o n c e i v a b l e t h a t t h e o b s e r v e d
b e h a v i o r a l e f f e c t s a r e d u e t o a n i m b a l a n c e of c a t e c h o l a m i n e s in t h e c e n ­
tra l nervous system ,
r a t h e r t h a n d u e t o p e r i p h e r a l e f f e c t s of t h e g e n e .
P a r t i c u l a r c h r o m o s o m e a r r a n g e m e n t s have b e e n p r o p o s e d as the
b a s i s f o r d i f f e r e n c e s in g e o t a x i s ( H i r s c h a n d E r l e n m e y e r - K i m l i n g , 1962)
a n d a l s o m a t i n g b e h a v i o r in D r o s o p h i l a ( K a u l a n d P a r s o n s , 1965; P a r ­
s o n s a n d K a u l , 1966; P r a k a s h , 1967; a n d S p i e s s a n d S p i e s s , 1967) a n d
in t h e w h i t e - t h r o a t e d s p a r r o w (Z o n o t r i c h i a a l b i c o l l i s ) ( T h o r n e y c r o f t ,
1966).
The a u th o rs concluded that the c h r o m o s o m a l a r r a n g e m e n ts as
f o u n d in t h e n a t u r a l p o p u l a t i o n s a r e b e s t a d a p t e d f o r r e p r o d u c t i v e f i t n e s s ,
t h o u g h e n v i r o n m e n t a l c o n d i t i o n s (food, t e m p e r a t u r e , a g e a t m a t i n g ) w i l l
-18-
e x e r t a c o n s i d e r a b l e i n f l u e n c e ( S p i e s s a n d S p i e s s , 1967).
T h e r e is s t r o n g n a t u r a l s e l e c t i o n f o r h i g h m a t i n g s p e e d in D r o s o p h i l a .
This w as indicated by a s y m m e t r i c a l s e le c tio n re s p o n s e .
Much g re a te r
r e s p o n s e w a s o b s e r v e d in t h e d o w n w a r d t h a n i n t h e u p w a r d d i r e c t i o n a n d
t h e h i g h l i n e w a s m u c h c l o s e r t o t h e c o n t r o l s ( M a n n i n g , 1961, 1963;
P r a k a s h , 1967).
P r a k a s h (1967) i n v o k e d t h e f o l l o w i n g m e c h a n i s m s t o e x p l a i n t h e
s t a b i l i t y of t h e g e n e f r e q u e n c y , a n d t h e r e f o r e t h e m e a n m a t i n g s p e e d in
n a tu ra l populations:
I.
H e te ro z y g o te s fo r the genes w hich affect m a le
m a tin g sp e e d exhibit o v e r d o m in a n c e w hich e n s u r e s both the m a in te n a n c e
of g e n e t i c v a r i a b i l i t y a n d t h e m e a n m a t i n g s p e e d a t a s t a b l e v a l u e .
Coun­
t e r b a l a n c e i n a n o t h e r c o m p o n e n t of f i t n e s s a s m a t i n g s p e e d i n c r e a s e s
could give a n in t e r m e d i a te phenotype the g r e a t e r o v e ra ll f itn e s s.
2.
S t a b i l i t y of t h e g e n e f r e q u e n c y a n d t h e m e a n m a t i n g s p e e d in a p o p u ­
lation m a y be m a in ta in e d by r e c u r r e n t m u ta tio n s.
3.
T h e s t a b i l i t y of
the gen etic v a r ia b ility and the m e a n m a tin g sp eed could b e m a in ta in e d by
f r e q u e n c y - d e p e n d e n t s e l e c t i o n of m a t i n g s p e e d .
A s t h e f r e q u e n c y of h i g h -
m a tin g s p e e d g en es i n c r e a s e s , the m a tin g sp e e d d e c r e a s e s and vice
.versa.
Such f r e q u e n c y -d e p e n d e n t s e le c tio n fo r m a tin g a c tiv ity has b e e n
d e m o n s t r a t e d in D r o s o p h i l a p s e u d o o b s c u r a .
-19-
B.
PHYSIOLOGIC
P h y s i o l o g i c a l e f f e c t s on m a t i n g b e h a v i o r a r e m u l t i p l e a n d c o v e r a n y
o r a l l f a c t o r s f r o m n e u r o p h y s i o l o g y t o t h e s i z e of t h e a n i m a l .
Several
of t h e s e f a c t o r s a r e c o n s i d e r e d , t h o u g h t h e r e a r e p r o b a b l y m a n y w h i c h
h a v e n o t b e e n i d e n t i f i e d , o r t h e i r s i g n i f i c a n c e is u n k n o w n .
I.
HORMONES
T h a t gonadal h o r m o n e s influence b e h a v i o r , and p a r t i c u l a r l y sexual
b e h a v i o r , h a s b e e n know n f o r a long t i m e .
M en w ere c a s tra te d as early
a s t h e b e g i n n i n g of t h e B y z a n t i n e E m p i r e (450 A. D. ) ( E n c y c l o p a e d i a
I n t e r n a t i o n a l , 1966) a n d t r u s t e d a s h a r e m g u a r d s .
The fact that an im als
b e c o m e m o r e docile a fte r c a s tr a tio n has b een o b serv ed , and c a s tra tio n
is w i d e l y p r a c t i c e d in a n i m a l p r o d u c t i o n ( M u m f o r d , 1917; A r o n s o n , 1959,
1965).
H o r m o n e s m a y a c t a t t h e m o l e c u l a r l e v e l by:
p e r t i e s of t h e m e m b r a n e s of m i t o c h o n d r i a .
2.
I.
Changing the p r o ­
Inducing an a l l o s t e r i c
c h a n g e in t h e c o n f o r m a t i o n of a p r o t e i n m o l e c u l e in o r d e r t o a l t e r it s
enzym atic activity,
tein.
5.
4.
3.
A l t e r i n g t h e r a t e of s y n t h e s i s of a s p e c i f i c p r o ­
S e r v i n g a s a c o - s u b s t r a t e in a s p e c i f i c e n z y m a t i c r e a c t i o n .
I n i t i a t i n g t h e t r a n s c r i p t i o n of a s p e c i f i c s e c t i o n of D NA .
The la st
m e c h a n i s m s e e m e d t o b e i n v o l v e d i n t h e r e s p o n s e of b l o w f l y l a r v a e t o
■- 2 0 -
e c d y s o n e , t h e e f f e c t s of a n d r o g e n s o n t h e v e n t r a l p r o s t a t e of t h e r a t , a n d
t h e e f f e c t s of e s t r o g e n s on t h e e n d o m e t r i u m of t h e r a t ' s u t e r u s .
RNA e x ­
t r a c t e d f r o m t h e s e m i n a l v e s i c l e of o n e r a t c a n , a f t e r b e i n g i n s t i l l e d i n t o
t h e l u m e n of t h e s e m i n a l v e s i c l e of a n o t h e r r a t , , l e a d to a r e s p o n s e s i m ­
i l a r to t h a t i n d u c e d b y t e s t o s t e r o n e .
the r e s p o n s e .
D e n a t u r e d RNA did n ot b r in g about
C h iro n o m u s la r v a e in je c te d w ith ecd y so n e show a c h a r ­
a c t e r i s t i c p a t t e r n of p u f f i n g of t h e B a l b i a n i r i n g s ( K a r l s o n , 1962, a, b ) .
L i a o a n d W i l l i a m s , a n d A s h m a n ( c i t e d b y V i l l e e , 1967) s u g g e s t e d t h a t
t e s t o s t e r o n e i n c r e a s e d t h e s y n t h e s i s of m R N A in t h e r a t ' s p r o s t a t e a n d
s o a f f e c t e d t h e r a t e of p r o t e i n s y n t h e s i s ( c . f . F r i e d e n , 1964; T a t a , 1964).
s o m e of t h e e a r l i e s t w o r k w i t h h o r m o n e i n j e c t i o n s w a s d o n e b y
D o m m a n d v a n D y k e (1932), w h o u s e d h e b i n o n t h r e e - d a y o l d m a l e c h i c k s .
They o b s e rv e d crow ing six days l a t e r , and a fte r ten days, tread in g .
F u r t h e r s i m i l a r s t u d i e s w e r e d o n e b y H a m i l t o n (1938), A l l e e _et _al (1939),
B r e n e m a n (1939). N o b l e a n d Z i t r i n (1942), B e a c h (1948), N a l b a n d o v a n d
B a u m (1948), M a s o n (1952), H e r r i c k a n d A d a m s (1956), a l l in d o m e s t i c
f ow l; B e n n e t t (1940) i n r i n g d o v e s , a n d S c h e i n a n d H a l e (1959, 1965) in
tu rk ey s.
F e m a l e s of t h e W i l s o n ' s P h a l a r o p e ( S t e g a n o p u s t r i c o l o r ) r e s e m b l e
-21-
in m a n y r e s p e c t s ( c o l o r , d i s p l a y , t e r r i t o r i a l i t y ) m a l e s of o t h e r
s p e c i e s (D y r e n f a r t h a n d H S h n l 1963; H o h n a n d C h e n g , 1967).
Q ualitative
a n a l y s e s of t h e t e s t i c u l a r a n d o v a r i a n h o r m o n e s of t h e s e b i r d s s h o w e d
t h a t t h e o v a r i a n t e s t o s t e r o n e c o n t e n t e x c e e d e d t h a t of t h e t e s t e s .
Dom­
e s t i c f o w l a n d t h e M a l l a r d (A n a s p l a t y r h y n c h o s ) , w h i c h . s h o w o b v i o u s
m a l e d o m i n a n c e , h a d a h i g h e r l e v e l of t e s t o s t e r o n e o n t h e t e s t e s t h a n in
t h e o v a r i e s ( c . f . P h i l l i p s a n d M c K i n n e y ,( 1962).
D i p p i n g h a t c h i n g e g g s i n t o a s o l u t i o n of e t h y l a l c o h o l w i t h t w o p e r ­
c e n t t e s t o s t e r o n e a d d e d a f f e c t e d t h e o r g a n i z a t i o n of s e x u a l b e h a v i o r in
m a l e s h a tc h e d f r o m eggs so t r e a t e d .
O n ly o n e of t e n s u c h m a l e s m a t e d ,
b u t s e m e n f r o m t h r e e of f o u r s u c h m a l e s f e r t i l i z e d e g g s .
T h e f a i l u r e to
m a te m a y have b e e n c a u s e d by a h o rm o n a l im b alan c e or a defective
n e u r a l m e c h a n i s m ( C l i c k , 1956).
I n j e c t i o n of e s t r o g e n in t o e g g s on t h e ■
f o u r t h d a y of i n c u b a t i o n r e s u l t e d in m a l e s w i t h b e h a v i o r s r a n g i n g f r o m
e s s e n t i a l l y n o r m a l t o d e f i n i t e l y n e u t r a l a t 2 2 - 2 4 m o n t h s of a g e ( D o m m
a n d D a v i s , 1948).
P h o e n i x et_ ad (1965) i n j e c t e d t e s t o s t e r o n e p r o p i o n a t e in to p r e g n a n t
guinea p i g s .
The fem ales bo rn fro m such m o th ers showed greatly re -
d u c e d c a p a c i t y t o d i s p l a y l o r d o s i s f o l l o w i n g a d m i n i s t r a t i o n of e s t r o g e n
a n d p r o g e s t e r o n e , b u t m a l e - I ik e m o u n t i n g b e h a v i o r w a s s h o w n b y m a n y
-.
-22-
of t h e m .
T h e m a l e s ib li n g s s h o w e d no s t r u c t u r a l a b n o r m a l i t i e s and
t h e i r b e h a v i o r w a s e s s e n t i a l l y n o r m a l ( c . f . B o s s , 1943; W i t s c h i , 1959).
G o l d s t e i n (1957) s u g g e s t e d t h a t g o n a d a l h o r m o n e s h a v e a g e n e r a l e f ­
f e c t on m a l e , o r f e m a l e s e x u a l p a t t e r n s a n d a s p e c i f i c e f f e c t a c t i n g p r i m ­
a r i l y on t h e n a t i v e p a t t e r n .
W o l f s o n (1954) c o n c l u d e d t h a t a n d r o g e n s
p l a y a n i m p o r t a n t r o l e in t h e r e g u l a t i o n of t h e a c t i v i t y a n d s i z e of t h e
secondary sex organs.
A l l a t e c t o m y , g o n a d e c t o m y , a n d a c o m b i n a t i o n of b o t h do n o t i n f l u e n c e
t h e m a t i n g b e h a v i o r of m a l e o r f e m a l e w a x m o t h s (G a l l e r i a m o n e l l a ) .
I m p l a n t a t i o n of a d d i t i o n a l c o r p o r a a l l a t a in p u p a e o r a d u l t s a l s o h a d no
e f f e c t ( R o e l l e r _et a l , 1963).
H o w e v e r , E n g e l m a n n (I960) a n d L o h e r (19611
f o u n d t h a t a l l a t e c t o m y in M a d e i r a c o c k r o a c h e s (L e u c o p h a e a m a d e r a e ’'
a n d M e d i t e r r a n e a n g r a s s h o p p e r s (S c h i s t o c i r c a g r e g a r i a ) r e s p e c t i v e l y ,
reduced or elim in ated m ating behavior.
R e m o v a l of o n e t e s t i s d i d n o t c h a n g e t h e m a t i n g b e h a v i o r of m a l e
quail, but b il a te r a l c a s tr a tio n elim in a te d copulation w ithin eight days.
R e p l a c e m e n t w ith an a n d r o g e n p e l le t r e s t o r e d the full b e h a v i o r w ithin
eight days.
C r o w i n g a n d s t r u t t i n g d i d n o t c h a n g e ( B e a c h a n d I n m a n , 19651.
I n a d d i t i o n t o t h e e f f e c t s of g o n a d a l h o r m o n e s , t h e e f f e c t s of t h y r o ­
x i n e on m a t i n g b e h a v i o r h a v e b e e n of p a r t i c u l a r i n t e r e s t t o s e v e r a l i n v e s ­
-23-
tigators.
A n d e r s o n a n d A n d e r s o n (1938) f o u n d a t e n d e n c y f o r t h e t h y r o i d
s e c r e t i o n to b e p o s i t i v e l y c o r r e l a t e d w i t h e m o t i o n a l t e s t s of r a t s a n d
n e g a t i v e l y w i t h t e s t s of s e x u a l b e h a v i o r ( c . f . L a s h l e y , 1924).
P e t e r s o n _et al_ (1952) f o u n d in g u i n e a p i g s t h a t t h e s e n s i t i v i t y of m a n y
of t h e r e p r o d u c t i v e t i s s u e s t o h o r m o n a l s t i m u l a t i o n m a y b e i n f l u e n c e d
b y t h e l e v e l of t h y r o i d a c t i v i t y .
T he re s u lts w e re equivocal (c.f. S al­
m o n , 193 6; Y o u n g e t ad, 1952; V a l e n s t e i n , 1955), b u t f e r t i l i t y w a s d e ­
c r e a s e d in b o t h s e x e s a f t e r t h y r o i d e c t o m y .
F o r f o w l , C r e w (1925) r e p o r t e d a n a c c e l e r a t i o n of g o n a d a c t i v i t y u p ­
on i n j e c t i o n of t h y r o x i n e in p h y s i o l o g i c a l d o s e s , a n d B e n o i t a n d A r o n
(1934) f o u n d t h a t t h y r o i d e c t o m y h a d a n i n h i b i t i n g e f f e c t o n t h e e n d o c r i n e
a n d g a m e t o g e n i c a c t i v i t y of t h e t e s t e s of W h i t e L e g h o r n s ( c . f . G r e e n ­
w o o d a n d C h u , 1939).
L a r g e q u a n t i t i e s of t h y r o x i n e c a u s e d h e n s to m o l t ,
b u t s m a l l e r d o s e s ' d e p r e s s e d s e x u a l a c t i v i t y w h i c h C o l l i a s G946) a t t r i b ­
u t e d t o i n c r e a s e d n e r v o u s n e s s a n d s e n s i t i v i t y of t h e s k i n .
The thyroid
a p p e a r s t o h a v e a g e n e r a l c a l o r i g e n i c e f f e c t a n d s p e c i f i c a c t i o n on o t h e r
horm ones
( B l i v a i s s , 1947).
O t h e r h o r m o n e s , p a r t i c u l a r l y t h o s e of t h e p i t u i t a r y a n d a d r e n a l
g l a n d s , h a v e n o t b e e n t h o r o u g h l y i n v e s t i g a t e d a s to t h e i r e f f e c t on s e x -
-24-
ual behavior.
S o m e w o r k h a s b e e n r e p o r t e d f o r fowl ( A n d e r s o n and
A n d e r s o n , 1938) a n d f o r g u i n e a p i g s ( J a k w a y , 1959).
2.
OTHER FACTORS
S o m e of t h e m o s t i m p o r t a n t f a c t o r s a f f e c t i n g s e x u a l b e h a v i o r in b i r d s
a r e th e b io lo g ic a l c y c le s , light and d a r k p e r io d s , and the conditions r e ­
l a t e d to t h o s e f a c t o r s ,
s u c h a s t e m p e r a t u r e , a v a i l a b i l i t y of f o o d , e t c .
( M o r g a n , 1965; B a r n e t t , 19-67).
I t is t h e t o t a l a m o u n t of r e l e v a n t s e n s o r y s t i m u l a t i o n r a t h e r t h a n a n y
p a r t i c u l a r k i n d of s t i m u l a t i o n t h a t a r r o u s e s s e x u a l b e h a v i o r a n d a l l o w s
r e p r o d u c t i o n t o t a k e p l a c e ( H i n d e , 1965).
P h o t o p e r i o d i c c o n t r o l of r e ­
p r o d u c t i v e c y c l e s in v a r i o u s b i r d s h a s b e e n r e v i e w e d b y L e h r m a n (1959),
M a r s h a l l (1959), a n d W i t s c h i (1959).
R e p o rts about p a rtic u la r species
w e r e p r e s e n t e d b y E a r n e r (1964) f o r t h e w h i t e - t h r o a t e d s p a r r o w ; M a r ­
s h a l l (1961) f o r Q u e l e a q u e l e a ; K a r a p e t i a n (1955) f o r t h e g u i n e a fowl;
K o n i s h i (1967) f o r t h e J a p a n e s e quail;. K i r k p a t r i c k a n d L e o p o l d (1952)
f o r t h e b o b w h i t e q u a i l ; L e h r m a n '1965) f o r t h e r i n g d o v e ; B i s o n e t f e
(1932) f o r t h e s t a r l i n g ; a n d D o l ' n i k (1964) f o r E r i n g i l i a c o e l e b s c o e l e b s .
E w i n g (1961) f o u n d t h a t D r o s o p h i l a m e l a n o g a s t e r m a l e s ,
selected for
l a r g e a n d s m a l l b o d y s i z e , d i f f e r e d in t h e i r c o u r t s h i p b e h a v i o r .
w as a n egative c o r r e la tio n b etw een body w eight and v ib ratio n .
There
But m a le s
-25-
t h a t a r e s m a l l due to e n v i r o n m e n t a l e ffe c ts did not b e h a v e lik e t h o s e s e l ­
e c t e d f o r s m a l l body s i z e , an d he c o n c lu d e d th a t the two f a c t o r s a r e not
genetically rela ted .
A ll s e le c te d lin es w e r e le s s activ e th an the c o n tro ls .
S m a l l m a l e s w e r e l e s s s u c c e s s f u l in o b t a i n i n g m a t e s w h e n in c o m p e t i ­
tion w ith la r g e o r c o n tro l m a l e s so th a t t h e i r in c r e a s e d v ib ra tio n m a y
h a v e b e e n d u e t o s e l e c t i o n p r e s s u r e to c o u n t e r a c t t h e o t h e r w i s e d e f i c i e n t
courtship behavior.
C.
PSYCHOLOGIC
T h e i m p o r t a n c e of p s y c h o l o g i c a l f a c t o r s in m a t i n g b e h a v i o r h a s b e e n
e x p r e s s e d b y A l l e n (1934) a n d Y o un g (1961).
B e a c h (1958) i n d i c a t e d t h a t
in p h y lo g e n y s e x u a l b e h a v i o r b e c o m e s e m a n c i p a t e d f r o m p h y s io lo g i c a l
f a c t o r s ( h o r m o n e s , e t c . ) a n d d e p e n d s m o r e on p s y c h o l o g i c a l f a c t o r s
(sen so ry stim ulation).
F o r birds,
e a r l y e x p e r i e n c e s e e m s t o b e of r e l a t i v e l y l i t t l e i m p o r ­
t a n c e ( W o o d - G u s h , I 96 0; S c h e i n a n d H a l e , 1965), b u t m a m m a l s s e e m to
r e l y t o a g r e a t e x t e n t o n l e a r n i n g in t h e s u c c e s s f u l e x e c u t i o n of m a t i n g
b e h a v i o r ( V a l e n s t e i n e t al,. 1955; V a l e n s t e i n a n d G o y , 1957; A n t h o n y ,
1958; D r o r i a n d F o l m a n , 1967).
L a s h l e y (1924) c o n s i d e r e d t h a t t h e
e n e r g y of l i b i d o m a y v a r y in q u a n t i t y b u t n o t in k i n d .
He e x p r e s s e d the
o p i n i o n t h a t s e x u a l b e h a v i o r of t h e r a t c a n b e r e d u c e d t o s t i m u l u s -
-26-
r e s p o n s e r e la tio n s h ip s , w hich a r e c o m p lex but c le a rly
principle.
reflexive
in
L e a r n in g does not e n te r the p ic tu r e as the m a l e w ill show
t h e f u l l y i n t e g r a t e d b e h a v i o r a f t e r p u b e r t y , t h o u g h h e is n o t s t i m u l a t e d
by a r e c e p t i v e f e m a le b e f o r e p u b e r ty .
T h e m e c h a n i s m i s o n e of l o w e r i n g
t h e t h r e s h o l d w h i c h r e s u l t s in i n c r e a s e d s e n s i t i v i t y t o s e l e c t i v e s t i m u l i
a n d l e s s t o o t h e r s ( c . f . B e a c h 1942; K e r r u i s h , 1955).
With- i n c r e a s e d
e x c i t e m e n t , t h e s t i m u l u s i s s i m p l i f i e d a n d t h e m a l e m a y a t t e m p t to m a t e
w ith p r a c tic a lly any s m a ll m oving object.
H ab itu atio n m a k e s a definite
c o n t r i b u t i o n t o t e r m i n a t i o n of a s e x u a l b o u t i n v o l v i n g t h e s a m e t w o i n d i v ­
iduals.
B u lls w ill continue to m a t e w h en new r e c e p tiv e f e m a le s a r e
i n t r o d u c e d ( H a l e a n d A l m q u i s t , I 9 6 0 ; M a r l e r a n d H a m i l t o n , 1966)..
Y o u n g a n d G r u n t (1951) n o t e d t h a t g u i n e a p i g s w i t h a l o w e r s e x d r i v e
w e r e le s s p e r s is te n t th an h ig h er d riv e m a le s whep th e ir initial efforts
w ere repelled.
1938).
T h is a l s o s e e m e d to b e th e c a s e f o r l i z a r d s (E v a n s,
S m i t h (1956) r e p o r t e d t h a t B / K s t r a i n m a l e s of D r o s o p h i l a s u b -
o b s c u r a h a d low m a t i n g s u c c e s s w h e n k e p t in g ro u p s b e f o r e m a tin g .
W h e n t h e m a l e s w e r e k e p t in t h e d a r k f o r 24 h o u r s , n o r m a l m a t i n g e n ­
sued.
S uch m a l e s w e r e r e p e l l e d w h e n m a t e d to i n s e m i n a t e d f e m a l e s .
W hen m a t e d to v i r g i n f e m a l e s a f t e r a t h r e e h o u r is o la tio n ,
only few c o p u ­
l a t e d , w h i c h i n d i c a t e d a g e n e r a l i z a t i o n of d i s c o u r a g e m e n t ( c . f . F e n n e l l
-27-
1945).
S a c h s (1966a) o b s e r v e d t h a t w h e n q u a i l m a l e s w e r e p u t t o g e t h e r , b o t h
g e n e r a lly a p p r o a c h e d and a t te m p t e d to g r a b eac h o th e r w ith the b e a k at
t h e b a c k of t h e h e a d o r n e c k .
T h i s b e h a v i o r is v e r y s i m i l a r t o t h a t a t
t h e b e g i n n i n g of m a l e - f e m a l e p a i r i n g s , a n d m o u n t i n g of m a l e s w a s o b ­
s e r v e d in s o m e causes.
It s e e m s th a t th e a p p r o a c h - p e c k - g r a b p a t te r n ,
w h i c h is a n d r o g e n d e p e n d e n t ( B e a c h a n d I n m a n , 1965), c a n s e r v e b o t h in
a g g r e s s i v e a n d s e x u a l b e h a v i o r d e p e n d i n g o n t h e r e s p o n s e of t h e p a r t n e r
( c . f . W o o d - G u s h , 1957,. 1958).
I n t h e s a g e g r o u s e ( C e n t r o c e r c u s u r o p h a s i a n u s ) , t h e m a s t e r c o c k is
u s u a lly l a r g e r , m o r e a g g r e s s iv e and dom inant, and tr e a d s m o r e hens
t h a n t h e o t h e r c o c k s ( A l l e n , 1934).
I n m i c e , r e p o r t s of c o r r e l a t i o n b e ­
tw een sexual and a g g re s s iv e behavior have been co n tra d icto ry (F re d e ri c s o n ^ t ad, 1955; L e v i n e , 1958; L e v i n e e t a l ,
1965),
T h e s t a t u s of t h e
a n i m a l in t h e s o c i a l h i e r a r c h y , a n d a g g r e s s i o n h a v e c o n s i d e r a b l e e f f e c t s
on t h e a m o u n t of s e x u a l b e h a v i o r e x h i b i t e d i n a f l o c k ( G u h l, 1966).
M a l e s of l o w r a n k m a y s h o w s y m p t o m s of p s y c h o l o g i c a l c a s t r a t i o n ( G u hl
_et_al, 1945; G u h l a n d W a r r e n , 1946; G u h l , , 1964).
When su ch m a le s a r e
p u t a l o n e w i t h a n u m b e r of f e m a l e s t h e y m a y b e a d e q u a t e in a l l r e s p e c t s .
M a l e s v e r y h i g h i n t h e s o c i a l o r d e r s p e n d a c o n s i d e r a b l e a m o u n t of t h e i r
-28-
t i m e in keeping o th e r
m a te m o s t frequently.
m a l e s f r o m m a t i n g s o t h a t t h e y t h e m s e l v e s do n o t
H e n s in t h e u p p e r o n e t h i r d of t h e r a n k o r d e r
c r o u c h e d l e a s t a n d w e r e m a t e d o n ly b y v e r y h i g h r a n k i n g m a l e s (Guhl,
1966).
L o w r a n k a m o n g f e m a l e s f a c i l i t a t e d s e x u a l a c t i v i t y ( G u h l e t al ,
1945; D a v i s , 1963).
V a l e n s t e i n a n d G o y (1957) a t t r i b u t e d s u c h e f f e c t s
of s o c i a l r a n k t o t h e g r e a t e r f r e e d o m of m o v e m e n t of d o m i n a n t a n i m a l s ,
w hich rnay a lso give th e m g r e a t e r le a rn in g o p p o rtu n itie s.
D is p la c e m e n t a ctiv ities a r e p re v a le n t in b e h a v io ra l conflict situations.
T h e s e b e h a v i o r s a r e c o n s i d e r e d i r r e l e v a n t to the s itu a tio n , b u t m a y be
an outlet fo r " f r u s t r a t i o n . "
G u h l (1961) d e f i n e d t h e i r o c c u r r e n c e a s b e ­
ing d u e to o n e d r i v e b e i n g , a t t h e s a m e t i m e , b o t h a c t i v a t e d a n d t h w a r t e d ,
o r th e y m a y b e p e r f o r m e d by an a n i m a l in w h ic h two o r m o r e i n c o m p a t ­
i b l e d r i v e s a r e s t r o n g l y a c t i v a t e d ; e a c h d r i v e p r e v e n t s t h e e x p r e s s i o n of
t h e o t h e r ( s ) ( c . f . H i n d e , 1961 a , b ) .
D.
NEUROLOGIC
T h i s a s p e c t i s of c o n s i d e r a b l e i n t e r e s t , a n d w i t h r e f i n e d m e t h o d s
g r e a t a d v a n c e s h a v e b e e n m a d e in u n d e r s t a n d i n g t h e f u n c t i o n a l r o l e of t h e
b r a i n in r e s p e c t t o b o d y f u n c t i o n s .
B e h a v i o r i s r e f l e c t e d in t h e s t r u c t ­
u r e a n d f u n c t i o n of t h e b r a i n a s a c e n t r a l c o o r d i n a t i n g o r g a n in t h e
-29-
a n i m a l b o d y ( C l o u d s l e y - T h o m p s on, 1961).
T h e s e x u a l a r o u s a l m e c h a n i s m (SAM) i n t h e m a l e f u n c t i o n s to i n ­
c r e a s e s e x u a l e x c i t e m e n t to t h e p o i n t w h e r e t h e c o p u l a t o r y t h r e s h o l d is
a t t a i n e d an d is a c t i v a t e d by m u l t i - s e n s o r y s t i m u l i .
t h e S A M to l o w e r t h e t h r e s h o l d .
H orm ones sensitize
S u r v i v a l of s e x u a l b e h a v i o r a f t e r r e m o v ­
a l of c o r t i c a l t i s s u e is p a r t l y a f u n c t i o n of p r e - o p e r a t i v e e x c i t a b i l i t y
( B e a c h , 1942).
H o rm o n e s a r e im p o r ta n t at the p e r ip h e r a l lev el and at the c e n tra l
l e v e l ( S e w a r d , 1941).
T hese substances can stim ulate or m odulate n e u r ­
o n s , w h i c h i n t u r n a r e c o n t r o l l e d b y t h e b r a i n in t h e i r p r o d u c t i o n ,
stor­
a g e , a n d r e l e a s e of n e u r o s e c r e t o r y m a t e r i a l ( S c h a r r e r , 1959, 1967;
S c h a r r e r a n d S c h a r r e r , 1963; B u l l o c k , 1963).
One a p p r o a c h to d i r e c t l y
o b s e r v e t h e f u n c t i o n of t h e b r a i n h a s b e e n t h r o u g h s t i m u l a t i o n b y e x o ­
g e n o u s e n e r g y o r c h e m i c a l s ( M i l l e r , 1957; F i s h e r , 1958).
F i s h e r 's d ata fa v o rs a "N eu ral C e n te r" .theory in w hich a selec tiv e ly
s e n s itiv e c e ll a r e a w ithin the s e n s o r y - m o t o r s y s t e m m a y block,
select
o r i n t e g r a t e p a t t e r n s of n e u r a l i m p u l s e s d e p e n d i n g in. l a r g e p a r t on t h e
l e v e l of t h e c r i t i c a l c h e m i c a l a c t i o n ( c . f . M e y e r ;
1963; M e y e r s a n d
H e s s , 1957).
F r o m p itu ita ry r e m o v a l and tra n s p la n ta tio n s Benoit and A s s e n m a c h e r
-30-
(1959) c o n c l u d e d t h a t s e x u a l r e g r e s s i o n i n . d u c k s is d u e t o a t e m p o r a r y d eficien cy in h y p o th alam ic stim u latio n .
H istological observations
( B e n o i t , . 1962; E a r n e r , . 1964; C h i a s s o n , 1967; K n i g g e , 1967) h a v e s h o w n
a d i r e c t b l o o d s u p p l y b e t w e e n t h e h y p o t h a l a m u s a n d t h e p i t u i t a r y in
birds,
so th a t n e u r o s e c r e t o r y s u b s t a n c e s c a n be t r a n s p o r t e d d ir e c tly
to the p itu ita ry .
T h i s s e e m s t o c o n t r o l t h e a n n u a l b r e e d i n g c y c l e in
b i r d s ( c . f . K o n i s h ' i , 1967 o n q u a i l ) .
The th a lam u s and hypothalam us
. .
s e e m to c o n t r o l th e m a t i n g r e a c t i o n s w ith o t h e r c e n t e r s b ein g f a c i lit o r y ( B e a c h , 1948; B r a d y , 1958; D e t h i e r a n d S t e l l a r , 1961; M o r g a n ,
1965) .
IV.
M E A SU R E M E N T OF SEXUAL BEHAVIOR
C a r b a u g h jet a l (1962) a s s i g n e d t h e v a l u e s of I, 2, 3 , 4 , 5, t o a p p r o a c h ,
g r a b , m o u n t , t r e a d , a n d c o p u l a t o r y m o v e m e n t s in W h i t e L e g h o r n s ,
respectively,
points:
W o o d - G u s h a n d O s b o r n e (1956) a s s i g n e d t h e f o l l o w i n g
s u c c e s s f u l t r e a d i n g , 5; t r e a d i n g , 4; m o u n t i n g m u t u a l l y i n i t i a t e d ,
3; m a l e i n i t i a t e d , 2; f e m a l e i n i t i a t e d , I.
B e a c h a n d I n m a n (1965) a l s o m e a s u r e d a p p r o a c h a n d m o u n t l a t e n c i e s
i n q u a i l , w h i c h a v e r a g e d a b o u t 5. 0 s e c o n d s a n d 2. 0 s e c o n d s ,
ively.
respect­
C o p u l a t i o n f r e q u e n c y w a s 1-16 d u r i n g t h e 15 m i n u t e s t e s t w i t h
-31-
m e d i a n of 5. 0.
F a r r i s (1967) f o u n d t h a t l a t e n c y of c o u r t i n g i n J a p a n e s e
q u a i l , in a c l a s s i c a l c o n d i t i o n i n g s i t u a t i o n , i s a b o u t 3 - 5 s e c o n d s . • In
m o s t c a s e s , d i s p l a y is t e r m i n a t e d b y c o p u l a t i o n .
G e n e r a l l y , in D r o s o p h i l a o n ly t h e l a t e n c y t o c o p u l a t i o n h a s b e e n
m e a s u r e d ( M a n n i n g , 1961, 1963); h o w e v e r , F u l k e r (1966) c o u n t e d in a d d i ­
t i o n t h e n u m b e r of c o p u l a t i o n s r e s u l t i n g in f e r t i l i z a t i o n , a n d t o t a l n u m ­
b e r of p r o g e n y .
R a s m u s s e n (1952) m e a s u r e d t h e s e x d r i v e of r a t s b y h o w r e a d i l y t h e y
w o u ld c r o s s a n e l e c t r i f i e d g r i d to r e a c h t h e i r p a r t n e r .
D e w s b u r y (1967)
q u a n t i f i e d t h e t o t a l t i m e r a t s s p e n t u n d e r o b s e r v a t i o n a s to:
3.
I.
Loco-
m otor-exploratory,
2.
G enital groom ing,
N on-genital g ro o m in g ,
4.
Sniffing f e m a l e ,
5.
N aso- n a s a l contact,
7.
L y i n g - d o w n b e h a v i o r in p e r c e n t , i n a s i t u a t i o n w h e r e f r e e c o p u l a t i o n
6.
Im m o b ility , and
w as possible.
Y o u n g a n d G r u n t (1951) s c o r e d s e x u a l b e h a v i o r of g u i n e a p i g s a s I
point fo r sniffing o r nibbling, 2 fo r n u z z l i n g , 3 fo r m o u n t in g , 4 fo r i n t r o ­
m is s io n , and 5 fo r ejaculation.
V.
S E L E C T IO N E X P E R I M E N T S AND A SSO C IA TED R E S P O N S E S
H a f e z (1962) d e f i n e d s e l e c t i o n a s t h e s y s t e m a t i c d i f f e r e n t i a l r e p r o ­
d u c t i o n of g e n o t y p e s on a n i n d i v i d u a l o r f a m i l y b a s i s .
Selection for som e
-32-
b e h a v i o r s is f a i r l y s u c c e s s f u l a n d r e s u l t s m a y b e a c h i e v e d in o n e o r t w o
generations.
R a s m u s s e n (1952) s e l e c t e d a l b i n o r a t s f o r f i v e g e n e r a t i o n s a c c o r d i n g
to th e e a s e w ith w h ic h th e y w o u ld c r o s s a n e l e c t r i f i e d g r i d to r e a c h an
a n i m a l of t h e o p p o s i t e s e x .
In the fifth g e n e r a t i o n , m a l e s a n d f e m a l e s
of t h e h i g h l i n e c r o s s e d s i x t i m e s a s f r e q u e n t l y a s t h o s e f r o m t h e l o w
line.
The high line c o p u lated s o o n e r a f te r the sex es w e r e put to g e th e r.
In th e fifth g e n e r a t i o n l i t t e r s i z e in th e low lin e w a s c o n s i d e r a b l y
g r e a t e r th a n in the high line.
T h e t i m e b e t w e e n p a i r i n g a n d b i r t h of t h e
young w a s s h o r t e r in th e low th a n in th e high lin e .
He suggested that
p a r t l y a h i g h e r o r l o w e r d e g r e e of h o r m o n a l p r o d u c t i o n a n d p a r t l y a
c h a n g e d s e n s i t i v i t y if t h e n e r v o u s s y s t e m t o t h e s e h o r m o n e s i s i n h e r i t e d .
F o m i n _et a l (1963) c o n c l u d e d t h a t h i g h s e x u a l d r i v e i n m a l e c h i c k e n s
w a s a c c o m p a n i e d b y l o w v i a b i l i t y a n d e g g p r o d u c t i o n of t h e i r o f f s p r i n g ;
w h i c h t h e y a t t r i b u t e d t o p o o r s e m e n q u a l i t y ( c . f . P e n q u i t e , 1930).
They
a l s o f o u n d t h a t t h e h i g h l y a c t i v e m a l e s w e r e f r o m d a m s w h i c h l a i d 1621% m o r e e g g s t h a n t h e . f l o c k a v e r a g e , a n d t h a t t h e s e m a l e s a r e l i g h t e r
th a n th e l e s s a c tiv e co ck s due to t h e i r e a r l i e r se x u a l m a t u r i t y (c.f.
T i n d e l l a n d A r z e (1965).
I n 1962, S i e g e l a n d S i e g e l p u b l i s h e d t h e r e s u l t s of s e l e c t i o n f o r t o t a l
-33-
n u m b e r of c o m p l e t e d m a t i n g s of c o c k e r e l s in e i g h t 1 0 - m i n u t e o b s e r v a ­
tions.
R e a l i z e d h e r i t a b i l i t i e s w e r e 0.10, 0 . 0 3 , a n d 0 . 0 9 in th e f i r s t ,
second and th ird g en era tio n s, resp ectiv ely .
Since h e rita b ility e s ti m a t e s
b a s e d on f u l l - s i b c o r r e l a t i o n s w e r e h i g h e r t h a n theys. r e a l i z e d , t h e y i m ­
p lied th a t e ith e r d o m in an ce o r m a t e r n a l effects w e r e involved.
The
m e a n h e r i t a b i l i t y e s t i m a t e s (f u ll - s i b c o r r e l a t i o n s ) f o r t h r e e g e n e r a t i o n s
w e r e 0. 32, 0. 3 0 , 0. 26, a n d 0. 24 f o r c o u r t s , m o u n t s , t r e a d s , a n d c o m ­
pleted m a tin g s, resp ectiv ely .
G enetic c o r r e la tio n s b etw een co m p leted
m a tin g s and o th e r se x u a l t r a i t s w e r e lo w e r than the phenotypic c o r r e ­
l a t i o n s , w h ic h i n d i c a t e d i m p o r t a n t e n v i r o n m e n t a l in f lu e n c e s on th e t r a i t s .
W o o d - G u s h a n d O s b o r n e (1956) a n d W o o d - G u s h (I960) f o u n d , f r o m
o b s e r v a t i o n s on B ro w n L e g h o r n s , t h a t t h e r e is little o r no r e l a t i o n s h i p
b e tw e e n s e m e n s a m p l e (am ount and quality) and the p o s itio n in the s e x u a l
hierarchy.
G r e a t d i f f e r e n c e s i n f e r t i l i t y b e c a m e a p p a r e n t in t h e m o s t a c t i v e a n d
m o s t inactive m a le s .
T h e r e w a s n o c h a n g e in b o d y a n d t e s t e s w e i g h t s
o r c r e a t i n e c o n t e n t in s e m i n a l p l a s m a b e t w e e n th e l i n e s .
They suggested
t h a t t h e c a u s a l m e c h a n i s m s of t h e d i f f e r e n c e s in m a t i n g f r e q u e n c y m i g h t
b e c o n n e c t e d w i t h t h e s e m e n p r o d u c t i o n o r t h e e j a c u l a t o r y p a t t e r n of t h e
-34-
two l i n e s .
C h i c k e n m a l e s s e l e c t e d f o r h i g h a n d l o w l e v e l s of a g g r e s s i o n s h o w e d •
s i g n i f i c a n t d i f f e r e n c e s in m a t i n g b e h a v i o r f r o m t h e s e c o n d g e n e r a t i o n on,
and c o u r t i n g , c r o u c h e s r e c e iv e d , and tr e a tin g , w e r e highly significantly
d i f f e r e n t in t h e t h i r d g e n e r a t i o n (G u h l, 1951).
S i e g e l a n d S i e g e l (1964)
o b t a i n e d r e p e a t a b i l i t i e s of 0 . 4 3 , 0 . 3 0 , 0 . 2 8 , a n d 0 . 3 1 , r e s p e c t i v e l y f o r
c o u r t s , m o u n t s , t r e a d s , an d c o m p l e t e d m a t i n g s in c h i c k e n s .
J a k w a y (1959) m e a s u r e d t h e o x y g e n . c o n s u m p t i o n of t w o l i n e s of g u i n e a
p i g s s e l e c t e d f o r h i g h a n d l o w m a t i n g a c t i v i t y a n d f o u n d t h a t t h e h ig h
s tr a in had a so m ew h at h ig h e r oxygen consum ption.
s tra in w e re h ea v ie r and had h eav ier t e s t e s .
M a l e s of t h e lo w
She s u g g e s te d t h a t e l e m e n t s
of s e x u a l b e h a v i o r m a y b e t h o u g h t of a s m e a s u r e s of t h e r e s p o n s e s of t h e
m a l e to th e e s t r u s f e m a l e .
S e l e c t i o n . f o r f a s t e r a n d s l o w e r m a t i n g s p e e d in D r o s o p h i l a m e l a n o gaster
s h o w e d q u i c k r e s p o n s e ( M a n n i n g , . 1961; P a r s o n s ,. 1964).
The lines
w e r e c l e a r l y s e p a r a t e d in t h e s e c o n d g e n e r a t i o n s ; h o w e v e r , f r o m t h e n on,
little fu rth e r p r o g r e s s w as m a d e.
dow nw ard d irectio n .
The
G r e a t e r p r o g r e s s w a s m a d e in the
b e tw e e n the high and low lin e s w as i n t e r ­
m e d i a t e , w h i c h is c o n s i s t e n t w i t h p o l y g e n i c c o n t r o l .
showed m a tin g sp eed s in te r m e d ia te b e tw e e n the
The back c ro s s e s
and the p a r e n t stock
-35-
w ith little o v erla p .
H e r i t a b i l i t y w a s e s t i m a t e d t o b e a b o u t 0. 30. ■ T h e r e
was. a n i n c r e a s i n g n u m b e r of e x t r e m e l y i n a c t i v e f l i e s w h i c h t h e r e f o r e
m a t e d slow ly.
D uring the o rig in a l m a t i n g s , the light w as s tro n g ly d i r ­
e c t i o n a l t o a t t r a c t t h e f l i e s t o o n e e n d of t h e m a t i n g c h a m b e r .
A fter th re e
to f o u r g e n e r a t i o n s , th e slo w lin e s w e r e m u c h l e s s a t t r a c t e d to the lig h t
t h a n t h e f a s t l i n e s , a n d a c o n s i d e r a b l e d i f f e r e n c e in g e n e r a l a c t i v i t y b e ­
tw e e n the lin e s w as o b s e rv e d .
The slow line showed g r e a t d is tu rb a n c e s
w h e n f i r s t p u t i n t o t h e m a t i n g c h a m b e r , b u t t h e f a s t l i n e f e m a l e s d i d n o t;
they th e r e f o r e m a te d f a s te r .
M a n n i n g (1961) c o n s i d e r e d t h a t t h e h i g h e r
f r e q u e n c y of l i c k i n g a n d s h o r t e r l a t e n c y of t h e f a s t m a l e s i n d i c a t e d t h a t
the sex u al r e s p o n s e th r e s h o ld had b e e n lo w ered .
The f a s t m a l e s would
a l s o c o u r t o t h e r o b je c ts in th e o b s e r v a t i o n c h a m b e r , w h ic h th e c o n t r o l o r
s l o w m a l e s d i d n o t do , i n d i c a t i n g t h a t f o r t h e f o r m e r , t h e s e o b j e c t s w e r e
a d e q u a t e s e x u a l s t i m u l i , ■w h i l e f o r t h e l a t t e r t h e y w e r e n o t .
There w ere
n o s i g n s of g e n e r a l m e t a b o l i c c h a n g e s i n t h e s e l e c t e d l i n e s a n d it s e e m e d
p r o b a b l e t h a t t h e a c c u m u l a t e d g e n e s a f f e c t t h r e s h o l d s in t h e n e r v o u s s y s ­
tem .
M a n n i n g (1963)
s e l e c t e d f o r m a t i n g s p e e d in m a l e D r o s o p h i l a o n ly .
H e f o u n d t h a t a f t e r 20 g e n e r a t i o n s n o p r o g r e s s w a s e v i d e n t i n t h e h i g h
-36-
line, though s e le c tio n d o w nw ard w as s u c c e s s fu l.
F e m a l e s of t h e lo w
lin e w e r e found n o t to b e s ig n if ic a n tly d i f f e r e n t f r o m th e c o n t r o l s so the
c h a n g e w a s a t t r i b u t e d e x c l u s i v e l y to th e m a l e s .
Since s o m e re s p o n s e
w a s s e e n i n t h e f e m a l e s i n l a t e r g e n e r a t i o n s , it w a s s u g g e s t e d t h a t in
t h e e a r l y g e n e r a t i o n s , o n ly s e x - l i m i t e d g e n e s w e r e i n v o l v e d , w h i c h w i t h
p r o g r e s s in s e l e c t i o n e x t e n d e d t o a u t o s o m a l g e n e s c o m m o n t o m a l e s a n d
fem ales.
F u l k e r (1966) r e p o r t e d t h a t f a s t D r o s o p h i l a m a l e s c o p u l a t e d
m o r e often, m o r e s u c c e s s f u l l y , and le ft m o r e p ro g e n y .
VI.
G E N E T IC AND O TH ER F A C T O R S IN FL U E N C IN G TH E M E A S U R E D .
U N S E L E C T E D TRAITS
It h a s b e e n e s t a b l i s h e d ab o v e th a t th e s e l e c t e d t r a i t (m a tin g b e h a v io r)
is u n d e r p a r ti a l genetic co n tro l,
H e r i t a b i l i t y e s t i m a t e s by v a r io u s a u t h ­
o r s f o r t h e a b o v e t r a i t i m p l y t h a t t h e v a r i a t i o n a t t r i b u t a b l e to e n v i r o n ­
m e n ta l conditions is c o n s id e ra b le .
G e n e ti c c o n t r i b u ti o n s to th e non-
s e le c te d c h a r a c t e r s th a t w e r e m e a s u r e d in this study d iffe r g re a tly f r o m
t r a i t to t r a i t .
A.
Egg P r o d u c ti o n and Egg Weight
T h r e e d if f e r e n t f a c t o r s (age at s e x u a l m a t u r i t y , p e r s i s t e n c y ,
rate)
a c c o u n t f o r t h e t o t a l n u m b e r of e g g s l a i d b y d o m e s t i c h e n s ( L e r n e r a n d
-37-
T a y l o r 1 1943).
S o c i a l s t a t u s a l s o i n f l u e n c e s eg g p r o d u c t i o n ( T i n d e l l a n d
C r a i g , I 96 0) .
Egg p ro d u ctio n v a r ie s g re a tly w ith e n v iro n m e n ta l conditions.
H erit-
a b ility e s t i m a t e s in c h i c k e n s r a n g e d f r o m 0-22%, d e p e n d in g on t h e i r
c o m p u t a t i o n ( D e m p s t e r jet a l , 1952).
H e r i t a b i l i t y e s t i m a t e s in C o tu r n i x
w e r e c o n s i d e r a b l y h i g h e r ( M a r k s a n d K i n n e y , 1964).
E gg w e ig h t s e e m s to b e c o n t r o l l e d by g e n e tic f a c t o r s to a g r e a t e r
e x t e n t t h a n e g g p r o d u c t i o n ( S h o f f n e r a n d S l o a n , 1948; S i t t m a n e t a l , 1966).
H o w e v e r , M a r k s a n d K i n n e y (1964) o b s e r v e d g r e a t f l u c t u a t i o n s i n h e r i t a b i l i t y e s t i m a t e s f o r e gg w e i g h t in q u a i l .
B.
H atchability and F e rtility
H a t c h a b i l i t y i s a f f e c t e d b y s t o r a g e of h a t c h i n g e g g s ( W o o d a r d e t a l ,
1966), i n b r e e d i n g ( S l t t m a n e t a l , 1966), a n d l e n g t h of p r o d u c t i o n of t h e
f e m a l e s ( F l o w e r , p e r s . c o m m u n . ).
D e m p s t e r e t a l (1952) e s t i m a t e d t h e
h e r i t a b i l i t y of h a t c h i n g p e r c e n t a g e a s 16%; w h e r e a s , P e n q u i t e e t a l (193 0)
r e p o r t e d z e r o h e r i t a b i l i t y in W hite L e g h o r n .
V a r ia tio n in h atch ab ility
c o u ld only to a s m a l l e x t e n t b e a c c o u n t e d f o r by v a r i a t i o n s i n f e r ti lit y .
F e r t i l i t y i s a f f e c t e d b y t h e r a t e of eg g p r o d u c t i o n of t h e f e m a l e s ( W a r r e n
a n d K i l p a t r i c k , 1929), a g e of t h e m a t e s ,
an d c o m p e tit io n b e t w e e n the
-38-
m a t e s ( W o o d a r d a n d A b p l a n a l p , 1967), a n d r o g e n l e v e l i n t h e b l o o d of
c o c k s ( B e r r y a n d B u r n h a m , 1962), p r e s e n c e of a h a r d s h e l l e d egg in t h e
u t e r u s a t t h e t i m e of a r t i f i c i a l i n s e m i n a t i o n ( P a r k e r , 1945), c l u t c h
l e n g t h ( B a m o r e u x , 1940), a n d s e x u a l a c t i v i t y of t h e f e m a l e s ( G u h l a n d
W a r r e n , 19.46).
C.
P o st-H a tc h M ortality
M o r t a l i t y in q u a i l c h i c k s i s u s u a l l y c o n c e n t r a t e d i n t h e f i r s t t h r e e
days.
I n b r e e d i n g s p r e a d s th e m o r t a l i t y o v e r th e f i r s t two w e e k s (S ittm an
_et al,, 1966).
D.
Sex R atio
T h e s e x r a t i o is in e q u i l i b r i u m w h e n in th e p o p u la tio n a s a whole
t h e t o t a l e f f o r t s p e n t in p r o d u c i n g t h e t w o s e x e s is. e q u a l .
m u t a n t s c a n c h a n g e t h e s e x r a t i o s ( H a m i l t o n , 1967).
X or Y
W a r r e n and K il­
p a t r i c k (1929) s u g g e s t e d t h a t f r e s h s p e r m a n d t h e f i r s t e g g s of c l u t c h e s
of m o r e t h a n f o u r e g g s p r o d u c e d m o r e m a l e s t h a n f e m a l e s .
E. Sexual M aturity
R e p o rte d h e r ita b ility e s ti m a t e s fo r th is t r a i t a r e f a ir l y high for d o m ­
e s t i c f o w l ( S h o f f n e r a n d S l o a n , . 1948) a n d f o r C o t u r n i x ( M a r k s a n d K i n n e y ,
1964; S i t t m a n e t a l , 1966).
Social statu s affects the age at sex u al m a tu r ity
of h e n s ( T i n d e l l a n d C r a i g , I 96 0) .
W i n g s t r a n d (1951) r e p o r t e d t h a t t h y r o ­
-39-
xine in jectio n s c a u s e d sex u al m a tu r ity in m a le ch ickens.
F.
Body W eight
J a p a n e s e q u a i l , f e d a 27% p r o t e i n t u r k e y s t a r t e r r a t i o n , w e i g h e d a s
a d u l t s : f e m a l e s ( a f t e r o n e m o n t h of la y) 137. I _+ I. 8 g r a m s , a n d m a l e s
1 0 3 . 7 _+ I. 0 g r a m s ( F r e e m a n , 1967).
Y a m a m o t o (1964) o b t a i n e d a 4 0 - d a y
w e i g h t f o r b o t h s e x e s of 88 _+ 4 . 28 g r a m s ( c . f . M a h n a n d B l a c k w e l l , 1967).
B o d y w e i g h t s a t s i x w e e k s a r e n e g a t i v e l y a f f e c t e d b y i n b r e e d i n g (S i t t m a n
_et _al, 1966).
H e r i t a b i l i t y e s t i m a t e s f o r s i x w e e k b o d y w e i g h t a r e of c o n ­
s i d e r a b l e m a g n i t u d e i n c h i c k e n s ( S h o f f n e r a n d S lo a n , . 1948) a n d a l s o i n
q u a i l ( M a r k s a n d K i n n e y , 1964; S i t t m a n e t a l , 1966).
G . T e s t e s W eight and C o lo r
■ A h e r l i a b i l i t y e s t i m a t e f o r t e s t e s w e i g h t in. c h i c k e n s w a s r e p o r t e d a s
0. 64 b y S i e g e l a n d S i e g e l (1964).
A ctual r e p o r te d w eights fo r C o tarn ix
t e s t e s , w h e n th e b i r d s w e r e k e p t u n d e r c o n s t a n t lig h t f o r 40 d a y s , w e r e
a b o u t BOOmg ( K o n i s h i , . 1967) a n d 1463 + 4 6 . IBmg. ( Y a m a m o t o , 1964).
Size
of t h e t e s t e s is a p p a r e n t l y a p r e c i s e f u n c t i o n of p i t u i t a r y g o n a d o t r o p i c
a c t i v i t y ( D o n ' n i k , 1964).
C a s p a r ! (1950) f o u n d t h a t i n E p h e s t i a k t r h n i e l l a t h e r e c e s s i v e a l l e l e
f o r t e s t e s c o l o r a c t e d a s d o m i n a n t w ith r e s p e c t to v ia b ility , and th e d o m ­
i n a n t a l l e l e f o r t e s t e s c o l o r a c t e d a s d o m i n a n t in r e s p e c t t o m a t i n g
-40-
behavior.
H.
B a s i c M e t a b o l i c R a t e (BM R)
B a s a l m e t a b o l i s m i n c l u d e s e n e r g y e x p e n d e d in r e s p i r a t i o n , b l o o d
c i r c u l a t i o n , i n t e s t i n a l c o n t r a c t i o n , a c t i v i t i e s of v a r i o u s o r g a n s , m a i n t e n ­
a n c e of m u s c u l a r t o n e , t h e r m a l e q u i l i b r i u m , e t c .
I t is p r i m a r i l y g o v ­
e r n e d b y t h e t h y r o i d a n d p i t u i t a r y g l a n d s ( H aw k , 1965; G u y t o n , 1966;
B e a t t i e a n d F r e e m a n , 1962).
T h e s u r f a c e la w (body w e ig h t '
67
) a c c o r d i n g t o Z e u t h e n (1953) w a s
f o r m u l a t e d i n 1837 b y S a r r u s a n d R a m e a u x 1 b u t K l e i b e r (1932) a t t r i b u t e d
i t t o R o b i q u e t a n d T i l l a y e i n 1839.
B M R is g r e a t l y in flu e n c e d by t e m p -
a t u r e ( M e l l e n a n d H i l l , 1955; B a r o t t a n d P r i n g l e , 1941).
A d u l t J a p a n e s e q u a i l c o n s u m e d o x y g e n a t a r a t e of 1 2 . 4 0 + . 24
m l / g m ^ ^ / h r . f o r f e m a l e s a n d 12.41 + . 2 0 f o r m a l e s ( F r e e m a n , 1967).
G i a j a a n d M a l e s , c i t e d b y L a s i e v s k i a n d D a w s o n (1967),. i n d i c a t e d a n
o x y g e n c o n s u m p t i o n f o r q u a i l ( 9 7 g m ) of 2 3 k c a l / 2 4 h r s . (4. 8 k c a l / l i t e r
of o x y g e n ) .
I.
P r o te in - B o u n d Iodine and T h y ro id F u n ctio n
T h y ro id function i n t e r f e r e s a n d / o r i n t e r a c t s with s e x u a l m a tu r a ti o n
of m a l e b i r d s w h e n t h e i r s e x o r g a n s t a k e p r e c e d e n c e in g r o w t h ( R a i l e t
—4 1 -
a l l 1964).
I n F a y o u m i f o w l, t h y r o i d a c t i v i t y c o i n c i d e d w i t h t h e r a t e of
b o d y g r o w t h w i t h a f o u r w e e k r e f r a c t o r p e r i o d ( K a m a r , 1961).
H igher
t h y r o i d a c t i v i t y s e e m s to b e r e l a t e d w i t h . f a s t e r g r o w th r a t e s ( B ie lli e r
a n d T u r n e r , 1950; G l a z e n e r e t a l , . 1949; M i x n e r a n d Upp., 1947).
T h y r o i d h o r m o n e s r w h e n p r e s e n t in n o r m a l a m o u n t s , a r e lo o s e l y bound
t o s p e c i f i c a l p h a g l o b u l i n s ( F r e i n k e l a t a l , . 1955; C a n t a r o w a n d S c h e p a r t z ,
1962; G u y t o n , , 1962).
A b o u t o n e t h i r d of t h e b i n d i n g s i t e s a r e o c c u p i e d b y
e n d o g e n o u s h o r m o n e in n o r m a l h u m a n s ( T u r n e r , 1966).
W hen-labeled
i o d i n e is a d d e d t o s e r u m , , i t w i l l a t t a c h u n t i l a l l b i n d i n g s i t e s a r e f i l l e d .
R a t s , m i c e a n d g u i n e a p i g s , a n d o t h e r m a m m a l s in a d d i t i o n t o a l p h a
g lo b u lin s h a v e a l b u m i n t h a t b in d thyroxine., w h e r e a s th e c h i c k e n has
m o s tly album in.
A vian s e r u m alb u m in binds both th y ro x in e and tr iio d o ­
t h y r o n i n e e q u a l l y ( M c F a r l a n d ed M 1 1966).
T he two h o r m o n e s have
e q u a l b i o l o g i c a l a c t i v i t y in b i r d s (R o b b in s a n d R a il, I960; T r i t s c h and
T r i t s c h , 1965).
G e n e ti c in f l u e n c e s on t h y r o i d s e c r e t i o n h a v e b e e n r e p o r t e d by E lI b i a r y a n d S h a f f n e r (1951), E l e f t h e r i o u a n d Z a r r o w (1961), S t a h l a n d T u m ­
o r (1961), S t a h l e t a l (1962), a n d C o l e (1966).
q u i t e h i g h ( S t a h l e t al ,, 1962).
H eritability estim ates w e re .
V ariab le in te ra c tio n s b etw een gonadal and
th y r o id h o r m o n e s , p a r t i c u l a r l y as r e l a t e d to BM R, have b e e n r e p o r t e d by
-42-
E n g b r i n g a n d E n g s t r o m (1959), S o l o m o n a n d D o w l i n g (I960) a n d G r a y a n d
B a c h a r a c h (1961).
T e s te s m e ta b o li s m is not in c r e a s e d w ith h ig h er th y 4
r o i d s e c r e t i o n a s i s t h a t of o t h e r t i s s u e s ( G u y to n , 1966), b u t t h y r o i d h o r ­
m o n e is n e e d e d f o r s e x u a l d e v e l o p m e n t ( M a q s o o d , 1952; S c h a r r e r a n d
S c h a r r e r , 1963).
J.
Blood G lu co se
In th e d o m e s t i c fowl, th e b lo o d s u g a r l e v e l v a r i e s o v e r a w ide r a n g e .
T h e l e v e l of i m m a t u r e f o w l of b o t h s e x e s a n d t h e m a t u r e f e m a l e s is c o n ­
s i d e r a b l y h i g h e r t h a n t h a t of t h e m a t u r e m a l e s .
V a l u e s of 172. 3 + 2. 95
m g % w e r e r e p o r t e d f o r W h i t e L e g h o r n b y T a p p e r a n d K a r e (1956).
This
is c o n s i d e r a b l y h ig h e r th a n the 80-135mg% r e p o r t e d fo r h u m a n s (Behr e n d t , 1957).
T h e g l u c o s e e s t i m a t e is a f f e c t e d by o t h e r r e d u c in g s u b ­
s t a n c e s i n t h e b l o o d (A n n i n o , I 96 0 ), l e n g t h of s t o r a g e of t h e w h o l e b l o o d ,
a n d h o r m o n e l e v e l s ( S t u r k i e , 1955; S a n d o z A t l a s of H e m a t o l o g y , 1952).
K.
H em atocrit
T h e t e r m h e m a t o c r i t v a l u e i s a p p l i e d t o t h e v o l u m e (in p e r c e n t ) of
p a c k e d r e d c e l l s i n a b l o o d s a m p l e (C a n t a r o w a n d S c h e p a r t z , 1962).
H e m a t o c r i t c a n b e d e t e r m i n e d g r o s s l y ( C a r t w r i g h t , 1962), o r b y m i c r o
m ethod.
V a l u e s r e p o r t e d f o r f e m a l e c h i c k e n s r a n g e d f r o m l e s s t h a n 30%
( N e w e l l a n d S h a f f n e r , 1950) t o a b o u t 36% ( S t u r k i e , 1955; C o h e n , 1967).
-43-
V a l u e s f o r q u a i l r a n g e d f r o m 2 9 - 4 5 % ( G o n z a g a a n d A l b a r e c e , 1963).
H e r i t a b i l i t y e s t i m a t e s f o r p a c k e d - c e l l v o lu m e in d o m e s t i c c h ic k s w a s
0 . 2 7 b y i n t r a - s i r e r e g r e s s i o n of o f f s p r i n g on d a m ( W a s h b u r n , 1967).
L.
H e a r t Rate
H e a r t r a t e i s o n e of t h e m o s t s e n s i t i v e i n d i c a t o r s t o j u d g e w h e t h e r
t h e r e is a c h a n g e i n t h y r o i d s e c r e t i o n r a t e ( G u y to n , 1966; H o h n , 1961).
o r B M R ( G r e e n , 1966).
T h e h e a r t r a t e s of c h i c k e n s h a v e b e e n r e p o r t e d
a s a b o u t 300 b e a t s p e r m i n u t e b y F l i c k (1967) a n d t h e B i o l o g i c a l H a n d ­
b o o k (1964).
M.
R e s p o n s e to A n e s t h e t i c s
P e n to b a r b i ta l has b e e n u s e d s u c c e s s fu lly w ith m a n y b ir d s w hen-in­
j e c t e d a t a r a t e of a b o u t 4 . 5 m g /IO Og m b o d y w e i g h t ( F r i e d b e r g , 1961).
T h e a g e n t a c t s b y b l o c k i n g t h e o x i d a t i o n of f l a v o p r o t e i n s b y t h e c y t o ­
c h r o m e s y s t e m (L u m b , 1963).
It a ls o inhibits a c e ty l- c h o l in e s y n th e sis
in t h e b r a i n ( R o s e n z w e i g _et al_, 1958).
I t w a s s u g g e s t e d b y G u y t o n (1962),
L a l e t a l (1964), a n d S l a t e r (1967) t h a t a p r e - a n e s t h e t i c a g e n t s u c h a s
a t r o p i n e b e u s e d f o r a n i m a l s w ith a h ig h B M R to r e d u c e s a liv a tio n .
The
a d v a n t a g e s of b a r b i t u r a t e s a r e t h a t r e s p i r a t i o n , c i r c u l a t i o n , m e t a b o l i s m
a n d s m o o t h m u s c l e s r e m a i n p a r c t i c a l l y n o r m a l u n t i l t h e f a t a l d o s e is
a p p r o a c h e d (S o i l m a n , . 1957).
-44-
M A T E R IA L S AND E X P E R I M E N T A L P R O C E D U R E
I.
E x p erim en tal A nim als
The
J a p a n e s e q u a i l u s e d a s t h e f o u n d a t i o n s t o c k in t h i s s t u d y w e r e
h a tc h e d a t the M o n tan a A g r ic u lt u r a l E x p e r i m e n t Station f r o m eggs ob­
t a i n e d f r o m t h e U n i v e r s i t y of C a l i f o r n i a , D a v i s , t h r o u g h t h e c o u r t e s y of
D r. H . A bplanalp, and f r o m a local fa n c ie r,
on S e p t e m b e r 22, 1966.
T h e e g g s f r o m t h e U n i v e r s i t y of C a l i f o r n i a w e r e l a i d b y d e s c e n d a n t s of
b i r d s o r i g i n a l l y i m p o r t e d b y t h e U n i v e r s i t y f r o m J a p a n in 1947.
i m a t e l y o n e h a l f of t h e e g g s c a m e f r o m e a c h s o u r c e .
w ing-banded and re c o rd e d .
A pprox­
The chicks w ere
T h e b e h a v i o r a l t e s t s s h o w e d no s ig n if ic a n t
d i f f e r e n c e s b e t w e e n th e two lin e s .
S e l e c t i o n of t h e m a l e s w a s b y t r u n c a t i o n in a n a t t e m p t to i n c r e a s e
and d e c r e a s e the m a tin g s c o r e .
The selection c rite rio n w as established
on t h e b a s i s of m a t i n g b e h a v i o r s c o r e s d e t e r m i n e d in t w o m a t i n g t e s t s of
2 0 - m i n u t e d u r a t i o n , b e g i n n i n g w i t h g e n e r a t i o n one (G - I ) .
p r a c t i c e d in t h e m a l e s o n l y .
control group.
Selection was
A ll f e m a l e s w e r e d ra w n at r a n d o m f r o m the
T h e c o n t r o l g r o u p w a s e s t a b l i s h e d in t h e o r i g i n a l g e n e r a ­
tio n f r o m m a l e s w ith i n t e r m e d i a t e s c o r e s an d any a v a ila b le f e m a le s .
No
c o n s c i o u s s e l e c t i o n w a s p r a c t i c e d in t h e c o n t r o l g r o u p , w i t h t h e e x c e p t
t i o n t h a t no c r i p p l e d ,
sick or v ery sm a ll b ird s w ere housed.
-45-
T h e s e l e c t i o n c r i t e r i o n ( t o t a l s c o r e ) w a s t h e s u m of n u m e r i c a l
s c o r e s fo r the following five b e h a v i o r a l c h a r a c t e r i s t i c s :
a.
P i c k (t h e p e c k - g r a b b e h a v i o r a s d e s c r i b e d b y S a c h s ; (1966a! one half point fo r e a c h o c c u r r e n c e .
b.
M o u n t i n g - o ne p o i n t f o r e a c h o c c u r r e n c e .
c.
C o p u l a t i o n ( d e s c r i b e d a s c l o a c a l c o n t a c t b y S a c h s (1966a.) two p o ints f o r e a c h o c c u r r e n c e .
d.
C o u r ti n g - one h a lf p oint f o r e a c h o c c u r r e n c e .
e.
D i s p l a c e m e n t a c t i v i t i e s ( m o s tl y p r e e n in g ) - m i n u s one half p o int
for each o c c u r r e n c e .
In the o r ig in a l g e n e r a t i o n (G-O)1 th e b i r d s w e r e h a n d le d s o m e ­
w h a t d i f f e r e n t l y f r o m t h e s u b s e q u e n t g e n e r a t i o n s d u e t o l a c k of e x ­
p e r i e n c e in t h e t e s t i n g , h a n d l i n g , a n d m a n a g e m e n t of q u a i l .
m a in differences w ere:
w eighing.
The
t e s t i n g p r o c e d u r e a n d t i m e of . t e s t i n g a n d
T h e o r i g i n a l t e s t i n g w a s d o n e in f o u r r u n s w i t h t h r e e d i f ­
ferent criteriaa.
E a c h m a l e w a s t e s t e d w i t h a s i n g l e f e m a l e f o r a p e r i o d of 30
m i n u t e s , w h i c h w a s d i v i d e d in to t w o t i m e s e g m e n t s , t h e f i r s t of
20 m i n u t e a n d t h e s e c o n d of 10 m i n u t e d u r a t i o n .
b.
E a c h m a l e w a s t e s t e d w ith two f e m a l e s fo r the s a m e p e r io d as
in a.
c.
S a m e a s a.
d.
E a c h m a l e w as t e s t e d w ith a f r e s h l y k illed fe m a le fo r the s a m e
-46-
p e r i o d a s in. a.
T h e m a l e s w e r e s e l e c t e d on t h e t o t a l n u m b e r of p o i n t s e a r n e d in t h e
fo u r t e s t s , though they w e r e m a t e d b e fo re the te stin g w as co m p lete d .
In
no o t h e r g e n e r a t i o n w e r e t h e m a l e s m a t e d b e f o r e c o m p l e t i o n of t h e m a t i n g
tests.
In t h i s g e n e r a t i o n ( G - 0 ) ,
se le c tio n took p la ce w hen the eggs w e r e
set.
S t a r t i n g in t h e f i r s t g e n e r a t i o n (G - I ) , t h e l e n g t h of t i m e f r o m i n t r o ­
d u c t i o n of t h e m a l e t o t h e f i r s t c o p u l a t i o n ( r e f e r r e d to a s l a t e n c y ) w a s
recorded.
T h e a c t u a l t i m e m e a s u r e m e n t w a s c o n v e r t e d to a v a l u e w h i c h
w a s h ig h e r , th e s h o r t e r th e i n t e r v a l to c o p u la tio n , a s follow s:
t h e t o t a l t e s t p e r i o d of 1200 s e c o n d s (20 m i n u t e s ' - 100%,
t h e t i m e t o t h e f i r s t c o p u l a t i o n a s a p e r c e n t a g e of 1200,
f r o m (a) a n d t a k e t h e s q u a r e r o o t .
b.
c.
a.
Let
calculate
s u b t r a c t (b)
If, f o r e x a m p l e , a p a r t i c u l a r m a l e
,
t o o k 120 s e c o n d s (10% of t o t a l t e s t t i m e ) t o t h e f i r s t c o p u l a t i o n , t h e n t h e
l a t e n c y v a l u e i s \ f l 0 0 - 10 = 9 . 5 .
T h e t o t a l n u m b e r of b i r d s i n v o l v e d in t h i s s t u d y is p r e s e n t e d in T a b l e
I by g e n e ra tio n s .
-47-
T a b l e I.
N o . of m a t i n g
High
N u m b e r of B i r d s I n v o l v e d in t h i s S t u d y
Lo w .
C ontrol
High
Low
48
32
, 37
34
24
37
73
36
21
39
29
9
257
164
134
G-O
G -I
G- 2
G- 3
G -4
G- 5
20
13
12
12
13
13
19
13
14
13
14
9
20
42
47
51
49
Total
83 ,
82
G ran d Total
N o . of f e . m a le s banded
N o . of m a l e s t e s t e d
S
— —
422
C ontrol
C ontrol
12
12
0
12
12
116
44
105
108
64
72
48
509
— —
419
O ther
49
36
24
109
618
In g e n e r a t i o n s one th r o u g h five, s i x - w e e k and final body w eig h ts w e r e
r e c o r d e d , b u t in G- O t h e s e w e i g h t s w e r e o b t a i n e d a t l a t e r d a t e s , 108 a n d
159 d a y s ,
respectively.
M a t i n g t e s t s t o o k p l a c e a t a n a g e of s i x to n i n e
w e e k s , d e p e n d i n g on t h e n u m b e r of l a y i n g f e m a l e s a v a i l a b l e f o r t e s t i n g
at any p a r tic u la r tim e .
No te stin g took p la c e b e fo re a r e a s o n a b le n u m ­
b e r of f e m a l e s h a d s t a r t e d t o l a y .
In th e o r i g i n a l g e n e r a t i o n , a n a t t e m p t w a s m a d e to m a t e e a c h s e l e c t ­
e d m a l e t o t w o f e m a l e s t o o b t a i n a s u f f i c i e n t n u m b e r of h a t c h i n g e g g s in
a short tim e.
T h is w o uld p r e v e n t an undue low hatch in g p e r c e n t a g e
c a u s e d b y l o n g e r s t o r a g e of t h e e g g s b e f o r e i n c u b a t i o n .
The m a le was
- 48 -
c a g e d b e t w e e n t h e t w o f e m a l e s a n d s h i f t e d a b o u t e v e r y 24 h o u r s .
This
r e s u l t e d in g r e a t l y i n c r e a s e d a g o n i s t ic i n t e r a c t i o n s b e t w e e n th e m a t e s ,
a n d in s e v e r a l c a s e s o n ly o n e f e m a l e p r o d u c e d o f f s p r i n g .
This p ro c e d u re
w a s m o r e d i s a d v a n t a g e o u s t h a n a l o n g e r s t o r a g e p e r i o d of t h e h a t c h i n g
e g g s , and w as th e r e f o r e abandoned.
beg in n in g w ith the G - I.
Single p a i r m a tin g s w e r e p r a c t ic e d
I n c a s e a m a t e d i e d e a r l y in t h e G - I, t h e s u r ­
viving m a t e w a s r e m a te d .
T h i s p r a c t i c e w a s a b a n d o n e d t h e r e a f t e r to
facilitate r e c o r d keeping.
I t w a s p l a n n e d to u s e e x c l u s i v e l y u n s e l e c t e d ,
ran d o m -m ate d , control
f e m a l e s a s m a t e s f o r th e s e l e c t e d high and low m a l e s .
This could not be
d o n e w h e n t h e n u m b e r of a v a i l a b l e f e m a l e s w a s i n s u f f i c i e n t .
t i o n a r o s e in t h e G - I a n d in t h e G - 4 .
This s itu a ­
In t h e G - I, s o m e f e m a l e s f r o m t h e
lo w e s t high and the h ig h e s t low m a t i n g s w e r e p o oled w ith th e c o n t ro l f e ­
m a l e s a n d th e n m a t e d a t r a n d o m to th e s e l e c t e d c o n t r o l m a l e s .
In the
G - 4 , t h e h i g h m a l e s w e r e d e l i b e r a t e l y m a t e d to f e m a l e s p r o d u c e d in t h e
h i g h l i n e , a n d t h e s e l e c t e d l o w m a l e s t o f e m a l e s p r o d u c e d in t h e l o w l i n e ,
w ith the r e s t r i c t i o n th a t full sib m a tin g s w e r e not allow ed.
The lines
w e r e s e p a r a t e d in t h e G - O .
I n t h e o r i g i n a l g e n e r a t i o n ( G - O ) , 14 s e l e c t e d h i g h a n d 11 s e l e c t e d l o w
m a l e s w e r e m a t e d to s t a r t f a m i l i e s .
I n t h e G - 5, t h e n u m b e r of e f f e c t i v e
—4 9 ”
f a m i l i e s h a d b e e n r e d u c e d t o o n ly t w o i n e a c h l i n e .
T h e h a t c h i n g d a t e s a n d a g e s a t t e s t i n g a r e i n d i c a t e d in T a b l e II b y
generations,
T a b l e II.
Gene­
ration
G-O
G -I
G -2
G- 3
G -4
G -5
H atch in g D a te s and A ges a t w h ic h v a r io u s T e s t s w e r e done
D ate
H atched
9 . 22:66
I . 07.67
4 . 23.67
7.2 3 .6 7
10. 2 2 . 6 7
2 .04.68
M ating
T e s t ( in d a y s^
59-87
40-60
42-50
44-50
54-62
44-49
M ated
67
65
50
50
63
50
. Physiol.
Test
101-156
90-109
74-88
75-90
85-100
D a y s of E g g
Production
60
73
63
70
73
T h e h a t c h i n g e g g s w e r e s t o r e d f o r 15 d a y s in t h e G - O a n d f o r 20 o r 2 1
d ay s in th e G - I t h r o u g h G - 5 a t a p p r o x i m a t e l y 5 5 ° F an d 60-70% r e l a t i v e
hum idity.
T h e y w e r e in c u b a te d o r i g i n a l l y a c c o r d i n g to th e r e c o m m e n d a ­
t i o n s of W o o d a r d e t a l (1965) b u t t h e p r o c e d u r e w a s l a t e r m o d i f i e d to a
c o n s t a n t t e m p e r a t u r e (99. 5 ° F ) t h r o u g h o u t t h e i n c u b a t i o n p e r i o d , a n d a
r e l a t i v e h u m i d i t y of 86% t o d a y 15, a n d 89% t h e r e a f t e r .
h a t c h e d i n a J a m e s w a y M o d e l 252 s i n g l e s t a g e i n c u b a t o r .
A ll chicks w e r e
A t t h e e n d of
t h e 18th d a y , t h e c h i c k s w e r e t a k e n f r o m t h e p e d i g r e e b a s k e t s , w i n g b a n d ed, r e c o r d e d , a n d p l a c e d in t o a c o m m u n i t y b a t t e r y b r o o d e r ( T a m e s w a y ) ,
w hich had b e e n ad a p te d fo r the s m a l l b i r d s .
F r o m th is t i m e until d i s ­
-50-
p o s a l of t h e b i r d s , c o n s t a n t l i g h t w a s p r o v i d e d .
at the fa rm ) w e r e a v ailab le f r e e choice.
W ater and feed (m ixed
T he t e m p e r a t u r e u n d e r the
h o v e r in t h e b a t t e r y r e m a i n e d a t IOO0 F a n d t h e r o o m t e m p e r a t u r e a t
70-75°F.
T h is a l lo w e d th e b i r d s to m o v e c l o s e r o r f a r t h e r aw a y f r o m
th e h e a t s o u r c e a c c o r d i n g to t e m p e r a t u r e c h a n g e s .
A t f o u r w e e k s of a g e t h e c h i c k s w e r e l e g - b a n d e d a n d h o u s e d in i n d i v ­
idual c a g e s ,
6 x 6 x 6 i n c h e s in s i z e .
Two w eeks l a t e r , they w e re w eighed
and m ating te sts w e re s ta rte d shortly th e re a fte r.
The cage ro o m was
h e a t e d to 7 2 - 7 4 ° F , b u t d u r in g th e s u m m e r m o n t h s , th is t e m p e r a t u r e w as.
often c o n s id e r a b ly ex c e e d e d .
D u e t o t h e v a r y i n g n u m b e r of m a t e s a v a i l a b l e f o r t e s t i n g , t h e s e l e c ­
tio n p r e s s u r e a p p l ie d v a r i e d f r o m g e n e r a t i o n to g e n e r a t i o n .
S e l e c t i o n of
m a l e s w a s b y t r u n c a t i o n in t h e h i g h l i n e a n d in t h e l o w l i n e , r a t h e r t h a n
by m i n i m u m culling le v e ls .
I n e a c h g e n e r a t i o n , 12 o r 13 m a l e s w e r e
s e l e c t e d in e a c h , t h e h i g h a n d t h e l o w l i n e .
A t t h e t i m e of m a t i n g , t h e m a l e s a n d f e m a l e s w e r e d e b e a k e d to r e ­
d u ce th e a g o n i s t ic m a l e - f e m a l e i n t e r a c t i o n s , p a r t i c u l a r l y d u rin g the
f ir s t few days a fte r p airin g .
T h e e x t e n t of d e b e a k i n g v a r i e d in t h e G - 2,
a s t h i s a s p e c t of m a n a g e m e n t w a s s u b j e c t t o c l o s e r i n v e s t i g a t i o n ( M a h n
a n d B l a c k w e l l , 1967).
-51-
T h e m a t e s r e m a i n e d t o g e t h e r f o r a t o t a l of a b o u t 25 d a y s a n d w e r e
then s e p a ra te d .
T he m a l e s w e r e s u b je c te d to p h y s io lo g ic a l t e s t s and the
f e m a l e s w e r e a l l o w e d to c o m p l e t e a b o u t 9 - 1 0 w e e k s of e g g p r o d u c t i o n ,
a f t e r w h i c h t h e y w e r e d i s p o s e d of.
T h i s m a n a g e m e n t m a d e it p o s s i b l e
t o o b t a i n a g e n e r a t i o n i n t e r v a l , of a b o u t t h r e e m o n t h s w i t h o u t o v e r l a p .
II.
T esting E quipm ent fo r B ehav io ral O bservations
T h e t e s t i n g w a s d o n e in t w o m a t i n g c a g e s .
T h e s e c a g e s c o n s i s t e d of
w e l d e d w i r e m e s h ( 1 x 2 i n c h e s o n c e n t e r ) o n t h e s i d e s a n d t h e to p , a n d a
s o l i d w o o d e n f l o o r c o v e r e d w i t h a b o u t o n e i n c h of w o o d s h a v i n g s .
The
s i d e s w e r e s o l i d w o o d f o r f o u r i n c h e s a b o v e t h e f l o o r to p r e v e n t s p r e a d ­
ing of t h e s h a v i n g s .
T h e t o t a l d i m e n s i o n s w e r e 18x18x15 i n c h e s .
c a g e s w e r e illu m in a te d f r o m above by f lo u r e s c e n t light.
The
A d o o r to the
f r o n t of t h e c a g e s a d m i t t e d t h e b i r d s t o b e t e s t e d .
III.
T esting P ro c e d u re
A f e m a l e w a s m a n u a l l y p l a c e d in t o e a c h of t h e c a g e s , w h i c h w e r e
s e p a r a t e d b y c a r d b o a r d t o e l i m i n a t e a n y s o c i a l f a c i l i t a t i o n d e p e n d i n g on
sight.
H ow ever, au d ito ry cues could not be elim in ated .
A m a le was
i n t r o d u c e d in t o c a g e n u m b e r I; w h e n h e d r o p p e d o n to t h e s h a v i n g s , a
stop w atch w as s ta r t e d and the t e s t had begun.
With th e s to p w a tc h ,
l a t e n c y t o c o p u l a t i o n w a s m e a s u r e d , a n d a n o t h e r w a t c h w;as u s e d to d e ­
-52-
t e r m i n e t h e e n d of t h e 20 m i n u t e t e s t p e r i o d .
The next m a le w as in tro ­
d u c e d into c a g e n u m b e r 2 five to te n m i n u t e s a f t e r the f i r s t m a l e had
b e e n p u t in t o c a g e I.
T h i s e l i m i n a t e d t h e n e c e s s i t y of s c o r i n g t h e g r e a t ­
e s t a c t i v i t y of t w o m a l e s s i m u l t a n e o u s l y .
Only la y in g h e n s not co n ta in in g a h a r d s h e l l e d egg w e r e u s e d .
Dif­
f e r e n t h e n d w e r e u s e d w i t h a v a r y i n g n u m b e r of m a l e s d e p e n d i n g u p o n
th eir receptivity.
No m a l e w as te s t e d tw ic e w ith the s a m e fe m a le .
T h e o b s e r v e r an d r e c o r d e r w e r e s e a t e d ab o u t s ix to s e v e n f e e t f r o m
the c a g e s , a n d u n l e s s r a p i d m o v e m e n t s o r loud, u n u s u a l n o i s e s w e r e
m a d e , th e b i r d s p aid little a tte n tio n to t h e i r s u r r o u n d in g s ( c .f. C a r b a u g h e t a l , 1962).
In s o m e c a s e s , w h en m a l e s m a t e d a l m o s t i m m e d ­
iately , the o b s e r v e r had not even r e t r e a t e d f r o m the cag e .
changing b ir d s ,
When e x ­
e ith e r the m a le o r the f e m a le , the cage w as a p p ro a c h e d
f r o m the sid e so th a t th e se c o n d p a i r w ould not be d is tu r b e d .
T h e m a t i n g t e s t s w e r e u s u a ll y done in th e e v e n i n g , th o u g h not r e g orously at any p a rtic u la r tim e.
depending on the t i m e a v a ila b le .
T h e l e n g t h of t h e s e s e s s i o n s v a r i e d
In g e n e r a l , a s the in v e s t ig a t io n p r o ­
g r e s s e d , t h e s e s s i o n s t e n d e d to b e c o m e l o n g e r a n d u p t o 35 m a l e s w e r e
t e s t e d in o n e e v e n i n g .
-53-
IV.
P h y sio lo g ic a l T estin g E q u ip m en t and P r o c e d u r e s
W ithin two o r t h r e e d a y s a f t e r the m a t e s had b e e n s e p a r a t e d , m e a s ­
u r e m e n t of o x y g e n c o n s u m p t i o n c o m m e n c e d .
T h i s w a s g e n e r a l l y d o n e in
t h e e v e n i n g s o r e a r l y m o r n i n g s in o r d e r to e l i m i n a t e a t e m p e r a t u r e
effect as fa r as possible.
T h e a p p a r a t u s ( F i g u r e I) u s e d h a d b e e n c o n ­
s t r u c t e d in t h e H o m e E c o n o m i c s R e s e a r c h D e p a r t m e n t of M o n t a n a S t a t e
U n i v e r s i t y , a n d w a s p r o v i d e d t h r o u g h t h e c o u r t e s y of P r o f e s s o r H e l e n
-54-
M ayfield.
I t c o n s i s t e d of a p l a s t i c c h a m b e r w i t h a r e m o v a b l e t o p a n d a n
in te rm e d ia te w ir e floor; B a r iu m H ydroxide L im e (B erilym e) w as placed
b e lo w the f l o o r to a b s o r b c a r b o n d io x id e.
The c h a m b e r w as fitted w ith an
oxygen supply f r o m the oxygen c y lin d e r, a co n n ec tio n to an oxygen supply
t o b e u s e d d u r i n g t h e t e s t (a IOOcc s y r i n g e ) , a n d a c o n n e c t i o n t o a m a n o ­
m e t e r (a g l a s s 0 - t u b e f i l l e d w i t h B r o d i e 1s f l u i d ) .
A fourth connection
w as s im ply an exhaust.
T h e m a l e s w e r e i n j e c t e d w i t h a c o m m e r c i a l p r e p a r a t i o n of S o d i u m
P e n t o b a r b i t a l (D i a b u t a l , D i a m o n d L a b o r a t o r i e s , I n c . , D e s M o i n e s , Iowa),
c o n t a i n i n g 6 Omg of t h e a c t i v e i n g r e d i e n t p e r m i l l i l i t e r .
The am ount in­
j e c t e d s u b c u t a n e o u s l y in t h e n e c k r e g i o n a v e r a g e d a b o u t 9 m g /lOOgm.
preanesthetic was used.
T h e b i r d s w e r e t h e n p l a c e d in a c a g e u n t i l t h e
a n e s th e tic a c tio n took effect.
m inute.
No
T h i s p e r i o d w a s t i m e d to t h e c l o s e s t h a l f
T h e b i r d s w e r e t h e n i n t r o d u c e d in t o t h e c h a m b e r a n d t h e c h a m ­
b e r w as sealed.
T h e p lu n g e r w a s r e m o v e d f r o m the s y r i n g e and the
s y s t e m flu sh ed w ith oxygen.
W hile opening the e x h a u s t, th e p lu n g e r w a s
i n s e r t e d to 8 0 m l a n d th e e x h a u s t w a s th e n c l o s e d .
A fter a c e rta in am ount
of o x y g e n p r e s s u r e h a d b e e n i n t r o d u c e d , t h e s u p p l y w a s c u t .
The tim e r
w a s s t a r t e d w h e n a n e q u i l i b r i u m h a d b e e n r e a c h e d in t h e s y s t e m .
w as continued until a tm o s p h e r ic p r e s s u r e had b een reg ain ed .
T im ing
-55-
T h e b i r d w a s s t i l l u n d e r t h e e f f e c t of t h e a n e s t h e t i c w h e n r e m o v e d
f r o m the c h a m b e r .
A f t e r t h e n e x t b i r d h a d b e e n s e a l e d in t h e c h a m b e r
a n d t h e t i m e r h a d b e e n s t a r t e d , t h e f i r s t b i r d w a s p l a c e d on h i s b a c k on
t h e t a b l e a n d h e l d in p l a c e b y tw o r u b b e r b a n d s a t t a c h e d t o t h e l e g s a n d
w i n g s a n d t w o n a i l s in t h e t a b l e s u r f a c e ( F i g u r e 2).
The h e a r t rate was
t a k e n t h r o u g h t w o e l e c t r o d e s (24 g a u g e h y p o d e r m i c n e e d l e s ) w h i c h w e r e
i n t r o d u c e d c l o s e t o t h e r i b s in e a c h s i d e of t h e t h o r a x .
The electrodes
w e r e c o n n e c t e d to a n e l e c t r o c a r d i o g r a p h ( S a n b o r n V i s o c a r d i e t t e , M o d e l
51).
R e c o r d in g c o n tin u e d fo r a p p r o x im a te ly one m in u te and the h e a r t
-56-
r a t e p e r m i n u t e w a s d e t e r m i n e d f r o m a c t u a l c o u n t s of t h e p e a k s d u r i n g
2 -4 five se c o n d p e r i o d s , w h ich w e r e th e n m u ltip lie d by an a p p r o p r ia te
f a c t o r to a c c o u n t f o r one w h o le m i n u t e .
T h e b i r d s w e r e th e n p la c e d into
th e ir home cages for recuperation.
A b o u t f o u r to f i v e d a y s l a t e r , t h e m a l e s w e r e w e i g h e d ( f i n a l w e i g h t ) ,
and u n d e r a n e s th e s i a , t h e i r blood w as d r a in e d f r o m the rig h t e x te rn a l
j u g u l a r a r t e r y into a t e s t tu b e to w h ic h h e p a r i n h ad b e e n a d d e d .
The
b i r d s w e r e h u n g h e a d d o w n a n d t h e s k i n of t h e n e c k w a s r e m o v e d b e f o r e
the a r t e r y w as se v e re d .
W hile the b lo o d w a s d ra in in g into th e t e s t tube,
two m i c r o h e m a t o c r i t tu b e s w e r e fille d . .
T h e b l o o d of t h e s e q u a i l m a l e s
c o a g u l a t e d v e r y r a p i d l y an d it w a s v e r y d iffic u lt to o b ta in m o r e th a n two .
t o t h r e e m i l l i l i t e r s of b l o o d b y d r a i n i n g .
Im m e d ia te ly a f te r collection,
the blood w as ta k e n to the la b o r a t o r y and the p l a s m a s e p a r a t e d f r o m the
cells.
T h e b l o o d w a s c e n t r i f u g e d f o r 20 m i n u t e s in a S e r v a l l , m o d e l N S E
centrifuge.
T h e m i c r o h e m a t o c r i t t u b e s w e r e p l a c e d in a n I n t e r n a t i o n a l
m ic ro c a p illa ry c e n trifu g e, m odel MB,
s p u n f o r 7 1 /2 m i n u t e s a n d t h e n
r e a d on a n I n t e r n a t i o n a l m i c r o h e m a t o c r i t r e a d e r .
T he p l a s m a w as a n a l y s e d fo r th y r o id a c tiv ity a c c o rd in g to the m e th o d
of S t e r l i n g a n d T a b a c h n i c k (1961).
The TBI r e s in w as obtained fro m
M a l l i n c k r o d t / N u c l e a r , G l e n d a l e , C a l i f o r n i a , a n d h a d a p o t e n c y of 0. 5
-57-
m i c r o c u r ie p e r vial.
O ne m i l l i l i t e r of p l a s m a w a s s h a k e n w i t h t h e r e s i n
in t w o m i l l i l i t e r s of b u f f e r f o r 45 m i n u t e s , d r i e d o v e r n i g h t a n d c o u n t e d
in a w e l l - t y p e s c i n t i l l a t i o n c o u n t e r ( T r a c e r l a b K e l e k e t , m o d e l S C - 7 3 ) f o r
t h r e e t i m e s one m in u te .
I n t h e G - 4 , o n e h a l f of t h e m a l e s of e a c h g r o u p w e r e u s e d f o r a b l o o d
g l u c o s e a n a l y s i s a c c o r d i n g t o t h e m e t h o d of F o l i n - W u (1920).
Known g lu ­
c o s e c o n c e n t r a t i o n s w e r e u s e d to e s t a b l i s h a c u r v e to w h ic h th e o th e r
re s u lts obtained w e re c o m p ared .
Due to th e high h e m a t o c r i t v a lu e and
t h e s m a l l a m o u n t of b l o o d , i t w a s n o t p o s s i b l e t o r u n b o t h t h e g l u c o s e
t e s t and the I 1
- u p t a k e on th e s a m e b i r d .
A fte r the blood te s t, th e m a l e s w e r e d is s e c te d , the t e s t e s w e r e r e ­
m o v e d a n d w e i g h e d o n a M e t t l e r b a l a n c e t o t h e n e a r e s t 0. I m g .
the te s t e s w as re c o r d e d .
C o l o r of
T h e w e i g h t of t h e t e s t e s w a s e x p r e s s e d a b s o l ­
u t e a n d in p e r c e n t of b o d y w e i g h t .
R e c o r d s k e p t on the f e m a l e s in c lu d e d s e x u a l m a t u r i t y (age a t f i r s t
e g g ) , e gg p r o d u c t i o n ( in p e r c e n t , on a h e n - h o u s e d b a s i s k
egg w e ig h t (one
e g g w e i g h e d p e r w e e k g a v e a g o o d e s t i m a t e of t h e a v e r a g e w e i g h t , c o m ­
p a r e d t o w e i g h i n g a l l e g g s , u n p u b . o b s . ), s i x w e e k a n d f i n a l w e i g h t s .
S T A T IS T IC A L ANALYSIS
H e rita b ility w as e s tim a te d for the s e le c te d c h a r a c t e r (m ating b e h a v ­
-58-
i o r ) a c c o r d i n g t o a m e t h o d o u t l i n e d b y S i e g e l (1965) a s h.2 = 2(&§ / Al ?) ,
w h e r e A O w a s ' t h e d i f f e r e n c e b e t w e e n t h e m e a n s of t h e u n s e l e c t e d m a l e
o f f s p r i n g of t h e h i g h a n d l o w l i n e , a n d A P t h e c u m u l a t i v e s e l e c t i o n d i f ­
ferential.
T h e h e r i t a b i l i t i e s of a l l c h a r a c t e r s w e r e a l s o e s t i m a t e d f r o m
t h e s e l e c t e d b i r d s b y s i r e - off s p r i n g r e g r e s s i o n a c c o r d i n g t o F a l c o n e r
(I960).
P h e n o t y p i c c o r r e l a t i o n s w e r e c o m p u t e d f o r a l l c h a r a c t e r s t e s t e d in
the s e le c te d m a l e s .
A n o t h e r s e t of p h e n o t y p i c c o r r e l a t i o n s w a s c a l c u l a t ­
ed b etw ee n s c o r e and the m e a s u r e d p h y sio lo g ical tr a i t s fo r th o se m a le s
producing offspring.
T h e l a t t e r s e t of c o r r e l a t i o n s w a s o b t a i n e d w i t h i n
lin e s, and a lso pooled.
R e a liz e d p r o g r e s s fo r the s e le c te d c h a r a c t e r w as e s t i m a t e d by the
r e g r e s s i o n of d e v i a t i o n s f r o m c o n t r o l ( d e p e n d e n t v a r i a b l e ) on g e n e r a t i o n
n u m b e r ( i n d e p e n d e n t v a r i a b l e ) i n a l l g e n e r a t i o n s w i t h t h e e x c e p t i o n of t h e
G - 3.
T h e r e w e r e n o c o n t r o l m a l e s t e s t e d f o r m a t i n g b e h a v i o r in t h e G - 3.
T he phenotypic, c o r r e l a t i o n co e ffic ie n ts w e r e te s t e d d i r e c t l y for
s i g n i f i c a n c e ( S n e d e c o r , 1946),
C o r r e la tio n s and r e g r e s s io n s b etw ee n the m ating s c o r e com ponents
of m a t i n g t e s t I a n d m a t i n g t e s t 2 w e r e c a l c u l a t e d .
V alues w hich w e re
-59-
m i s s i n g f r o m t h e o b s e r v a t i o n s w e r e e s t i m a t e d in s o m e c a s e s t o f a c i l i t a t e
t h e c o m p u t e r (IBM 1620) a n a l y s i s of t h e d a t a .
In t h e s e c a s e s , the n u m b e r
of a d j u s t m e n t s m a d e w a s s u b t r a c t e d f r o m t h e d e g r e e s of f r e e d o m w h e n
d eterm in in g significance.
-60-
RESULTS
I.
R e s p o n s e in t h e S e l e c t e d T r a i t
F i g u r e 3 p r e s e n t s g r a p h i c a l l y t h e e f f e c t s of s e l e c t i o n f o r h i g h a n d
low m a tin g s c o r e s ;
A s h o w s t h e m e a n s c o r e s of a l l m a l e s t e s t e d w i t h i n
t h e l i n e s , B g i v e s t h e m e a n s c o r e s of t h e s e l e c t e d m a l e s w i t h i n t h e l i n e s ,
a n d C p r e s e n t s t h e r e g r e s s i o n l i n e s o n t h e s c o r e s of t h e h i g h a n d l o w
line.
T h e v a l u e s in t h e g r a p h (3C) w e r e a d j u s t e d f o r e n v i r o n m e n t a l
fluctuations.
B oth r e g r e s s i o n lin es show a n egative slope w ith a slight
o v erall divergence.
I t is e v i d e n t t h a t d i v e r g e n c e b e t w e e n t h e l i n e s o c ­
c u r r e d i n g e n e r a t i o n o n e (G- I ) .
A n a n a l y s i s of v a r i a n c e i n d i c a t e d t h a t
t h e h i g h a n d l o w l i n e s w e r e c l e a r l y s e p a r a t e d in t h e G - I a n d r e m a i n e d so
to..the e n d of t h e e x p e r i m e n t w i t h t h e e x c e p t i o n of t h e G - 2.
The m e an
m a t i n g s c o r e s of a l l m a l e s t e s t e d b y l i n e s a n d g e n e r a t i o n s a r e c o m p i l e d
in T a b l e III.
T h e h e r i t a b i l i t y f o r s c o r e w a s c a l c u l a t e d a c c o r d i n g t o S i e g e l (1965);
t h e r e s u l t s a r e g i v e n i n T a b l e IV.
T h e h e r i t a b i l i t y of m a t i n g s c o r e w a s
a l s o e s t i m a t e d b y s i r e - o f f s p r i n g r e g r e s s i o n (h^
e r s o n (1959) a n d F a l c o n e r (I 960).
= 2b) a c c o r d i n g t o D i c k ­
The e s tim a te d h e rita b ility w as 0.27 fo r
the high line a n d 0 .3 6 f o r th e low lin e.
The pooled e s tim a te w as 0.28.
H e r i t a b i l i t i e s of t h i s m a g n i t u d e s u g g e s t t h a t g e n e t i c p r o g r e s s f r o m s e l -
- 6 1-
— High
__ L o w
C ontrol
G-O
G -1
G -2
G-3
G -4
G- 5
F i g u r e 3. R e s p o n s e of S e l e c t i o n f o r H i g h a n d L o w M a t i n g S c o r e s .
A. M e a n S c o r e s of a l l M a l e s t e s t e d w i t h i n t h e L i n e s a n d G e n e r a t i o n s .
B. M e a n S c o r e s of t h e S e l e c t e d M a l e s w i t h i n t h e L i n e s a n d G e n e r a t i o n s .
C. M e a n S c o r e s of a l l M a l e s t e s t e d w i t h i n t h e H i g h a n d L o w L i n e a d j u s t ­
ed fo r E n v i r o n m e n t a l F l u c t u a t i o n s w ith R e g r e s s i o n L i n e s fitted.
-— 6Z-—
ection should be p o ssib le.
W i t h the. e x c e p t i o n of t h e G - 2 , e a c h s u c c e e d i n g g e n e r a t i o n s h o w s a
low ered heritability estim ate.
H e r i t a b i l i t y e s t i m a t e s in t h e c o n t r o l g r o u p
could h av e g iv e n s o m e clue to w h e th e r th is w a s r e a l o r w a s c a u s e d by th e
environm ent.
However,
s i n c e o n l y 12 m a l e s w e r e t a k e n a t r a n d o m f r o m
the c o n tro l g roup, and te s t e d fo r m a tin g b e h a v io r p e r g e n e ra tio n (except
G -3 ), it w a s n o t p o s s i b l e to e s t i m a t e th e h e r i t a b i l i t y by th e m e t h o d above.
T able V gives the c o r r e la tio n s and r e g r e s s io n s b etw een the total
s c o r e s in t h e f i r s t a n d s e c o n d m a t i n g t e s t s i n g e n e r a t i o n s t w o , t h r e e a n d
five.
T a b l e YI g i v e s t h e c o r r e l a t i o n s b e t w e e n t h e i n d i v i d u a l c o m p o n e n t s
of m a t i n g s c o r e i n t e s t I a n d t e s t 2 of g e n e r a t i o n t w o a n d t h r e e .
Table
VII p r e s e n t s t h e m e a n o c c u r r e n c e s of t h e c o m p o n e n t s of m a t i n g s c o r e in
g e n e r a t i o n s two and t h r e e .
In g e n e r a l , th e c o m p o n e n ts w e r e highly c o r ­
r e l a t e d , b ut the. c o r r e l a t i o n s b e t w e e n c o u rtin g and the o t h e r m a tin g c o m ­
p o n e n t s d i f f e r In m a g n i t u d e b e t w e e n t h e l i n e s . ■
I
'
.
T h e r e p e a t a b i l i t y of m a t i n g s c o r e c o m p o n e n t s in t e s t o n e a n d t e s t
t w o c a n b e c o n s i d e r e d t h e u p p e r l i m i t of h e r i t a b i l i t y a s it i n c l u d e s g e n e t i c
a n d e n v i r o n m e n t a l i n f l u e n c e s w h i c h c o n t r i b u t e t o t h e s i m i l a r i t i e s of
s c o r e s on t h e s a m e i n d i v i d u a l a t d i f f e r e n t t i m e s .
In th e G - 2 an d G -3 ,
t h e s e r e p e a t a b i l i t i e s w e r e d e t e r m i n e d f o r a l l m a l e s t e s t e d in t h e s e l e c t e d
-
63
-
a n d c o n t r o l g r o u p s , a n d a r e p r e s e n t e d i n T a b l e VI.
T h e s t a t i s t i c s i n T a b l e VI a n d t h e m e a n s i n T a b l e VII of t h e m a t i n g
s c o r e c o m p o n e n ts i n d i c a t e th a t in the h ig h a n d low l i n e s in th e G - 2 and
G - 3, t h e o c c u r r e n c e of p i c k s a n d m o u n t s w a s g r e a t e r i n t e s t o n e t h a n in
t e s t t w o , w h e r e a s the, n u m b e r of c o p u l a t i o n s a n d c o u r t s i n c r e a s e d in t e s t
t w o o v e r t h a t of t e s t o n e .
T h is stro n g ly su g g e s ts th a t the m a l e s b e c a m e
m o r e e f f i c i e n t in t h e s e c o n d t e s t in a c h i e v i n g c o p u l a t i o n .
The controls
f o l l o w e d t h e s a m e p a t t e r n w i t h t h e e x c e p t i o n t h a t t h e n u m b e r of p i c k s
o b s e r v e d i n c r e a s e d f r o m t e s t one to t e s t two.
T h o u g h t h i s p a t t e r n is
q u i t e c o n s i s t e n t in t h e t w o m e n t i o n e d g e n e r a t i o n s , t h e p i c t u r e is s o m e ­
w h a t d i f f e r e n t i n t h e G - 5.
I n t h e G - 5 , t h e r e is a c o n s i s t e n t i n c r e a s e in
t h e f r e q u e n c y of a l l m a t i n g s c o r e c o m p o n e n t s o b s e r v e d , f r o m t e s t o n e to
t e s t two.
I n t h i s g e n e r a t i o n , t h e e f f i c i e n c y of t h e l o w a n d c o n t r o l g r o u p s
i n c r e a s e d , t h o u g h n o t t o t h e e x t e n t of t h e e a r l i e r g e n e r a t i o n s .
f i c i e n c y of t h e h i g h g r o u p d e c l i n e d s o m e w h a t .
The ef­
The re la tiv e efficiencies
a r e p r e s e n t e d in T a b l e VIII a n d w e r e c a l c u l a t e d b y d i v i d i n g t h e a c t u a l
o b s e r v e d f r e q u e n c y of Y ( m o u n t o r c o p u l a t e ) b y t h e o b s e r v e d f r e q u e n c y
of X ( p i c k o r ' m o u n t ) . • T h e c o r r e l a t i o n b e t w e e n t h e c o m p o n e n t s . of t h e
m a t i n g s c o r e of t e s t o n e a n d of t e s t t w o a r e p r e s e n t e d in T a b l e IX.
T h e d e c l i n e of a v e r a g e m a t i n g s c o r e s , a s m e n t i o n e d a b o v e , is to
- 64-
s o m e e x t e n t r e l a t e d t o t h e n u m b e r of m a l e s n o t m a t i n g d u r i n g t h e tw o
tests,
o r m a t i n g d u r i n g o n ly o n e , u s u a l l y t h e s e c o n d t e s t .
Table X
s h o w s t h e n u m b e r a n d p e r c e n t a g e s of a l l m a l e s t e s t e d w i t h i n t h e l i n e s
t h a t fa ll into t h e s e c a t e g o r i e s .
The a v e r a g e c o n v e rte d la te n c ie s w ithin
l i n e s a n d g e n e r a t i o n s a r e p r e s e n t e d i n T a b l e XI.
T h e a v e r a g e l a t e n c i e s to c o p u l a t i o n a s m e a s u r e d f r o m t h e G - I on
sh o w e d a c o n s is te n t len g th en in g eac h g e n e r a tio n in the low group.
In
the high g ro u p , th e l a te n c y d e c r e a s e d to th e G - 3 and th e n i n c r e a s e d
again.
T h i s i s d u e in p a r t t o t h e h i g h p e r c e n t a g e of m a l e s n o t c o n t r i b ­
uting to th e m e a s u r e m e n t .
F o u r t e e n s e l e c t e d high m a l e s and eleven
s e l e c t e d l o w m a l e s w e r e m a t e d i n t h e G-O t o s t a r t f a m i l i e s w i t h i n t h e
high and low g r o u p s , re s p e c t iv e l y .
O f f s p r i n g of o n ly t w o of t h e s e f a m ­
i l i e s w e r e a v a i l a b l e f o r m a t i n g s in t h e G - 5, i n e a c h t h e h i g h a n d l o w
lines.
A p r e d o m i n a n t n u m b e r of t h e s e l e c t e d m a l e s t r a c e d t o a s i n g l e
o r i g i n a l m a l e in e a c h lin e .
T h i s r e d u c t i o n in t h e n u m b e r of f a m i l i e s
w a s d u e t o t h e f a i l u r e of t h e m a t i n g s to p r o d u c e o f f s p r i n g .
The c o rre la tio n b etw een s c o re and latency for all m a le s te ste d was
0. 81, i n d i c a t i n g t h a t a c l o s e r e l a t i o n s h i p e x i s t e d b e t w e e n t h e t w o m e a s ­
u re m e n ts , as expected.
T h e t o t a l m a t i n g s c o r e s h o w e d no c o n s i s t e n t
r e l a t i o n s h i p w i t h t h e s i x w e e k b o d y w e i g h t of t h e m a l e s .
The co rrela.-
- 65 -
t i o n s r a n g e d f r o m - . 11 t o 0. 28,
10 t o 0 . 2 9 , a n d f r o m - . 6 1 t o 0 . 0 7
in t h e h i g h , lo w , a n d c o n t r o l l i n e s , r e s p e c t i v e l y .
T h e r e f o r e , the s ix
w e e k w e i g h t h a s l i t t l e i n f l u e n c e on t h e p o s s i b l e s u c c e s s in m a t i n g .
Some
of t h e v a r i a t i o n i n s c o r e m a y b e d u e t o e a r l i e r o r l a t e r s e x u a l m a t u r i t y
of s o m e m a l e s w i t h o u t r e g a r d t o b o d y w e i g h t .
S i m i l a r r a n g e s of c o r r e l a ­
t i o n s w e r e o b t a i n e d ( T a b l e XII) w h e n s i x w e e k b o d y w e i g h t w a s c o m p a r e d
w i t h t h e i n d i v i d u a l c o m p o n e n t s of m a t i n g s c o r e .
When s c o r e com ponents
w e r e r e l a t e d to t h e f i n a l w e i g h t of t h e m a l e s ( T a b l e XII), t h e r e w a s a
f a i r l y g o o d c o n s i s t e n c y in t h e s i g n of t h e c o r r e l a t i o n s , t h o u g h t h e m a g ­
n itu d es flu ctu ated w ith the individual com ponent, and am ong g e n e ra tio n s .
The o b s e r v e d co u rtin g b e h a v io r took p lace m o r e freq u en tly a fte r than
b e fo re copulation.
M o s t m a l e s c o n s i s t e n t l y c o u r t e d a f t e r c o p u l a t i o n in
both m a tin g tests.
I n t h o s e c a s e s w h e r e t h e m a l e c h a n g e d h i s t i m e of
c o u r ti n g , th e c h a n g e w a s f r o m c o u r t i n g b e f o r e c o p u la tio n in m a tin g t e s t
o n e t o c o u r t i n g a f t e r c o p u l a t i o n in t e s t tw o .
T h e p e r c e n t a g e of m a l e s
c o u r t i n g b e f o r e a n d a f t e r c o p u l a t i o n a r e p r e s e n t e d in T a b l e XIII f o r t h e
G - 4 a n d t h e G - 5.
P h e n o ty p ic c o r r e l a t i o n s b e tw e e n s c o r e and the u n s e le c te d c h a r a c t e r s
w hich w e r e c a lc u la te d fo r the s e le c te d m a l e s w ithin the lin e s and pooled
a r e p r e s e n t e d i n T a b l e XV.
- 66-
II.
R e s p o n s e in th e U n s e l e c t e d P h y s i o l o g i c a l T r a i t s
A.
R e s u l t s in t h e M a l e s
M e a s u r e m e n t s of m o s t c h a r a c t e r s i n v e s t i g a t e d in t h e m a l e s c Oim- .
m e n c e d i n t h e G-O a n d w e r e c a r r i e d o u t t h r o u g h t h e G - 4 ,
generations.
but
i. e. , f o r f i v e
M e a s u r e m e n t s in t h e G - 5 w e r e n o t c o m p l e t e d f o r a l l t r a i t s ,
any a v a ila b le i n f o r m a tio n f r o m th e G - 5 w a s inclu d ed .
The m e a s ­
u r e m e n t s p r e s e n t e d i n t h i s s e c t i o n a r e f r o m s e l e c t e d m a l e s ' o n ly .
I.
H atching P e r c e n ta g e
H a t c h i n g p e r c e n t a g e r e f e r r e d t o t h e p e r c e n t a g e of c h i c k s h a t c h e d f r o m
a g i v e n n u m b e r of e g g s p l a c e d in t h e i n c u b a t o r .
p r o d u c t i o n of t h e s u b s e q u e n t g e n e r a t i o n ,
I t a l w a y s r e f e r r e d to t h e
i. e. , h a t c h i n g p e r c e n t a g e of
G- O r e f e r s t o t h e p r o f i c i e n c y of t h e m a l e s i n t h a t g e n e r a t i o n t o p r o d u c e
t h e G - I.
D u r i n g t h e c o u r s e of t h e e x p e r i m e n t p r o c e d u r a l c h a n g e s w e r e
m a d e , a s d e s c r i b e d ab o v e. .
The G -I eggs w e re s to re d for a longer p e r ­
i o d of t i m e , a n d a f t e r t h e G - 2, t h e h a t c h i n g r e g i m e w a s a l t e r e d s o m e ­
w hat.
T h e a v e r a g e h a t c h i n g p e r c e n t a g e of a l l e g g s s e t is p r e s e n t e d in
T a b l e XVI.
A ll g ro u p s show a s i m i l a r t r e n d in th a t t h e r e w as a h ig h e r h a tc h a b ilit y r e c o r d e d i n t h e G - I , a n d a g e n e r a l d e c l i n e t o o k p l a c e t h e r e a f t e r . to.
the G -4 .
I n a l l g e n e r a t i o n s ( e x c e p t t h e G - 5), t h e c o n t r o l s h a t c h e d a t a
-67-
r a t e s o m e w h e r e b e t w e e n t h a t of t h e h i g h a n d l o w l i n e s .
T o a s c e r t a i n s o m e of t h e r e a s o n s f o r t h e l o w e r h a t c h a b i l i t y in t h e
l a t e r g e n e r a t i o n s , a l l u n h a t c h e d e g g s w e r e b r o k e n on d a y 18 in t h e G - 4 .
T h e r e s u l t s a r e p r e s e n t e d in T a b l e X V I I ,
T h e re w as a co n sid era b le dif­
f e r e n c e b e t w e e n l i n e s in t h e p e r c e n t f e r t i l e a n d t h o s e p i p p e d in t h i s g e n ­
eration.
T h e l a t e d e a d e m b r y o s a r e m o r e n u m e r o u s in t h e l o w a n d Con ­
t r o l l i n e s t h a n in t h e h i g h l i n e .
2.
P o st-H a tc h M ortality
P o s t - h a t c h m o r t a l i t y i n c l u d e d a l l c h i c k s t h a t d i e d b y t h e t i m e of
housing at fo u r w eek s.
In g e n e r a t i o n z e r o to g e n e r a t i o n t h r e e , th e n o r ­
m a l p a t t e r n of m o r t a l i t y w a s o b s e r v e d , i. e. , m o s t c h i c k s d i e d b e f o r e t h e
f i f t h d a y of a g e a n d f e w t h e r e a f t e r .
was considerably m o re variable.
H owever,
in t h e G - 4 t h e t i m e of d e a t h
T a b l e XVIII s h o w s t h e p e r c e n t a g e of
b i r d s l o s t d u r i n g t h e f i r s t f o u r w e e k s of l i f e .
3.
Sex R atio
W i t h i n t h e g e n e r a t i o n s , t h e r e w a s s o m e v a r i a t i o n a m o n g t h e l i n e s in
t h e n u m b e r of m a l e s a n d f e m a l e s h o u s e d .
T h i s is s h o w n in T a b l e XIX.
I n t r a - a n d i n t e r - g e n e r a t i o n d i f f e r e n c e s in s e x r a ti o p r o b a b l y c a n be
a t t r i b u t e d to c h a n c e s i n c e t h e o v e r a l l r a t i o s a r e v e r y c l o s e t o 1:1, a n d
t h e n u m b e r of m a t i n g s i n v o l v e d in e a c h g r o u p p e r g e n e r a t i o n w a s r e l a t ­
-68-
ively s m a ll.
4.
T h e r e w a s no c o n s i s t e n t p a t t e r n f o r th e d i f f e r e n t li n e s .
Six W e e k a n d F i n a l Body W eights
A s m e n t i o n e d in t h e p r o c e d u r e s e c t i o n , t h e c o l l e c t i o n of b o d y
w e i g h t s a t s i x w e e k s a n d a t t h e e n d of e a c h g e n e r a t i o n w a s s t a r t e d in t h e
G - I.
T h e w e i g h t s of G-O w e r e n o t c o m p a r a b l e , h e n c e t h e y w e r e n o t
p r e s e n t e d i n T a b l e XX.
5.
T e s te s W eight
T h e a b s o l u t e a n d r e l a t i v e t e s t e s w e i g h t s a r e s h o w n in T a b l e XXI.
B o t h m e a s u r e m e n t s of t h e t e s t e s w e i g h t s r e m a i n e d r e l a t i v e l y c o n s t a n t
thro u g h o u t the ex p e rim e n t.
6.
B asic M etabolic Rate
T h e b a s i c m e t a b o l i c r a t e w a s e s t i m a t e d in t h r e e w a y s :
a n i n d i v i d u a l r e q u i r e d t o u s e 80 m l . of o x y g e n ,
C o nsum ed p e r g r a m p e r hour ( m l/g m /h r ) , and
2,
3.
I.
The tim e
m i l l i l i t e r of o x y g e n
oxygen consum ed p e r
g r a m of b o d y w e i g h t to t h e t w o - t h i r d p o w e r p e r h o u r ( m l / g m
2/3
/hr).
T h e l a t t e r e s t i m a t e t a k e s i n t o c o n s i d e r a t i o n t h e s u r f a c e a r e a of t h e o r ­
ganism .
A v e r a g e v a lu e s and s ta n d a r d d e v iatio n s o btained w ith the t h r e e
e s t i m a t e s a r e p r e s e n t e d in T a b l e XXII.
-69-
7.
A nesthetic O ut-tim e
A n e s t h e t i c o u t - t i m e m e a s u r e d t h e t i m e f r o m i n j e c t i o n of t h e a n e s ­
th e tic ag en t until th e b i r d lo s t its b a la n c e .
T h e r e w e r e s o m e difficul-
ti e s in a c c u r a t e l y m e a s u r i n g th is t i m e , a s s o m e b i r d s w ould le a n
a g a i n s t t h e w a l l of t h e c a g e a n d n o t f a l l o v e r , a n d o t h e r s w o u l d s i t d o w n
b e fo re the a n e s th e tic b e c a m e effective.
The cage was shaken at in te r ­
v a l s to o b s e r v e w h e t h e r t h e p a r t i c u l a r b i r d c o u l d r e g a i n i t s b a l a n c e .
T h e a v e r a g e t i m e to e f f e c t a n e s t h e s i a is g i v e n in T a b l e XXIII.
8.
131
I o d i n e _____- U p t a k e
A c c o r d i n g t o S t e r l i n g a n d T a b a c h n i c k (1961), t h e u p t a k e of iodine-*"^
r e p r e s e n t s t h e i n v e r s e of t h e e n d o g e n o u s p r o t e i n - b o u n d i o d i n e l e v e l .
H o w e v e r , B l a c k m o r e (1967) f o u n d t h a t i n r a t s s e l e c t e d f o r d i f f e r e n t
t h y r o i d a c t i v i t i e s , th e two m e a s u r e m e n t s v a r i e d to g e t h e r .
The counts
p e r m i n u t e w i t h i n l i n e s a n d g e n e r a t i o n s a r e p r e s e n t e d in T a b l e XXIV.
9.
H em atocrit
D u p lic a te b lo o d s a m p l e s w e r e t a k e n in m i c r o h e m a t o c r i t tu b e s and
r e a d a f t e r s p i n n i n g t h e m f o r 7 1/2 m i n u t e s .
T h i s i n f o r m a t i o n is c o m ­
p i l e d in T a b l e XXV .
10.
H e a r t Rate
The r e a s o n fo r m e a s u r i n g h e a r t r a t e w a s the e x p e c ta tio n th a t th e r e
-70-
c o u l d b e a d i v e r s i o n of t h e h i g h a n d t h e l o w l i n e s in t h e s p e e d of b o d i l y
processes.
M a l e s i n t h e h i g h l i n e w o u l d b e e x p e c t e d to h a v e a g r e a t e r
e n e r g y t u r n o v e r w h i c h m i g h t b e e x p r e s s e d in s o m e of t h e o t h e r p h y s i o l o ­
g i c a l m e a s u r e m e n t s , a s w e ll a s in th e h e a r t r a t e .
H e a rt rate responds
v e r y p r e c i s e l y to c h a n g e s in t h e m e t a b o l i c r a t e ( G r e e n , 1966).
The ob­
s e r v e d a v e r a g e h e a r t r a t e s a r e p r e s e n t e d i n T a b l e XXVI.
11.
Blood G lu co se
B l o o d g l u c o s e l e v e l s w e r e e s t i m a t e d b y t h e c l a s s i c a l m e t h o d of F o l i n -
Wu (1920), w h i c h m e a s u r e s t o t a l r e d u c i n g s u b s t a n c e s in t h e b l o o d .
Since
n o t e n o u g h b l o o d c o u l d b e d r a w n f r o m t h e C o t u r n i x m a l e s t o do b o t h t h e
I
131
- u p t a k e a n d t h e b l o o d g l u c o s e t e s t s , t h e m a l e s of t h e G - 4 w e r e r a n -
d o m ly d iv id e d into two g r o u p s .
O n e g r o u p w a s u s e d f o r I 131 t e s t s a n d
the o th e r g ro u p fo r blood g lu co se d e te rm in a tio n .
S i x m a l e s of. t h e h i g h
l i n e a n d f o u r e a c h of t h e l o w a n d c o n t r o l l i n e s w e r e u s e d f o r t h e g l u c o s e
d e t e r m i n a t i o n (S ee T a b l e XXV II).
B.
S tatistical R esults
H e r i t a b i l i t i e s of t h e c h a r a c t e r s m e a s u r e d w e r e e s t i m a t e d b y s i r e o f f s p r i n g r e g r e s s i o n a n d a r e p r e s e n t e d in T a b l e XXVIII a s t h r e e d i f f e r e n t
estim ates:
I.
w ith in the high line,
2.
w ith in th e low lin e,
3.
pooled.
S o m e of t h e e s t i m a t e d v a l u e s a r e n e g a t i v e , w h i c h is l o g i c a l l y n o t
-71-
possible,
S o m e of t h e f a c t o r s w h i c h m a y h a v e c o n t r i b u t e d to t h i s m a y b e
t e c h n iq u e , a c t u a l v a r i a t i o n in th e b i r d s s a m p l e d , the r e l a t i v e l y s m a l l
n u m b e r s of b i r d s m e a s u r e d p e r g e n e r a t i o n , a n d e n v i r o n m e n t a l e f f e c t s .
A ll p o s s i b le phenotypic c o r r e l a t i o n s w e r e c a lc u la te d b e tw e e n the
c h a r a c te r s m e a s u r e d for all selec ted m a le s com bined o v er all g e n e r a ­
tions.
M a n y of t h e s e c o r r e l a t i o n s w e r e n o t s i g n i f i c a n t l y d i f f e r e n t f r o m
zero.
T h e v a l u e s t h a t a r e s i g n i f i c a n t . ( P ^ . 05), a r e p r e s e n t e d in T a b l e
X XI X .
T h e n u m b e r of o b s e r v a t i o n s e n t e r i n g in t o t h e c a l c u l a t i o n s a r e
in c lu d e d in th e t a b le ,
s i n c e t h e r e w a s s o m e v a r i a t i o n in t h e a m o u n t of
data available.
C.
R e s u l t s in t h e F e m a l e s
W i t h t h e e x c e p t i o n of G - I a n d G - 4 , a l l f e m a l e s w e r e d r a w n f r o m t h e
c o n tro l population.
No c o n s c i o u s s e l e c t i o n w a s p r a c t i c e d on th e f e m a l e s
w ith the ex ce p tio n th a t f e m a le s w hich w e r e obviously sick, crip p le d , or
v e ry sm a ll w e re not housed.
H o w e v e r , it w a s n e c e s s a r y t h a t any f e m a l e
to b e m a t e d m u s t h a v e la id a t l e a s t one egg.
Thus all late m a tu rin g fe ­
m a l e s w e r e not giv en an o p p o rtu n ity to p ro d u c e o ffspring.
m e a s u r e d in t h e f e m a l e s w e r e :
The tra its
p e r c e n t p r o d u c t i o n on a h e n - h o u s e d b a s i s ,
e g g w e i g h t , d a y s to s e x u a l m a t u r i t y ,
s ix w e e k and final body w eights.
T h e m e a n s a n d s t a n d a r d d e v i a t i o n s f o r a l l f e m a l e s t e s t e d in t h e f i v e g e n ­
-72-
e r a t io n s a r e li s t e d below:
Egg production, p e rc e n t
62. 71 + 2 2 . 4 7
Egg weight, g m
10. 40 +
I. 28
Sexual m a tu r ity , days
45.76 +
8.85
Six w e e k w eight, g m
1 3 1 . 0 5 + 13. 04
F in a l weight, g m
1 3 5 . 9 0 + 13. 02
T h e c o r r e l a t i o n s b e t w e e n t h e s e t r a i t s a r e p l a c e d in T a b l e XXX.
I n t h e G - 4 , 12 f e m a l e s e a c h w e r e k e p t f r o m t h e h i g h a n d t h e l o w l i n e .
T h e f e m a l e s p r o d u c e d by the low line la id a t a h ig h e r r a t e th ro u g h o u t the
t e s t in g p e r i o d th a n th e f e m a l e s p r o d u c e d by the high lin e.
Their average
f i n a l n u m b e r of e g g s w a s 4 1 . 7 0 (57. 12%), c o m p a r e d t o 34. 55 (47. 33%)
e g g s f o r t h e h i g h l i n e f e m a l e s in 73 ^ a y s .
and one high lin e -fe m a le s died.
D u rin g th is p e r i o d , two low
T h e a v e r a g e n u m b e r of d a y s t o s e x u a l
m a t u r i t y w a s 57. 25 f o r t h e h i g h a n d 57. 82 f o r t h e l o w f e m a l e s .
G - 5, t h e s a m e n u m b e r of f e m a l e s w a s r e t a i n e d f r o m e a c h g r o u p .
In the
In th e
h ig h lin e , one f e m a l e d ie d b e f o r e r e a c h i n g s e x u a l m a t u r i t y a n d one did
n o t r e a c h m a t u r i t y a t t h e a g e of 73 d a y s .
A v e ra g e days to s e x u a l m a t u r ­
i t y of t h e r e m a i n i n g 10 f e m a l e s w a s 4 4 . I d a y s .
of l o w f e m a l e s ,
In c o n tra st', in th e g r o u p
six died b e fo re re a c h in g se x u a l m a tu r ity , the a v e r a g e age
of t h e r e m a i n i n g s i x w a s 53 d a y s a t s e x u a l m a t u r i t y , a n d of t h e s e s i x ,
-73-
t w o m o r e h a d d i e d b y 73 d a y s of a g e .
Ill.
R e sp o n ses in U n se le c te d B eh av io ral T r a its
A.
D isplacem ent A ctivities
A s m e n t i o n e d b e f o r e , d i s p l a c e m e n t a c t i v i t i e s c o n s i s t e d m a i n l y of
preening.
S i n c e i t o c c u r r e d v e r y f r e q u e n t l y in s o m e m a l e s a n d n o t in
o t h e r s , th e se data w e re not analysed.
E a c h o c c u r r e n c e of p r e e n i n g w a s
m u l t i p l i e d b y 1 /2 a n d s u b t r a c t e d f r o m t h e t o t a l s c o r e of t h e o t h e r c o m ­
ponents.
T h e l o w l i n e m a l e s w e r e s e l e c t e d on t h e i r l o w o v e r a l l s c o r e s ,
a n d if a m a l e d i d a c o n s i d e r a b l e a m o u n t of p r e e n i n g , h e h a d a b e t t e r
c h a n c e to b e s e l e c t e d in t h e l o w l i n e t h a n a m a l e w h o r e m a i n e d i n a c t i v e
th ro u g h o u t the te s t.
I n t h e h i g h l i n e , t h e r e w a s l e s s l i k e l i h o o d of a m a l e
t h a t did m u c h p r e e n i n g to b e s e l e c t e d .
It w o u ld t h e r e f o r e b e p o s s i b l e t h a t
t h e f r e q u e n c y of p r e e n i n g w o u l d i n c r e a s e w h i l e t h e m a t i n g a c t i v i t y re.-,
m a in e d static.
T h e m a t i n g s c o r e s of m a l e s in t h e l o w l i n e a r e c o n s i d e r e d
w i t h r e s p e c t t o d i s p l a c e m e n t a c t i v i t y i n T a b l e XIV.
It b e c a m e a p p a re n t
t h a t in t h e l a s t g e n e r a t i o n s ( G -4 ) a n d G - 5) t h e r e o c c u r r e d a c o n s i d e r a b l e
i n c r e a s e in d i s p l a c e m e n t a c t i v i t i e s .
T h e f r e q u e n c i e s of d i s p l a c e m e n t
a c t i v i t i e s o b s e r v e d in th e hig h a n d c o n t r o l g r o u p s s h o w e d no p a r t i c u l a r
trend.
B.
O ther B eh av io rs
-74-
In t h e c o u r s e of t h e s t u d y ,
it w a s o b s e r v e d t h a t t h e m e m b e r s ( m a l e
o r f e m a l e ) of t h e l o w g r o u p b e c a m e m o r e d i f f i c u l t to h a n d l e .
e d to b e m o r e e x c i t e d , f l u t t e r e d m o r e ,
held by hand.
They s e e m ­
and escaped m o r e frequently when
W h e n t h e l o w m a l e s w e r e i n t r o d u c e d in t o t h e m a t i n g c a g e ,
t h e y h a d a t e n d e n c y t o j u m p a n d b o l t , a n d s h o w e d m o r e i n j u r i e s e v e n in
their home cages.
A f t e r t h e s e l e c t e d m a l e s w e r e m a t e d in t h e G - 5
m o r e t h a n h a l f of t h e m p i c k e d t h e f e m a l e s s o s e v e r e l y t h a t t h e y s t o p p e d
l a y i n g ( S e e F i g u r e 4), a n d t w o of t h e m d i e d .
This s e v e r e picking o c c u r ­
r e d in s p i t e of t h e d e b e a k i n g p r a c t i c e d a t t h e t i m e of m a t i n g .
F i g u r e 4.
M istreated F em ales
A gonistic
-75-
i n t e r a c t i o n b e t w e e n m a t e s of C o t u r n i x is. w e l l k n o w n t o w o r k e r s in t h e
f i e l d ( W o o d a r d ^ t a l , 1966), a n d o c c a s i o n a l l y it o c c u r r e d in a l l g r o u p s .
T h e r e is a c o n s i d e r a b l e d i f f e r e n c e in f r e q u e n c y of s u c h i n t e r a c t i o n b e ­
tw een the g r o u p s .
I t o c c u r r e d in f i v e of t h e n i n e l o w l i n e m a t i n g s , in
f o u r of t h e 48 c o n t r o l m a t i n g s , a n d n o n e : i n t h e h i g h l i n e m a t i n g s .
-76-
T a b l e - I I I . M e a n s a n d S t a n d a r d D e v i a t i o n s o f M a t i n g S c o r e , D i f f e r e n c e in
S c o r e s b e tw e e n H igh and L ow L ine, and S e le c tio n D iffe re n tia l.
G eneration
M ean and S.D .
H igh
D ifferen ce Selection *
H igh-L ow D ifferential
Low
C ontrol
Low
High
18.
80
13.99
1.8, 16 d 14 : 7-2 . . ;
. V
G-O
'
G -I
23. 67+18. 54 14. 99+12. 41 13. 46+15. 27
8. 68
16. 17
13. 76
G- 2
20. 59+15. 40 18. 64+10. 19 11. 46+13. 35
I. 95
17. 44
5. 14
G- 3
33. 54+17. 29 20. 33+14. 87
G -4
24 . 04+19. 52 15..40 4il l. .04 20.. 00+ 9.11
G-5
10. 78+- 4 ,1 2
17. 12 .14. 33
13. 21
2. 83+ 7. 96 14. 42 + 26 . 05
81.6 4 .
13. 87
7. 95
15. 57
' 8. 50
* m e a n s c o r e of s e l e c t e d m a l e s m i n u s m e a n s c o r e of a l l m a l e s
tested.
T a b l e IV, I n t r a - g e n e r a t i o n a n d C u m u l a t i v e H e r i t a b i l i t y E s t i m a t e s f o r
M a t i n g S c o r e i n t h e H i g h a n d "Low 'L i n e .
G eneration
G -I
W ithin G e n e ra tio n
C um ulative
H i g h _______L o w _______________H i g h
Low
1.29
.93
G- 2
.13
.12
G -3
.55
.70
G -4
.27
.33
. 28
.35
G-5
.20
.26
.20
. 26
0
-77-
Table V. Correlations and Regressions of Total Score in Mating Test
one and Mating Test two in Generations two, three and five.
G eneration
C ontrol
Low
High
G -2
r
. 55
b
. 65
r
. 08
b
. 07
r
. 64
b
G -3
. 64
.66
. 61
. 55
—
—
G-5
. 50
. 58
. 53
I. 05
.16
3.68
.
62
T a b l e VI. C o r r e l a t i o n s a n d R e g r e s s i o n s o f M a t i n g S c o r e C o m p o n e n t s
in M atin g T e s t one and M a tin g T e s t tw o in G e n e r a t i o n s tw o and t h r e e .
High
G -2
Low
b
. 29
. 39
. 65
r
. 35
. 35
'. 53
.
83
.49
b
Mount
r
. 39
. 28
, 39
.
63
. 64
. 45
. 31
. 47
. 93
. 47
. 53
b
Copulate
.46
r
. 01
. 50
I. 46
. 66
. 01
. 39
. 93
.
. 32
. 44
. 70
. 80
. 79
. 42
. 43
. 60
.
83
. 50
C ontrol
G -3
H igh .
Low
. 55
. 54
P ick
b
C ourt
r
62
-78-
Table VII. Mean Number of Occurrence of Pick, Mount, and Copu­
lation in Mating Test one and Mating Test two in Generations two and
three.
Low
High
Test I
2
C ontrol
I
2
I
2
2. 08
2. 08
1.98
3.33
I . 67
2.38
P ick
G- 2 Mount
Cop.
4. 41
3. 95
I.. 54
3. 46
2. .19
2. 8.1
4. 62
2. 1.9
I . 62
4 , :1.9
2. 57
I.. 95
P ick
G- 3 Mount
Cop.
8.56
7. 47
3.62
6.79
5. 62
5. 32
4. 90
3.28
I . 77
4. 23
3, 13
2.38
T a b l e VIII. R a t i o s b e t w e e n t h e M e a n N u m b e r of P i c k , M o u n t , a n d
C o p u l a t i o n i n M a t i n g T e s t o n e a n d M a t i n g T e s t tw o in G e n e r a t i o n s
two, t h r e e , and five.
Low
H igh
Ix : y
I
2
I
2
P ic k on m ount
G - 2 P i c k on c o p .
M o u n t on co p .
. 90
. 35
. 39
. 63
. 81
I. 28
. 85
. 35
. 41
, 61
. 47
. 76
P ic k on m ount
G - 3 P i c k o n co p .
M o u n t on c o p .
. 87
. 42
.48
. 83
. 78
. 95
. 67
. 36
. 54
. 74
. 56
. 76
P i c k on m o u n t
G - 5 P i c k o n co p .
M o u n t on c o p .
. 87
. 61
.69
. 78
. 52
. 67
. 43
. 43
I. 00
. 69
. 54
. 78
C ontrol
I
2
I. 00
. 85
. 85
, 50
,71
1,43
. 32
. 20
. 63
. 71
. 60
. 84
t 7 9 “■
T a b l e IX. C o r r e l a t i o n s b e t w e e n C o m p o n e n t s of M a t i n g S c o r e in M a t i n g
T e s t o n e a n d M a t i n g T e s t t w o in G e n e r a t i o n s tw o , t h r e e , a n d f iv e .
high
G-5
G -2
G- 3
m ount, copulate c o u rt m o u n t copulate c o u rt mount, copulate c o u rt
pick
mount
cop.
. 81
. 67
. 90
. 57
.. 57
,.55
. 96
36
.77
. 90
. 98
. 79
.
. 92
86
. 78
. 47
. 84
.
. 87
36
. 42
low
pick
mount
c o p . ..
.
86
.45
. 54
.
■
. 04
,24
. 29
.61
. 18
. 21
.89
. 73
. 64
. 86
.49
. 42
, 20
. 45
-. 01
. 54
. 21
. 12
. 28
control
. 98
pick
mount
cop..'.
. 92
. 58
. 6i
. 74
. 95
T a b l e X. N u m b e r a n d P e r c e n t a g e s of M a l e s t h a t d i d n o t m a t e , a n d
t h o s e M a le ' s w h i c h m a t e d i n o n l y o n e of t h e t w o M a t i n g T e s t s f o r
G e n e r a t i o n s one to five.
Generation
________ H i g h _____ ___________
L o w ____________
C ontrol
0
I
0
1
. 0
I
.
.Nd:
No.,. %
No. . %
N p. % ' '
No.
%.
• % • , No, .
G -I
7
' 2 2 ' .' 4
G -2
5
14 :. 11
G -3
3
•9'
G -4
2
" -9 -
G-5
20
' 13
13
'3 6 C
4
: Tl
'
2 .
-■ T7 • L . , 0
...
0
. I
' .
8
30'.
3
14
. 6
• 29' . •. 4 . 333
2
■ -6. .
8
21
'• 9
: 23 ..
6
■ 2-6 .
LS-4- L' 3
8
5 . 1 8 . :■ 7
4
•44
- 4
■'25
%
' NOT .TESTED
' 2 .
; 4 4 : . . I- . •
1-7'
'. 8
.3
'. .25
• .8
' ' - 7.5
-80-
T a b l e XI. A v e r a g e c o n v e r t e d L a t e n c i e s t o C o p u l a t i o n of t h e T e s t e d
M a l e s in G e n e r a t i o n s one to five.
H igh
Low
C ontrol
G -I
13.99
10. 69
12.96
G- 2
13. 54
13. 26
9.1 5
G- 3
16. 84
.12.98
G -4
13. 76
12. 39
. 12. 37
G -5
7. 68
4. 42
10. 01
T a b l e XII. C o r r e l a t i o n s b e t w e e n C o m p o n e n t s of M a t i n g S c o r e a n d T o t a l S c o r e
w i t h S i x W e e k a n d F i n a l B o d y W e i g h t s in t h e S e l e c t e d a n d C o n t r o l G r o u p s in
G e n e r a t i o n s two, t h r e e , and four.
G--3
G- 2
G-4
low
control
high
low
high
low
control
6 wk final
6 wk final
6 wk final
6 wk final
6 wk final
6 wk final
6 wk final
6 wk final
.05
.14
-.3 1
-.2 4
- . 2 4 - .61
. 16 . 01
. 22
08
. 17 . 14
- . . 3 1 -..27
.01
-.0 8
.08
-.1 8
-.2 7
- .2 5 -.61
. 15 . 01
. 25
-.01
. 22 . 07
-.0 5 -.2 4
-.4 6
copulate - . 2 4
.02
.26
.06
-.3 4 -.6 4
. 17 . 00
. 29
. 07
. 30 . 19
.0 1 -.2 8
-.63
.1.2
.12
-.1 6
-.4 3
.0 3 -,2 7
. 16 . 10
. 19
. 17
. 08 . 24
. 0 8 - , IP - . 4 4
. 14
. 29
high
pick
mount
.
-
81
-
court
total
N
- . 11
37
-.0 9
37
21
21
12
12
34
34
39
.
39
28
25
-.0 1
25
29
-.61
29
12
"A
-82-
T a b l e XIII. P e r c e n t a g e of M a l e s C o u r t i n g b e f o r e o r a f t e r C o p u l a t i o n
w i t h i n L i n e s i n t h e G - 4 a n d G - 5.
High
Low
C ontrol
Not
Not
Not
B e fo re A fter co u rtin g B efo re A fte r courting:.B efore A fte r co u rtin g
4
60
36
3
62
40
8
67
25
G - 5 - I* 16
24
59
11
11
78
33
25
42
G- 5- 2
38
49
44
22
.33
• 17
67
17
G -4
14
* s e v e r a l m a l e s c h a n g e d in t h e t i m e of c o u r t i n g , b u t in a l l s u c h c a s e s ,
" b e f o r e " in t e s t o n e b e c a m e " a f t e r " in t e s t tw o .
T a b l e XIV. S c o r e s of a l l L o w L i n e M a l e s a n d of t h o s e P r o d u c i n g O f f ­
s p rin g w ith R e s p e c t to D is p la c e m e n t A c tiv itie s w ithin G e n e r a tio n s .
Generation
G- 5
S c o re w ithout
displacem ent
prod.
all
offspring
S c o re w ith
displacem ent
prod.
all
offspring
F r e q u e n c y of
displacem ent
prod.
all
offspring
20. 0
14. 7
18.6
13.8
2. 6
1.8
21. I
5. 3
20.3
4. 3
I. 5
I. 2
16.9
9- 0
15.4
5. 5
3. 0
7. 0
5. 9
5. 0
2. 8
I. 7
6. I
6. 7
-83-
T a b l e X Y .. P h e n o t y p i c C o r r e l a t i o n s b e t w e e n M a t i n g S c o r e a n d t h e
U n s e le c te d C h a r a c t e r s w ithin the H igh and Low L ine and P ooled; o v er
all . . G e n e ra tio n s, fo r the M ales p ro d u cin g O ffspring.
S co re vs.
x
x.
x
x
x
x.'
x
x.
x.
x
x
x.
x
x
x
High
H atchability
M ortality
M ale O ffspring
F em ale offspring
6 w eek w eight
F in a l w eight
T e s te s w eight
% of bod y
BMR
A n e s t h e t i c O u t ^t i m e
I-*- ^ I u p t a k e
H em atocrit
Latency
H eartrate
cc oxygen c o n ­
sum ed/hr.
*
.
Low
- . 3 3 ( 62 ) * *
, 1 2 ( 62 )
- . 23 (62)
. 2 3 ( 62 )
. 02 ( 62 )
01 (62)
. 30 (62)
2 9 ( 62 )
. 13 ( 62)
- . 19 .('6 %)
.
. 05 (48)
17 (48)
.
2 4 (4 8 )
- . 01 ( 62 )
- . 1 4 (48)
Pooled
-.15 ( 63 )
. 18
.13
. 13
-.1: 3
- . 24
.17
. 10
.25
-.42
(63)
(63)
( 63 )
(63)
(63)
( 63 )
( 63 )
( 63 ) *
( 631* * .
- . 57 (52.)**
-.10 ( 52 )
. 6 8 ( 52 )
- . 04 (63)
-.11
( 52 )
- . 26 ( 125) * *
.1 4 (125)
08 (125)
. 08 (125)
- . 03 (125)
- . 09 (125)
. 23 (125)**
• 21 (.125). *
.16 (125)
- . 25'(125)**
- . 20 (100)*
-.. 20 (100)*
. 39 (100)**
- . 02 (125)
13 .(100)
>!<>!< = P C . 01
= P < . 05
T a b l e XVI. A v e r a g e H a t c h i n g P e r c e n t a g e s of E g g s S e t w i t h i n
L in es and G en eratio n s.
G eneration
High
. Low
G-O
G -I
G -2
G- 3
G -4
G-5
59. 3
69. 6
55.9
32.8
39. 2
44. 9
42. 6
4.1. I
34. 5
45 . I
20. 3
24. 5
C ontrol
50. 0
63. I
45.9
32.9
25. 3
40. I
-84-
T a b l e XVI I.
D i s p o s i t i o n of a l l E g g s S e t i n t h e G - 4 (in p e r c e n t ) .
H igh
infertile
E a rly dead
Late dead
P ipped
H atched
H a t c h e d of f e r t i l e
T a b l e XVII I.
cent) ,
20.
11.
12.
14.
41 .
51.
86
66
27
11
10
94
Low
C ontrol
43. 79
11. 11
46 .
6.
19.
2.
25.
47 .
22 . 88
I. 96
20. 26
35. 63
21
96
00
53
32
10
P o s t - H a t c h M o r t a l i t y w i t h i n L i n e s a n d G e n e r a t i o n s (in p e r ­
G eneration
H igh
Low
G-O
G -I
G -2
G-3
G -4
6. 6
10. 4
9.8
6. 9
4. 0
16. 4
3. 6
9. 7
9,8
24.0
6.4
7. 5
18.8
7. 0
3.0
C ontrol
T a b l e XI X. S e x R a t i o s a n d N u m b e r s of M a l e s a n d F e m a l e s w i t h i n L i n e s
and G en eratio n s.
34:33
26:20
37:25
Ix
.
92 :
1:1.55
I : .95
I: . 9 7
1:1.67
N o.
C ontrol
54:49
I : ..91
L I . 03
109:113
O O
40:37
1:1. 12
22:34
I: I . 12
38:36
I: . 97
35:34
I: . 77
9:15
L .68
1:1
( 2 31 :2 30 )
Low
'
75:86
5 9: 6 6
N o.
I—
High
O
G-O
G -I
G -2
G-3
G -4
Total
No.
I— 1
G eneration':
( 1 4 4 :1 5 6 )
25:26
7:11
13:22
1:1.04
I : I . 57
I : . 59
1:1.06
( 20 8:2 21 )
-85-
Table XX. Average Male Six Week and Final Body Weights within
lines and Generations (in grams).
Generation
6 wk.
High
G -I
G -2
G- 3
G -4
G- 5
108. 0
102. I
104. 7
103.2
105. 8
L ow
F inal
124. 0
106.8
HO. 0
113.8
& wk..
F inal
100.0 ■
105.2
105.0
120. 0
108. 3
107. 0
111.3
99.0
106.9
C ontrol
16'w k .
. "Final
113.
104.
105.
100.
108.
3
3
5
3
7
.120.0
106. 5
114. 3
HO. 0
T a b l e XXI . A v e r a g e T e s t e s W e i g h t ( in g r a m s ) a n d a s P e r c e n t of B o d y
W eight w ithin L in es and G e n e ra tio n s .
G e n e - ________ H i g h _______________________ I ow______________ C o n t r o l
W eight
ration
W eight
W eight
%
%
G-O
G -I
G -2
G- 3
G -4
2.35
'
2.52
1 . 9&
1.88
2. 36
2. 52'" '
2. 16
2. 4 4 :
2 . 44
2 . 36 . . ,
2.44
2. 07
2. 46
2.21
2 . 32 <
1.98
2 . 65 :
L 81
2. 25
2.8 H
2.30
-
2. 20:.
2. 40 •
2 . 35 :
2. 4 6 ,.,
%
2. 17
2. 19
2. 30
'
2.075
2.46
T a b l e XXI I.
E s t i m a t e s of B a s i c M e t a b o l i c R a t e
G -I
G -2
G -3
G-r4
U
si
CO.'')
I
I
G e n e r a t i o n __________ _________________________________________ L o w __________________ C o n t r o l
M in­
M in­
.M in­
i
/
2
/
?
,
u tes m l / g m / h r m l / g m - , --/hr utes m l / g m / h r .
utes m l / g m / h r
16.43
m l / gm
2 /5 /hr
/i.i.'
13,31
+ 1. 91
1 5 . 6 9 ■ . 2i 66
+ 1,38
+7. 88
13. 10
±2/16
2.59
±15.81 . . + 1 . 2 9
12. 65
±2.. 19
2, 61
98
12. 34
+3. 03
_ 2 . 32
19. 34
+9. 51 . • ± • 9 5
11.03
±1.30
17. 56
±12.92
12. 95
± 2 . 79
. 2:90
14. 92
+
L l i 36
+5.52
14. 22
+2. 10
. 2. 67
17. 14
+7.46 - ± 1 .2 0
12. 65
+ 1.65
15.26
±3.91
. 3 . 12
±1:81
15.06
+2. 38
15. 05
+9. 17
2, 98
14. 31
± 2 . 40
15.77
+6.56
14. 34
± S . 99 -
.
I B . 12
+ 1 3 . 2 1 ::
.
13.83
t 6 . 35
2,69
.
..±1,74
. . 2.76
■ ±1 - 79
/.
.2.78
± . 61
13.48
± 1 . 35
. 2. 87
. . +.78
13.75
±1.. 22
.
-8 7 -
T a b l e X X III. A v e r a g e A n e s t h e t i c O u t - t i m e ( i n m i n u t e s ) w i t h i n L i n e s
and G e n e r a tio n s.
G eneration
High
G-O
G -I
G -2
G- 3
G -4
8. 00
5.43
4.9
4.89
5. 05
L ow
C ontrol
9.68
8.33
6. 73
4. 6
4.44
4. 23
5.33
5. I
4 . 07
4.42
T a b l e X XI V . A v e r a g e C o u n t s ( p e r m i n u t e ) of I ^ l U p t a k e w i t h i n L i n e s
and . G enerations.
G eneration
G-O
G -I
G -2
G- 3
G -4
H igh
N
L ow
3567.0 .
2855.5
1080.I
I
10
11
10
5
' 3912.5.
3124.4
1080.I
2098.0
■ 2518.5
2098.0
25.18. 5'
N '
• GontLol
,:2 9 6 1 .I
2.
10"
. 2810.0
LI
. 1108.0
10 ' •. 2029.4
5
. 2503...6
N
5
10
9
6
5
T a b l e X X V . A v e r a g e H e m a t o c r i t V a l u e s (in p e r c e n t ) w i t h i n L i n e s a n d
G enerations.
G eneration
G -I
G -2
G -3
G -4
H igh
57. 5
54. I
■
53.8
50.0
* no v a lu e s - a c c id e n t w ith c e n tr if u g e .
Low
C ontrol
58. 0
*
55. 6
54. 5
54. 2
52. 7
56.0
53.7
- 88-
T a b le X X V I. A v e r a g e H e a r t R a te s
G e n e r a tio n s.
G eneration
G- O
G -I
G -2
G- 3
G -4
T a b l e XXVII.
G -4.
( b e a t s / m i n u t e ) w i t h i n L i n e s and
High
Low
C ontrol
591.3
544 . 5
589.6
570 . 9
483. 2
586. 4
587.3
56 4. 0
575.5
59 6. 7
596.5
612.6
513.3
569.0
584 . 7
A v e r a g e B l o o d G l u c o s e (in m g ..% ■) . w i t h i n L i n e s
H i g h __________ L ow
C ontrol
197. I
227. 0
240. 5
in
-89-
T a b l e XXVIII. S i r e - O f f s p r i n g R e g r e s s i o n s an d H e r i t a b i l i t i e s fo r
v a r io u s T r a i t s w ith in th e H igh and L ow L in e and P o o le d fo r all
G enerations.
C haracter
Low
H igh
b
.
34
,28
68
-.1 1
. 56+
.
.
28
.
23
07
00
. 30
. 13
. 00
. 09
.
- .
-.0 9
-.0 4
. 50
. 01
. 02
.41
. 13
-.5 1
. 12
26
- .
.
02
. 56
.
02
.
04
.82
. 26
. 24
.45
+ not significantly d ifferen t f r o m zero .
h2
52
. 14+
.
. 6I
. 26
. 00
. 18+
-.28
-.29
-.0 3
. 05
.
18
. 21
. 18
-.29
b
. 04
. 27
- . 04
. 21
. 18
- .
02
. 06
.11
- . 14
08
54+
24
. 14
.
.
-.
42
36
12+
22 +
02
- .
10
. 36
.41
. 35
h2
On
O
22
- . 22
. Ol
.
b
I
H atchability
M ortality
M ale off-spring
F e m a le off-spring
6 w k. wt.
F in a l wt.
T e s t e s wt.
% of b o d y w t .
BMR tim e
O utbtim e
!■*-3 u p t a k e
H em atocrit
Score
L atency
H e a rt rate
c c /hr.
h2
Pooled
,48
, 28
20
. 13
-.0 5
, 26
T a b l e X XI X .
M ales.
Significant P h en o ty p ic C o r r e la tio n s betw een v ario u s T r a its , pooled for all selected
6 wk,, F i n a l T e s t e s % of
wt.
w eight body
w t.
N
H a tc h a b ility
P ost-H atch
M ortality
6 w k . w t.
194
. 23
>i-*
194
184
184
BM R Outtim e tim e
I 131
Score
Laten- H eart
rate
cy
180
150
169
127
180
hr.
14
38
138
CC /
. 50
>!' *
- . 17*
.
28*
-
-.28
>r *
-.17* -.4 6
>!-'!<
. 17* - . 2 1
>!' *
.43
.45
'I' >!<
. 17* . . 18*
. 26
'!'=!<
. 50
-.25
>!' -!<
. 16*
. 53*
.
36 *
.
34*
.
36*
- .
38 *
- .
22*
. 86
-I' >!<
. 16
(170)*
% of b o d y
A nesthetic
O ut-tim e
. 24
*
I
>!' *
CO
CN
NI
BMR tim e
-.23
**
-.4 7
**
. 36
'(*
**
. 19*
-
l_u ptake
. 27
.81
-c*
Score
**
= P < . 01
. 37
**
-90-
. 27
'r >1'
.20
=1->!'
. 59
>|c*
T e s t e s w t.
P < \ 05
F ertility
. 14
F i n a l w t.
*
177
Glucose
-91-
T a b l e X X X . C o r r e l a t i o n s a m o n g M e a s u r e d T r a i t s in t h e F e m a l e s ,
P o o le d for a ll G e n e r a tio n s.
% production
Egg w eight
6 wk. w eight
F in a l w eight
*>:< = P
„ 01
*
Egg
w t.
6 wk.
w t.
Final
wt.
Sexual
M aturity
. 30**
. 28**
. 19**
. 25**
. 15*
. 98**
18**
. 44 **
-.32**
-.1 0
= P ^
05
c
- 92-
D IS CU S S IO N
I.
G E N E T IC CONSIDERATIONS
S i n c e c o n s i d e r a b l e v a r i a b i l i t y s e e m e d t o b e p r e s e n t in t h e p a r e n t
g e n e r a t i o n , a n d v a r i a b i l i t y i s n e c e s s a r y f o r c h a n g e to o c c u r in a p o p u ­
lation,
it w a s p r o j e c t e d a t t h e b e g i n n i n g of t h e e x p e r i m e n t , f r o m t h e
r e s u l t s in t h e l i t e r a t u r e , t h a t a s e p a r a t i o n of t h e h i g h a n d l o w l i n e s in
m a t i n g b e h a v i o r c o u l d b e a c h i e v e d b y s e l e c t i o n in l e s s t h a n t h e f i v e
g e n e ra tio n s studied.
S e p a r a t i o n of t h e t w o s e l e c t e d l i n e s w a s a c h i e v e d b y t h e G - I a n d no
f u r t h e r p r o g r e s s w a s m a d e in s u b s e q u e n t g e n e r a t i o n s .
This conclusion
is s u p p o r t e d b y t h e r e s u l t s of a n a n a l y s i s of v a r i a n c e w h i c h s h o w e d t h a t
t h e m e a n m a t i n g s c o r e s in t h e G - I w e r e s i g n i f i c a n t l y d i f f e r e n t f r o m e a c h
o t h e r ( P < . 05).
T h i s l e v e l of s i g n i f i c a n c e r e m a i n e d in a l l s u b s e q u e n t
g e n e r a t i o n s w i t h t h e e x c e p t i o n of G - 2 .
In this g e n e ra tio n , the m e a n
s c o r e s of t h e h i g h l i n e w e r e h i g h e r t h a n t h o s e of t h e l o w l i n e , b u t t h i s
d iffe re n c e w as not s ta tis tic a lly significant.
S im ilar observations w ere
m a d e b y M a n n i n g (1961) a n d P a r s o n s (1964) w i t h s e l e c t i o n f o r m a t i n g
s p e e d in D r o s o p h i l a .
T h e d i f f e r e n c e b e t w e e n t h e m e a n s c o r e s w a s of a b o u t t h e s a m e m a g ­
n i t u d e in t h e G - I, G - 4 , a n d G - 5.
T h e r e w a s o n ly a s m a l l d i f f e r e n c e in
-93-
t h e G - 2. b u t a m u c h l a r g e r d i f f e r e n c e in t h e G - 3 ( s e e T a b l e HI).
The
g r e a t f l u c t u a t i o n in t h e s e c o n d a n d t h i y d g e n e r a t i o n s w a s p r o b a b l y due. t o
nongenetic effects.
Such effects ( te m p e r a tu re , hum idity, b a r o m e tr ic
p r e s s u r e , feed, housing,
e tc .) m a y a ls o have c o n trib u te d to the d e c r e a s ­
ing m a t i n g s c o r e s in t h e G - 4 a n d G - 5.
T h e l a r g e p e r c e n t a g e of m a l e s in
t h e s e tw o g e n e r a t i o n s n o t c o p u l a t i n g o r c o p u l a t i n g , in o n l y o n e of t h e tw o
m a t i n g t e s t s ( T a b l e X) c o n t r i b u t e d to t h e d o w n w a r d t r e n d of t h e m e a n
s c o r e s a s w e l l a s t h e s h i f t in s e l e c t i o n p r e s s u r e .
T h e l a c k of f u r t h e r p r o g r e s s is a t t r i b u t e d to a l o s s of e f f e c t i v e s e l ­
e c tio n p r e s s u r e in tb e l a t e r g e n e r a t i o n s .
This m ay have been caused
by su ch f a c t o r s as:
a.
A s e l e c t i o n i n d e x in w h i c h t h e c o m p o n e n t s w e r e n o t p r o p e r l y w e i g h t e d
B o t h M a n n i n g (1963) a n d S i e g e l (1965.) s e l e c t e d on t h e b a s i s of a s i n g l e
criterion.
T h e f o r m e r h a d n o s u c c e s s , b u t t h e l a t t e r a u t h o r d id .
Sie­
g e l s e l e c t e d in b o t h s e x e s , w h e r e a s o n ly m a l e s w e r e s e l e c t e d b y M a n n i n g ,
as done h e r e .
In t h i s e x p e r i m e n t t h e v a l u e g i v e n to c o p u l a t i o n w a s t w o
p o i n t s a n d u n d e r i d e a l c o n d i t i o n s a c c o u n t e d f o r o n e h a l f of t h e s c o r e .
F r e q u e n t l y , m a l e s t h a t c o p u l a t e d s e v e r a l t i m e s , b u t d i d n o t e n g a g e in a
g r e a t a m o u n t of p r e l i m i n a r y b e h a v i o r s , h a d a l o w e r s c o r e t h a n m a l e s
w h i c h did a g r e a t a m o u n t of p i c k i n g , m o u n t i n g o r c o u r t i n g , b u t c o p u l a t e d
- 94-
o n ly i n f r e q u e n t l y o r n o t a t a l l .
T h e d e c l i n i n g e f f i c i e n c y of t h e h i g h l i n e
m a l e s in a c h i e v i n g , c o p u l a t i o n w a s o b s e r v e d t h r o u g h t h e g e n e r a t i o n s .
In
t h e G - 2 c o p u l a t i o n a c c o u n t e d f o r 4 4 . 02% of t h e t o t a l s c o r e a n d in t h e G - 5
c o p u l a t i o n s a c c o u n t e d o n ly f o r 38. 60% of t h e t o t a l s c o r e in t h e h i g h g r o u p .
T h e s e l e c t i o n p r e s s u r e s h i f t e d , in t h e h i g h l i n e f r o m c o p u l a t i o n s to. l o w e r
m ating b eh av io rs.
I n t h i s s t u d y , t h e s e q u e n c e of m a t i n g b e h a v i o r s f r o m
th e l o w e s t to th e h i g h e s t w a s c o u r t i n g , p i c k i n g , m o u n t i n g , a n d c o p u latio n .
I n t h e l o w l i n e , a s h i f t in s e l e c t i o n p r e s s u r e a l s o o c c u r r e d , b u t o n e in a
different direction.
S i n c e t h e f r e q u e n c y of d i s p l a c e m e n t p r e e n i n g s ,
w h ich w e r e m u l tip l ie d by one half point an d s u b t r a c t e d f r o m th e total
s c o r e , lo w e re d the to ta l s c o r e , t h e r e w as an in a d v e rte n t shift f r o m c o p ­
u l a t i o n to i n c r e a s e d f r e q u e n c y of d i s p l a c e m e n t a c t i v i t i e s .
With an in­
c r e a s e in d i s p l a c e m e n t a c t i v i t y , Eind c o n s e q u e n t l y l o w e r m e a n s c o r e s ,
it
w ould be e x p e c te d th a t copulation w ould ac c o u n t fo r an i n c r e a s e d p e r c e n ­
t a g e of t h e l o w e r m e a n s c o r e s .
T h e p e r c e n t a g e of t h e s c o r e in t h e G - 2
acc o u n ted fo r by copulation w as 35.76%.
I t r o s e to 4 2 . 11% in t h e G - 4
a n d t o 7 8 . 4 3 % in t h e G - 5 f o r t h e l o w g r o u p .
H o w e v e r , i n t h e G - 5 o n ly
nine m a l e s w e r e involved, th e re b y in c r e a s in g the c h a n c e f lu c t u a ti o n s .
T h e o c c u r r e n c e of t h i s s h i f t in s e l e c t i o n p r e s s u r e is s u p p o r t e d b y d a t a
f o u n d in T a b l e s V, VI, IX, XIII, a n d b y t h e d e c r e a s i n g h e r i t a b i l i t i e s in
-95-
T a b l e IV.
S h i f t s in s e l e c t i o n p r e s s u r e t h r o u g h s e l e c t i o n h a v e b e e n g i v e n
a s a r e a s o n f o r a s y m m e t r i c a l r e s p o n s e b y B o h r e n _et a l (1966) a n d E r l e n m e y e r - K i m l i n g e t a l (1962).
T he situ a tio n could have b e e n ch an g ed by e ith e r w eighting copulations
c o n s i d e r a b l y h i g h e r o r b y d i s r e g a r d i n g a l l o t h e r o b s e r v e d b e h a v i o r s in
t h e s e l e c t i o n c r i t e r i o n , a s d o n e b y S i e g e l (1965).
C a f b a u g h e t al. (1.962).
a n d W o o d - G u s h a n d O s b o r n e (1956) a s s i g n e d v a l u e s s i m i l a r t o t h o s e u s e d
in t h i s s t u d y to t h e o b s e r v e d a c t i v i t y of t h e m a l e s .
The la tte r authors
c o n s i d e r e d o n l y m o u n t i n g , i n a d d i t i o n t o t r e a d i n g , in d o m e s t i c f o w l a n d
w e r e a b l e to m a k e c o n s i d e r a b l e s e l e c t i o n p r o g r e s s .
C a r b a u g h _et a l
(1962) s c o r e d t h e a c t i v i t y of W h i t e L e g h o r n s in r e s p o n s e t o s t u f f e d f e ­
m a l e s , b u t d i d n o t a t t e m p t t o s e l e c t o n t h e b a s i s of t h i s t o t a l s c o r e ,
b.
S m a l l n u m b e r of s e g r e g a t i n g a l l e l e s .
M a n n i n g (1961) a c h i e v e d c o m ­
p l e t e s e p a r a t i o n of h i s f a s t a n d s l o w m a t i n g l i n e s in t h e s e c o n d g e n e r a t i o n
a n d m a d e no f u r t h e r p r o g r e s s ,
u te d th is to polygenic c o n tro l.
Since the F j w as i n t e r m e d i a t e , he a t t r i b ­
A s i m i l a r p l a t e a u ing a f t e r t h e f i r s t g e n ­
e r a t i o n w a s o b s e r v e d in th is study.
T h e p r e s e n t w r i t e r i s of. t h e o p i n i o n
t h a t t h e r e s u l t s of t h i s i n v e s t i g a t i o n a n d t h e r e s u l t s of M a n n i n g m a y b e
b e t t e r e x p l a i n e d o n t h e b a s i s of v e r y f e w s e g r e g a t i n g a l l e l e s a c t i n g a d d i t i v e l y , t h a n on t h e b a s i s of p o l y g e n e s .
I t is p r o b a b l e t h a t o n ly o n e g e n e
-96-
w ith tw o .a lle le s acting c o m p le te ly ad d itiv e ly w as involved.
I t is u n l i k e l y
t h a t t h e v a r i a t i o n of p o l y g e n e s c o u l d b e e x h a u s t e d in o n e o r t w o . g e n e r a ­
tions .
c.
Sm all population size.
In s m a l l p o p u l a t i o n s , t h e a c t u a l v a r i a t i o n
o b s e r v a b l e i s s m a l l e r t h a n in l a r g e p o p u l a t i o n s .
T h e s m a l l n u m b e r of
i n d i v i d u a l s a v a i l a b l e r e s t r i c t s t h e n u m b e r of m a l e s w h i c h m a y b e d i s ­
carded.
C r o w a n d M e J tt o n (1955) h a v e e m p h a s i z e d t h a t p o p u l a t i o n s s m a l l ­
e r t h a n a f e w h u n d r e d m e m b e r s a r e v e r y s u s c e p t i b l e t o t h e e f f e c t s of
genetic drift.
d.
S e l e c t i o n in o n e s e x o n ly .
S e l e c t i o n in o n ly t h e m a l e s w o u l d d i l u t e
t h e s e l e c t i o n d i f f e r e n t i a l a s w a s e x p e r i e n c e d b y M a n n i n g (1963).
The f e ­
m a l e s a r e c o n s i d e r e d to b e of e q u a l g e n e t i c e n d o w m e n t a n d c o n t r i b u t e
th e re fo re z ero selection differential.
C o n seq u en tly , the se le c tio n dif­
f e r e n t i a l of t h e m a l e s i s h a l v e d a s o n e m a l e a n d o n e f e m a l e a s a p a i r p r o ­
duced th e ir offspring.
e.
D e c r e a s e in t h e n u m b e r of f a m i l i e s .
I n i t i a l l y 14 h i g h m a l e s a n d Tl
l o w m a l e s w e r e m a t e d - t o a t o t a l of 39 f e m a l e s t o e s t a b l i s h f a m i l i e s .
The
f a i l u r e to p r o d u c e o ffs p rin g and o t h e r g e n e t ic a n d / o r n o n - g e n e t i c f a c t o r s
r e d u c e d t h e n u m b e r of e f f e c t i v e f a m i l i e s t o t w o Tn e a c h of t h e h i g h a n d l o w
lin e s in th e fifth g e n e r a t i o n .
T h e p r e d o m i n a n t n u m b e r of t h o s e m a l e s b e ­
l o n g e d to a s i n g l e f a m i l y i n e a c h l i n e .
T h i s r e d u c t i o n in t h e n u m b e r of
-97-
f a m i l i e s v e r y p r o b a b l y r e n d e r e d the- p o p u l a t i o n m o r e s u s c e p t i b l e to g e n ­
etic d rift, and it r e d u c e d v a ria b ility .
The selection differential rem a in ed
a p p r o x i m a t e l y t h e s a m e i n a l l s u c c e e d i n g g e n e r a t i o n s ( T a b l e III).
How­
e v e r , t h e r e l a t i v e c o n t r i b u t i o n of t h e c o m p o n e n t s m a k i n g , u p t h e d i f f e r e n ­
tial shifted as explained a^ove.
T h e o v e r a l l r e g r e s s i o n of s c o r e ( a d j u s t e d f o r e n v i r o n m e n t a l f l u c t u a ­
t i o n s ) on g e n e r a t i o n s is n e g a t i v e .
low g r o u p s follow,
T he r e g r e s s i o n lin e s fo r th e high and
r e s p e c t i v e l y , t h e e q u a t i o n s Y = 14. 78 - 3 . 2 8 X a n d
Y = 9 . 5 0 - 3 . 80 X, w h e r e Y is t h e d e p e n d e n t v a r i a b l e ( s c o r e ) a n d X i s t h e
independent v a r ia b le (generation).
fo r the c o n t ro l g ro u p .
I n t h e G - 3 , no, s c o r e s w e r e o b t a i n e d
It is p o s s i b l e t h a t th e tw o .lin e s w o u ld h av e show n
a g r e a t e r d iv e rg e n c e w ith such in fo rm a tio n a v ailab le.
The h e rita b ility e s tim a te s for s c o re d e te rm in e d by sire -o ffsp rin g
r e g r e s s i o n a n d b y t h e m e t h o d of S i e g e l (1965) a n d F a l c o n e r (1954), a g r e e
w e l l w i t h e a c h o t h e r a n d w i t h t h o s e p u b l i s h e d b y S i e g e l (1965) f o r d o m e s ­
t i c f o w l.
I n a d d i t i o n t o ' t h e s h i f t in e m p h a s i s o n t h e c o m p o n e n t s of m a t i n g s c o r e
in s e l e c t i o n , an a p p a r e n t g e n e tic c h a n g e b e c a m e e v id e n t in o th e r b e h a v ­
io r a l t r a i t s w hich w e r e not m e a s u r e d .
" B e h a v i o r a l C o n s i d e r a t i o n s " p. 118.
T hese a re discu ssed under
- 98-
T h e g e n e t ic c o n t r i b u t i o n s to th e n o n - s e l e c t e d , p h y s io lo g i c a l c h a r a c t ­
e r s , a s e s t i m a t e d by s i r e - o f f s p r i n g r e g r e s s i o n a r e c o n s i d e r e d individ­
ually.
E v i d e n c e e x i s t s t h a t t h e e s t i m a t e of g e n e t i c c o r r e l a t i o n s b e t w e e n
the s e le c te d c h a r a c te r (score) and all oth er m e a s u r e d c h a r a c te r s w e re
effectively zero .
T h i s is b a s e d on t h e c o r r e l a t i o n b e t w e e n s c o r e in t h e
s i r e s an d th e o t h e r t r a i t s in th e o f f s p r in g .
This m e a n s th at selec tio n fo r
i n c r e a s e d a n d d e c r e a s e d m a t i n g b e h a v i o r s h o u l d n o t e f f e c t a c h a n g e in t h e
non-selected c h a ra c te rs .
D e m p s t e r e t a l (1952) r e p o r t e d a h e r i t a b i l i t y f o r h a t c h a b i l i t y of 16%
b y o f f s p r i n g - d a m r e g r e s s i o n , w h e r e a s P e n q u i t e e t a l (1930) o b t a i n e d z e r o
h e rit a b il ity in W h i te ' L e g h o r n s .
f o r h a t c h a b i l i t y i s lo w .
L e r n e r (1961) s u g g e s t e d t h a t h e r i t a b i l i t y
In th is in v e stig a tio n , the d a m 's c o n trib u tio n w a s
n o t c o n s i d e r e d a n d h e r i t a b i l i t y of h a t c h a b i l i t y w a s b a s e d e x c l u s i v e l y on
v a r i a t i o n a m o n g ■m a l e s .
T h e c a l c u l a t e d h e r i t a b i l i t y w a s 7, 3%.
T h e h e r ita b ility e s ti m a t e fo r p o s t- h a t c h m o r t a li ty w as 54.3%.
c o m p a ra b le valu es w e r e obtained f r o m the lite r a tu r e .
No
The early m o rta l­
i t y f o l l o w e d t h e p a t t e r n r e p o r t e d f o r J a p a n e s e q u a i l b y S i t t m a n et a l (1966).
T h e r a t i o s of m a l e s t o f e m a l e s p r o d u c e d b y t h e l i n e s i n e a c h g e n e r a - .
tion show ed c o n s id e r a b le fluctuation, b u t the o v e ra ll r a ti o s w ithin the
■l i n e s w e r e v e r y c l o s e to 1:1.
The n egative r e g r e s s io n s obtained for p e r ­
- 99-
c e n t a g e s of b o t h m a l e a n d f e m a l e o f f s p r i n g a r e p r o b a b l y d u e t o t h o s e
fluctuations.
T h e g e n e t i c v a r i a n c e of m a l e a n d f e m a l e o f f s p r i n g w a s
e x a c t l y t h e same-; a s e x p e c t e d ; u n l e s s a c o n d i t i o n - l i k e m e i o t i c d r i v e c
exists.
•■
T h e d e t e r m i n a t i o n of s e x d e p e n d s p r i m a r i l y on t h e p r e s e n c e o r
a b s e n c e of t h e s e x c h r o m o s o m e .
The pooled h e rita b ility e s tim a te s fo r body w eight at six w eeks and
f i n a l w e i g h t w e r e 42 a n d 36% r e s p e c t i v e l y .
These estim ates are sim ilar
to t h o s e o b t a i n e d b y M a r k s a n d K i n n e y (1964) f o r s i x w e e k s b o d y w e i g h t .
S i t t m a n e t ad (1966), h o w e v e r , c a l c u l a t e d a c o n s i d e r a b l y h i g h e r h e r i t a b i l ­
i t y f o r 20 w e e k w e i g h t of C o t u r n i x m a l e s .
T h e o n l y h e r i t a b i l i t y e s t i m a t e of t e s t e s w e i g h t f o u n d - i n t h e l i t e r a t u r e
w a s 64% in c h i c k e n s ( S i e g e l a n d S i e g e l , . 1964).
The sire -o ffs p rin g r e g r e s ­
sio n e s t i m a t e in th is study show ed c o n s id e r a b le v a r ia tio n f r o m g e n e r a tio n
to .g e n e ra tio n , w ith an o v e ra ll slightly negative e stim a te .
The phenotypic
c o r r e l a t i o n b e tw e e n body w eight and t e s t e s w eight w as highly significant.
T h i s m a y b e a s s u m e d t o b e d u e t o .e n v i r o n m e n t a l r a t h e r t h a n g en et ic factors.
The heritability e stim ate for b asic m etabolic rate as determ in ed h e re
s h o w e d a v a l u e of 22%.
■l i t e r a t u r e .
N o e s t i m a t e s f o r t h i s t r a i t w e r e f o u n d in t h e
T h e e s t i m a t e of B M R u s e d f o r th e c a l c u l a t i o n of h e r i t a b i l i t y
-
100-
did not ta k e into c o n s id e r a tio n d if f e r e n c e s in body s iz e .
I t is t h e r e f o r e
q u i t e p o s s i b l e t h a t a c o n s i d e r a b l e p o r t i o n of t h e h e r i t a b i l i t y e s t i m a t e f o r
B M R is d u e t o d i f f e r e n c e s in b o d y s i z e .
A n e s t h e t i c o u t - t i m e s e e m e d to b e in flu e n c e d p r e d o m i n a n t l y by e n v i r ­
o n m en tal conditions.
The h e ritab ility e s tim a te w as effectively z e ro for
this tra it.
T h e e s t i m a t e of h e - r i t a b i l i t y of
^-.uptake w as also z e r o .
Stahl
_et _al (1962) r e p o r t e d a h e r i t a b i l i t y of g r e a t e r t h a n o n e f r o m i n t r a - s i r e
r e g r e s s i o n f o r t h y r o i d s e c r e t i o n in N e w H a m p s h i r e f o w l .
G r a y and
B a c h a r a c h (1961) s u g g e s t e d t h a t t h r e e f o u r t h s of t h e v a r i a t i o n i n P B I in
m o n o z y g o tic tw in s is due to h e r e d i t y , an d one f o u r th due to e x p e r i m e n t ­
al e r r o r .
It s e e m s t h a t t h e g e n e t i c c o n t r i b u t i o n to P B I i s o f t e n o v e r ­
s h a d o w e d b y t h e m e t h o d s of i t s d e t e r m i n a t i o n .
B l a c k m o r e (1967) f o u n d
t h a t p r o g r e s s w a s e r r a t i c in.. Khts t h a t w e r e m a s s s e l e c t e d f o r h i g h a n d
low PBI; h o w ev er,
s e l e c t i o n on a f a m i l y b a s i s y i e l d e d r e s u l t s w h i c h
w o u ld s u p p o r t e i t h e r r e l a t i v e l y low h e r i t a b i l i t y , o r g r e a t e x p e r i m e n t a l
e r r o r in t h e d e t e r m i n a t i o n of a v a l i d e s t i m a t e of P B I .
T h e h e r i t a b i l i t y of h e m a t o c r i t v a l u e s w a s e s t i m a t e d h e r e a s 48%,
w h i c h i s s i m i l a r t o t h e 39% r e p o r t e d b y W a s h b u r n (1967), e s t i m a t e d f r o m
the sip e c o m p o n e n t in th e A t h e n s - C a n a d i a n r a n d o m - b r e d population.
-101-
P a r t of t h e d i f f e r e n c e b e t w e e n t h e e s t i m a t e s m a y b e d u e t o t h e m e t h o d
of e s t i m a t i o n .
L a t e n c y is g r e a t l y in f l u e n c e d by e n v i r o n m e n t a l c i r c u m s t a n c e s as
in d ic a te d by the low h e r it a b il ity and the high phenotypic c o r r e l a t i o n
w ith s c o re .
T h e r e v i e w e d l i t e r a t u r e y i e l d e d no. e s t i m a t e of h e r i t a b i l i t y f o r
h e a rt rate.
A n e s t i m a t e of 25% w a s o b t a i n e d in t h e p r e s e n t i n v e s t i g a ­
tion.
The genetic c o n sid era tio n s s u m m a riz e d :
I n t h e c o u r s e of t h e s e l e c t i o n e x p e r i m e n t f o r i n c r e a s e d a n d d e ­
c r e a s e d m a t i n g a c t i v i t y , t h e - l i n e s w e r e s e p a r a t e d i n t h e G - I a n d no
fu rth e r p r o g r e s s w as achieved.
L a c k of f u r t h e r p r o g r e s s i s a t t r i b u t e d
to. l o s s of e f f e c t i v e s e-l ec ti on p r e s s u r e .
T h e d e c r e a s i n g s c o r e s in t h e
h ig h a n d low l i n e s w e r e due to d i f f e r e n t f a c t o r s :
In the h igh line t h e r e
w a s a s h i f t f r o m c o m p l e t e d m a t i n g s ( c o p u l a t i o n ) t o b e h a v i o r s of l e s s e r
i m p o r t a n c e (picking, m o u n tin g , and co u rtin g ).
In the lo w .lin e , a shift
of s e l e c t i o n p r e s s u r e f r o m c o p u l a t i o n t o d i s p l a c e m e n t a c t i v i t i e s o c c u r ­
red.
E n v i r o n m e n t a l e f f e c t s a n d p a r t i c u l a r l y t o t h e l a r g e n u m b e r of
m a l e s in b o t h l i n e s t h a t d i d n o t m a t e o r m a t e d in o n ly o n e of t h e tw o
■m a t i n g t e s t s c o n t r i b u t e d t o t h e d o w n w a r d t r e n d of t h e s c o r e s .
-102W h ere c o m p a r is o n s w e r e p o ssib le , the h e r liability e s tim a te s for
th e n o n - s e l e c t e d t r a i t s w e r e s i m i l a r to t h o s e r e p o r t e d in th e l i t e r a t u r e .
Ip. t h e c o u r s e of t h e f i v e g e n e r a t i o n s s t u d i e d , s e l e c t i o n f o r m a t i n g
s c o r e did not a p p e a r to h a v e a l t e r e d th e p h y s i o l o g i c a l p a r a m e t e r s
m easured.
- 103-
II.
P H E N O T Y P IC CONSIDERATIONS
A.
P h y s i o l o g y of t h e M a l e
M e a s u r e m e n t s of t h e o r g a n i s m a s it e x i s t s r e p r e s e n t t h e p h e n o t y p e .
T h i s s e c t i o n i s d e v o t e d t o a n a t t e m p t t o e l u c i d a t e s o m e of t h e c o m b i n a ­
t i o n s of g e n e t i c a n d e n v i r o n m e n t a l e f f e c t s w h i c h b r o u g h t a b o u t t h e a c t u a l
observations m ade.
M a t i n g b e h a v i o r i s a n e x p r e s s i o n of h e a l t h y ,
sexually m a tu r e o r g a n ­
i s m s , b u t c a n b e e x p r e s s e d in m a n y d i f f e r e n t w a y s .
in m o s t anim als,
It is e a s y to o b s e r v e
and p a r t i c u l a r l y in c a p t iv e b i r d s , a s it o c c u r s f r e ­
q u en tly , and t a k e s s o m e t i m e in its e x e c u tio n .
T o t a l m a t i n g s c o r e a n d l a t e n c y to c o p u l a t i o n a r e h i g h l y s i g n i f i c a n t l y
c o r r e l a t e d ( r = 0. 81).
T h is should.be e x p e c te d f r o m the te stin g p r o c e d u r e
a n d t h e m e t h o d of. m e a s u r i n g l a t e n c y .
It m a y be r e c a l l e d f r o m the p r o ­
c e d u r e s e c t i o n t h a t t h e l a t e n c y w a s c o n v e r t e d to a v a l u e w h i c h w a s g r e a t ­
e r th e s h o r t e r th e a c t u a l t i m e i n t e r v a l to co p u la tio n .
T o a t t a i n a h i g h s c o r e , a m a l e m u s t s t a r t m a t i n g a t t e m p t s e a r l y in
the te st.
T h e g r e a t e s t a c t i v i t y of m a l e s i s g e n e r a l l y o b s e r v e d d u r i n g t h e
f i r s t f i v e t o s i x m i n u t e s of t h e t e s t .
t i m e a f t e r 10 m i n u t e s .
F e w m a l e s c o p u la te d fo r the f i r s t
A f te r a m a l e h as co p u la te d s e v e r a l t i m e s , he
w i l l a b s t a i n f or , s o m e n o n - s p e c i f i c p e r i o d .
T h is m a y b e due to fatigue,
d i m i n i s h e d n o v e l t y of t h e f e m a l e ( S c h e i n a n d H a l e , 1965), o r h a b i t u a t i o n
-.104-
( H a l e a n d A l m q a i s t , I96 0; M a r l e r a n d H a m i l t o n , 1966).
T h i s p e r i o d of
s e x u a l q u i e s e n c e s e e m e d to o c c u r w ith a l l m a l e s , b u t th o s e th a t m a t e d
e a r l y h a d a g r e a t e r o p p o r tu n ity to m a t e a g a i n a f t e r th e r e s t th a n th o s e
m a le s w hich m a te d fo r the f i r s t tim e a fte r a .lo n g e r laten cy p erio d .
I.
R elationships betw een som e M e a su re m e n ts
The c o rre la tio n s betw een m a tin g sc o re and c e rta in unselected c h a r ­
a c t e r s of t h o s e m a l e s w h i c h p r o d u c e d o f f s p r i n g a r e f o u n d in T a b l e XV
and a r e d i s c u s s e d below:
a.
A h i g h l y s i g n i f i c a n t n e g a t i v e c o r r e l a t i o n (r = - . 2 6 ) of s c o r e w i t h
hatching p e rc e n ta g e w as calcu la ted for th o se m a le s producing o ffsp rin g .
One w o u ld e x p e c t the h i g h e r s c o r i n g m a l e s to m a t e m o r e f r e q u e n t ly a f t e r
they had b een p a ire d .
T h e r e f o r e , the eggs la id by t h e i r m a t e s should
h a v e a h i g h e r f e r t i l i t y t h a n t h o s e of t h e m a t e s of l o w s c o r i n g m a l e s .
T h is is s u p p o r te d by a s m a ll, n o n - s ig n if ic a n t p o sitiv e c o r r e l a t i o n
( r = 0. 12) b e t w e e n s c o r e a n d f e r t i l i t y a n d t h e a c t u a l p e r c e n t a g e of f e r t i l i t y
as estab lish ech in the G -4 .
a n d C r a i g . (1959).
S i m i l a r findings w e r e r e p o r t e d by M cD an iel
H o w ev er, negative c o r r e la tio n s b etw ee n fe rtility and
s c o r e h a v e b e e n f o u n d b y P a r k e t e t a l (1942), R a s m u s s e n (1952), a n d F o ­
m i n e t a l (1963).
C r a f t arid T h o m p s o n (1930) f o u n d po r e l a t i o n s h i p b e ­
t w e e n t h e n u m b e r of m a t i n g s of t h e m a l e s a n d t h e f e r t i l i t y of t h e e g g s
- 105-
Iaid by the f e m a l e s .
The negative c o rre la tio n betw een s c o re and hatchability suggests that
o th e r fa c to r s b e s id e s fe rtility affected the hatching p e rc e n ta g e .
Data
c o l l e c t e d in th i s stu d y an d th e l i t e r a t u r e c i ta ti o n s i m p l i c a t e th e following
fa c to r s and conditions.
M a le -fe m a le agonistic interactio n s w e re reduced as fa r as possible
b y d e b ea ik in g b o t h m e m b e r s of a p a i r a t t h e t i m e of p a i r i n g a s d e s c r i b e d
b y M a h n a n d B l a c k w e l l (1967).
W o o d a r d a n d A b p l a n a l p . (1967) s u g g e s t e d
t h a t t h i s i n t e r a c t i o n i s o n e of t h e r e a s o n s f o r l o w e r f e r t i l i t y a n d s u b s e ­
q u e n t l y l o w e r h a t c h i n g , p e r c e n t a g e in y o u n g quail..
C r o o k e d n e c k d w a r f s h a v e b e e n d e s c r i b e d b y S i t t m a n (1967) a n d S i t t m a n a n d C r a i g (1967) in q u a i l w h i c h d i d n o t h a t c h .
In th e G - 4 , two f a m ­
i l i e s of t h e l o w l i n e a n d o n e f a m i l y pf t h e c o n t r o l s p r o d u c e d c r o o k e d
necked birds.
T he co ndition w as not ev id en t at hatching, but w as obvious
a t t h e t i m e of h o u s i n g .
No c ro o k e d n e c k e d b ir d s w e r e p ro d u c e d when
crooked necks m a les w e re m a te d to,their s is te rs .
su b leth al condition.
This m a y have been a
A dded evidence can be draw n f r o m the m o rta lity r e ­
c o r d s of t h e m a l e s h a t c h e d f r o m t h e c r o o k e d n e c k m a t i n g s ,
These m a les
d i e d a t a c o n s i d e r a b l y h i g h e r r a t e t h a n m a l e s in t h e g e n e r a l p o p u l a t i o n s .
L a t e d e a d e m b r y o s w a s t h e s e c o n d l a r g e s t f a c t o r a f t e r f e r t i l i t y to
-106-
r e d a c e h a t c h a b i li f t r i n t h e G - 4 .
T h is m a y in d ic a te n u tr itio n a l e ffe c ts
as has b een su g g e ste d by s e v e r a l a u th o r s.
S e a s o n i s k n o w n t o i n f l u e n c e t h e p e r c e n t h a t c h in q u a i l ( W o o d a r d e t
a l , 1965).
T h e f a i r l y c o n s i s t e n t d e c l in e in a ll lin e s t h r o u g h o u t all g e n ­
e r a t i o n s w o u l d p r e c l u d e a n y g r e a t i m p o r t a n c e of t h e s e a s o n s in t h i s
p a r t i c u l a r study.
b.
A h i g h l y s i g n i f i c a n t p o s i t i v e c o r r e l a t i o n of s c o r e w i t h t e s t e s w e i g h t
(r = 0. 23) a n d r e l a t i v e t e s t t e s w e i g h t ( r = 0 . 21) w a s t e s t i m a t e d f o r t h o s e
m a le s w hich s ir e d offspring.
The c o r r e l a ti o n betw een s c o r e and te s te s
w e ig h t i n d i c a t e d t h a t h i g h e r m a t i n g a c t iv it y w a s o b s e r v e d in m a l e s w h ic h
had l a r g e r te s te s .
T h i s o b s e r v a t i o n a g r e e s w i t h t h e f i n d i n g s of J a k w a y
(1959) w h o r e p o r t e d t h a t t h e t e s t e s of h i g h s c o r i n g g u i n e a p i g m a l e s w e r e
h e a v i e r t h a n t h o s e of l o w s c o r i n g m a l e s .
T e s t e s w eight w as a ls o highly
significantly c o r r e l a t e d w ith six w eek and final body w eight when all s e l ­
e c t e d m a l e s w e r e c o n s i d e r e d ( S ee T a b l e X X I X ) .
T h e s e two c o r r e l a t i o n s
l e a d t o t h e c o n c l u s i o n t h a t s m a l l e r m a l e s h a d a p o o r e r c h a n c e of s u c ­
cessfu lly m a tin g than la r g e r m a le s .
F r o m t h e s e c o n s i d e r a t i o n s , one w o u ld e x p e c t th a t th e r e l a t i v e t e s t e s
w e ig h ts w ould follow the s a m e p a t te r n .
H o w e v e r , t h e i n c r e a s e in t e s t e s
w e i g h t d i d n o t s e e m t o k e e p p a c e w i t h t h e i n c r e a s e in b o d y w e i g h t , a s
s h o w n b y t h e l o w e r l e v e l of s i g n i f i c a n c e ( P -C. 05) of t h e c o r r e l a t i o n b e -
-1 0 7 -
t w e e n s c o r e a n d r e l a t i v e t e s t e s w e ig h t a s c o m p a r e d to th e c o r r e l a t i o n
b e t w e e n s c o r e a n d a b s o l u t e t e s t e s w e i g h t (P<C. 01).
E s t i m a t e s of t h e
g en etic c o r r e la tio n s b etw ee n s c o r e and te s t e s w eights (absolute and r e l a ­
tive) a r e not sig n ific a n tly d if f e r e n t f r o m z e r o .
This indicated that e n v ir ­
o n m e n t a l i n f l u e n c e s ( l i g h t , f e e d , e t c . ) a r e of c o n s i d e r a b l e i n f l u e n c e in
d e t e r m i n i n g t e s t e s s i z e ( S a c h s , 1966b; K o n i s h i , . 1967; W i l s o n a n d S l o p e s ,
1967).
The a v e r a g e te s te s w eights w ithin g ro u p s and g en e ra tio n s ran g ed
f r o m 2 . 1 7 t o 2. 65 g r a m s a t .an a g e of a b o u t IQO d a y s .
T h e se absolute
t e s t e s w e ig h ts w e r e m o r e th a n tw ic e as high as the w e ig h ts r e p o r t e d by
K o n i s h i (1967) f o r 48 d a y o l d m a l e q u a i l u n d e r c o n s t a n t l i g h t .
F r o m I. 81
to 2 . 4 6 p e r c e n t of t h e b o d y w e i g h t w a s a c c o u n t e d f o r b y t h e t e s t e s , w h i c h
is a m u c h g r e a t e r p r o p o r t i o n t h a n t h e r e l a t i v e v a l u e s r e p o r t e d by R i d d l e
(1947) in p i g e o n s .
H i s t o l o g i c a l o b s e r v a t i o n s w o u l d b e r e q u i r e d to a s c e r ­
ta in w h e th e r the re la tiv e ly l a r g e r te s te s show le s s activ ity th an the r e l a ­
tively s m a l l e r te s t e s as p o o r e r fe rtility has b een r e a liz e d by m a le s w ith
■the l a r g e r t e s t e s .
H&hn (1948) o b s e r v e d i n m a l l a r d d u c k s t h a t a c t i v i t y
of t h e s e m i n i f e r o u s t u b u l e s w a s n o t n e c e s s a r y f o r m a t i n g t o t a k e p l a c e
a s long a s th e i n t e r s itu t ia l c e l ls w e r e p ro d u c in g a n d r o g e n s .
A n u m b e r of the p h e n o ty p ic c o r r e l a t i o n s b e tw e e n u n s e l e c t e d c h a r a c -
-1 0 8 -
t e r s of a l l s e l e c t e d m a l e s w a r r a n t i n d i v i d u a l d i s c u s s i o n .
These c o rre la ­
t i o n s a r e f o u n d in T a b l e X XI X .
a.
A s i g n i f i c a n t n e g a t i v e c o r r e l a t i o n ( r = - . 17) w a s o b t a i n e d b e t w e e n f i n ­
al w eight and p o s t-h a tc h -m o rta lity .
h e a v i e r a t t h e e n d of t h e e x p e r i m e n t ,
T h is w ould in dicate th a t m a l e s ,
s ir e d chicks w hich died at a low er
r a te than th o se s i r e d by s m a l le r m a le s .
It is p o s s i b l e t h a t c h ic k s s i r e d
b y s m a l l e r m a l e s w e r e s m a l l e r a t t h e t i m e of h a t c h i n g , a n d d i d n o t h a v e
th e s a m e c h a n c e t o . g e t to food a n d w a t e r a s l a r g e r c h i c k s .
b.
The c o r r e l a ti o n s b e tw e e n p o s t- h a tc h - m o r ta lity and BM R (r = - .2 8 ) and
a n e s t h e t i c o u t - t i m e ( r = - . 17) w e r e s i g n i f i c a n t .
T h e s e two c o r r e l a t i o n s
a r e p r o b a b l y due- t o t h e s a m e b i o l o g i c a l f a c t o r s a s B M R a n d a n e s t h e t i c
o u t - t i m e a n d a r e h i g h l y s i g n i f i c a n t l y ( r = 0. 29) c o r r e l a t e d .
A possible
ex p lan atio n m a y b e th a t m a l e s w ith a high BM R s i r e d ch ick s that a lso had
a high BM R.
Suc h, c h i c k s m a y s h o w g r e a t e r g e n e r a l a c t i v i t y a f t e r h a t c h ­
in g , w h i c h w o u l d b r i n g t h e m b y c h a n c e m o r e e a s i l y to f o o d a n d w a t e r .
T h i s a s s u r e d t h e i r s u r v i v a l to a g r e a t e r d e g r e e t h a n f o r t h o s e c h i c k s
w hich w e r e I e s s active.
T h e e s t i m a t e of B M R a s u s e d f o r t h e a b o v e c o r r e l a t i o n i s v e r y c r u d e .
N o i m p l i c a t i o n i s m a d e t h a t t h e r e i s a d i f f e r e n c e in t h e -c h e m i c a l a c t i v i t y
of t h e t i s s u e s of t h e m a l e s w i t h i n t h e d i f f e r e n t l i n e s .
A n y d i f f e r e n c e s in
-109-
ttie e s t i m a t e d B M R a r e d u e to a g r e a t e r e x t e n t to s e a s o n a l v a r i a t i o n s a n d
w eight d iffere n ce than any other facto r,
c.
I
A s i g n if i c a n t (r= - . 2 1 ) n e g a t iv e c o r r e l a t i o n w a s c a l c u l a t e d b e t w e e n
131
-uptake and p o st-h a tc h m o rta lity .
T h e m e a s u r e m e n t of I
in t h e p l a s m a w a s d o n e to e s t i m a t e t h e P B I of t h e m a l e q u a i l .
131
-uptake
A ccording
t o S t e r l i n g a n d T a b a c h n i c k (1961) t h e a d d e d l a b e l e d i o d i n e w i l l a t t a c h to
s o m e blood p r o te in s u n til a ll binding s ite s a r e occupied o r an e q u ilib riu m
has b e e n e s ta b lis h e d b e tw e e n the la b e le d I
fo r a binding site .
g e n o u s l e v e l of P B I .
131
and su b sta n c e s com peting
T h is w o u ld r e s u l t in h i g h e r cou n ts w ith a lo w e r e n d o ­
B l a c k m o r e (1967) o b s e r v e d t h a t in r a t s s e l e c t e d f o r
h i g h a n d l o w P B I l e v e l s , t h e r e o c c u r r e d a n i n c r e a s e in c o u n t w i t h a n i n ­
c r e a s e in P B I .
T h e c o u n t s v a r i e d g r e a t l y w i t h . t h e . s e a s o n s in t h i s s t u d y
a s h a d b e e n o b s e r v e d i n d e e r m i c e b y E l e f t h e r i o u a n d Z a r r o w (1961) a n d
in N e w H a m p s h i r e f o w l b y S t a h l a n d T u r n e y (1961).
G reat experim ental
e r r o r s in t h e d e t e r m i n a t i o n of P B I a r e a p p a r e n t l y to b e e x p e c t e d (G u y to n ,
1966) .
The negative c o rre la tio n betw een I I
- uptake and p o s t- h a tc h m o r ta lity
i n d i c a t e s a l o w e r d e a t h r a t e in c h i c k s s i r e d b y m a l e s w i t h a " h i g h e r " P B I .
T h i s d o e s n o t a g r e e w i t h the. i n t e r d e p e n d e n c e of P B I a n d B M R a n d t h e
c o r r e la tio n b e tw e e n BM R and p o s t -h a t c h m o r ta lity .
S in c e o n ly I
131
-110u p t a k e w a s u s e d to e s t i m a t e P B I , no c o n c l u s i o n c a n be d r a w n d i r e c t l y
w h e th e r P B I and I
131
- u p t a k e a r e i n v e r s e l y f e l a t e d i n q u a i l o r if t h e
f i n d i n g s of B l a c k m o r e (op. c i t . ) a p p l y h e r e a l s o .
co rre la tio n betw een I
131
In the l a t t e r c a s e , th e
-u p ta k e and p o s t- h a t c h m o r t a l i t y w ould a p p e a r
to be re a l .
d.
C o r r e l a t i o n s b e t w e e n - 1-*-^ I - u p t a k e a n d s i x w e e k b o d y w e i g h t ( r = 0 . 2 6 ) , '
fin al body w eig h t (r=0.58), a n e s th e tic o u t- tim e (r= 0.36), h e a r t r a te
( r = 0 . 2 7 ) , a n d B M R ( r = 0. 47) w e r e a l l s i g n i f i c a n t a n d p o s i t i v e .
The r e l a ­
t i o n s h i p s f o u n d b e t w e e n I ^ ^ - u p t a k e a n d t h e t w o p a e a s u r e m e n t s of b o d y
w e i g h t w o u l d f o l l o w e x p e c t a t i o n s if I
-uptake estim a te d PB I directly.
S im i la r r e a s o n s w ould a lso acc o u n t fo r the po sitiv e c o r r e l a t i o n betw een
I ^ I - u p t a k e a n d h e a r t r a t e f o u n d in t h i s s t u d y c a n b e e x p l a i n e d on t h e
sam e basis.
G u y t o n (1966) ant} H o h n (1961) i n d i c a t e d t h a t h e a r t r a t e is
o n e of t h e m o s t s e n s i t i v e m e a s u r e m e n t s to j u d g e w h e t h e r t h e r e i s p r e s ent a d e c r e a s e d o r in c r e a s e d P B I level.
T h e p o s i t i v e c o r r e l a t i o n of I 13 1
uptake and BM R follow ed the s a m e tre n d .
the con ten tio n th a t I
131
T h ese six exam ples support
-u p ta k e as m e a s u r e d in this e x p e r i m e n t w as d i r ­
e c tly r e l a t e d to th e e n d o g e n o u s P B I l e v e l .
A c o rre la tio n between-1
131
-uptake and BM R m e a s u r e d by m l / g m / h r
g a v e a s i g n i f i c a n t ( r = - . 20) e s t i m a t e w h i c h w o u l d r e f u t e t h e a b o v e c o n t e n ­
tion,
H o w e v e r , th e s a m e c o m p a r i s o n b e t w e e n g e n e r a t i o n s is p o s itiv e ,
-111-
w h ic h s in c e high B M R r e f le c ts high th y r o id activ ity , could ind icate th a t
h i g h I 131 - u p t a k e e s t i m a t e s h i g h t h y r o i d a c t i v i t y .
An explanation for
t h e s e c o r r e l a t i o n s m a y i n v o l v e s e a s o n a l c h a n g e s in p l a s m a p r o t e i n
lev els w hich a r e not g enetically d e te rm in e d ,
T h e B M R of a n o r g a n i s m i s p r i m a r i l y g o v e r n e d b y t h e t h y r o i d a n d
t h e p i t u i t a r y ( B l i v a i s s , 1947; H a w k , 1965; G u y t o n , 1 9 6 6 k
The average
a m o u n t of o x y g e n c o n s u m e d b y t h e C o t u r n i x in t h i s s t u d y , w h e n e x p r e s s e d
in m l / g r n '
/hr,
a g r e e w i t h t h a t r e p o r t e d f o r q u a i l b y F r e e m a n - (1967).
T h i s m e a s u r e m e n t t a k e s i n t o c o n s i d e r a t i o n t h e s u r f a c e a r e a of t h e b o d y
a s p r o p o s e d b y S a r r u s a n d R a m e a u x (Z e u t h e n , . 1953) o r R o b i q u e t ancj
T i l l a y e ( K l e i b e r ,. 1932).
W hen the am o u n t c o n s u m e d w as e x p r e s s e d as
m i l l i l i t e r of o x y g e n c o n s u m e d p e r g r a m of b o d y w e i g h t p e r h o u r ( m l /
g m / h r ) , the v a lu e s o b ta in ed lie b e tw e e n th o s e r e p o r t e d fo r the house
s p a r r o w a n d t h e c a n a r y a c c o r d i n g t o t h e B i o l o g i c a l H a n d b o o k (1964).
T h is in d ic a te s th a t fo r their- size, q uail have a c o n s id e ra b ly h ig h e r BMR
than the above m e n tio n ed b ir d s .
H e n r y _et al^ (1934) a t t r i b u t e d t h i s h i g h
oxygen c o n s u m p tio n to p r o te i n r a t h e r th a n fat m e t a b o l i s m .
This la tte r
p o i n t i s a l s o s u p p o r t e d b y th $ h i g h pro tfein , r e q u i r e m e n t of q u a i l ( W o o d a r d
e t a l , ' 1965).
e.
T h e c o r r e l a t i o n o b t a i n e d b e t w e e n f e r t i l i t y an d r e l a t i v e t e s t e s w e i g h t
-112-
w a s s i g n i f i c a n t a n d n e g a t i v e (r= - . 38).
A s im ila r tre n d w as indicated
w hen f e r tility w as c o r r e l a t e d w ith the a b s o lu te t e s t e s w eight.
c o r r e l a t i o n (r = —. 2 6 ) , h o w e v e r , w a s n o t s i g n i f i c a n t .
This,
I t is p o s s i b l e t h a t
the l a r g e r te s te s (rela tiv e and absolute) have a re la tiv e ly s m a l le r am ount
of a c t i v e s e m i n i f e r o u s t u b u l e s .
O r , if m o r e a c t i v e s e m i n i f e r o u s t u b u l e s
p r o d u c e d m o r e s p e r m , t h a t t h e r e a r e a r e l a t i v e l y g r e a t e r n u m b e r of
abnorm al sperm atozoa.
H istological exam inations a r e n e c e s s a r y for
choosing b e tw e e n the t w o . a l t e r n a t i v e s .
2.
Individual M e a s u r e m e n ts
T h e a v e r a g e n u m b e r of c o p u l a t i o n s o b s e r v e d in t h e G - 5 w e r e 2.1 ,
I. I, a n d 2. 7 f o r t h e h i g h , lo w , a n d c o n t r o l g r o u p s d u r i n g t h e t w o t w e n t y
m inute t e s t s .
T h i s a g r e e s f a i r l y w e l l w i t h t h e I. 5 c o p u l a t i o n s o b s e r v e d
in t h e y o u n g e s t g r o u p of b i r d s t e s t e d b y W o o d a r d a n d A b p l a n a l p (19-67)
d u r i n g a f i f t e e n m i n u t e p e r i o d , b u t is c o n s i d e r a b l y l o w e r t h a n t h e f r e ­
q u e n c i e s r e p o r t e d b y B e a c h a n d I n m a n - (1965).
T h e p a r e n t g e n e r a t i o n ' s r e p r o d u c t i v e r a t e w a s 59, 39, a n d 50 p e r ­
c e n t i n t h e h i g h , , lo w , a n d c o n t r o l g r o u p s , r e s p e c t i v e l y .
ity i n c r e a s e d in the G - I an d d e c lin e d s te a d i ly t h e r e a f t e r .
The hatchabilIn the G - I ,
th e lo n g e r (20-21 days) s t o r a g e p e r i o d w a s u s e d fo r t h e . f i r s t ti m e . . In
th is g e n e ra tio n , the high g ro u p ex ce ed ed , and the c o n tro ls a p p ro a c h e d ,
-113-
t h e h a t c h a b i l i t y r e p o r t e d b y S t e v e n s (1961) u n d e r s e m i - n a t u r a l c o n d i t i o n s .
T h e s t o r a g e p e r i o d d i d n o t s e e m t o h a v e a d e t r i m e n t a l e f f e c t on h a t c h a b i l i t y , c o n t r a r y t o f i n d i n g s b y W o o d a r d _et a l (1965).
As m entioned b e ­
f o r e , f e m a l e s i n t h i s e x p e r i m e n t w e r e .r e q u i r e d to h a v e l a i d o n ly one e g g
p r i o r to m a t i n g .
F lo w e r (p e rs. co m m u n . ) found th at eggs p ro d u ced at
t h e b e g i n n i n g of t h e l a y i p g p e r i o d h a t c h e d a t a l o w e r r a t e t h a n . t h o s e
• l a i d a f t e r t h e f i r s t m o n t h of p r o d u c t i o n .
T h e r e l a t i v e p r o p o r t i o n of t h e s e x e s i n t h e G - 4 d i f f e r g r e a t l y b e t w e e n
the lines.
T h e p o i n t i s of i n t e r e s t s i n c e i n t h i s g e n e r a t i o n t h e c h i c k s
w e r e r e m o v e d f r o m the in c u b ato r e a r l i e r than u s u a l.
I c h i n o e e t a l (1967)
f o u n d t h a t i n t h e s t r a i n s of c h i c k e n s a n d t h e i r c r o s s e s t h e y s t u d i e d , t h e
fem ales g en erally hatched e a rlie r.
H o w e v e r , . in th is study, th e v a r i a ­
ti o n s in s e x r a t i o s e e m to b e due to c h a n c e .
.
T h e p o s t - h a t c h m o r t a l i t y in .the f i r s t f o u r g e n e r a t i o n s w a s p a t t e r n e d
a s d e s c r i b e d b y S i t t m a n e t a l (1966).
The w e a k e r b ird s and all others
w h ic h f o r s o m e r e a s o n did n ot ta k e in enough food a n d / o r w a t e r , died by
th e fifth day. . In th e .f o u r t h g e n e r a tio n , t h e r e w e r e r e l a t i v e l y low l o s s e s ,
but they w e r e s p r e a d out o v e r th e w hole brooding, p e r io d w ithout a peak.
P a r t of t h i s m a y h a v e b e e n d u e t o t h e r e l a t i v e l y e a r l y r e m o v a l of t h e
c h i c k s f r o m t h e i n c u b a t o f , w h i c h d i d n o t p e r m i t a n y w e a k b i r d s to h a t c h .
-114-
T h e m o r t a l i t y of t h e s e c h i c k s a n d t h o s e w h i c h h a d h a t c h e d l a t e r o u t s i d e
the in c u b a to r did not d iffe r.
T h e s e l a t e r h a t c h e d c h i c k s h a t c h e d in r e g u l ­
a r q u a i l e g g f l a t s i n w h i c h t h e e g g s t h a t r e m a i n e d u n h a t c h e d a t t h e t i m e of
t h e r e m o v a l of t h e c h i c k s f r o m t h e i n c u b a t o r w e r e s t o r e d u n t i l t h e y w e r e
broken.
I t w a s n o t i c e d t h a t s o m e of t h e t e s t e s s e e m e d to h a v e a m e l a n i n d e p o ­
s i t in t h e m .
R e c o r d s w e r e k e p t . o f t h e e x t e n t & f r e q u e n c y of i t s o c c u r r e n c e ,
b u t t h e d e p o s i t s s e e m e d t o o c c u r a t r a n d o m w i t h i n t h e m a l e s of a l l t h r e e
groups.
C a s p a r ! (1950) f o u n d t h a t t e s t e s c o l o r i n E p h e s t i a k u h n i e l l a w a s
r e l a t e d to f i t n e s s a n d m a t i n g b e h a v i o r .
a p p a re n t in this e x p e rim e n t.
Such a s s o c ia t io n s w e r e not
M e l a n i n d e p o s i t s in t h e a b d o m e n a n d b o d y
w a l l o f b r o i l e r s h a v e b e e n s t u d i e d b y J a a p (1958), H u n t s m a n e t a l (1959,
I 9 6 0 ) , a n d ' K u i t (1967).
N o n e of t h e s e a u t h o r s r e f e r r e d t o d e p o s i t s of
c o l o r in t h e t e s t e s .
N o m e a s u r e m e n t s w e r e f o u n d i n t h e l i t e r a t u r e c o m p a r a b l e to w h a t w a s
called anesthetic ou t-tim e h ere.
N e v e r t h e l e s s , L u m b (1963) i n d i c a t e d
t h a t g r e a t e r a m o u n t s of p e n t o b a r b i t a l a r e r e q u i r e d w i t h a h i g h e r B M R .
I t w a s o b s e r v e d e a r l y t h a t t h e p r e s c r i b e d a m o u n t f o r p e t b i r d s of 4. 5 m g /
IOOgm ( F r i e d b e r g , . 1961) w a s n o t a d e q u a t e t o i n d u c e g e n e r a l a n e s t h e s i a .
T h e a m o u n t h a d t o b e a l m o s t d o u b l e d i n o r d e r to o b t a i n a s u f f i c i e n t d u r a ­
t i o n a n d d e p t h of a n e s t h e s i a .
This la r g e quantity in c r e a s e d saliv atio n
-115-
( c . f . A d r i a n ! , I 96 0) , w h i c h . c a u s e d t h e l o s s of s o r n e b i r d s d u r i n g , o r a f t e r
a lm o st every testing period.
agent,
A tropine, when u se d as a p rean e sth etic
r e d u c e s t h e B M R of t h e b i r d a n d l o w e r s t h e p e n t o b a r b i t a l r e q u i r e ­
m e n t f o r g e n e r a l a n e s t h e s i a . ( G u y to n ,. 1962).
S i n c e t h e o b j e c t w a s to
m e a s u r e t h e B M R a n d h e a r t r a t e , i t w a s f e l t t h a t t h e i n j e c t i o n of a n a d d i ­
t i o n a l a g e n t w o u l d i n c r e a s e t h e . r a n g e of i n t e r a c t i o n s a n d a t r o p i n e w a s
th e re fo re not used.
The h e m a to c rit levels re m a in e d static through th e.fo u r generations
in w h i c h t h e y w e r e m e a s u r e d .
T h e l e v e l s f o u n d in t h i s e x p e r i m e n t a r e
a p p r o x i m a t e l y 50 p e r c e n t h i g h e r t h a n t h o s e . r e p o r t e d b y G o n z a g a . a n d
A l b a r e c e (1963) f o r q u a i l .
T h e s e h ig h e r le v e ls a r e p ro b a b ly due to the
a l t i t u d e r a t h e r t h a n t e c h n i q u e ; t h e l o c a t i o n of t h e b i r d s h e r e w a s c l o s e t o
5 0 00 f e e t a b o v e s e a . l e v e l .
g e s t e d b y C o h e n (1963).
The blood w as d ra w n f r o m an a r t e r y as su g ­
T h e r a t e of b l e e d i n g v a r i e d a m o n g b i r d s , a n d
w o u l d t h e r e b y i n f l u e n c e thq. r e l a t i v e t i m e of s a m p l i n g .
I t is f e l t , h o w ­
e v e r , t h a t t h e f o r m e r f a c t o r i s of g r e a t e r i n f l u e n c e t h a n t h e l a t t e r . T he r e s u l t s in d ic a te d th a t the h e a r t r a t e s did not d iffe r b e tw e e n the
groups.
T h e l i t e r a t u r e r e p o r t e d no h e a r t r a t e s f o r q u a il, b u t th e l e v e ls
o b t a i n e d w e r e s i m i l a r t<? t h o s e r e p o r t e d f o r c a n a r i e s ( B i o l o g i c a l H a n d ­
b o o k , 1964), o r t w i c e a s h i g h a s t h o s e r e p o r t e d b y F l i c k (1967) f o r c h i c k ­
-116-
ens.
T h is a ls o in d ic a te d th a t fo r t h e i r s iz e , quail have a high m e t a b o l ­
ism .
T h e l e v e l s of b l o o d g l u c o s e w e r e o b t a i n e d f o r o n ly a s m a l l n u m b e r of
b i r d s a n d w e r e s o m e w h a t h i g h e r t h a n t h e v a l u e s r e p o r t e d f o r White L e g ­
h o r n s b y S t u r k i e (1955) a n d T a p p e r a n d K a r e (1956,. I 9 6 0 ) .
T h is w ould be
e x p e c te d fo r two r e a s o n s ; the above m e n t i o n e d a h t h o r s m e a s u r e d blood
g l u c o s e o n ly , w h e r e a s h e r e t o t a l r e d u c i n g s u b s t a n c e s w e r e m e a s u r e d
a c c o r d i n g t o t h e t e c h n i q u e of F o l i n - Wu. (1920).
Secondly, the h ig h er BM R
of q u a i l o v e r t h a t of c h i c k e n s w o u l d t e n d t o a c c o u n t f o r h i g h e r l e v e l s .
T h e d i s c u s s i o n of t h e m a l e p h y s i o l o g y a l l o w s t h e f o l l o w i n g c o n c l u s ­
ions:
a.
S ele ctio n fo r in c r e a s e d .a n d d e c r e a s e d m a tin g s c o r e fo r five g e n e r a ­
t i o n s e f f e c t e d n o c h a n g e i n t h e p h y s i o l o g y of t h e m a l e s .
b.
M a t i n g s c o r e a s m e a s u r e d h e r e w a s r e l a t e d to t h e s i z e of t h e t e s t e s
a n d a s h o r t l a t e n c y to c o p u l a t i o n .
c.
I
1- u p t a k e v e r y p r o b a b l y m e a s u r e d P B I r a t h e r t h a n t h e i n v e r s e of it.
B.
I.
P h y s i o l o g y of t h e F e m a l e s
Egg P r o d u c tio n and Egg Weight
T h e a v e r a g e e g g p r o d u c t i o n r e a c h e d b y 4 6 6 f e m a l e s (62. 7%) w a s n o t
a s h i g h a s r e p o r t e d b y W o o d a r d e t a l (1965).
H ow ever, this figure w as
-117-
o b t a i n e d on a h e n - h o u s e d b a s i s a n d - i n c l u d e d t h e p e r i o d of m a t i n g , d u r i n g
w hich s o m e fe m a le s alw ays stop-laying.
This red u ce d the a v e ra g e p r o ­
duction.
T h e e g g w e i g h t ( 1 0 . 4 0 g m ) i s c l o s e to t h a t r e p o r t e d b y t h e a b o v e
authors.
T h e e g g w e i g h t r e p r e s e n t s 7 . 7 % of t h e b o d y w e i g h t , w h i c h - i s
c o n s i d e r a b l y m o r e t h a n t h e 4 . 7 - 5 . 5% r e p o r t e d b y R i d d l e (1947) f o r p i g ­
eons and ring doves.
T h e r e l a t i v e l y l a r g e e g g s a l s o g i v e a n - i n d i c a t i o n of
t h e h i g h m e t a b o l i c a c t i v i t y of t h e s e b i r d s .
T h e c o r r e l a t i o n b e t w e e n eg g
w e i g h t a n d p e r c e n t p r o d u c t i o n ( r = 0. 30) i s c o n t r a r y t o e x p e c t a t i o n .
The
i n c r e a s e d e g g w e i g h t w i t h g r e a t e r r a t e of p r o d u c t i o n m a y b e a p e c u l i a r ­
i t y of q u a i l r e l a t e d t o , t h e i r e n e r g y m e t a b o l i s m .
2.
S e x u a l.M aturity
This c h a ra c te r v a rie d considerably.
T h e a v e r a g e n u m b e r of d a y s t o
s e x u a l m a t u r i t y w a s s lig h tly l e s s th a n 46 d a y s , w h ic h c o r r e s p o n d s w ith
t h e o b s e r v a t i o n s of W o o d a r d e t a l (1965).
The c o rre la tio n betw een s e x ­
u a l m a t u r i t y a n d s e x w e e k b o d y w e i g h t (r = - . 32) w a s e x p e c t e d a s t h e d i f ­
f e r e n c e in body w eig h t b e tw e e n m a l e s and f e m a le s is a t tr ib u t e d la rg e ly
t o , t h e r e p r o d u c t i v e o r g a n s of t h e . f e m a l e s a t t h a t a g e ( S i t t m a n e t al,. 1966).
T he h e a v ie r f e m a le s la id s o o n er a fte r the six w eek w eighing date than
t h e l i g h t e r h e n s ..
F a l c o n e r (I960) a n d K i n n e y a n d S h o f f n e r (1965) e x p l a i n e d t h a t b i r d s
-118-
w h ic h a r e l a r g e r f r o m g e n e tic c a u s e s r e a c h s e x u a l m a t u r i t y l a t e r and
la y fe w e r e g g s, b u t th e eggs a r e l a r g e r .
B ird s th a t a r e la r g e r fro m
e n v iro n m e n ta l c a u s e s r e a c h se x u a l m a tu r ity e a r l i e r and la y m o r e eggs
w h i c h a r e n o t v e r y d i f f e r e n t in w e i g h t .
3.
B ody W eight
T h e b o d y w e ig h ts o b ta in e d c o r r e s p o n d w e ll w ith th o s e r e p o r t e d by
F r e e m a n - (1967).
T h e s i x w e e k w e i g h t r e p r e s e n t e d a b o u t 96% of t h e f i n a l
w e ig h t, w h ic h is s o m e w h a t h ig h e r th a n th e e s t i m a t e p r o v id e d by S ittm a n
jet ^ l (1966).
H o w e v e r , i t is p o s s i b l e t h a t t h e r e is a g e n u i n e d i f f e r e n c e
b e tw e e n th e b ir d s s tu d ie d by S ittm a n et a l an d th o s e u s e d h e r e .
The c o r ­
r e la tio n b e tw e e n s ix w e e k s w e ig h t a n d fin a l body w e ig h ts w a s , •a s e x p e c t­
ed, h ig h ly s ig n if ic a n t (r = 0 .9 8 ) .
C.
B E H A V IO R A L C O N SID E R A T IO N S
:
T h e o r g a n i s m ( th e i n d i v i d u a l a n d t h e s p e c i e s ) is m a i n t a i n e d b y b e ­
h a v i o r t o a s i m i l a r d e g r e e a s b y a l l p h y s i c a l a n d c h e m i c a l p r o c e s s e s in
p h y sio lo g y an d g e n e tic s .
B e h a v io r c a n b e lo o k e d upon a s e x istin g d y n a ­
m i c a l l y t h o u g h n o n - v a r i a b l e in a g i v e n e n v i r o n m e n t .
S in c e a s ta tic e n v i r ­
o n m e n t d o e s n o t e x i s t in n a t u r e , v a r i a b i l i t y a n d a d a p ta b ility h a v e n a t u r ­
ally b e e n s e le c te d fo r.
T h i s e n a b l e s t h e o r g a n i s m to e x i s t w i t h i n a
r a n g e r a t h e r t h a n a s p e c i f i c c o n d i t i o n ( c . f . K i r k p a t r i c k , . 1919).
O n ly o u t ­
-119-
s i d e t h i s r a n g e w o u l d l i f e of a s p e c i f i c s p e c i e s b e c o m e - i m p o s s i b l e a s
h as h a p p e n e d in th e g e o lo g ic a l p a s t.
I t s e e m s t h e r e f o r e of g r e a t e s t a d ­
v a n t a g e f o r t h e o r g a n i s m to m a i n t a i n v a r i a b i l i t y a n d a d a p t a b i l i t y to p e r ­
s i s t r e la tiv e ly e ffic ie n tly .
g e n e tic h o m e o s ta s is .
T h is w o u ld le a d t o .s o m e p h y s io lo g ic a l an d
D e v ia tio n s f r o m su c h an e q u ilib r iu m m a y a d a p t an
o r g a n i s m b e t t e r f o r a s p e c ific e n v iro n m e n t, b u t w ith i n c r e a s e d h o m o ­
z y g o s ity it s o v e r a l l f i t n e s s w o u ld b e r e d u c e d .
G r e a t v a r i a b i l i t y w a s o b s e r v e d in t h e - m a n y d i f f e r e n t p a t t e r n s of
m a t i n g b e h a v i o r o b s e r v e d d u r i n g . m o r e t h a n .300 h o u r s of t e s t i n g .
In
g e n e r a l , t h e m a t i n g b e h a v i o r of t h e J a p a n e s e q u a i l o b s e r v e d d u r i n g t h i s
e x p e r i m e n t c o n f o r m e d w e l l w i t h t h a t d e s c r i b e d b y B e a c h a n d I n m a n (1965)
a n d F a r r i s (1967).
B u t s i n c e t h e a b o v e a u t h o r s d id n o t e m p h a s i z e t h e
p o s t - c o i t a l c o u r t i n g , i t is p o s s i b l e t h a t t h i s b e h a v i o r w a s o b s e r v e d
m o re. fre q u e n tly d u rin g th is in v e stig a tio n .
In m a n y c a s e s , th e b r o a d c a s t , id e n tific a tio n , an d s y n c h r o n iz a tio n
s t i m u l i , a s d e s c r i b e d f o r b i r d s b y H i n d e (1959), S c h e i n a n d H a l e (1965),
a n d G u h l (1961) a n d f o r D r o s o p h i l a b y S m i t h (1956) w e r e p a r t i a l l y o r c o m ­
p le te ly a b s e n t in -th e b i r d s t e s t e d .
B e a c h (1942) g a v e t h e i n t e r a c t i o n s of
m a l e a n d f e m a l e t o r e a c h t h e c o p u l a t e r y t h r e s h o l d i n a n e a t t a b l e of
a ro u s a l v alu es.
T h i s t y p e of m a l e - f e m a l e i n t e r a c t i o n s e e m e d , to p e r t a i n
-120-
o n ly s l i g h t l y o r n o t a t a l l to t h e s e q u a i l .
In so m e c a s e s , v e r y few s e c ­
onds w e r e r e q u i r e d f o r th e m a l e to c o p u la te .
T h e r e s e e m e d to b e a
f a c t o r of s u r p r i s e i n v o l v e d a s s o m e t i m e s t h e f e m a l e s b e c a m e u n r e c e p t iv e a f te r th e f i r s t c o p u la tio n .
O n ly a f t e r a p e r i o d of q u i e t n e s s of b o th
p a r t n e r s w o u l d t h e m a l e b e s u c c e s s f u l a g a i n i n h is r e n e w e d c o p u l a t o r y
a tte m p ts.
O c c a s i o n a l l y a m a l e w o u ld s u c c e s s f u l l y c o p u l a t e b y t a k i n g t h e
fe m a le "by s u r p r is e . "
n u m b e r of m a l e s .
O n ly r a r e l y w e r e . f e m a l e s r e c e p t i v e to a . l a r g e
G e n e r a l l y a f t e r tw o o r t h r e e o b s e r v a t i o n p e r i o d s f
t h e f e m a l e s h a d to b e c h a n g e d a s t h e y b e c a m e v e r y a g g r e s s i v e t o w a r d s
th e m a l e s .
O ne c o m m o n a t t i t u d e to p r e v e n t a m a l e f r o m m o u n t i n g is
f o r t h e f e m a l e to r e m a i n u p r i g h t , i. e . , h e r h e a d . c o n s i d e r a b l y h i g h e r ,
t h a n h e r b a c k , s o t h a t t h e m a l e c o n t i n u a l l y s l i d e s off w i t h o u t g a i n i n g a
f o o th o l d .
S e x b e h a v i o r h a s b e e n c o n s i d e r e d a n i n s t i n c t (L a s h l e y , 1924) a n d
a c c o r d i n g to S c h e i n a n d H a l e (1965), n o l e a r n i n g is r e q u i r e d f o r t h e s u c ­
c e s s f u l e x e c u t i o n of t h e m a t i n g a c t in b i r d s .
S p o n ta n e ity a n d e n d o g e n e ity
of b e h a v i o r is o n e of t h e m o s t i m p o r t a n t a s p e c t s o f i n s t i n c t ( K o n is h i,
1966).
H o w e v e r , L e n n e b e r g (1967) s t a t e d t h a t t h e r e i s n o r e a l d i c h o t o m y
b e t w e e n b e h a v i o r t h a t i s s p e c i e s s p e c i f i c , a n d t h a t w h i c h is d u e to p l a s ­
ti c it y (no v el a c t s t h a t c a n b e l e a r n e d ) .
M o s t b e h a v i o r of h i g h e r a n i m a l s
-IZ l-
d e p e n d s on s p e c i e s - s p e c i f i c i t y an d c i r c u m s t a n c e .
tic ity is an e v o lu tio n a ry p h enom enon.
T h e d e g r e e of p l a s ­
So b e h a v i o r is a n i n t e g r a l w h o le
a n d a d i v i s i o n b e t w e e n p h y s i o l o g y a n d b e h a v i o r is a n a r t i f a c t .
T he m o s t c o m m o n ly o b s e rv e d o r ty p ic a l b e h a v io r se q u e n c e w as as
fo llo w s:
T he fe m a le w as p r e s e n t in .th e m a tin g c a g e .
The m a le w as
ta k e n f r o m h is h o m e c a g e , h is le g b a n d n u m b e r w a s r e c o r d e d , a n d he
w a s th e n in tr o d u c e d in to th e m a tin g c a g e .
f r o n t e d w i t h a g r e a t n u m b e r of s t i m u l i .
H e r e he w a s su d d e n ly c o n ­
T he c o m p lic a tio n s and m u ltip le
i n t e r a c t i o n s of s t i m u l i in t h e e x e c u t i o n of f e e d i n g h a v e b e e n d e s c r i b e d b y
d e R u i t e r (1963) a n d s i m i l a r c o m p l i c a t e d i n t e r a c t i o n s s e e m e d to b e i n ­
d ic a te d h e re .
I n t h e c a s e of t h e m a l e q u a i l , t h e r e w a s t h e e x t r a l i g h t ,
m o r e s p a c e , h a v i n g b e e n h a n d l e d a n d o t h e r l e s s o b v io u s c h a n g e s p l u s
any i n t e r n a l c h a n g e s h e m a y h av e u n d e r g o n e , th ro u g h b ein g h an d led , an d
t h e g e n e r a l w e l l - b e i n g a n d h e a l t h of t h e a n i m a l on t h i s p a r t i c u l a r d a y a n d
tim e .
Of a l l t h e p o s s i b l e r e a c t i o n s h e m a y s h o w to t h e m u l t i t u d e of
s t i m u l i , t h e o b s e r v e r s w e r e i n t e r e s t e d o n ly in h i s r e s p o n s e t o t h e f e m a l e .
L a s h l e y (1924) i n d i c a t e d t h a t w i t h p u b e r t y , t h e s t i m u l u s " f e m a l e " g a i n s in
i m p o r t a n c e a n d i s r e s p o n d e d to s e l e c t i v e l y b y t h e m a l e .
T h o se m a le s
w h i c h m a t e d v e r y r a p i d l y ( w ith i n a f e w s e c o n d s ) m u s t h a v e b e e n a b l e to
d is c r im in a te f a s t and a c c u ra te ly b etw ee n se x u a l and n o n -s e x u a l s tim u li.
-122-
I n t h e - l a t e r g e n e r a t i o n s ( G - 4 a n d G - 5), t h e m a l e s c o u l d b e i d e n t i f i e d
a s to w h i c h s e l e c t e d l i n e t h e y b e l o n g e d , b y h o w t h e y r e a c t e d to b e i n g h a n ­
d le d .
T h e m a l e s f r o m t h e h ig h g r o u p w e r e g e n e r a l l y q u i e t , w h e r e a s t h e
m a l e s f r o m , the- lo w g r o u p g e n e r a l l y a t t e m p t e d v i g o r o u s l y to . e s c a p e f r o m
th e hand.
In t h e - m a t i n g c a g e m o s t m a l e s w o u l d s t a n d s t i l l f o r s o m e tiim e
t o " t a k e in t h e n e w s u r r o u n d i n g s , " b u t t h e l o w m a l e s f r e q u e n t l y w o u l d ,
a f t e r h a v i n g b e e n p l a c e d in t h e s h a v i n g s , f ly u p, h i t t h e t o p of t h e c a g e ,
m a k e Toud n o is e s , th ro w sh a v in g s, and m o r e o r le s s frig h te n .th e fe m a le
and se e m in g ly th e m s e lv e s .
W hen, s u c h a m a l e fin a lly s e ttle d .d o w n , he
w o u l d b e c o m e a w a r e of t h e f e m a l e a n d r e a c t to h e r a c c o r d i n g t o his- s e x
d riv e .
T h e lo w l i n e m a l e s in g e n e r a l w e r e c l u m s i e r in t h e i r m a t i n g
a tte m p ts.
M a n y of t h e h i g h m a l e s w o u l d i m m e d i a t e l y g r a b t h e fem ale-,
m o u n t a n d c o p u l a t e w i t h i n a m a t t e r of s e c o n d s .
I t w a s f o u n d in D r o s o ­
p h i l a t h a t a f t e r t h r e e t o f o u r g e n e r a t i o n s of s e l e c t i o n f o r m a t i n g s p e e d ,
a d i f f e r e n c e in g e n e r a l a c t i v i t y b e c a m e e v i d e n t a n d t h a t p h o t o t r o p i s m
w a s c o n s i d e r a b l y r e d u c e d i n t h e lo w l i n e .
T h e lo w l i n e a l s o e x h i b i t e d
g r e a t d i s t u r b a n c e w h e n f i r s t p l a c e d i n t o t h e m a t i n g c h a m b e r ( M a n n in g ,
1961).
H e a t t r i b u t e d t h e s e c h a n g e s to a c c u m u l a t e d g e n e e f f e c t s on t h r e s ­
h o l d in t h e c e n t r a l n e r v o u s s y s t e m , a n d P r o m p t o v (1940) to . e n d o c r i n e
g la n d s.
M a n n in g a ls o c o n s i d e r e d th a t u n d e r a r t i f i c i a l c o n d itio n s d i f f e r ­
-123-
en t s tim u li o c c u r th a n -in n a t u r e and t h e r e b y a l t e r th e b e h a v io r r e p e r ­
to ire .
T h o r p e (1963) s u g g e s t e d t h a t s u c h a b e h a v i o r a l c h a n g e i n t h e r e ­
l e a s e r q u a l i t i e s of s t i m u l i d e p e n d s o n t h e s e n s o r y f i l t e r i n g f u n c t i o n s of t h e
c e n t r a l n e r v o u s s y s t e m a n d is u l t i m a t e l y d e t e r m i n e d b y D NA .
If th e f e m a l e w a s n o t r e c e p t i v e , h e w o u ld m a i n t a i n h is h o ld a n d c o n ­
t i n u e in h i s a t t e m p t s t o ;m o u n t h e r .
Y o u n g a n d G r u n t (1951) a n d E v a n s
(1938) n o t i c e d s i m i l a r l y i n g u i n e a p i g s a n d l i z a r d s t h a t l o w d r i v e m a l e s
w e r e l e s s p e r s i s t e n t in t h e p u r s u i t of a f e m a l e t h a n t h e h i g h d r i v e m a l e s .
T h e m a l e m a y t h e n l e t t h e f e m a l e go a n d e x p l o r e , o r h a v i n g a c h i e v e d c o p ­
u la tio n , d is p la y and " cooh. "
T h is l a s t m e n tio n e d b e h a v io r is a v e ry so ft
sound e m itte d by s o m e m a le s and h as b e e n .d e s c r ib e d fo r th e Z e b ra -fin c h
b y M o r r i s (1954).
S i n c e t h e b a c k g r o u n d n o i s e in t h e o b s e r v a t i o n r o o m w a s
t o o g r e a t , n o a t t e m p t w a s m a d e to r e c o r d t h e f r e q u e n c y of t h e s o u n d e m i s ­
sio n .
I t m a y b e a v o c a l d i s p l a y to s e r v e i n . c o n s o l i n g t h e f e m a l e .
M o r r i s a l s o d e s c r i b e d a r a s p i n g s o u n d o f t h e f e m a l e Z e b r a f in c h .
M any fe m a le q u a il e m itte d th is sound a f te r th e y b e c a m e " a n n o y e d " by th e
a t t e n t i o n of t h e m a l e s .
The m a le m ay have m a te d s e v e ra l tim e s , but
w h e n . t h e f e m a l e b e g a n to r a s p h e w o u l d i m m e d i a t e l y t u r n a w a y a n d . a s s u m e
a s u b m is s iv e p o s tu r e o r fle e .
If p u r s u e d b y th e f e m a le , w h o .e x te n d s h e r
n e c k w h i l e m a k i n g , t h e s o u n d , t h e m a l e m a y c r o u c h in a c o r n e r o f .t h e c a g e
-124-
o r s t a n d u p a n d e x t e n d h i s h e a d t h r o u g h . t h e w i r e to t h e o u t s i d e of th e
cage.
If th e f e m a l e a t t a c k s th e m a l e e a r l y in th e t e s t , th e m a l e m a y b e
d r i v e n to f a t i g u e o r , a s h a s a l s o b e e n o b s e r v e d , t h e m a l e s u d d e n l y s t o p ­
p e d r u n n i n g , t u r n e d to t h e f e m a l e , c o p u l a t e d , a n d t h e n . t u r n e d d e f e n s i v e
ag ain .
T h e .f e m a le m a y o r m a y n o t co n tin u e h e r p u r s u i t a f t e r su c h a .c o p ­
u la tio n .
If. s u c h a m a l e w a s r e m o v e d a n d r e p l a c e d b y a n o t h e r , t h e f e ­
m a l e w o u ld e i t h e r a s s u m e th e m a tin g p o s t u r e o r im m e d i a te l y a tta c k .th e
m a le .
T h i s w o u l d b e a n e x a m p l e of f e m a l e s e x u a l s e l e c t i o n a n d d i s c r i m ­
i n a t i o n a s h a s b e e n d e s c r i b e d b y D a r w i n - (1874).
T h e c o u rtin g d is p la y b e g a n -in m o s t c a s e s a f te r c o m p le te d c o p u la tio n
w i t h l o o s e n i n g of t h e f e a t h e r s a n d v i g o r o u s s h a k i n g b y t h e m a l e .
He th e n
s p r e a d h is w in g s s o m e w h a t,, lo w e r e d th e m , e x te n d e d h is n e c k a t any .
•
.
a n g l e f r o m a b o u t t h e h o r i z o n t a l t o -a b o u t 5 0 ° u p a n d w a l k e d s t i f f - l e g g e d
a ro u n d th e f e m a le .
T h i s d i s p l a y o c c u r r e d c o n s i d e r a b l y m o r e o f te n a f t e r
th a n b e f o r e c o p u la tio n .
a fte r
T h e p e r c e n t a g e of m a l e s c o u r t i n g b e f o r e a n d . .. .
c o p u l a t i o n a r e c o m p i l e d in T a b l e X III.
D isp la y a c tiv itie s b e fo re
a n d a f t e r c o p u l a t i o n a r e k n o w n to, o c c u r i n a t l e a s t t h e Z e b r a f i n c h - ( M o r ­
r i s , , 1954), t h e M a l l a r d (H ohn,, 1948; L o r e n z , . 1958), t h e E u r o p e a n A v o c e t
(M a k k in k ,. 1936) a n d t h e B r e w e r B l a c k b i r d ( H o w e l l a n d B a r t h o l o m e w ,
1952).
-125-
. . T id b ittin g a s d e s c r ib e d by s e v e r a l a u th o rs o c c u r r e d a t t i m e s , but
n o t in t h e s a m e m a n n e r a s in t h e d o m e s t i c f o w l.
T h e m a l e w o u ld s t a n d
s t i f f l y w i t h a s t i f f n e c k a n d e x e c u t e r a p i d p i c k i n g m o v e m e n t s in t o t h e a i r .
T h is o c c u r r e d m o s t fre q u e n tly w hen th e f e m a le , a fte r s e v e r a l s u c c e s s iv e
c o p u l a t i o n s , w a s n o l o n g e r r e c e p t i v e , b u t d id n o t r e a c t a g g r e s s i v e l y t o ­
w a r d s th e m a le .
I t s e e m s to h a v e a c o n s o l i n g e f f e c t o n t h e f e m a l e .
I n s o m e m a m m a l s n u z z l i n g i s k n o w n to o c c u r b e f o r e c o p u l a t i o n
(Y o u n g a n d G r u n t , 1951).
T h e a n a l o g o u s b e h a v i o r i n t h e q u a i l s e e m s to
b e s o f t p i c k i n g to t h e n e c k a n d h e a d r e g i o n b y b o t h m a l e a n d f e m a l e .
T h i s h a s a l s o b e e n o b s e r v e d in t h e g r o u s e (A lle n ,. 1934).
T h e p i c k i n g is
c o n s i d e r a b l y d i f f e r e n t f r o m t h e p i c k - . t o - g r a b w h i c h t h e m a l e e x e c u t e s in
a n a t t e m p t t o m o u n t . . I f t h e f e m a l e d i d n o t p a r t i c i p a t e , t h e m a l e o f te n
p i c k e d in t o t h e a i r .
I t is d i f f e r e n t f r o m t i d b i t t i n g a s t h e m a l e is n o t
p h y sic a lly te n s e .
A f t e r c o p u l a t i o n a n d d i s p l a y , t h e tw o p a r t n e r s m o r e o r l e s s i g n o r e d
e a c h o t h e r a n d w a l k , s t a n d o r b a t h e in t h e s h a v i n g s .
T h is c a lm m a y la s t
f r o m a f e w s e c o n d s to a f e w m i n u t e s a f t e r w h i c h t h e m a l e m a y j u m p u p
an d r a p e th e " u n s u s p e c tin g " fe m a le .
th ro u g h o u t th e t e s t .
S u ch a l te r n a t io n s m a y c o n tin u e
T h e r e a r e a g r e a t n u m b e r of v a r i a t i o n s to t h e p a t - .
t e r n s i n d i c a t e d w i t h m a n y o t h e r b e h a v i o r s c o n t r i b u t i n g to t h e o v e r a l l
-1 '2 6 ~
p ic tu re ,
s u c h a s p r e e n i n g , w h i c h m a y b e a r e l e a s e of t e n s i o n - i n t h e m a l e
(H ohn,, 1948) a n d c r o w i n g . • M o r e t h a n h a l f of t h e c o p u l a t i o n s o b s e r v e d
w ere rap es.
T h i s r a p i n g h a s a l s o b e e n o b s e r v e d o n a r e g u l a r b a s i s in
a t l e a s t t h e Y e l l o w h a m m e r ( A n d r e w , 1956), Z e b r a f i n c h ( M o r r i s ,. 1954),
a n d M a l l a r d (H&hn,. 1948).
C o u r t s hip; i s a n e x p r e s s i o n of t h e t e n d e n c i e s
to f l e e , a t t a c k a n d b e h a v e s e x u a l l y t o w a r d s t h e m a t e (H in d e ,, 1950; W o o d - ■
G u s h , . 1956; T i n b e r g e n , , 1965).
E v e n th o u g h th e q u a il in m o s t c a s e s s h o w ­
e d -little p r e c o p u la to r y b e h a v io r, t h e r e w a s a good in d ic a tio n th a t fe a r
w as p re se n t.
T h i s h a s a l s o b e e n o b s e r v e d b y H o h n (1948) i n M a l l a r d s
w h i c h w i l l n o t r a p e t h e i r ow n m a t e s , b u t w i l l do s o w i t h s t r a n g e f e m a l e s .
I t c o u l d b e r e a s o n e d t h a t s u c h a m a l e i s m o r e a f r a i d of t h e s t r a n g e f e ­
m a l e t h a n of h i s o w n p a r t n e r .
S a c h s (1966a) i n d i c a t e d t h a t t h e i n i t i a l m o v e m e n t of q u a i l m a t i n g a n d
a t t a c k b e h a v i o r , t h e p i c k - g r a b s e q u e n c e , a r e t h e s a m e , a n d o n ly a f t e r
th e one a t ta c k e d d o e s n o t r e s p o n d d o e s th e b e h a v io r t u r n to c o p u la tio n .
It is th e r e f o r e a n -in tim id a tio n d is p la y . . T h is c o n c lu sio n c a n b e s u p p o rte d
by th e o b s e r v a tio n s h e r e .
T h e r e is n o s u g g e s t i o n i n t h e l i t e r a t u r e t h a t
r a p i n g , i s o n e w a y of o v e r c o m i n g f e a r ; h o w e v e r , t h e w r i t e r s u b s c r i b e s to
th a t id e a .
R ap in g ta k e s th e f e m a le u n a w a r e an d th e p o s t- c o i ta l d isp la y
m a y th e n , s e rv e -to . c o n s o le th e f e m a le a n d r e d u c e te n s io n in th e m a le .
-127 -
T h e s o c i a l i n t e r a c t i o n s w h i c h a r e of s u c h g r e a t i m p o r t a n c e in m a t i n g b e ­
h a v i o r u n d e r n a t u r a l a n d f l o c k c o n d i t i o n s ( G u h l 1. 1966; G i n s b u r g , . 1965;
L e v i n e e t a l , . 1965) w e r e r e d u c e d a s a l l b i r d s w e r e i n d i v i d u a l l y c a g e d .
T h e r e p e a t a b i l i t y of t h e m a t i n g s c o r e c o m p o n e n t s w a s c a l c u l a t e d in
g e n e r a tio n s tw o ,a n d th r e e .
R e p e a t a b i l i t i e s of i n d i v i d u a l c o m p o n e n t s d i f ­
f e r e d b e tw e e n .th e g ro u p s .
W h e n . t h i s w a s c o m p a r e d w i t h th e . r e p e a t a b i l i t y
of t h e t o t a l s c o r e s in t e s t o n e a n d t e s t tw o ,, i t b e c a m e e v i d e n t t h a t p a r t ­
i c u l a r l y i n t h e lo w g r o u p e i t h e r l e a r n i n g o r a r e d u c t i o n of " t i m i d i t y "
o c c u r r e d in th e se c o n d te s t .
J u s t i c e e t a l (1962) s u g g e s t e d t h a t a r o o s t e r
s h o u l d h a v e c o n s i d e r a b l e e x p e r i e n c e a n d p r a c t i c e in s e x u a l b e h a v i o r b e ­
f o r e te s tin g h im .
T h is co u ld p o s s ib ly h a v e e lim in a te d th e sh ift f r o m
m a t i n g s c o r e to a n o t h e r b e h a v i o r .
I f t h e c h a n g e t h a t c a m e a b o u t w a s of t h e k i n d d e s c r i b e d a b o v e , o n e
I
w o u l d e x p e c t t h a t t h e m o r e " t i m i d " b i r d s w o u ld , d u r i n g t h e . f i r s t t e s t ,
e n g a g e i n a r e l a t i v e l y g r e a t e r f r e q u e n c y of p i c k i n g c o m p a r e d t o . t h e l e s s
" tim id " m a l e s .
T h e r e s h o u l d a l s o b e a r e l a t i v e l y g r e a t e r i n c r e a s e in
t o t a l s c o r e f r o m t e s t o n e t o t e s t tw o .
T h e r e l a t i v e l y g r e a t e r i n c r e a s e in
m a t i n g s c o r e s i n t h e G - 5 is a p p a r e n t f r o m T a b l e V f o r t h e lo w g r o u p , a n d
a c o m p a r i s o n of t h e e a r l i e r w i t h t h e l a t e r g e n e r a t i o n s s h o w a n i n c r e a s i n g
r e g r e s s i o n b e t w e e n . t e s t o n e a n d t e s t tw o , s u p p o r t i n g t h e i n t e r a c t i o n of
s e l e c t i o n f o r lo w s c o r e a n d " t i m i d i t y . "
-128-
T h e e x p e c t e d r e l a t i v e l y g r e a t e r f r e q u e n c y of p i c k i n g d u r i n g t e s t o n e
w a s o b s e r v e d , a s t h e r e l a t i v e e f f ic ie n c y , i n a c h i e v i n g c o p u l a t i o n i n c r e a s e d
i n t h e lo w g r o u p th o u g h n o t in t h e h i g h .g r o u p - i n .t h e G -5 - ( S e e T a b l e V I I I ) .
T h e s e d a ta s u p p o r t th e c o n te n tio n th a t s e le c tio n w as confounded b e ­
t w e e n v e r y d i f f e r e n t b e h a v i o r s in b o t h g r o u p s .
In th e h ig h g ro u p , th e
s h i f t w a s f r o m c o p u l a t i o n t o T o w e r m a t i n g b e h a v i o r s a n d - i n t h e lo w l i n e ,
t h e e m p h a s i s i n t h e s e l e c t i o n c r i t e r i o n s h i f t etd f r o m c o p u l a t i o n t o . d i s ­
p la c e m e n t a c tiv itie s.
L a te n c y , i s h i g h l y s i g n i f i c a n t l y c o r r e l a t e d ( r = 0. 81) w ith , s c o r e i n a l l
s e le c te d m a le s .
T h e a v e r a g e - l a t e n c y , i n c r e a s e d in t h e T a s t g e n e r a t i o n ,
w h i c h m a y b e r e l a t e d - t o . t h e s h i f t i n s e l e c t i o n e m p h a s i s in b o t h l i n e s .
On
th e a v e r a g e , th e la te n c i e s a r e - l o n g e r th a n .th o s e r e p o r t e d by B e a c h and
■ In m an -(1 9 6 5 ).
T h e - s h o r t e s t l a t e n c y t o . c o p u l a t i o n w a s I. 4 s e c o n d s a n d
t h e l o n g e s t o n e m e a s u r e d a l m o s t 19 m i n u t e s .
T h e l o n g e r - l a t e n c i e s to
c o p u la tio n in th e . lo w lin e a l s o s u p p o r t th e -c o n te n tio n f o r " t i m i d i t y . "
The
a v e r a g e - l a t e n c i e s f o r t h e h i g h g r o u p a r e m u c h s h o r t e r i n . s p i t e of th e
g r e a t e r p e r c e n t a g e o f - m a l e s t h a t d i d n o t m a t e in t h i s - l i n e a s c o m p a r e d t o
t h e lo w l i n e .
. I t is c o n c l u d e d t h a t t h e m a t i n g b e h a v i o r o b s e r v e d d u r i n g t h i s s t u d y - .
c o n f o r m e d w e l l to t h a t d e s c r i b e d i n t h e l i t e r a t u r e .
C h a n g e s in .th e f r e -
-129-
q u e n c y of m a t i n g b e h a v i o r c o m p o n e n t s c a m e a b o u t a s a r e s u l t of s e l e c t ­
io n f o r i n c r e a s e d an d d e c r e a s e d m a tin g a c tiv ity .
T h e h ig h a n d lo w l i n e s
d if f e r e d c o n s id e r a b ly in t h e i r r e a c t i o n to b e in g h a n d le d to w a r d s th e en d
of t h e e x p e r i m e n t .
-130-
L IT E R A T U R E C IT E D
A b p l a n a l p , H . 1961.
2 :4 3 9 -4 4 8 .
L in e a r h e r lia b ility e s tim a te s .
G e n e tic a l R e s e a rc h .
A d r i a n i , J . I 9 6 0 . T h e P h a r m a c o l o g y o f A n e s t h e t i c D r u g s , f o u r t h ed .
S p r i n g f r i e l d , 111. , C . C .. T h o m a s , p . 77.
A l l e e , W. C . , N . E . C o l l i a s a n d C . Z . L u t h e r m a n . . 1939. M o d i f i c a t i o n
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