Some factors affecting the development of the eggs of the Mormon cricket (Anabrus simplex Hald)
by Orville B Hitchcock
A THESIS Submitted to the Graduate Committee in partial fulfillment of the requirements for the
degree of Master of Science in Entomology
Montana State University
© Copyright by Orville B Hitchcock (1939)
Abstract:
The experiments show that Mormon cricket eggs received the greatest stimulation when exposed to
-10°C.
Eggs which were hold at a constant temperature of 25°C. required more degree hours for hatching than
those which were alternated between 10° and 25°C.
Development in the Mormon cricket embryo continues throughout the winter regardless of the cold
temperatures to which they are subjected.
These cold temperatures have a stimulating effect upon the developing embryo.
The data on egg development does not indicate the presence of a true diapause in this stage of the life
cycle.
More oxygen was consumed per egg when they were alternated between 10° and 25°C. than when held
at a constant temperature of 25°C.
When eggs were alternated between 10° and 25°C. there was a much higher per cent hatch than when
they were held at a constant temperature of 25°C. In every case a higher per cent hatch was obtained in
the 10° cabinet.
Crickets which were confined in their activities by pen, barrier, etc., failed to lay fertile eggs.
Within wide limits soil moisture conditions have very little effect upon hatching of Mormon cricket
eggs. SOME FACTORS AFFECTIMG THE DEVELOFKERT OF THE EGGS
OF TEE IIORLIOM CRICKET (Anabrus sim p le x R aid)
Ly
O r v ill e B. H itchcock
A THESIS
S u b m itted t o th e G raduate Committee
in
p a r t i a l f u l f i l l m e n t o f th e re q u ire m e n ts
f o r th e d e g re e o f
M aster o f S c ie n ce i n Entomology
at
Montana S ta te C o lle g e
Approved:
In Charge o f M ajor Work
/3
i^m,
C hairm an, Exam ining Committee
C teylm ah, G raduate Committee
Bozenan, Montana
J u n e , 1939
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TABLE CF CONTENTS
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Fage
ABSTRACT .................. . . . . . . . . . . . . . . . . . . . . . .
J
INTROnUCTIOIT . . . . . . . . . . . . . . . . . . . . . . . . .
I*
LITERATURE . . . . . . . .
.................. . . . . . . . . . . . . .
5
. . . . . . . . . . . . . . . . . . .
8
STIMULATING EFFECT OF LOTT TIZPERATURES . . . . . . . . . . . .
IO
EFFECT OF ALTERNATING TETffERATURES
. . . . .
12
, , . . . .
13
PROCEDURE
...........................
. . . . . . . .
EFFECT OF FIELD THIPERATURES
EFFECT OF ALTERNATING TEMPERATURES ON FIELD EGGS
OXYGEN CONSUMPTION . . . . . . .
. .
... . . . . . . . . . . .
DIAPAUSE . . . . . . . . ...................... .... . . .
. . .
16
. . . . . . . .
19
TEMPERATURES PRODUCING MAXIMUM BATCH .....................................................
- 20
^
13
PER CENT HATCH
FERTILITY OBSERVATION . . . . . .
W '
EFFECT OF MOISTURE ON HATCHING
SUMMARY
. . . . . . . .
. . . .
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BIBLIOGRAPHY . . . . .
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63354
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15
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22
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25
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• . . . . . . .
21
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26
. ABSTRACT
The. e x p e rim e n ts show t h a t Eormon c r i c k e t eggs re c e iv e d th e
g r e a t e s t s tim u la tio n when exposed t o -IO eC.
Eggs w hich w ere h e ld a t a c o n s ta n t te m p e ra tu re o f 2 $ eC. r e q u ir e d
more d e g re e h o u rs f o r h a tc h in g th a n th o s e w hich w ere a l t e r n a t e d betw een
IO e and 25°C.
Development i n th e Uoraon c r i c k e t embryo c o n tin u e s th ro u g h o u t t h e
w in te r r e g a r d le s s o f t h e c o ld te m p e ra tu re s t o w hich th e y a r e s u b je c te d .
These c o ld te m p e ra tu re s have a s tim u la tin g e f f e c t upon th e d e v e lo p in g embryo.
The d a ta on egg developm ent does n o t i n d i c a t e th e p re s e n c e o f a
t r u e d ia p a u s e i n t h i s s ta g e o f t h e l i f e c y c le .
Uore oxygen was consumed p e r egg when th e y were a l t e r n a t e d b etw een
IOe and 2 5 eC. th a n when h e ld a t a c o n s ta n t te m p e ra tu re o f 2 $ eC. .
When eggs w ere a l t e r n a t e d betw een 10® and 25®C. th e r e was a much
h ig h e r p e r c e n t h a tc h th a n when th e y w ere h e ld a t a c o n s ta n t te m p e ra tu re o f
2$eC.
I n e v e ry c ase a h ig h e r p e r c e n t h a tc h was o b ta in e d i n t h e 10® c a b in e t.
C ric k e ts w hich w ere c o n fin e d i n t h e i r a c t i v i t i e s by p e n , b a r r i e r ,
e tc .,* f a i l e d t o la y f e r t i l e e g g s .
W ith in w ide l i m i t s s o i l m o is tu re c o n d itio n s liave v e ry l i t t l e
e f f e c t upon h a tc h in g o f Lloraon c r i c k e t e g g s.
'
INTRODUCTION
The Mormon c r i c k e t , A nahrus sim p le x (H a ld )f h as b e e n p r e s e n t i n
Montana f o r a g r e a t many y e a r s , b u t i t was n o t u n t i l 1926 t h a t i t was
re c o rd e d d o in g e x te n s iv e damage t o c r o p s .
S in ce t h a t tim e s e r io u s o u tb re a k s
have o c c u rre d i n p r a c t i c a l l y a l l p a r t s o f t h e S t a t e , w ith th e e x c e p tio n o f
th e n o r th e a s te r n c o u n tie s .
These o u tb re a k s have b e e n so s e r io u s t h a t i t has
b een n e c e s s a ry f o r th e F e d e ra l Governm ent, S t a t e , c o u n tie s , and in d iv id u a ls
t o expend la r g e sums o f money f o r eq u ip m en t, m a t e r i a l s , and la b o r i n t h e
p ro te c tio n o f c ro p s.
A lthough th e cam paigns have been q u ite e f f e c t i v e from
a c ro p p r o t e c t i o n s ta n d p o in t, m ore in f o r m a tio n co n ce rn in g th e e f f e c t o f
c lim a te , p a r a s i t e s , and o th e r f a c t o r s w o u ld , u n d o u b te d ly , be o f v a lu e i n
fo r m u la tin g a more e f f e c t i v e c o n tr o l program .
S in ce p r a c t i c a l l y no work h as b e e n done on th e eggs o f t h e Mormon
c r i c k e t , s tu d ie s on t h i s s ta g e o f t h e l i f e c y c le w ere u n d e rta k e n .
The
e x p erim en ts w ere c a r r i e d o u t i n a n a tte m p t t o o b ta in some d e f i n i t e in fo rm a tio n
on the following points*
(l) The presence or absence of a diapause period, %
(2) the effect of temperature on egg development, (3) the effect of moisture
on h a tc h in g , and (W g e n e r a l f a c t o r s a f f e c t i n g f e r t i l i t y .
Some d e f i n i t e
in fo rm a tio n on th e above f a c t o r s may a id m a t e r i a l l y i n p r e d i c t i n g w ith some
d eg ree o f a c c u ra c y , th e p o s s i b i l i t y o f t h e i n s e c t a p p e a rin g i n o u tb re a k
num bers.
The o c c u rre n c e o f a diapause p e rio d d u rin g th e egg s ta g e m ig h t
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. Ih s w r i t e r w ish es t o acknow ledge h is in d e b te d n e s s t o b o th D r.H .B .
M ills and Mr. James H. P epper f o r th e suggest!one-of th e p ro b le m , and f o r t h e i r
h e lp f u l s u g g e s tio n s and c r i t i c i s m s d u rin g th e c o u rse o f t h e s tu d y .
-
have c o n s id e ra b le e f f e c t on t h e tim e o f s p r in g h a tc h in g .
I f su ch a p e rio d
e x i s t s i t i s im p o rta n t t o know -when i t o c c u rs and w h at c o n d itio n s a r e
n e c e s s a ry to b re a k i t .
I f t h e r e i s no d ia p a u se i t i s d e s i r a b l e t o know how
much accum ulated te m p e ra tu re i s n e c e s s a ry t o d e v e lo p and h a tc h th e e g g .
Some knowledge o f t h e m o is tu re c o n d itio n s n e c e s s a ry f o r h a tc h in g
i s a l s o o f im p o rta n c e .
I t may be p o s s ib le t h a t a n e x tre m e ly w et o r d ry sea so n
m ig h t be u n fa v o ra b le f o r em ergence and t h a t t h e numbers o f c r i c k e t s would b e
g r e a t l y re d u c ed when t h e eggs a r e s u b je c te d to such c o n d itio n s .
There is
a ls o a p o s s i b i l i t y t h a t t h e u s e o f d u s t and a r t i f i c i a l b a r r i e r s may have some
e f f e c t upon th e f e r t i l i t y o f t h e a d u l t s .
T his p a p e r em bodies r e s u l t s o f e x p erim en ts w hich w ere c a r r i e d o u t
• i n a n a tte m p t to answ er th e above q u e s tio n s .
LITERATURE
C a ru th e rs (7) s t a t e s t h a t a low te m p e ra tu re , th o u g h i t i n t e r r u p t s
th e developm ent o f th e O rth o p te ra n em bryo, a c t s a s a s tim u lu s w hich
a c c e le r a te s developm ent a s soon a s t h e te m p e ra tu re i s r a i s e d .
He a l s o fo u n d
t h a t i n some s p e c ie s a te m p o ra ry c o o lin g seems t o be a c o n d itio n n e c e s s a ry
f o r norm al d ev elo p m en t, and e g g s k e p t a t a c o n s ta n t h ig h te m p e ra tu re from
th e tim e o f o v ip o s itio n f a i l to d e v e lo p .
Bodine (2) found t h a t t h e r a t e o f egg developm ent i n c e r t a i n
O rth o p te ra (g ra s s h o p p e rs ) was a f f e c t e d by te m p e ra tu re a n d , t h a t o th e r f a c t o r s
b e in g c o n s ta n t, t h e in c re m e n t i n r a t e seemed t o in c r e a s e i n d i r e c t p r o p o r tio n
to th e in c r e a s e i n te m p e ra tu re w ith in th e norm al l i m i t s o f d ev elo p m en t.
He
a ls o found t h a t ex p o su re t o low te m p e ra tu re s p ro d u ced an a c c e l e r a t i v e
e f f e c t on su b se q u e n t developm ent o f eggs a t c o n s ta n t te m p e r a tu r e s .
Uvarov (17) e x p la in s t h a t low te m p e ra tu re s p ro d u ce a n a c c e l e r a t i o n
i n t h e developm ent o f t h e O rth o p te ra n embryo o n ly when i t i s s u b je c te d to
t h e i r a c ti o n a t a d e f i n i t e s ta g e i n i t s d ev elo p m en t.
He s t a t e s t h a t i n
n a t u r e , m ost of th e A c rid id a e b e g in developm ent s h o r t l y a f t e r th e eggs a re
la id .
Development i s th e n i n t e r r u p t e d and o n ly resum es a g a in th e n e x t s p rin g
when t h e te m p e ra tu re , a f t e r w in te r c o o lin g , r i s e s above t h e d ev elo p m en tal
zero .
He f u r t h e r e x p la in s t h a t t h i s i n t e r r u p t i o n o f d ev elo p m en t, o r
em bryonic d ia p a u s e , c a n n o t be e x p la in e d by t h e a c t i o n o f low te m p e ra tu re s
b e c a u s e , i n many s p e c ie s o f te m p e ra te r e g io n s , o v ip o s itio n ta k e s p la c e q u ite
e a r l y i n autum n, o r even i n summer, and t h e d ia p a u s e b e g in s when te m p e ra tu re s
a r e w e ll above t h e d e v elo p m en ta l z e r o .
A ls o , a tte m p ts t o b re a k th e d ia p a u se
i n th e la b o r a to r y by k e e p in g eggs a t h ig h te m p e ra tu re s f a i l , a t l e a s t , i n
th e case o f c e r t a i n s p e c ie s .
T h is , he s a y s , i s in d ic a te d b y /th e f a c t t h a t ,
i n th e c a s e o f some t r o p i c a l s p e c i e s , t h e em bryonic d ia p a u se c o in c id e s w ith
th e d ry s e a s o n , and t h e eggs h a tc h a f t e r th e f i r s t r a i n .
Bodine (2) i n h i s work on t h e oxygen re q u ire m e n ts o f d e v e lo p in g
O rth o p te ra n eggs made th e fo llo w in g o b s e r v a tio n s .
The embryo f i r s t goes
th ro u g h a r a p id p e rio d o f'd e v e lo p m e n t an d , a f t e r re a c h in g a c e r t a i n s ta g e ,
i t u n dergoes h ib e r n a tio n w hich i s fo llo w e d b y an in c r e a s e i n a c t i v i t y o r
developm ent a s i s shown by t h e oxygen consum ption th ro u g h o u t th e s e s ta g e s .
He f u r t h e r s t a t e s t h a t su ch rhythm seems n e c e s s a ry f o r t h e n orm al developm ent
o f th e organism and t h a t i t i s o f i n t e r e s t t o n o te t h a t changes i n th e r a t e
o f oxygen consum ption tak e;; p la c e i n th e e a r l y s p r in g when th e te m p e ra tu re
i s c o n s id e ra b ly below th e s o - c a lle d d ev elo p m en tal z e r o .
From t h i s he
co n clu d es t h a t , in th e c a se of g ra s sh o p p e r e g g s , te m p e ra tu re i s n o t
n e c e s s a r i l y a l i m i t i n g f a c t o r i n c o n t r o l l i n g gas exchange d u rin g grow th o r
norm al d evelopm ent, and th e m o rp h o lo g ica l e v id en c e i n d i c a t e s t h a t d e f i n i t e
developm ent o c c u rs d u rin g th e s e p e rio d s even th o u g h t h e eggs a r e ex p o sed t o
te m p e ra tu re s su p p o se d ly below th o s e r e q u ir e d f o r n orm al d ev elo p m en t.
He a l s o
p o in te d o u t t h a t eggs w hich had b e e n exposed t o 2 5 * C ., when s u b se q u e n tly
r e tu r n e d t o low te m p e r a tu r e s , showed no n a rk e d d e c re a se i n r a t e o f developm ent
d e s p ite th e f a c t t h a t th e y w ere expo sed t o e x tre m e ly low te m p e r a tu r e s .
He
f u r t h e r s t a t e s t h a t dev elo p m en t, once s t a r t e d , seems in d e p e n d e n t, o r a t l e a s t ,
n o t c o r r e l a t e d , w i t h e x te r n a l te m p e r a tu r e s , b u t eggs w i l l n o t h a tc h a t th e s e
low te m p e ra tu re s i f l e f t c o n tin u a lly ex p o sed t o th e m .
He c o n clu d e s t h a t some
mechanism a c ts w ith in t h e eggs w h ich makes d ev elo p m en t, i n a m easu re,
in d e p e n d e n t o f e x te r n a l te m p e r a tu r e s . ;
P a rk e r ( 1 1 ) , i n h is w ork on th e eggs o f M elanonlus m exicanus
m exicanus S a u ssu re and Camnula p e llu c id a S cu d d er, found t h a t th e eggs p la c e d
a t c o n s ta n t h ig h te m p e ra tu re s th e day th e y w ere l a i d , h a tc h e d i n a n a v erag e
o f 26 d a y s, w h ile eggs p la c e d a t 0 ° im m e d ia te ly a f t e r t h e y w ere l a i d and l a t e r
p la c e d a t c o n s ta n t h ig h te m p e r a tu r e s , d e v elo p e d much more r a p i d l y and h a tc h e d
11 d ays a f t e r b e in g s u b je c te d t o a c o n s ta n t h ig h te m p e ra tu re .
Eggs w hich were
a llo w ed p a r t i a l developm ent a f t e r b e in g l a i d and th e n s u b je c te d t o lowte m p e ra tu re s showed an in c r e a s e i n r a t e o f developm ent when l a t e r r e tu r n e d
t o c o n s ta n t h ig h te m p e r a tu r e s .
Eggs p la c e d a t a l t e r n a t i n g te m p e ra tu re s
showed a g r e a t in c r e a s e i n r a t e o f developm ent o v e r eggs h e ld a t c o n s ta n t
te m p e ra tu re s .
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-G io d in e ( $ ) , i n h is w ork on oxygen consum ption o f M elanonlus
f f e r e n t i a l l s . k e p t a t c o n s ta n t h ig h te m p e ra tu re s from th e tim e o f la y in g
u n t i l h a tc h in g , o b ta in e d t h e fo llo w in g r e s u l t s .
T here i s a f a i r l y r a p id
r i s i n g r a t e o f oxygen consum ption d u rin g th e f i r s t t h r e e w eeks o f developm ent
w h ich i s fo llo w e d by an e q u a lly r a p id d e c re a s e t o a minimum v a lu e .
T his
r e l a t i v e l y low r a t e o f oxygen consum ption c o n tin u e s o v e r a p e r io d o f tim e
(d ia p a u s e ) a t th e end o f w hich a n in c r e a s e i n r a t e o c c u rs an d c u lm in a te s i n
t h e h a tc h in g o f th e eg g .
B u rk h o ld er ( 6 ) , when w ork in g w ith s in g le eggs o f Melanop.lus.
d i f f e r e n t i a l i s . found t h a t , i n g e n e r a l , c y c le s o r rhythm changes i n r a t e o f
oxygen consum ption s u b s t a n t i a t e r e s u l t s o b ta in e d upon l a r g e r numbers o f eggs
b y p re v io u s w o rk e rs .
PROCEDURE
On O cto b er 2k a la r g e number o f eggs w ere c o lle c te d from t h e f i e l d
n e a r B i l l i n g s , b ro u g h t i n t o th e la b o r a to r y and c a n d le d .
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Only th o s e w h ic h
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showed developm ent w ere s e le c te d f o r th e e x p e rim e n t.
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The eggs w ere d iv id e d
i n t o f i v e l o t s o f Ij-OO eggs e a c h , p la c e d i n m o is t sand and numbered fro m I
to 5 .
L ot I was p la c e d a t a c o n s ta n t te m p e ra tu re o f 25 C.
w ere c o o led t o v a ry in g low p o in ts i n t h e fo llo w in g m anner.
L o ts 2 t o 5
L ot 2 was h e ld a t
10*0 , f o r one d a y , 2 *0 . f o r one d a y , r e tu r n e d t o 1 0 *0 . , and p la c e d a t 2 5 *0 .
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■ - : .
on t h e s i x t h d a y .
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'-V
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L ot 3 was s i mi l a r l y co o led t o - 5 * 6 ., r a i s e d t o 10*0. and
t r a n s f e r r e d to 25*0. on th e s i x t h d a y .
Lot Zj. was c o o le d t o -1 0 * 0 . and l o t 5
t o - 15ec . and th e n b o th w ere b ro u g h t up t o 25*0.
On t h s s i x t h day a l l l o t s
w ere at 25*0. c o n s ta n t te m p e ra tu re and IOOJo r e l a t i v e h u m id ity .
The fo re g o in g tr e a tm e n t i s t a b u l a t e d i n t a b l e I :
TABLE !.-T e m p e ra tu re s t o w hich Mormon c r i c k e t eggs w ere s u b je c te d i n
s tu d y o f e f f e c t o f c o o lin g on egg d ev elo p m en t.
Lot I
Temp.
Days
25*
7
-
Lot 2
Temp. Days
10*
I
2
I
10
h
25 ■ I
■ Lot ?
Temp. Days
I
10*
I
2
I
-5
10
3
I
25
L ot Ii
Temp. Days
10*
I
2I
I
-5 '
-10
I
2
10
I
25
Lot 5
Temp. Days
10*
I
I
2
I
-5
I
-1 0
I
-15
10
I
I
25
, .
On t h e s e v e n th day e a c h l o t was r e d iv id e d in to two l o t s o f 200 eggs
each.
One o f t h e s e was k e p t a t 25* c o n s ta n t te m p e ra tu re and t h e o th e r
a l t e r n a t e d f o r one day i n t e r v a l s betw een 25°C . and 10*0.
;
Eggs w ere c o l l e c t e d from t h e same a r e a i n th e f i e l d a t i n t e r v a l s
o f a p p ro x im a te ly two weeks th ro u g h o u t t h e w i n t e r .
s e le c te d i n t h e same m anner a s t h e above e g g s .
l o t s o f 200 each and p la c e d i n m o is t s a n d .
These w ere c a n d le d and
They w ere d iv id e d i n t o tw o
One l o t was h e ld a t a c o n s ta n t
te m p e ra tu re o f 2 5 *0 . a n d t h e o th e r a l t e r n a t e d betw een 25*0 . and 10*0 . a s
p r e v io u s ly d e s c r ib e d .
Eggs w ere c o l l e c t e d o n th e fo llo w in g d a t e s : IIov. 8 ,
Mov. 2 2 , D ec. 6 , Dec. 2 1 , J a n . 7» and J a n . 2 J .
As soon a s th e f i r s t eggs c o l l e c t e d on O cto b er 21+ w ere s u b je c te d
t o th e above tr e a tm e n t, 20 eggs w ere ta k e n from e ac h l o t and p la c e d i n a
B a r c r o ft d i f f e r e n t i a l manometer and t h e r a t e o f oxygen consum ption d e term in e d
Eggs w hich w ere c o l l e c t e d l a t e r i n t h e f i e l d w ere a l s o ru n i n t h e manometer
im m ed iately a f t e r b e in g b ro u g h t i n t o th e l a b o r a t o r y .
Twenty eggs from e ac h
l o t w ere ru n a g a in a t i n t e r v a l s o f a p p ro x im a te ly JO d a y s .
T his p ro c e d u re was c o n tin u e d th ro u g h o u t th e e x p e rim e n ta l p e r io d .
STIMULATING EFFECT OF LOW TEMPERATUBES
The m ost s a t i s f a c t o r y way t o e x p re s s th e a c c u m u la tiv e e f f e c t o f
te m p e ra tu re s i s by means o f d e g re e h o u r s .
O th e r m ethods have b e en u sed b u t
th e y do n o t g iv e an a c c u r a te com parison betw een d i f f e r e n t l o t s .
A d e g re e
hour i s d e fin e d a s t h e p ro d u c t o f th e te m p e ra tu re , , ( i n d e g re e s C e n tig ra d e )
tim e s th e number o f h o u rs a t w hich th e eggs w ere exposed t o su ch te m p e ra tu re .
I n t h i s way a l l changes i n te m p e ra tu re can be e x p re s s e d on a common b a s i s .
C ric k e t eggs w h ich had n o t y e t b e en exposed t o c o ld te m p e ra tu re s
i n th e f i e l d w ere c o l l e c t e d .
The e g g s w ere b ro u g h t i n t o t h e la b o r a to r y and
w ere s u b je c te d to v a ry in g low te m p e ra tu re s a s shown i n T ab le I .
They w ere
h e ld a t a c o n s ta n t te m p e ra tu re o f 25 #C. u n t i l no f u r t h e r h a tc h in g to o k p la c e .
The eggs w hich were n o t exposed t o low te m p e ra tu re s r e q u ir e d t h e g r e a t e s t
number o f d e g re e h o u rs t o com plete th e h a tc h in g .
When th e eggs w ere s u b je c te d
to low te m p e ra tu re t h e r e was a v e ry n o tic e a b le s tim u la tin g e f f e c t .
The
g r e a t e s t s tim u la tio n to o k p la c e i n th e eggs w h ic h w ere low ered t o -1 0 * .
These
r e q u ir e d 10,207 d e g re e h o u rs l e s s th a n th o s e w hich had had no p re v io u s c o ld
tr e a tm e n t.
When th e eggs w ere lo w e re d to -15* th e r e was a r e t a r d i n g e f f e c t .
I t to o k 5 ,5 5 0 more d e g re e h o u rs f o r t h e eggs t o h a tc h th a n th o s e w hich had
b een low ered to -1 0 * .
-10
Thus i t w i l l be se e n t h a t lo w e rin g th e te m p e ra tu re to
d e c re a se d th e number o f d e g re e h o u rs b y a p p ro x im a te ly 1 0 ,0 0 0 when compared
w ith u n tr e a te d e g g s .
As th e te m p e ra tu re was lo w ered from a p p ro x im a te ly 25*C.
t o 5 *C. t h e r e was a g ra d u a l d e c re a s e i n h a tc h in g tim e .
From 5 * t o -1 0 * 0 . a
r a p id d e c re a se to o k p la c e b u t when low ered t o - 15* t h e r e was a m arked in c r e a s e
i n t h e d e g re e h o u rs n e c e s s a ry to h a tc h t h e e g g s.
i n Table I T and shown g r a p h ic a ll y i n f i g u r e I .
These d a ta a r e ta b u l a t e d
-
11 -
TABLE I I .- D e g r e e h o u rs n e c e s s a r y to h a tc h eggs c o l l e c t e d O ctober 2Z4. a f t e r
b e in g s u b je c te d t o t h e v a ry in g te m p e ra tu re s g iv e n i n T ab le I .
Lot No.
I
2
3
b
A verage
Eggs h e ld a t a c o n s ta n t
te m p e ra tu re o f 2 5 eC
a f t e r tr e a tm e n t
% H atch
Degree h o u rs
n e r ea?
'
35,257
1 0 .5
5 0 ,0 0 0
1 1 .5
2 6 ,2 5 0
0 .0
2 5 ,0 5 0
7 .5
2 .0
30.600
5 1 ,1 0 1
Eggs s u b je c te d t o a l t e r n a t i n g
te m p e ra tu re s o f IOeC and 25*0
a f t e r tr e a tm e n t
D egree h o u rs
% Hatch
n e r e ez
2U,908
5 9 .0
2 3 ,bob
1 2 .5
5 0 .0
22,2b5
20,165
51+.5
23.857
Ii 3 .5
7 .9
22,915
35000
CONSTANT
<3 25000
TEMP. Zd'c
ITERNATING TEMP. IO-ZSeC
20000
TEMPERATURE IN DEGREES CENTIGRADE
F ig u re I .
1*9.9
- 12-
.
EFFECT CF AITEEIIATIUG TELTERATIffiES
The eggs w ere t r e a t e d a s shown i n T able I and w ere th e n s u b je c te d
t o a l t e r n a t i n g te m p e ra tu re s o f 10* and 25°C. f o r e q u a l p e r io d s o f 21+ h o u rs . Twenty f o u r th o u san d n in e hundred and e ig h t (21+,908) d e g re e h o u rs w ere
n e c e s s a ry t o h a tc h eggs w hich w ere n o t s u b je c te d to c o ld te m p e r a tu r e s .
As
i n th e p re v io u s e x p e rim e n t, th e g r e a t e s t s tim u la tio n to o k p la c e a t - 10*.
A t t h i s te m p e ra tu re o n ly 20,165 d e g re e h o u rs w ere n e c e s s a ry t o h a tc h th e e g g s .
A gain a r e t a r d i n g e f f e c t was produced in th e eggs w hich w ere lo w ered t o -15*
and 23 ,8 5 7 d eg ree ho u rs w ere r e q u ir e d t o h a tc h th e m .
A com parison betw een
th e eggs n o t s u b je c te d to low te m p e ra tu re s and th o s e low ered t o - 1 0 “ show
t h a t a p p ro x im a te ly I+,700 d eg ree h o u rs m ore w ere n e c e s s a ry t o h a tc h th e eggs
w hich had load no p re v io u s tr e a tm e n t.
I t a ls o to o k 3#692 d eg ree h o u rs more
t o h a tc h th e eggs w hich were low ered t o - 15* th a n th o s e w h ich were s u b je c te d to
-10 *
A gain th e r e was a g ra d u a l d e c re a s e i n d e g re e h o u rs n e c e s s a ry t o h a tc h
th e eggs a s th e te m p e ra tu re was low ered from a p p ro x im a te ly 2 5 * t o - 2 *.
From
- 2 * t o - 10* t h e r e was a r a p i d d e c re a s e and from - 10* t o - 1 5 * th e r e was a
r a p id in c r e a s e i n th e d e g re e h o u rs r e q u ir e d f o r h a tc h in g .
These d a ta a r e
re c o rd ed i n T able I I and shown g r a p h ic a ll y i n f ig u r e I .
A com parison o f th e eggs w hich were h e ld a t a c o n s ta n t te m p e ra tu re
o f 25* and th o s e w hich w ere a l t e r n a t e d b etw een 10* and 2 5 * show t h a t t h e r e i s
a v e ry d e f i n i t e a c c e l e r a t i o n p ro d u ced by th e a l t e r n a t i n g te m p e r a tu r e s .
An
av erag e o f 31*101 d eg ree h o u rs was n e c e s s a ry t o h a tc h t h e eggs a t a c o n s ta n t
,
te m p e ra tu re .
hours l e s s . .
:
'
■
■
’
:
:
.
;
.
1
...
Those w hich w ere a l t e r n a t e d av erag ed o n ly 2 2 ,9 1 5 , o r 8 ,1 8 6 d e g re e
-1 3 EFFECT. OF FIELD TEMPERATURES
The eggs "which w ere u s e d i n t h e s e e x p e rim e n ts w ere c o l l e c t e d a t tw oweek i n t e r v a l s from O ctober 2l± t o Ja n u a ry 2 $ .
c o n s ta n t te m p e ra tu re o f 25*0.
A ll e x p e rim e n ts w ere ru n a t a
The v a r io u s l o t s showed a su b seq u en t d e c re a s e
i n th e number o f d e g re e hours p e c e s s a ry f o r h a tc h in g .
T h i r t y - f i v e th o u san d
two hundred and f i f t y sev e n ( 3 5 *257) d e g re e h o u rs w ere r e q u ir e d t o h a tc h eggs
c o lle c te d on O ctober 2 4 .
Those t h a t w ere b ro u g h t i n from t h e f i e l d a t
su b seq u en t i n t e r v a l s o f a p p ro x im a te ly two weeks showed a s te a d y d e c re a s e i n
th e number o f d e g re e h o u rs r e q u ir e d f o r h a tc h in g .
The l a s t l o t o f eggs w hich
were c o lle c te d on Jan u a ry 25 r e q u ir e d o n ly 6,571 d eg ree h o u rs .
T h is was
28 ,886 l e s s th a n w ere n e c e s s a ry f o r th e eg g s w h ich w ere b ro u g h t i n on
O ctober 2 ^ .
See T able I I I and f i g u r e 2 .
EFFECT OF ALTERNATING TEMPERATURES OH FIELD EGGS
Eggs w ere c o l l e c t e d as i n th e p re v io u s e x p erim en t and a l t e r n a t e d
betw een 10
and 25*.
They, a l s o , showed a la r g e d e c re a s e i n th e number o f
d eg ree h o u rs n e c e s s a ry f o r h a tc h in g .
The e g g s t h a t were b ro u g h t i n from th e
f i e l d on O ctober 2lj. h a tc h e d i n 2l|.,908 d e g re e h o u r s .
There was a r a p id d e c re a s e
i n th e number o f d e g re e hours n e c e s s a ry t o h a tc h t h e eggs w hich w ere c o l l e c t e d
a t la te r d a te s .
Jan u a ry 2 5 .
Only 6>520 w ere r e q u ir e d f o r th o s e t h a t w ere b ro u g h t i n on
T his was 18,588 l e s s th a n w ere r e q u ir e d f o r th e eggs c o lle c te d .
on O ctober 2I4. a p p ro x im a te ly t h r e e months e a r l i e r .
See T ab le I I I and f ig u r e 2 .
-
table
14 -
I II .-D e g r e e h o u rs n e c e s s a r y t o h a tc h eggs c o l l e c t e d a t d i f f e r e n t
p e rio d s d u rin g t h e w in te r from O ctober 2 4 t o Jan u ary 2 3 .
E g g s.h e ld a t a c o n s ta n t
tenrne n a tu re . o f 26*0
Degree h o u rs
# H atch
n e r ec?
1 0 .5
55,257
1 3 .0
21,646
18,600
5 -5
13,266
4 .5
8 .5
7 ,658
8 ,4 0 0
1 1 .5
6.371
1 0 .5
D ate
c o lle c te d
O c t. 24
Nov. ' 8
Nov. 22
D eo. 6
D ec. 21
Jan. 7
J a n . 2?
A verage
15,885
8 .8
Eggs s u b je c te d t o a l t e r n a t i n g
te m p e ra tu re s o f in * n <md P5er:
D egree h o u rs
% H atch
ner e c r
24,908
5 9 .0
16,403
4 6 .5
16,422
5 4 .5
1 1 ,0 5 4
6 4 .5
6,751
6 2 .5
7 ,5 0 9
’ 6 8 .0
* 6 .3 2 0
9 0 .5
1 2 ,7 6 6
6 3 .6
34000
30000
(9 26000
cl
«
«
22000
CONSTANT TEMP. 25°C.
ALTERNATING TEMP. IOe-25 *C.
1 18000
o 14000
NOV 13 . NOV23
DECS
DEC 13 DEC 23
date collected
JAN2
JAN 12
J A N 22
- .
-1 5 - ::::
OXIGEU C0ITSTMPTI01I
A com parison o f th e r a t e o f oxygen consum ption o f eggs h e ld a t a
c o n s ta n t te m p e ra tu re o f 25*0 . and th o s e a l t e r n a t e d betw een 10* and 25*0 .
show t h a t th e a l t e r n a t i n g te m p e ra tu re s have a s tim u la tin g e f f e c t on th e e g g s.
A ll o f t h e s e eggs w ere s u b je c te d t o th e v a ry in g te m p e ra tu re c o n d itio n s
shown i n T able I .
Those h e ld a t 25*0. had an a v erag e r a t e o f oxygen
consum ption o f 2.510x1O- ^ c c . o f Og p e r egg f o r a 2 -h o u r p e r io d .
The eggs
w hich w ere s u b je c te d t o th e a l t e r n a t i n g te m p e ra tu re s consumed 2 .^ 8 7 x l0 -3 c c .
o r .177xlO ”* c c . more p e r e g g .
L ikew ise th e eggs c o lle c te d from th e f i e l d
th ro u g h o u t th e w in te r and a l t e r n a t e d betw een 10* and 25*0 . consumed .519xl0~3
c c . o f Og more th a n th o s e w h ich w ere h e ld a t t h e c o n s ta n t te m p e ra tu re .
T h is
in c r e a s e i n oxygen consumed i n d i c a t e s g r e a t e r em bryonic a c t i v i t y and i s i n
l i n e w ith p re v io u s d a ta w hich shows s tim u la tio n i n th e eggs w hich w ere
a l t e r n a t e d betw een 10* and 25*0.
Twenty eggs w ere p la c e d i n th e manometer
f o r e a c h e x p erim en t an d s in c e th e eggs a re sm all i t is ob v io u s t h a t r e l a t i v e l y
sm all amounts o f oxygen w ould be consumed.
The E a r c r o f t d i f f e r e n t i a l
manometer i s an e x tre m e ly s e n s i t i v e in s tru m e n t and c a p a b le o f m easu rin g
a c c u r a te ly such sm all q u a n t i t i e s .
w? j w , - .
.
-
16 -
TABLE IV .-A verage amount o f oxygen consumed (cci.x lO -3 ) p e r c r i c k e t egg
. i n a 2 -h o u r p e r io d .
.■
Eggs s u b je c te d t o low te m p e ra tu re s
o u tlin e d in Table I .
C o n sta n t 25 ° A lte r n a tin g ,
L o t.
10 and 25°
Uo.
c c . 02 x 10 -3
c c . OgxlO^)
o e r ee.e?
n e r ece
I
2 .0 8 2
3 .1 8 9
1
.8
1
3
2
3 .0 3 7
2.183
2 .0 6 9
5
2 .3 5 5 ■
2 .0 5 6 .
b
2 .781 „
• 2.1+25
5
Average
2 .310
2.1+87
:
P e r io d i c a l c o l l e c t i o n s from
th e f i e l d
D ate
C o n sta n t 25 6 A lte r n a tin g
c o lle c te d ■
10 and 25°
CCeO2 XlO- S
c c . OpxlO-S
n e r ene- n e r erst
O c t. 21+
. 2 .0 8 2
3 .1 8 9
Uov. 8
' 3 .0 5 7
3 .6 2 9
2 .5 7 0
Uov. 22
3 .1 6 6
2 .7 0 8
Dec. 6
3 .6 8 6 ■■
1.721
Dec. 21'
3 .1 3 7
2 .7 8 6
Jan. 7
5 .MiO
-
Average
2.671
3 .1 9 0
•
DIAPAUSE
The d a ta o b ta in e d from f i e l d eg g s show t h a t r e g a r d le s s o f low
te m p e r a tu r e s , th e eggs c o n tin u e t o d ev elo p
th ro u g h o u t th e w in te r .
They even
seem t o be s tim u la te d by t h e low te m p e ra tu re s t o w hich th e y tir e s u b je c te d .
I n th e l a t e f a l l th e p re s e n c e o f w h a t a p p e a rs t o b e a f u l l y d e v elo p e d embryo
h as le d t o th e b e l i e f t h a t a t r u e d ia p a u s e e x i s t s d u rin g t h i s p e r io d o f th e
i n s e c t ’s l i f e c y c le .
The s u p p o s itio n has b e en t h a t th e d ia p a u se p e r io d
b e g in s i n th e f a l l b e fo re c o ld w e a th e r s e t s i n and t h a t i t l a s t s u n t i l th e
w e ath e r warms up i n th e s p r in g .
.
, , ;
^
There seems to be some d isa g re e m e n t among b i o l o g i s t s a s to w hat
r e a l l y c o n s t i t u t e s a d ia p a u se and w h a t c a u se s i t t o ta k e p l a c e .
, ■-
I t may be
V
c o n sid e re d a s a d e f i n i t e in h e r e n t c h a r a c t e r i s t i c p o s s e s s e d b y th e i n d iv id u a ls ,
o t i t may be th e r e s u l t o f e x te r n a l e c o lo g ic a l f a c t o r s .
-
.
-
I n any e v e n t th e
-
p resu m p tio n i s t h a t a l l p h y s io lo g ic a l fu n c tio n s a r e a t a minimum.
'
U n fo rtu n a te ly
•
.
-1 7 -
t h i s i s b a se d u s u a lly on v i s u a l o b s e rv a tio n s and does n o t o f te n in c lu d e
r e a c tio n s o f a chem ical n a tu r e w hich may be e s s e n t i a l f o r t h e f u r th e r
developm ent o f t h e o rg a n ism .
A s tu d y o f t h e e x i s t i n g l i t e r a t u r e on d ia p a u s e
w i l l s u b s t a n t i a t e th e p re c e d in g s ta te m e n ts .
Eenneguy ( 10) d e fin e d d ia p a u s e
as a c e s s a tio n o f a c t i v i t y , em bryonic o r o th e rw is e , and n o t n e c e s s a r ily
c o n d itio n e d by te m p e ra tu re .
TJvarov ( l 6 ) s t a t e s t h a t d ia p a u s e sh o u ld b e
r e s t r i c t e d t o c a s e s i n w hich a c t i v i t y o r developm ent i s a r r e s t e d s p o n ta n e o u s ly .
Tfhen a c t i v i t y o r developm ent i s i n t e r r u p t e d by th e d i r e c t in f lu e n c e o f
u n fa v o ra b le c o n d itio n s , and resum ed a s soon as th e c o n d itio n s become f a v o r a b le ,
a q u ie s c e n t s ta g e r e s u l t s w hich c an n o t be c l a s s i f i e d as d ia p a u s e .
He f u r t h e r
s t a t e s t h a t d ia p a u se may o c c u r i n any s ta g e o f developm ent o f an i n s e c t and
em bryonic d ia p a u s e s a r e e x e m p lifie d by t h e eggs o f g ra s s h o p p e rs .
Boyce (5 )
i n h i s w ork on th e d ia p a u s e phenomenon o f i n s e c t s d e f in e s d ia p a u s e a s a s t a t e
o f s p o n ta n e o u sly a r r e s t e d developm ent b ro u g h t a b o u t d i r e c t l y by p h y s io lo g ic a l
fa c to rs .
He s u g g e s ts t h a t some o f t h e cau ses o f d ia p a u se may be d r y n e s s , *
c o ld , h e a t , hydrogen io n c o n c e n tr a tio n , enzym es, horm ones, and Houbands
h y p o th e s is o f urem ic p o is o n in g .
S l i f e r ( 13) , woricing on th e eggs o f M elanonlus
d i f f e r e n t i a l ! s . found t h a t th e eggs d ev elo p a t 2 5 *0 . f o r a th re e -w e e k s 1 p e rio d
a t w hich tim e th e y c e a se developm ent and e n te r a t r u e d ia p a u s e .
D uring t h i s
d ia p a u se no m i t o t i c s p in d le s a r e fo u n d and developm ent seems c o m p le te ly
a rre ste d .
V
A:.'
F aure (9) e x p la in s t h a t th e eggs o f L o cu sta p a r d a lin a l i e dormant
i n d ry s o i l f o r many months and t h a t th e y may be e x p e c te d t o h a tc h a b o u t t e n
days a f t e r th e f i r s t r a i n i n warm w e a th e r.
days o ld w i l l h a tc h i f m o is tu re i s a d d e d .
He fo u n d t h a t eggs one t o fo u r te e n
I f no m o is tu re i s added and th e
eggs a r e l e f t d ry th e y w i l l re m a in I n d ia p a u s e a s lo n g a s th r e e y e a r s .
M o istu re , i n h i s o p in io n , seems t o be th e f a c t o r c o n t r o l l i n g d ia p a u se i n
th is c ase.
Bodine (3 ) s t a t e s t h a t d ia p a u se i n t h e eggs o f M elanoulus
d i f f e r e n t l a l i s i s , w ith in l i m i t s , in d e p e n d e n t o f te m p e ra tu re above d ev elo p m en tal
zero f o r i t s o c c u rre n c e , b u t r e l a t i v e l y dependent on te m p e ra tu re s above developm ental z e ro f o r i t s d u r a tio n .
th e d ia p a u se f a c t o r i n th e s e e g g s .
Lov/ te m p e ra tu re s 10* t o 0°C . d e s tr o y
Bodine (U) s t a t e s t h a t t h e - s o - c a l l e d
d ia p au se f a c t o r s can b e th o u g h t o f i n s e v e r a l w ay s, e i t h e r a s c h e m ic a l,
p h y sico -ch e m ic al o r p e rh a p s p h y s io lo g ic a l g e n e tic f a c t o r s p r e s e n t i n more o r
l e s s c o n s ta n t amounts i n th e egg a t th e tim e of la y in g .
These d ia p a u s e f a c t o r s
i n th e egg o f JI. d i f f e r e n t a l i s d u rin g th e c o u rse o f t h r e e w e ek s' developm ent
in c r e a s e e i t h e r i n p o te n cy o r amount u n t i l th e y r e a c h a c e r t a i n th r e s h o ld
v a lu e , a t w hich tim e th e y i n h i b i t a l l d ev elo p m en tal p r o c e s s e s .
TThen k e p t a t
a c o n s ta n t h ig h te m p e ra tu re th e s e f a c t o r s g r a d u a lly lo s e t h e i r p o te n c y o r
s tr e n g th , and a f t e r a p e r io d of tim e d ev elo p m en tal f a c t o r s g a in an u p p e r hand
and norm al developm ent e n s u e s .
Low te m p e ra tu re s w i l l , how ever, d e s tr o y th e
d ia p au se f a c t o r s and when eggs s u b je c te d t o low te m p e ra tu re s a re th e n p u t a t
h ig h te m p e ra tu re s , norm al developm ent w i l l im m ed iately b e g in .
S l i f e r (ill) found t h a t th e g ra s sh o p p e r embryo tw e n ty days o ld b e g in s
a long em bryonic d ia p a u s e and by com paring embryos e i g h t d ay s o r a month
o ld e r s u p e r f i c i a l l y , a t l e a s t , th e r e i s no f u r t h e r d ev elo p m en t.
I f such
embryos a r e f i x e d , s e c tio n e d , s t a i n e d , and examined m ic r o s c o p ic a lly t h e y . w i l l
b e fo u n d t o c o n ta in few o r no d iv id in g c e l l s .
Embryos l e s s th a n th r e e w eek o f
a g e , on th e o th e r h an d , d is p la y g r e a t numbers o f m i t o t i c f i g u r e s .
There i s
a ls o no c h a n g e -in th e p o s i t i o n o f th e mebryo d u rin g t h e d ia p a u s e p e r io d .
-
19 -
E ic h a rd s (12) s t a t e s t h a t d ia p a u s e i n d i s t i n c t i o n t o h ib e r n a tio n
i s an in h e r e n t o b lig a to r y c h a r a c t e r i s t i c w hich may be in d e p en d e n t o f
te m p e ra tu re f o r i t s o c c u rre n c e , th o u g h i t s d u r a tio n i s a f f e c t e d by te m p e ra tu re
and o t h e r f a c t o r s .
I t i s m a n ife s te d a s a r e t a r d a t i o n o r c e s s a tio n o f g ro w th ,
m i t o s i s , m e ta b o lism , and m ovements.
I t o c c u rs a t d i f f e r e n t s ta g e s i n
d i f f e r e n t s p e c ie s b u t a lm o st alw ays a t a p a r t i c u l a r d ev elo p m en tal s ta g e i n
any one s p e c ie s .
I f d ia p a u se in v o lv e s a g r e a t r e d u c tio n i n p h y s io lo g ic a l a c t i v i t y
th e n th e d a ta o b ta in e d in d ic a te t h a t su ch a c o n d itio n a p p a r e n tly d o es n o t
e x i s t i n Mormon c r i c k e t eggs d u rin g th e p e rio d i n w hich
made.
o b s e rv a tio n s w ere
T his i s deduced from t h e d a ta o b ta in e d from eggs c o l l e c t e d a t
a p p ro x im a te ly tw o-w eek i n t e r v a l s from O cto b er 2tj. t o Ja n u a ry 23 •
There was
a s u c c e s s iv e d e c re a s e i n d e g re e h o u rs n e c e s s a ry t o h a tc h th e eggs i n th e
la b o r a to r y f o r e ac h c o l l e c t i o n a s t h e w in te r p r o g r e s s e d .
T h is e x p la in s t h a t
th e r e was c o n tin u o u s p h y s io lo g ic a l a c t i v i t y i n th e embryo d u rin g , t h i s p e r io d .
PEE CENT HATCH
T em perature c o n d itio n s have a m arked e f f e c t upon th e p e rc e n ta g e
o f Mormon c r i c k e t eggs w hich h a tc h .
T h is may be see n b y making a com parison
• o f eggs w hich were h e ld a t a c o n s ta n t te m p e ra tu re o f 25 C. "with th o s e w hich
w ere s u b je c te d t o a l t e r n a t i n g te m p e ra tu re s o f 10® and 2 5 eC. (T able I l ) .
■
•
-
.
.
-
/
.
-
;
-
%
-
:
:
.
In
■
th e c a s e o f t h e eggs w hich w ere c o lle c te d O ctober 2I4. and s u b je c te d t o th e
v a ry in g low te m p e r a tu r e s , a s shown i n T able I , a much h ig h e r p e r c e n t h a tc h
was o b ta in e d .in th o s e s u b je c te d t o t h e a l t e r n a t i n g te m p e ra tu re s (1+9.9^)# th a n
th e eggs h e ld a t th e c o n s ta n t te m p e ra tu re (7«9z«).
T h is was a l s o t r u e o f t h e eggs w hich w ere c o lle c te d from th e
f i e l d a t i n t e r v a l s th ro u g h o u t th e w in te r .
In t h i s c a s e 63»6/2 o f th o s e
s u b je c te d t o th e a l t e r n a t i n g te m p e ra tu re s h a tc h e d a s compared w ith 8 .8 # a t
c o n s ta n t te m p e ra tu re .
See T able I I I .
T h is i s f u r t h e r p ro o f t f th e s tim u la tin g e f f e c t o f a l t e r n a t i n g
te m p e ra tu re s .
. mTEEATUBBS PRODUCING MAXIMUM HATCH
Tflhen c r i c k e t eggs a r e a l t e r n a t e d f o r 2^. h o u r p e rio d s betw een 25 C
t o IO eC ., a la r g e p e rc e n ta g e o f th e h a tc h o c c u rs on th e days when th e y a re
s u b je c te d t o th e low er te m p e ra tu re .
Of t h e eggs c o lle c te d O cto b er 2t* and
t r e a t e d a c c o rd in g t o T able . I , 6 1 .0 3 # o f them h a tc h e d i n th e 10° c a b in e t,
w h ile o n ly 3 8 .9 6 # o f them h a tc h e d i n th e 2 5 * c a b in e t.
T his was a l s o t r u e o f th e eggs w hich w ere c o l l e c t e d a t i n t e r v a l s
th ro u g h o u t th e w i n t e r .
The p e r c e n t h a tc h f o r th e s e groups o f eggs w ere
7 7 .6 2 # a t 10° and o n ly 2 2 .3 8 # a t 25e S
See T ab le V.
TARTR v .- P e r c e n t h a tc h a t th e d i f f e r e n t te m p e ra tu re s d u rin g a l t e r n a t i o n .
Eggs s u b je c te d t o v a ry in g
Tmv te m n e n a tu re s
# h a tc h
L o t. Ho.
# h a tc h
a t 26 eC.
a t 10°C.
I
4 5 .5 7 .
5W+3
2
3 6 .0 7
63.93
6 1 .6 6
3
3 8 .3 4
5 8 .8 2
4 1 .1 8
U
3 3 .6 7
■ 5 . ■ ■ 66.33
;
Average.
61.03
3 8 .9 6
F ie ld Eggs
■
# h a tc h
D ate
c o lle c te d a t 10°C.
O c t. 2l±
5 4 .4 3
ITov. 8
7 2 .3 2
Hov. 22
6 6 .6 6
Dec. 6
8 4 .4 2
Dec. 21
9 0 .4 0
Jan. 7
8 0 .1 4
J a n . 21 ' 9 6 .0 2
Average
7 7 .6 2
# h a tc h
a t 26°C.
4 5 .5 7
2 7 .7 8
3 3 .3 4
' 1 5 .5 8
9 .6 0
1 9 .8 6
4 .9 8
2 2 .3 3
FERTILITY OBSEEVAlIOIi
O b se rv a tio n s made i n th e f i e l d th e l a s t two y e a r s , 1937-1958»
in d i c a t e t h a t f i e l d a c t i v i t i e s , s u c h a s d u s tin g and th e u s e o f m e ta l b a r r i e r ,
have a marked, e f f e c t upon t h e f e r t i l i t y o f t h e eggs l a i d i n th o s e a r e a s w here
e x te n s iv e c o n tr o l o p e r a tio n s have b e e n c a r r i e d o n .
A lth o u g h th e c o n tr o l
work g r e a t l y red u ced th e c r i c k e t p o p u la tio n s th e y w ere s t i l l p r e s e n t i n
s u f f i c i e n t numbers t o b r in g th e p o p u la tio n back t o i t s o r i g i n a l s t a t e .
m a n y ,c a s e s , how ever, t h i s d id n o t happen.
In
The eggs a p p a r e n tly w ere n o t
f e r t i l e , a t l e a s t th e y d id n o t d e v elo p and h a tc h .
As a r e s u l t o f t h i s i t
was n o t n e c e s s a ry t o c a r r y on c o n tr o l work i n th e s e a re a s th e fo llo w in g y e a r .
On t h e 1 2 th o f J u ly a p p ro x im a te ly 120 fem ale c r i c k e t s w hich had
c o p u la te d i n th e f i e l d w ere c o l l e c t e d and b ro u g h t in to th e la b o r a to r y .
These
w ere p u t i n t o pens h a v in g a la y e r o f sand on th e b o tto m i n w hich th e eggs w ere
d e p o s ite d .
The eggs w ere s i f t e d o u t e v e ry e v e n in g , p la c e d i n sa n d , and p u t o u t
o f d oors f o r s e v e r a l w eek s.
c o ld w e a th e r s e t i n .
c a n d le d .
They were b ro u g h t i n t o th e greenhouse b e fo re
The eggs w ere ta k e n from th e sand on Jan u a ry 10 and
Out o f - 2159 eggs l a i d i n th e s e p e n s , o n ly 2,1$ showed developm ent
a f t e r a p e rio d o f f iv e m o n th s.
F iv e th o u sa n d th r e e hundred t h i r t y sev en
(5*337) eggs w ere c o l l e c t e d i n t h e f i e l d .
See Table V I.
Of th e s e
68,76% showed d ev elo p m en t.
. : ■
These d a ta in d i c a t e t h a t eggs .la id h y a d u lts w h ic h a r e impeded i n
t h e i r movements o r area i r r i t a t e d , a r e l e s s l i k e l y t o be f e r t i l e th a n th o s e
l a i d u n d er norm al c o n d itio n s .
-
22 -
TABLE V I .-Tha e f f e c t o f c o n fin em en t on f e r t i l i t y .
Date fem ales
c o lle c te d
J u ly 12
J u ly 29
Aug. 12
Aus:. 29
D ate eggs
la id
J u ly 15
Aug. I
Aug. 15
S e n t. I
Humber
la id
681
528
. 380
C5C50
2139
Humber showing
no developm ent
671
W i
373
550
2088
N o.showing ; fe showing
developm ent developm ent r
10
: 1.1+6
6.1+5
3k
; 1 .8 5
7
0
0
2.1+
51
EFFECT OF MOISTURE OH HATCHCHG
I I o is tu r e seems t o have v e ry l i t t l e e f f e c t upon th e h a tc h in g o f
Mormon c r i c k e t eggs e x c e p t i n c a s e s w here t h e s o i l i s e x tre m e ly d ry o r w e t.
W ell dev elo p ed eggs w ere p la c e d i n s te n d e r d is h e s c o n ta in in g 200
grams o f sand w h ich had been d r i e d a t 100°C. t o c o n s ta n t w e ig h t, and v a ry in g
amounts by w e ig h t o f m te r w e r e added t o t h e d i s h e s .
They w ere th e n h e ld a t
100/S r e l a t i v e h u m id ity so t h a t no w a te r w ould b e l o s t th ro u g h e v a p o r a tio h .
The eggs w ere h e ld u n d e r th e s e c o n d itio n s u n t i l no f u r t h e r h a tc h in g to o k
p la c e .
A v e ry s m a ll p e r c e n t (7*33/»)
th e eggs p la c e d i n sand w h ich
c o n ta in e d no f r e e m o is tu re h a tc h e d . , Such a c o n d itio n w ould seldom i f e v e r
be fo u n d i n th e f i e l d . I t w ould th e r e f o r e be o f l i t t l e im p o rtan ce from a
.
■
.•
■■■■:■ .
. ;
- v
,
..
.
;
n a t u r a l c o n tr o l s ta n d p o in t. Ho eggs h a tc h e d i n t h e sand c o n ta in in g $5 % w a te r
w hich was beyond t h e s a t u r a t i o n p o in t f o r t h e sa n d u s e d .
C ric k e ts g e n e r a lly
la y t h e i r eggs on s id e h i l l s and o th e r a re a s w here th e ground w ould n o t rem ain
s a tu r a te d f o r lo n g p e r io d s .
T h is c o n d itio n would a l s o have t o be re g a rd e d a s
u n im p o rta n t from a n a t u r a l c o n tr o l s ta n d p o in t.
h a v in g a low m o is tu re c o n te n t .
The eggs h a tc h e d b e s t i n s o i l
As th e amount o f w a te r was in c r e a s e d , th e p e r
cent
o f h a tc h d e c re a se d ( f i g u r e 3)*
In san d c o n ta in in g 5 Pe r c e n t w a te r
th e g r e a t e s t number o f eggs h a tc h e d (W /O .
These d a ta a r e ta b u la te d i n
T able V II, and a r e shown g r a p h ic a ll y i n f ig u r e 3 .
I t w ould seem from t h i s in f o m a t io n t h a t lo n g p e r io d s o f c o n tin u e d
w et w e a th e r i n th e s p r in g m ig h t have a te n d e n c y t o r e t a r d th e h a tc h in g o f th e
c ric k e t eg g s•
I t i s n o t p ro b a b le , how ever, t h a t su ch c o n d itio n s w i l l e x i s t
i n a r e a s w hich a r e n o rm a lly i n f e s t e d w ith Mormon c r i c k e t s .
TABLE V I I . -P e r c e n t h a tc h o f eggs p la c e d i n san d c o n ta in in g v a ry in g
amounts o f m o is tu r e .
P e n lic a tio n
I
2
?
A verage
O
# T.Tol s-bnre bv w e ig h t i n t h e sand
25
50
20
10
15
8 .0
0
6 0 .0
5 8 .0
5 0 .0
2 2 .0
1 6 .0
0
1 6 .0
1 0 .0
4 7 .5
5 7 .5
5 5 .0
5 5 .0
Ao.o 4 2 .5
7 .3 3
4 8 .o
O
1 8 .0
k.o
5
7 4 .0
1 0 .0
3 4 .1 6
4 3 .0
38.33
15
20
2 5 .8 4
25
PER CENT MOISTURE
F ig u re 3
2 4 .5 0
_35___
0
0
0
0
-
25 -
SUMtJARY,
'
. -
■ ..
Fewer d e g re e h o u rs w ere n e c e s s a ry to h a tc h Mormon c r i c k e t eggs
•which w ere exposed t o -IO eC. th a n w ere r e q u ir e d f o r th o s e s u b je c te d to
h ig h e r o r lo w er te m p e r a tu r e s .
C ric k e t eggs w hich w ere a l t e r n a t e d betw een 10* and 25*C. r e q u ir e d
few er d e g re e h o u rs t o h a tc h th a n th o s e w h ich w ere h e ld a t a c o n s ta n t
te m p e ra tu re o f 25*.
The Mormon c r i c k e t embryo c o n tin u e s t o d e v e lo p i n th e f i e l d d u rin g
th e w in te r m onths, r e g a r d le s s o f th e c o ld te m p e ra tu re s t o w h ich th e y a r e
c o n tin u a lly ex p o sed .
The c o ld t em p eratu res have a s tim u la tin g e f f e c t upon th e d e v e lo p in g
em bryo.
T h e rra te o f oxygen consum ption o f eggs s u b je c te d t o a l t e r n a t i n g
te m p e ra tu re s o f 10* and 2 5 0C. i s g r e a t e r th a n th o s e h e ld a t a c o n s ta n t
te m p e ra tu re o f 25°C.
A g r e a t e r p e r c e n t o f h a tc h i s o b ta in e d from eggs s u b je c te d t o th e
a l t e r n a t i n g te m p e ra tu re s th a n from th o s e h e ld a t th e c o n s ta n t te m p e ra tu re .
A much h ig h e r p e r c e n t o f t h e eggs w hich w ere s u b je c te d t o
a l t e r n a t i n g te m p e ra tu re s h a tc h e d i n th e 10° c a b in e t th a n a t 25 C.
C ric k e t eggs w h ich w ere l a i d i n p en s w ere a p p a r e n tly i n f e r t i l e
and f a i l e d t o d e v e lo p .
S o il m o is tu re c o n d itio n s w ith in w ide l i m i t s have v e ry l i t t l e e f f e c t
■- - :
■■
:
upon th e h a tc h in g o f c r i c k e t e g g s.
'
...
'
.
-
26 -
BIELIOGRAPHT
(1)
(
Bodlrie, J .H .
1925•
2)
'
1929.
(3)
E f f e c t o f T em perature on r a t e o f Em bryonic Development
o f c e r t a i n O rth o p te ra . Jo u r .E x p . Z o o l. 1)2:91-109.
___________
.
1952.
F a c to r s I n f lu e n c in g th e R ate o f R e s p ira to ry M etabolism
o f a D eveloping Egg ( O r th o p te r a ) . R h y s.Z o o l. 2:l)59-lt.82.
H ib e rn a tio n and D iapause i n c e r t a i n C r th o p te r a .
I I . Response t o T em perature d u rin g H ib e rn a tio n and
D ia p au se . R hy s.Z o o l. 5*538»
(4)
1932*
(5 )
Boyce, A.M,
1931.
H ib e rn a tio n and D iapause i n c e r t a i n O r th o p te r a .
I I I . D iapause—A Theory o f i t s Mechanism.
R hys. Z o o l. 5*549»
The D iapause Phenomenon i n I n s e c t s , w ith s p e c ia l
R eferen ce t o R h a g o lite s c o m n lita . Jo u r.E co ri.E n t.2 lj.:1 0 1 8 .
(6)
B u rk h o ld e r, J .R .
1934» A Q u a n tita tiv e S tu d y o f R e s p ir a to r y M etabolism i n
s in g le D eveloping E g g s. ( O r th o p te r a ) . P h y s .Z o o l. 7 :2 4 7 .
(7)
C a r u th e r s , E .E .
1925. H otes on th e Taxonomy, Development and L ife H is to ry o f
c e r t a i n A c r id id a e .
(8)
D ixon, M.
1934»
(9 )
T ran s.A m .E n t.S o c. 49*7-24»
F a u re , J .C .
1932.
(1 0 ) • Henneguy, F .
1904.
( l l ) P a r k e r , J .R .
1930.
M anom etric M ethods.
Cambridge U n iv e rs ity P r e s s .
The P h ases o f L o c u sts i n South A f r ic a .
25:295-424» .
Les I n s e c t e s .
B u l.E n t.R e s.
P a ris .
Some E f f e c ts o f T em perature and M o istu re upon M elanonlus
m exicanus m exicanus S a u ssu re and Camnula p e llu c id a
S cu d d er. ( O r th o p te r a ) . M ont.A g r.E x p .S t a . B u i. 225.
(12)
R ic h a rd s , G l e n A . , J r .
1937. I n s e c t Development A nalyzed by E x p e rim en ta l M ethods.
J o u r . TT.Y. E n t. S oc. 1^5*149-210.
(13)
S l i f e r , E.H .
1931.
I n s e c t D evelopm ent.
G rasshopper Embryo.
I I . M ito tic A c t i v i t y i n th e
Jo u r.M o rp h , and P h y s io l. 51*613-618.
( I h)
1932.
I n s e c t D evelopm ent. IV . E x te rn a l M orphology o f
G rasshopper Embryo o f known age and w ith a known
T em perature H is to r y . J o u r. Morph. 53*1»
(15)
Thomas, V. and E o d in e, J.H .
1936. O xygen.Consumption and r a t e s o f D e h y d ratio n o f G rasshopper
E ggs. P hys. Z o o l. 9*455«
( l£ )
ITvarov, B .P .
1928.
L o cu sts and G ra ssh o p p e rs.
Im p e ria l B ureau o f E n t.3 2 -3 8 .
(17)
1931.
I n s e c ts and C lim ate*
T ra n s .E n t.Soc* London.