Factors influencing the determination of wing formation in the aphid, Rhopalosiphum padi (L.)
(Homoptera: Aphidae)
by Michelle Diane Hardisty Gaudet
A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE
in ENTOMOLOGY
Montana State University
© Copyright by Michelle Diane Hardisty Gaudet (1978)
Abstract:
The determination of wing form in the aphid Rhopalosiphum padi (L.) was examined with respect to
photoperiods and- plant hormones (GA- = gibberellic acid and ABA = abscisic acid) and the
underlying physiological mechanisms were considered.
Virginoparae of R_. padi were reared under two photoperiodic regimens. One group was reared under
increasing photoperiods, while the other group was reared under decreasing photoperiods. When the
number of alate and apterous offspring produced were compared between regimens it was found that
aphids reared under increasing photoperiods produced more apterous progeny than those reared under
decreasing photoperiods.
Two plant hormones were tested for possible effects upon wing dimorphism in R. padi and a significant
treatment effect (P = 0.01) was received at the F10 generation in the 16-hour photoperiodic regimen.
Whether these plant hormones influence wing dimorphism in the aphid via changes in the physiology
of the host plant or directly on the physiology of the aphid is unknown.
The volume of the corpus allatum in R. padi was measured as a parameter of its activity. Aphid
mothers that produced mostly apterous progeny had a larger corpora allata (P = 0.035) than those
mothers that produced predominantly alate offspring. The data obtained confirm the studies of White
(1971). It is proposed from these results that corpus allatum activity and high titers of JH are associated
with the production of apterous offspring. STATEMENT OF PERMISSION TO COPY
In p r e s e n tin g t h i s th e s is in p a r t i a l
f u l f i l l m e n t o f the
requirem ents f o r an advanced degree a t Montana S t a t e U n i v e r s i t y ,
I agree t h a t the l i b r a r y s h a ll make i t f r e e l y a v a i l a b l e f o r
in s p e c tio n .
I f u r t h e r agree t h a t permission f o r e x te n s iv e copying
o f t h i s t h e s is f o r s c h o l a r l y purposes may be granted by my major
p ro fe s so r, o r,
in his absence, by th e D i r e c t o r o f L i b r a r i e s .
understood t h a t any copying or p u b l i c a t i o n o f t h i s
It
is
th e s is f o r
f i n a n c i a l gain s h a l l not be a llow ed w ith o u t my w r i t t e n p erm ission.
S ig n a tu r e
Date
FACTORS INFLUENCING THE DETERMINATION OF WING FORMATION IN THE
APHID, Rhopalosiphuiti padi ( L - ) (HOMOPTERA: APHIDAE)
by
MICHELLE DIANE GAUDET
A th e s is subm itted in p a r t i a l f u l f i l l m e n t
o f the requirem ents f o r th e degree .
of
MASTER OF SCIENCE
in
ENTOMOLOGY
Approved:
C ha irp ers o n , g r a d u a te Committee
GraduatevDean
MONTANA STATE UNIVERSITY
Bozeman, Montana
November, 1978
m
ACKNOWLEDGEMENT
I would l i k e t o o f f e r my s in c e r e g r a t i t u d e to my m ajor p r o fe s s o r .
Dr.
S a ra le e Neumann V is s c h e r , f o r her enthusiasm , encouragement and
e
d i r e c t i o n throughout t h i s research and f o r her c o n s t r u c t iv e c r i t i c i s m
o f t h i s m a n u sc rip t.
I a ls o want to thank my o th e r committee members o f
.D rs. G. R. Ro'emhild, N. L. Anderson and I .
and h e lp fu l
K.. M i l l s f o r t h e i r advice
suggestions concerning th e p r e p a r a tio n o f t h i s m anuscript.
I wish to thank Dr.
E. Smith f o r h is help w ith th e s t a t i s t i c a l
ment o f the data and personnel a t th e B e l t s v i l l e A g r i c u l t u r a l
tre a t­
Research
Center f o r t h e i r c o n fir m a tio n o f th e i d e n t i f i c a t i o n o f th e a p h id ,
Rhopalosiphum padi Lin n .
F in a lly ,
I e s p e c i a l l y thank my husband for.
his a d v ic e , kindness and p a tie n c e which allow ed me to put my best
e f f o r t i n t o t h i s re s e a rc h .
iv
TABLE OF CONTENTS
Page
V i t a ....................... .... ................................................................ ....
A c k n o w l e d g m e n t .......................
L i s t o f Tables
..........
. .
.......................................................................... ...
.......................................................................... ...........................
ii
. iii
. .
v
L i s t o f F i g u r e s ............................................................................................................... vi
A b s tra ct
.
. ...................................................................................................................... v i i
In tro d u c tio n
.................................................................................................
M a t e r i a l s arid Methods .
. . . .
.............................................................................................
I
7
I .
P h o t o p e r i o d .................................................
7
I .
P la n t H o rm o n e s .............................................
7
Measurement o f the Corpus A l l a t u m ...........................................
9
III.
R e s u l t s ..........................................................................................................
11
I .
P h o t o p e r i o d ..................................................................................................11
II.
P l a n t H o rm o n e s ............................................................................................. 13
III.
Measurement o f the Corpus A lla tu m
...........................................
25
D i s c u s s i o n .....................................................................................................
27
S um m ary...........................
31
A p p e n d i x .....................................
32
L i t e r a t u r e C ite d
.................................................................................................
? • . 35
V
LIST OF TABLES
■
Table
I .
II.
III.
IV .
V.
V I.
V II.
'
'
■■
■'
,
1
The Number o f A l a t e and Apterous O ffs p r in g In Each o f the
through to the F^ G enerations a t Two Photoperiods . . .
Page
12
T o ta l Number o f A l a t e and Apterous A d u lts Produced in
Each o f the Two P hotoperiodic R e g i m e n s ............................12
The E f f e c t o f Treatm ents Over 11 G enerations on the
Production o f Apterous O f f s p r in g - 16 Hour Photoperiod . .
The E f f e c t o f Treatments Over 8 G enerations on the
Production o f Apterous O f f s p r i n g - Ambient Photo­
p erio ds
.....................................................................
F Values Obtained From the Data Using Least-Squares
A n a l y s i s .......................................................
14
15
17
Measurement o f the Corpus A lla tu m Gland in A d u lt Aphids
That Produced Predom inantly Apterous O ffs p r in g . . . . . .
26.IV
Measurement o f the Corpus A lla tu m Gland in A d u lt Aphids
That Produced Predom inantly A l a t e O f f s p r i n g . . . . . . . .
26
vi
LIST OF FIGURES
Figure
1.
2.
3.
4.
5.
Page
Percent Apterous O ffs p r in g That Occurred in Each T r e a t m e n t .
in th e Ambient Photoperiod Regimen Over 8
G e n e r a t i o n s ............................................................
19
P ercent Apterous O f fs p r in g That Occurred in Each Treatm ent
in th e 16 Hr. Photoperiod Regimen Over 11
. G e n e r a t i o n s .................................................
20
P ercent Apterous O ffs p r in g That Occurred in the. Treatm ents .
ABA-60 and GA,- 6 in th e 16 Hr. Photoperiod Regimen
Over 11 G enerations
......................................................................• ■ •
22
Percent Apterous O f fs p r in g That Occurred in th e GA,-6 0
Treatm ent and th e Control in th e 16 Hr. Photoperfod
Over 11 G e n e r a t i o n s ...................................................................................
23
P ercent Apterous O ffs p r in g That Occurred in the Treatments
ABA-6 and ABA-60 in th e 16 Hr. Photoperiod Regimen
Over 11 G enerations
................................................................
24
v ii
ABSTRACT
The d e te r m in a tio n o f wing form in th e aphid RhopaTosiphum padi
( L . ) was examined w it h re s p e c t to photoperiods and- p l a n t hormones
(GA- = g i b b e r e T l i c a c id and ABA = a b s c is ic a c i d ) and th e u n d e rly in g
•p h y s io lo g ic a l mechanisms were con sid e re d .
V irg in o p a r a e o f R_. padi were re a re d under two p h o to p e rio d ic r e g i ­
mens.
One group was re a re d under in c r e a s in g p h o to p e rio d s , w h ile the
o th e r group was re a re d under decreasing p h oto periods .
When th e number
o f a l a t e and apterous o f f s p r i n g produced were compared between regimens
i t was found t h a t aphids re a re d under in c r e a s in g photoperiods produced
more apterous progeny than those re a re d under d ecreasing photoperiods.
Two p l a n t hormones were t e s te d f o r p o s s ib le e f f e c t s upon wing
dimorphism in R. padi and a s i g n i f i c a n t tre a tm e n t e f f e c t (P = 0 .0 1 )
was re c e iv e d a t the F1- g e n e ra tio n in th e 16-hour p h o to p e rio d ic r e g i ­
men.
Whether these p l a n t hormones i n f l u e n c e wing dimorphism in the
aphid v ia changes in th e physiology o f th e host p l a n t o r d i r e c t l y on
th e phy siology o f th e aphid is unknown.
The volume o f th e corpus a l latum in FL padi was measured as a
param eter o f i t s a c t i v i t y .
Aphid mothers t h a t produced m ostly apterous
progeny had a l a r g e r corpora a l l a t a (P = 0 .0 3 5 ) than those mothers t h a t
produced p redom inantly a l a t e o f f s p r i n g .
The data o b ta in e d c o n firm the
s tu d ie s o f White (1 9 7 1 ) .
I t is proposed from these r e s u l t s t h a t
corpus a l latum a c t i v i t y and high t i t e r s o f JH are a s s o c ia te d With th e
p ro d u c tio n o f apterous o f f s p r i n g .
INTRODUCTION
The aphid Rhopalosiphum padi
(L .)
pest in Montana, not o n ly because i t
because i t
i s an im p o rta n t a g r i c u l t u r a l
feeds upon c e re a l
c rops, but
is a v e c to r o f th e RPV i s o l a t e o f B a rle y Y ello w Dwarf V iru s
( H a r r i s and Maramorosch, 1 9 7 7 ).
The development o f e f f e c t i v e c o n tro l
o f t h i s pest r e q u ir e s a thorough understanding o f i t s o n to g en e s is , in
p a r t i c u l a r th e f a c t o r s which determ ine th e p roduction o f winged fo rm s .
Several environm ental
fa c to rs ,
in c lu d in g p h o to p e rio d , te m p e ra tu re ,
h u m id ity , n u t r i t i o n and crowding can i n f l u e n c e a l a r y polymorphism in
aphids (Lees.
1 9 6 6 ). . These environm ental
r e g u la t o r s a re thought to a c t
through th e neuroendocrine system, and c o n s id e ra b le re se a rch has been
d i r e c t e d towards d e s c r ib in g the developmental processes and under­
s ta n d in g th e p h y s io lo g ic a l mechanisms in v o lv e d (Johnson and B i r k s ,
I9 6 0 ; Johnson, 1966; Lees, 1966; W h ite ,
1965; 1968; 1971; 1972; White
and Gregory, 1 9 7 2 ).
Wing dimorphism in IR. padi has been examined in terms o f crowding
(Dixon and G len, 1 9 7 1 ), n u t r i t i o n a l
1971) and th e c r i t i c a l
s ta tu s
(Noda, 1956; Dixon and G len,
tim e o f wing development (Noda, 1958)..
Poor
n u t r i t i o n and crowding s tim u la te d th e p roduction o f a l a t e s , w ith
crowding being most e f f e c t i v e l a t e in th e f i r s t i n s t a r
(21 hours a f t e r
b irth ).
The p re s e n t i n v e s t i g a t i o n was undertaken to e v a lu a te th e r o l e o f
photoperiod as a d i r e c t environm ental s tim ulus to wing development arid
2
to t e s t th e p o s s i b i l i t y t h a t environm ental
f a c t o r s could a c t i n d i r e c t l y
to s t i m u l a t e wing fo rm a tio n through changes in hormone t i t e r s o f th e
host p l a n t .
Corpus a l latum a c t i v i t y was examined in c o n ju n c tio n w ith
th e p roduction o f a l a t e versus apterous o f f s p r i n g .
LITERATURE REVIEW
Photoperiod
The e f f e c t o f photoperiod on form p roduction and wing dimorphism
was reviewed by Lees in 1966.
He concluded t h a t in h e teroecious
species o f a p h id s , lo n g e r photoperiods cause a h ig h e r p roduction o f
a l a t e progeny.
C u rre n t t h e o r i e s concerning t h i s p h o to p e rio d ic response
have been c o m plicated by th e disagreement among authors as to whether
th e photoperiod a c ts d i r e c t l y on th e aphid to produce th e response
(Lees, 1966) or i n d i r e c t l y through n u t r i t i o n a l
a p h id s '
host
p la n t
changes in the
(Johnson, 1966; S u th e r la n d , 1969; H a rrew ij n ,
1972;
1976a; 1976b).
P la n t Hormones
The importance o f p a r e n ta l
n u t r i t i o n from th e host p l a n t on a l a r y
polymorphism in aphids has been w e ll documented in th e l i t e r a t u r e .
Myzus p e rs ic a e S u lz . was found to produce more a l a t e s when fed on
p la n ts in f l o w e r than when fed on p la n ts in th e young o r post flo w e r in g
stages ( P i n t e r a ,
1 9 5 7 ).
Apterae o f Aphis c r a c c iv o r a Koch, re are d on
mature bean f o l i a g e produced more a l a t e o f f s p r i n g than those m aintained
on g e rm in a tin g s e e d lin g s (Johnson and B i r k s ,
1960; Johnson, 196 5 ).
With aphids re are d on young f o l i a g e , e s p e c i a l l y on s e e d lin g s , wing
dimorphism was shown to be d i r e c t e d towards the apterous course
(Schaefers and Judge, 1971; H a rre w ij n ,
1972; 1 9 7 3 ).
4
Much emphasis has been placed on th e host p l a n t f l u c t u a t i o n o f
v a rio u s n u t r i e n t s such as amino a c i d s , sugars, s t e r o l s and ions in
response to environm ental c o n d itio n s
(p h o to p e rio d and te m p e ra tu re )
p r e v io u s ly a s s o c ia te d w ith wing dimorphism (Dadd, 1968; M i t t l e r ,
1972;
H a r r e w i j n , 1972; 1973; 1976a; 1976b; W h ite , 1972; L e ch s te in and
L le w e lly n ,
1 9 7 3 ).
L im ite d c o n s i d e r a t i o n , however, has been given to
th e r o l e o f p l a n t hormones in the phenomenon o f wing dimorphism.
C y to k in in
(N® Benzyl aden in e ) was found to cause th e pro d u c tio n o f few er
a l a t e s in the aphid Chaetosiphon f r a g a e f o l i i
Montgomery, 1 9 7 3 ).
(C o c k re ll)
(S chaefers and
G i b b e r e l l i c a c id (GAg) and a b s c is ic a c id were found
to reduce th e tim e needed f o r development in Aphis fabae Scop.
(S c h r e u r e r ,
197 6 ).
Corpus A llatu m
The aphid corpus a ll a t u m gland was f i r s t observed by Nubert in 1913
d u rin g i n v e s t i g a t i o n on th e nervous system o f Rhynchotes ( C a z a l, P.
1 9 4 8 ).
P f l u g f e l d e r (1 9 36 ) described th e corpus a ll a t u m and the two
corpora c a rd ia c a o f Pemphigus b u rs a riu s
( L . ) and found th e r e t r o c e r e b r a l
organs in t h i s aphid were w e ll formed and d i s t i n c t .
Cazal
(1948) s t u ­
d ie d th r e e species o f aphids, Macrosiphum rosae Reaumer, Aphis sp. and
Pemphigus sp. w ith re s p e c t to t h e i r r e t r o c e r e b r a l organs and found
t h a t these were v ery d i s t i n c t in Pemphigus, but in th e o th e r two the
corpora p a ra c a rd ia c a ( corpora c a r d i a c a ) were d i f f i c u l t to dete rm in e .
5
He n oted, however, t h a t th e sym pathetic nervous system was s i m i l a r to
t h a t de sc ribe d f o r hemipteraris.
C a z a l's work s e v e ra l h i s t o l o g i c a l
s tu d ie s concerning neurosecre­
t i o n in aphids, have been published (Johnson, 1962; 1 96 3 -, G a b r i e l ,
Bowers and Johnson, 1 9 6 6 ).
196.5;
Other re s e a rc h e rs have de sc ribe d the stoma-
t o g a s t r i c nervous system o f th e green peach aphid (J ak a o k a , 1969) th e
greenbug (Saxena
(ParG e t a l . ,
and Chada, 1971) and Macrosiphum euphobiae (Thomas)
1974)..
The p h y s io lo g ic a l mechanisms u n d e r ly in g the c o n tr o l o f wing dim or­
phism in aphids a r e s t i l l
a s u b je c t o f c o n tro v e rs y (W h ite , 1 9 7 1 ).
in fo r m a tio n has been o b ta in e d by h i s t o l o g i c a l
s tu d ie s o f th e develop­
mental processes in v o lv e d in the pro d u c tio n o f d i f f e r e n t form s;
fin d in g s o f Johnson and B irk s
(I9 6 0 )
Much
suggested t h a t a l l
The
aphids begin
development as presumptive a l a t a e and t h a t a p te ra e and in te r m e d ia te s
a re forms which have been d i v e r t e d from th e a l a t e course du rin g d e v e l­
opment.
Research undertaken by White (1 9 71 ) confirm ed th e s e conclu­
sions and c o n tr ib u te d th e evidence t h a t th e re g re s s io n o f wingbuds .in - '
apterous forms b o r e
a ,close r e l a t i o n s h i p to th e a c t i v i t y o f the corpus
a ll a t u m in th e pa ren ts and l a r v a e .
The e x t e n t o f loss o f wingbuds in.
embryos appeared to -depend upon m aternal corpus a ll a t u m a c t i v i t y - d u r i n g
th e tim e t h e embryo was d e v e lo p in g .
In p o stnatal
d e te r m in a tio n o f
a p t e r a e , which can occur u p .to 48 hours a f t e r b i r t h
■higher corpus a lla t u m a c t i v i t y o f th e i n d i v i d u a l
( Kawada, 1 9 6 5 ),
aphid appeared to. be
.
6
the. c o n t r o l l i n g f a c t o r .
Also Rhopalosipkum padi
(I.)
has been' shown
to produce a l a t e s by crowding nymphs a t tw enty-one hours a f t $ r b i r t h
(Noda5 1 9 5 8 ).
MATERIALS AND METHODS
Photoperiod
V irg in o p a r a e o f Rhopalosiphum padi
( L . ) were c o l l e c t e d on
T r i t i c u m . a e s t i vum ( L . ) o f an unknown c u l t i v a r grown in a greenhouse
a t Montana S ta te U n iv e r s ity , o n 'J u l y 6 ,
1977 and t r a n s f e r r e d to a green­
house i n s e c t a r y onto th e s p rin g wheat c u l t i v a r
l Noranal , T.
a es tiv u m .
Apterous aphids and t h e i r host p la n ts were then separated i n t o two
photoperiod regimens.
One group was re are d in a P e r c iv a l c o n t r o l l e d
environment chamber a t photoperiods in c r e a s in g from 14 hours daylength
on J u ly 6 , 1977 t o 16 hours d a yle n g th beginning on August 6 , 1977 and
ending September 2 ,
1977.
The o th e r group was re a re d in a c o n t r o l l e d
environment room a t ambient photoperiods d ecreasing from 15 hours and
31 minutes on J u ly 6 , 1977 to 13 hours and 13 minutes o f daylength by
September 2,
n a lly
1977.
( 1 8 - 2 4 . 5 C ).
-
Temperatures in both environments f l u c t u a t e d d i u r - .
Aphids were re a re d on s in g le wheat p la n ts grown in
aluminum cake pans ( 2 2 .9 cm in d ia m e te r X 8 . 9 cm deep) placed under
c lo t h
( c h i f f o n ) cove re d, c l e a r p l a s t i c c y lin d e r s
in d i a m e t e r ) .
( 2 7 . 9 high X 2 1 .6 cm
To avoid crowding, no more than 40 aphids were allow ed
t o develop w i t h i n a s in g le cage.
Aphids were t r a n s f e r r e d t o new cages
and handled using techniques described by H. F. Van Emden (1 9 7 2 ).
P la n t Hormones
V irg in o p a r a e o f th e aphid R.. padi were re are d a ccording to methods
d e sc rib e d in the photoperiod s e c t io n .
Fg apterous a d u l t s were taken
8
frpm c u l t u r e c o lo n ie s m a intaine d in th e two p h o to p e rio d i c regimens and
tra n s fe rre d
c u ltiv a r
(September 9,
l N o ra n a '; T.
1977) one per cage onto th e s p rin g ,w h e a t
aestivum
(seeded August 2 3 , 1 9 7 7 ).
Twelve cages
o f aphids were m a in tain e d a t th e 16-hour photophase in a P e r c iv a l con­
t r o l l e d environment chamber, w h ile tw e lv e a d d i t i o n a l
cages were main­
t a i n e d in a second c o n t r o l l e d environment chamber a t ambient photonp e rio d de cre a sing from 12 hours 58 minutes to 8 hours 50 minutes dayle n g th (U .S . N a u tic a l Almanac O f f i c e ,
1 9 7 7 ).
Temperatures in both
environments f l u c t u a t e d d i u r n a l I y from 1 8 - 2 4 .5 C, as in th e photoperiod
e xperim ent.
S ix t r e a t m e n t s , w it h two r e p l i c a t e s each, were a d m in is te re d to
aphids in each photo period regimen, beginning upon th e o b s e rv a tio n o f
th e f i r s t Fy nymphs (September IO-September 12, 1 9 7 7 ).
Ten ml o f
tr e a tm e n t s o l u t i o n were a p p lie d per cage on a l t e r n a t e days, w ith s ix ml
sprayed onto th e aphids and the lea v es o f th e p l a n t , w h ile th e remain­
ing fo u r were w atered to th e base o f th e p l a n t .
th e p la n ts were given d i s t i l l e d w a te r .
On n o n -tre a tm e n t days,
Hormone s o lu tio n s
(g ib b e re llic
a c id and a b s c is ic a c i d ) 1 prepared by d i s s o l v in g the q u a n t i t y o f the
s o l i d hormone needed in 20 ml 95% ETOH and d i l u t i n g t h i s s o lu tio n w ith
one T i t e r o f d i s t i l l e d w a t e r , were a d m in is te re d a t two c o n c e n tra tio n s
I.
The g i b b e r e l l i c a c id used by th e a u th o r is r e f e r r e d to as GA? i f
th e type o f g i b b e r e l l i n i s not s p e c i f i e d by o th e r authors r e f e r r e d
to in t h i s t e x t , i t w i l l be d e sig n a te d as GA. ABA r e f e r s to
a b s c is ic a c id .
9
(6 mg /
L, d i s t HgO & 60 mg /
L d i s t HgO) (V is s c h e r,
1977, unpublished
d a ta ).I
To a void crowding, th e number o f o f f s p r i n g produced was l i m i t e d so
th a t to ta l
number o f aphids in th e cage never exceeded n i n e t y , w ith th e
average being f o r t y .
The youngest nymph i n th e cage, re g a r d le s s o f
f o r m , w a s chosen to be th e p a re n t o f th e n ext g e n e r a tio n .
form o f th e o f f s p r i n g was determined a t th e a d u l t s ta g e .
The wing
Results were
a nalyzed s t a t i s t i c a l l y beginning w it h the F10 g e n e r a t io n , a llo w in g
t h r e e g e n e ra tio n s to in s u r e t h a t th e r e s u l t s expressed would be those
o f th e tr e a tm e n ts t e s t e d r a t h e r than those o f previous r e a r i n g co n d i­
tio n s
(Noda, 1958; Lees,
1 9 6 6 ).
Measurement o f the Corpus A lla tu m
T h i r t e e n a d u l t aphids which produced m ainly apterous o f f s p r i n g and
t h i r t e e n a d u lt s which produced m ostly a l a t e o f f s p r i n g were taken from
th e two experim ents d e s c rib e d .
These aphids were f i x e d in a lc o h o l i c
Bouin's s o l u t i o n c o n ta in in g 0.5% t r i c h l o r o a c a t i c a c id and double
embedded in m e t h y l - b e n z o a t e - c e l l o i d i n s o lu t io n fo llo w e d by p a r a f f i n .
Aphids were sectio n e d t r a n s v e r s e l y a t 8p and s ta in e d f o l l o w i n g the p ro ­
cedure f o r Ewen's A ld e h y d e -fu c h s in (Barbosa, 1974) (see appendix f o r
th e a d a p ta tio n o f t h i s
procedure f o r use w ith a p h i d . t i s s u e s ) .
The
le n g th and w id th o f th e corpus a ll a t u m were measured in a s e c tio n a t .I
I.
Dr. S. IN. V is s c h e r - B iology D e p t . , Montana S t a t e U n i v e r s i t y ,
Bozeman, Montana, 59717
10
i t s maximum r e p r e s e n t a t io n using a s c re w -ty p e e yepiece m icrom eter a t
800x and th e approxim ate volume o f th e gland was c a l c u l a t e d assuming
it
to be an e l l i p s o i d having equal minor axes as d e s c rib e d by White
(1 9 65 ) and B u rrin g to n (1 9 7 3 ) .
In t h i s pa per, th e corpus a l latum a c t i v i t y
(by c a l c u l a t i o n o f
gland volume) o f mothers t h a t produced predom inantly apterous o f f s p r i n g
i s compared w ith mothers t h a t produced m ostly a l a t e o f f s p r i n g .
The
form o f th e o f f s p r i n g was judged upon r e a r i n g to a d u lth o o d , r a t h e r than
through e s tim a tio n s o f wingbud d e g en era tio n in the embryo as in the
experim ents performed by White (1 9 71 ) and would be a more a c c u ra te ,
assessment o f th e f i n a l
form o f the a p h id .
t i o n o f form has been demonstrated in
Since p o s tn a ta l
de te rm in a ­
p a d i , a c o r r e l a t i o n obtained
between th e corpus a ll a t u m a c t i v i t y o f the mother and form de te rm in a ­
t i o n o f th e o f f s p r i n g would suggest t h a t p re n a ta l d e te r m in a tio n was th e
predominant p a t t e r n in t h i s s p e c ie s . ,
RESULTS
Photoperiod
The numbers o f a l a t e and apterous o f f s p r i n g produced in each o f
th e Fj through to th e Fg g e n e ra tio n s a t the two photoperiods a re shown
in T able I .
The number o f a l a t e and apterous a d u lt s produced in each
o f these two photo p erio d regimens a re presented in T able I I .
A to ta l
o f 571 aphids were re a re d in th e two regimens w ith 282 re are d under
ambient photoperiods and 289 re a re d a t th e 14-16 hour photo periods.
S i x t y a l a t e and 222 apterous a d u lts were produced under ambient photop e r io d s , w h ile 25 a l a t e s and 264 a pterous a d u lts were produced in th e
14-16 hour p h o to p erio d s .
Comparison o f these r e s u l t s by Chi-Square
a n a ly s is r e v e a le d s i g n i f i c a n t d i f f e r e n c e s between regimens (X
=
1 6 .9 7 5 6 , P = 0 .0 0 0 0 2 ) .
A s i g n i f i c a n t tr e a tm e n t e f f e c t was observed between the two photo­
period regimens.
More apterous i n d i v i d u a l s were o b ta in e d under i n ­
c r e a s in g photoperiods than were o b ta in e d under d e cre a sin g p h oto periods .
This is in accordance w it h th e r e s u l t s obta ine d by M a c G i l l i v f y and
Anderson in 1964; Johnson in 1965; and White in 1946, w ith Macrosiphum
e u p h o rb ia e , Aphis c r a c c i v o r a , and M a c r o s ip h o n ie lla sanborni respec­
t i v e l y as c i t e d by Lees ( 1 9 6 6 ) . .
phum padi
The r e s u l t s suggest t h a t R hopalosi-
( L i n n . ) responds s i m i l a r l y to o th e r species .of hete ro ec io u s
aphids w ith re s p e c t to photo period in d e te r m in a tio n o f th e production
o f a l a t e versus apterous o f f s p r i n g ,
i.e .,
in c re a s in g photoperiods cause
12
TABLE I .
THE .NUMBER OF ALATE and APTEROUS-OFFSPRING IN EACH OF THE
F1 THROUGH TO THE F5 GENERATIONS AT TWO PHOTOPERIODS. .
F1 G e n e ra tio n
#
F2 G e n eratio n
F3 G e n eratio n
F^ G en eratio n
Fg G eneration
# A p t# A p t-'
# A p t# A p t# A p tAl a te erotis # A Ia te te ro u s # A Ia te te ro u s # A Ia te te ro u s # A Ia te te ro u s
*Am bient
P hotop e rio d s
14-16 h r.
Photop e rio d s
0
4
TABLE I I .
-
2
21
21
11
62
15
7
42
O
58
■ 14-16 h r.
Photo­
p e rio d
T o ta l #
o f aphids
27
97
I
40
0
70
' 14
79
TOTAL NUMBER OF ALATE AND APTEROUS ADULTS PRODUCED IN EACH
OF THE TWO PHOTOPERIODIC REGIMENS.
# o f Al ate. A d u lts
* Ambient
P hotop e rio d
.
#
o f A pterous A d u lts
T o ta l # o f.A p h id s
60
222
282
.25
264
289
486
571
85.
* Amb le n t p h o to p e rio d was 15- h rs and 31 m inutes o f day le n g th a t the
b e g in n in g o f th e s tu d y and 13 h rs and 13 m inutes a t th e end o f the
s tu d y .
13
th e pro d u c tio n o f apterous o f f s p r i n g w h ile decreasing photoperiods i n i
t i a t e t h e p roduction o f a l a t e o f f s p r i n g .
P la n t Hormones
The r e s u l t s o f tr e a tm e n ts conducted over 11 g e n e ra tio n s on wing
dimorphism in th e 16 hour photoperiod regimen a re shown in Table I I I . .
No data a re a v a i l a b l e f o r th e tap w a te r c o n tr o ls a f t e r th e
genera­
t i o n due to deaths o f the a d u lts chosen to be the parents o f the
and F ^
g e n era tio n s in cages #32 and #38.
T a b le IV d e p ic ts th e i n f l u e n c e o f tre a tm e n ts conducted over e ig h t
g e n e ra tio n s on wing dimorphism in th e ambient photoperiod regimen.
Treatments in t h i s regimen f a c i l i t a t e d th e growth o f powdery mildew on
the p l a n t s ,
r e s u l t i n g in th e death o f some p la n ts and th e aphids th e r e
on and no data were o b ta in e d in th e s e .
In th e above Tables ( I I I
& IV ) the form o f th e mother is d e p ic te d
as A, B5 or C meaning r e s p e c t i v e l y , a l a t e , apterous or both a l a t e and
a p te ro u s .
To e s tim a te th e age o f th e m other, th e date o f her f i r s t
o f f s p r i n g i s recorded and inclu d e d in th e a n a ly s is as a v a r i a b l e .
It
was found upon a n a ly s is t h a t th e age and th e form o f th e mother were
not s i g n i f i c a n t v a r i a b l e s i n t h i s e xperim ent.
The F values o b ta in e d using a Least-Squares A n a ly s is o f Variance
f o r th e v a rio u s tr e a tm e n ts a re presented in Table V.
versus a l a t e progeny were compared, f o r a l l
When apterous
th e g e n e ra tio n s re are d in
14
TABLE I I I
THE EFFECT OF TAEATWWTS OVER I l CtWEAATIOWS OW THE PAOOUCTIOH OF APTEROUS OFFSPAIWC 16 HR. PHOTOPERIOD
F , G tn e r it1 on O ite o f
F0 G e n e ritlo n Oete o f
f . C e n e n tlo n D ite o f
F . . G e n e n tlo n
7
* A p t- 1st O ff - F or# o f "
# A p t- l i t O ff- F ore o f
• A p t- U t O ff - F or# o f
# A p tm ent* I A l i t e e r o u l s p r in g
M o th e r0 P A l i t e t r o u t ip r l n g
H ith e r I A U te e r e u i s p r in g
M other I A H te t r o u t
T rn it1
C ig t«
27
33
PB
34
29
35
30
36
31
37
32
3B
ABA
ABA
ABA
ABA
GA1
GA:
GA,
GA:
6
6
60
60
6
6
60
60
o tL o
D h‘ o
T HtO
T HjO
257
258
259
259
257
258
256
259
257
259
257
258
10
13
10
9
7
Il
B
9
A
7
9
5
O
O
O
0
O
0
0
O
O
O
O
O
B
I
6
B
a
B
B
B
a
B
B
B
213
263
263
265
2(3
266
2(2
265
264
266
263
264
10
8
8
I
9
10
11
7
12
7
IO
8
O
O
O
O
O
O
O
O
O
O
O
O
8
13
10
8
10
8
9
9
B
8
6
7
O
O
I
O
O
O
O
O
O
2
O
O
B
B
B
6
B
B
I
B
B
B
B
B
269
B
B
B
272
270
277
267
274
270
273
270
27
23
14
2
5
14
26
24
20
7
31
0
0
14
30
37
i
0
0
I
0
0
B
B
W
B
B
B
B
B
B
*
F1, G in e r it lo n O ite o f
F 1, O e n e n tlo n O i t i o f
F11 G e n e ritlo n O ite o f
D ltl of
15
F A p t- l i t O ff u
F A p t- l i t O ff - Form o f
11
I A p t- l i t O ff ­ Form o f
T re a t­ l i t O f f ­ Form o f
W th e r
M other F A l i t e e r o u l ip r ln g
M other F A l i t e t r o u t ip r l n g
M other f A l i t l t r o u t s p r in g
C ig e f ment s p r in g
?1
33
PR
34
29
3r)
30
31
17
ARA 6
ABA 6
ABA 60
ABA 60
GA1 6
GA, 6
GA^ 60
GA1 60
D fL 6
0 h' o
B
B
B
B
B
A
B
B
B
B
277
279
282
PBfl
Pfll
?R4
277
281
282
PA?
12
8
0
0
0
0
A
0
0
22
269
288
289
296
288
291
291
289
291
289
11
12
19
14
31
35
16
23
17
3
B
B
A
A
A
B
B
6
B
B
62
41
11
0
15
0
0
24
16
2
297
295
297
301
295
298
299
297
297
297
8
0
IS
49
16
42
28
22
21
30
B
B
8
8
8
B
B
B
A
64
O
O
28
52
3
2
7
22
35
306
301
306
306
306
306
304
304
307
307
20
43
44
13
ii
23
33
23
15
5
* -Oite U n iv illtb le
F , , G e n e n tlo n D ite o f
F1, G e n e r itIon Oete o f
F1- G e n e n tlo n O i t i o f
F1, G e n e ritIo n
I A p t- 1st O ff- Form o f
15
I A p t- l i t O ff - F or# o f
F A p t- l i t O ff - Form o f
I A p t- F o r* o f
T re itM other I A l i t e t r o u t ip r l n g
M other I A le te t r o u t ip r l n g
M other # A l e t i t r o u t M other
Chjh I ment I A l i t e e ro u s s p r in g
27
33
20
34
29
15
30
16
31
37
ABA 6
AIiA 6
ABA 60
ABA 60
GA, 6
GA* 6
GA 60
GAC 60
0 4 ,0
D HjO
3
38
4
11
10
7
24
23
19
12
23
6
29
19
14
28
14
19
20
42
314
310
312
314
111
HO
308
308
316
116
A
B
B
B
C
A
C
C
A
14
21
34
J
37
7
7
7
17
5
'8
12
28
38
20
29
47
28
13
39
318
315
117
I lB
318
HS
318
318
319
120
SI
S
24
11
20
I
19
7
SO
27
7
SS
14
33
16
39
29
21
39
22
323
319
320
320
121
317
324
322
324
325
8
C
B
B
A
B
B
B
A
B
33
37
31
38
22
16
41
9
St
32
4
25
4
9
27
41
14
42
26
11
A
6
C
6
B
B
B
B
B
B
15
TABLE IV .
Cage#
?5d
31a
?6a
32a
?7a
13a
?fia
14a
29a
35a
30a
16a
THE EFEECT OF TREATMENTS OVER 8 GE NERAT IONS ON THE PRODUCTION Of APTEROUS OFFSPRING - AMBIENT PHOTOPER10 0 .
T , G e n e ra tio n Oate o f
F . G en e ra tio n Date o f
F» G en e ra tio n Date o f
Fln G eneration
T re a t'
I A p t- l i t O ff - Form o f
I A p t- l i t O ff - Form o f
» A p t- l i t O f f - Form o f
# A p tm ent # A la te e r o u i s p r in g
M other # A la te e r o u i s p r in g
M ather I A le te e r o u l s p r in g
M other I A la te erous
ABA 6
ABA 6
ABA 60
ABA 60
GA1 6
GA 6
GA: 60
GAj1 60
D M,0
D HpO
T HpO
T H*0
3
8
5
5
3
9
0
0
0
0
0
0
0
0
0
0
4
I
0
H
7
14
8
10
B
B
B
B
B
B
B
B
B
B
B
B
261
260
262
259
259
261
261
261
261
260
263
262
i
0
O
0
0
0
0
0
0
0
0
I
10
5
B
6
10
9
I
4
13
8
6
7
B
B
276
269
271
267
268
273
269
273
269
271
272
276
B
B
B
A
O
0
0
0
I
I
0
0
3
I
0
B
O
8
B
B
B
B
I*
a
3
9
10
2
10
10
13
9
8
6
A
?78
278
201
275
281
319*
278
284
280
288
284
286
0
3
B
B
B
0
I
I
0
0
6
2
0
20
I
6
B
B
B
B
B
8
A
13
12
7
20
3
I
13
2
2
10
4
I
• - A d u lt wandered o f f o f th e p la n t end was re p la c e d by an a d u lt o f th e lame g e n e ra tio n and tre a tm e n t.
Cage#
ment
25a
31a
76a
32a
27#
33a
28a
14a
79a
ISa
IOa
16a
ABA 6
ABA 6
ABA 60
ABA 60
GA, 6
GA1 6
GA1 60
GA31 60
o iL o
0 H‘ 0
T H‘ 0
T HjO
Cage#
T re a t
m ent
25a
31a
I'6a
12a
27a
13a
28a
14a
29a
36a
IUa
ABA 6
ABA 6
ABA 60
ABA 63
GA1 6
GA3 6
GA1 60
G A' 60
0 N-O
D H‘ 0
T H‘ 0
F1- G e n e ra tio n Date o f
F ,, G eneration Date o f
# A p t- 1st O ff
I A p t- l i t O ff- Form o f
1st O ff- Form o f
M
ith
e
r
# A la te erous s p rin g
M o th e r
I A la te erous s p r in g
s p r in g
292
290
289
291
290
290
290
293
288
296
297
B
B
B
B
A
A
B
B
R
A
B
R
0
12
0
14
6
12
13
7
13
33
13
12
23
7
I
6
0
I
11
13
0
9
301
299
299
300
305
305
305
305
298
305
B
B
B
B
C
B
B
6
C
B
A
F 1 - G e n e ra tio n
14
I A p t- form o f
M other
# A la t e e ro u s
14
30
31
40
20
*
14
R
*
*
*
33
*
*
0
•-D a ta U n a v a ila b le
a
ABA ■ I b s c l s l c a c id and GA stands f o r g lb b e r e l i c
I) - A * e la t e ; B ■ a p t e r o u s ; C • a la te ♦ a p te ro u s .
a c id
F 11 G e n e ra tio n Date o f
Form o f
1
I A p t- l i t O ff
M other I A la te e r o u i Ip rln g
2
*
A
A
B
13
7
325
325
C
C
6
7
0
33«
•
A
C
12
2
332
A
70
28
13
•
1«
29
316
311
B
C
8
A
A
A
B
C
C
319
C
27
39
3
4
18
5
10
«1
42
7
I
6
0
IZ
11
3
22
4
313
309
309
32
5
316
315
form o f
M other
3
3
0
323
316
16
the 16-hour, p h o to p e rio d , s i g n i f i c a n t l y more apterous o f f s p r i n g (P =
0 . 0 1 ) were o b ta in e d .
This is c o n s is te n t w ith r e s u l t s o b ta in e d from
r e a r i n g aphids in long photoperiods
(1 6 -h o u r ) in uncrowded c o n d itio n s . .
S i g n i f i c a n t tr e a tm e n t e f f e c t s were o b ta in e d in th e F jq g e n e ra tio n
(P. = 0 . 0 1 ) i n d i c a t i n g t h a t p l a n t hormones a f f e c t wing dimorphism in the
aphid Ry p a d i .
F igures
1 -5 a re g ra p h ic a l
date these r e s u l t s .
p o rtra y a ls
The r e s u l t s o f a l l
in an a tte m p t to f u r t h e r e l uci
tre a tm e n ts given in the ambient
p h o to p e rio d , i l l u s t r a t e d in Figure I , i n d i c a t e t h a t i n s u f f i c i e n t data
were o b ta in e d to i l l u s t r a t e any d i s t i n c t tr e n d s .
apterous o f f s p r i n g /
The mean percent
g e n e ra tio n in each tr e a tm e n t a d m in is te re d in the
16-hour photoperiod is
shown
in F ig u re 2.
Figures
3 -5
are t r e a t ­
ments o f th e 16-hour p h o to p e rio d , separated out to i n d i c a t e tr e n d s .
Young f o l i a g e i s known to d i r e c t wing dimorphism toward an
apterous course, w h ile m aturing or senescent t i s s u e a llo w s f o r th e p ro ­
d u c tio n o f a l a t e o f f s p r i n g .
I t has a ls o .b e e n shown t h a t in young,
g r o w in g .t is s u e , l e v e l s o f GA a re h tg h , whereas in m a turing o r senescent
t i s s u e , l e v e l s o f ABA.are high (Leopold.and Kriedmann, 1 9 7 5 ).
I f these
two p l a n t hormones have an i n f l u e n c e on wing dimorphism, i t would be
expected t h a t high l e v e l s o f GA would i n i t i a t e th e ,p r o d u c tio n o f
a pterous o f f s p r i n g , w h ile high l e v e l s o f ABA would a ll o w f o r th e p ro ­
d u c tio n o f a l a t e o f f s p r i n g .
17
TABLE V.
F VALUES OBTAINED FROM THE DATA USING LEAST-SQUARES ANALYSIS
1
■■
16 h r.
G eneration
Frn
F °
f P
pI O
rF15
ib
'1C
F17
Photoperiod
F Value
2 0 .7 2 7 **
.740
3.2 8 6
.465
.661
.181
1.866
1.832
Comparison of. ambient and 16 h r .
Comparison o f apterous v . s .
9 .2 4 **
.
Ambient Photopertpd
F Value
.625
.509
.387
.000
D/U
D/U
D/U
D/U
photoperiod combined = .628
a l a t e p roduction in 16 h r .
photoperiod =
18
The s i g n i f i c a n c e o b ta in e d a t th e
g e n e ra tio n in th e 16-hour
photoperiod regimen tends to support t h i s h y p o th e s is .
Aphids had con­
tin u e d along an apterous course o f development, as would be expected
due to the i n f l u e n c e o f p h o to p e rio d , u n t i l
reached.
th e F ^ g e n e ra tio n was
At t h i s ti m e , th e development o f a ! a t e o f f s p r i n g became
ap p are n t in the h ig h e r c o n c e n tr a tio n o f ABA and the low er c o n c e n tra tio n
o f GAg, w h i le th e o th e r tre a tm e n ts continued along an apterous course
o f development.
It
i s a t th e F jq g e n e ra tio n t h a t the f i r s t tre a tm e n t
e f f e c t s would be observed due to th e 3 g e n era tio n s necessary to remove
th e e f f e c t s o f previous c o n d itio n s .
The h ig h ly v a r i a b l e data obtained
in th e ambient photoperiod could be a t t r i b u t e d to the occurrence o f
powdery m ildew , o r to changes in th e phy siology o f th e host p l a n t t h a t
accompany de cre a sing p h oto periods .
No s i g n i f i c a n t tr e a tm e n t e f f e c t s were o b ta in e d , perhaps in p a r t ,
because o f th e high v a r ia n c e in t h a t regimen.
That no s i g n i f i c a n t
tr e a tm e n t e f f e c t s were o b ta in e d in th e g e n e ra tio n s a f t e r th e F j 0 r a is e s
many questions t h a t may be e x p la in e d in p a r t by the Figures 2
to 5.
Two o b s e rv a tio n s become apparent in Figure 2.
t h a t t h e r e were s i m i l a r i t i e s
between c e r t a i n tre a tm e n ts and second,
t h a t a peak o f a l a t e p roduction occurred in a l l
d i f f e r e n t g e n e r a tio n s .
F irs t,
th e tr e a tm e n ts a t
Figure I .
Percent apterous o ffs p rin g th a t occurred in each treatm ent in the ambient
photooeriod regimen over 8 generations.
--------- Abscisic Acid, 6 m g /L dist. HgO
--------- Abscisic Acid, 6 0 m g/L dist. HgO
---------Gibberellic Acid, 6 m g/L dist. HgO
---------Gibberellic Acid, 6 0 mg/L dist HgO
........... Distilled 8 Top HgO Control
GENERATION NUMBER
Percent apterous o ffs p rin g th a t occurred in each treatm ent in the 16 hour
photoperiod regimen over 11 generations.
APTEROUS OFFSPRING
Figure 2.
\ \
Abscilic Acid , 6 m e / L d i l l . MgO
\
'
Abscisic A e id 1 6 0 n »e /L d i l l . H2O
G ib b e rillic Acid, 6 m g / L d isl. M2O
G ib b srs llic A cid. G O m g /L disl. H2O
D is tille d
Fl I
FI2
FI3
GENERATION NUMBER
H2O Costrol
\
21
The s i m i l a r i t y between th e two tr e a tm e n ts - ABA-60 and GA0 -6. a re
illu s tra te d
in Figure
3. .
Aphids under
these two
tr e a tm e n ts fo llo w e d th e same tre n d w it h re s p e c t to wing dimorphism
u n til
the
g e n e ra tio n was reached, a f t e r which th e GA3 -S t r e a t e d
aphids fo llo w e d an apterous course o f development w h ile th e ABA-60
t r e a t e d aphids began producing p re d o m in a tly a ! a t e o f f s p r i n g .
As i t
is
sometimes the case t h a t when ABA is found a t high l e v e l s in p l a n t t i s ­
sue GA occurs a t low l e v e l s and v ic e versa (Thomas e t .
C h ris p e e ls and Varner
th e re fo re ,
it
a l . in 1965;
in 1966;' c i t e d in Leopold and Kriedmann, 1 9 7 5 ),
is not s u r p r is i n g t h a t a s i m i l a r b e h a v io ra l tr e n d was
e xperien ced by th e aphids under th e t r e a t m e n t s , ABA-60 and GA3 -6.
A s i m i l a r tr e n d between th e GA3- 60 tr e a tm e n t and th e c o n tro l
shown in F ig u re 4.
is
When.compared to the c o n t r o l , the GA3- 6 tr e a tm e n t
seems to have produced a s l i g h t l y a p t e r i z i n g e f f e c t w it h the f l u c t u a ­
t io n s delayed by a g e n e r a tio n .
As h ig h e r l e v e l s o f GA3 would be expec­
te d to i n f l u e n c e wing dimorphism towards an apterous course and as th e
c o n tr o l was under c o n d itio n s conducive to apterous pro d u c tio n (1 6 -h o u r
p h o to p e r io d ), i t
seems reasonable t h a t these two regimens should be
s i m i l a r , alth o u g h th e response o f one is delayed one g e n e r a tio n .
The e f f e c t s o f the two c o n c e n tr a tio n s o f ABA on wing dimorphism
as shown in
F ig u re 5
may be i n t e r p r e t e d , to mean t h a t two generations
more were needed in th e ABA 6 tr e a tm e n t b e fo re th e l e v e l s o f ABA b u i l t
up enough to cause th e p roduction o f a l a t e s .
Figure 3.
Percent apterous o ffs p rin g th a t occurred in the treatm ents ABA-60 and GA3-G
in the 16 hour photoperiod regimen over 11 generations.
\
\
---------- A b s c is ic A c id , 6 0 m g / L
----------G ibtoSfSlIic A c id , 6 m g / L
GENERATION NUMBER
d is t
MgO
d ie t HgO
Figure 4.
P ercent apterous o f f s p r i n g t h a t occurred in th e GA^-GO tr e a tm e n t and the
c o n tr o l in the 16 hour photoperiod o v er 11 g e n e r a tio n s .
IOO
....... .
X
o
Z
xX
N
A
80
CC
85
fe
6
S
O
S
5
40
S
3
S5
20
H
/.
7
li­
V
X
\
/■
/
\
..... X
\/v
y
X
\
X
G ib tw r e llic A c id , 6 0 m g /L d ie t
■ D is tille d HgO C o n tro l
F ll
FI2
GENERATION
FI3
NUMBER
H 2O
IX )
OJ
Fiaure 5
y
'
Percent apterous o ffs p rin g th a t occurred in the treatm ents ABA-6 and ABA-60
in the 16 hour photoperiod regimen over 11 generations.
--------- AblCiliC A c id ,
--------------- A b ic ii ie
F ll
FI2
GENERATION
FI3
NUMBER
6 m g /L d i l l H2O
A c id , 6 0 m g / l d in H2O
25
That d i s t i n c t m orphological changes occurred in response t o th e
tre a tm e n ts a d m in is te re d in the 16-hour photoperiod is e v id e n t by the
f ig u r e s p re s e n te d .
Whether the hormone tre a tm e n ts are somehow compen­
sated f o r by th e aphid a f t e r prolonged exposure, o r i f th e v a r i a b i l i t y
in h e r e n t in th e experim ent is r e s p o n s ib le f o r the la c k o f s i g n i f i c a n c e
ob ta in e d a f t e r th e
g e n e r a tio n ,
is not known.
Corpus A lla tu m
The c a l c u l a t e d v o lu m e tr ic measurements o f the corpus a l latum
glands o f t h i r t e e n aphids t h a t produced m ostly apterous, o f f s p r i n g a re
presented in T able V I .
These measurements in t h i r t e e n a d u lt s t h a t p ro ­
duced m a inly a l a t e progeny a re i l l u s t r a t e d
in Table V I I .
When the
volumes o f these two groups were compared by a n a ly s is o f v a r ia n c e , th e y
were found to d i f f e r s i g n i f i c a n t l y
(F = 4 .9 8 3 1 8 ; P = 0 . 0 3 5 ) .
The high c o r r e l a t i o n between th e corpus a l latum s i z e o f the mother
and form p roduction in th e o f f s p r i n g suggests t h e r e i s p r e n a t a l , r a t h e r
than p o s t n a t a l , d e te r m in a tio n o f wing form in IR. p a d i .
Since the s iz e
o f th e corpus a l latum gland is thought to i n d i c a t e i t s a c t i v i t y
1 9 6 8 ), i t
(W h ite ,
seems l i k e l y t h a t the pro d u c tio n o f apterous progeny is under
th e c o n tr o l o f j u v e n i l e hormone.
I t must be kept in mind, however,
t h a t th e r e i s c o n tro v e rs y re g a rd in g th e v a l i d i t y o f using th e volume o f
th e corpus a l latum as an i n d i c a t o r o f i t s
and Dogra, 1 9 7 2 ).
a c tiv ity
(S ta a l,
1961; G i l l o t
26
TABLE V I .
MEASUREMENT OF THE CORPUS ALLATUM GLAND IN ADULT APHIDS THAT
PRODUCED PREDOMINANTLY APTEROUS OFFSPRING. ' :
Date 1977
Fixed
310
314
282
307
310
304
292
314
304
307
223
231
230
Aphid
D e s c r ip tio n
27
20
35
28
35
35
35
27
28
37
12
Ila
12
F.o
Fr;
FgF^3
F^
F j3
F rj
F rf
Fr^
F j3
Fg
Fr
F3
a la te
apterous
a la te
apterous
apterous
a la te
apterous
apterous
a la te
apterous
apterous
apterous
apterous
# & Form o f Progeny
# a la te
# apterous
3
7
I
4
7
7
0
14
0
12
0
2
0
Volume?
o f CA(Uli)
23
47
14
29
29
28
42
48
44
42
19
8
24
4 5 .6
4 6 .1
2 8 .8
7 2 .3
6 6 .8
6 2 .8
6 1 .6
4 7 .6
6 8 .7
4 3 .2
8 3 .8
6 6 .8
5 6 .6
MEASUREMENT OF THE CORPUS ALLATUM GLAND IN ADULT APHIDS
THAT PRODUCED PREDOMINANTLY ALATE OFFSPRING. .
TABLE V I I .
Date 1977
Fixed
314
310
.305
304
311
311
304
306
304
310
222
231
229
Pot#
Pot#
.
34a
29
27a
32a
26a
31a
36
34a
30
33
IOa
16a
IOa
Aphid
D e s c r ip tio n
F19
F1v
F j1
F jj
F jf
Fjp
F j3
F jj
F j;
F jj
Fg
Fp
■ F j3
a la te
a la te
a la te
a la te
apterous
a la te
apterous
apterous
apterous
a la te
a la te
apterous
a la te
# & Form o f Progeny
# a la te
# apterous
6
37.
18
4
13
28
23
41
24
21
23
10
30
A n a ly s is o f V aria n c e Comparison o f th e Above Data:
f = 4 .9 8 3 1 8 = P = 0 .3 5 1 9
0
20
12
0
2
3
.19
22
14
12
7
0
0
..
Volume?
o f CA(Hl i )
2 6 .7
4 7 .7
4 7 .1
2 6 .2
5 6 .5
3 1 .4
4 7 .1
6 9 .1
4 4 .5
5 2.7
4 3 .2
5 6 .5
4 7 .6
DISCUSSION
Aphids a re s aid to begin development as presumptive a l a t a e , so
t h a t a p te r a e and i n te r m e d ia te forms a r e those which a re thought to have
been d i v e r t e d from the a l a t e course d u rin g development.
Phonological
s ig n a ls such as p h o to p e rio d , te m p e ra tu re , h u m id ity , crowding and n u t r i ­
t i o n t r i g g e r development o f the embryo towards an a l a t e o r apterous
course.
This developmental
d e te r m in a tio n as a response must occur
i n d i r e c t l y through th e r e p r o d u c t iv e physiology o f th e m other, or by a
d i r e c t response through th e p h y sio lo g y o f th e o f f s p r i n g .
Lees (1964)
w it h the use o f p i n p o in t l i g h t sources, showed t h a t p h o to -re c e p to rs a re
lo c a te d on th e head o f th e a d u l t a p h id , Megoura v i c i a e Buck, and t h a t
form d e te r m in a tio n was brought about through the r e p r o d u c t iv e physio­
logy o f th e m other.
O ther re se a rc h e rs
(Noda, 1958; Kawada, 1965;
W h ite , 1971) suggest t h a t o f f s p r i n g have th e a b i l i t y to determ ine t h e i r
own wing form up to 48 hours a f t e r b i r t h .
The c o r r e l a t i o n o b ta in e d in t h i s paper between th e corpus a l latum
s iz e o f th e mother and form p roduction in th e o f f s p r i n g suggests t h a t
t h e r e may be p r e n a ta l d e te r m in a tio n o f wing form in Rhopalosiphum padi
( L .).
Since s iz e o f th e corpus a l latum gland has p r e v io u s ly been
used as a ^param eter o f i t s a c t i v i t y
(W h ite , 1 9 6 8 )j t h i s would sug­
gest t h a t th e pro d u c tio n o f apterous progeny may be under th e c o n tro l
o f j u v e n i l e hormone.
The r e s u l t s o f th e photoperiod study i n d i c a t e t h a t R. padi r e a c ts
in a manner s i m i l a r to o th e r species o f h e teroecious aphids w ith regard
28
to the i n f lu e n c e o f photoperiod on wing dimorphism.
. V
■
'
•
'
-V
, I n c r e a s i n g : photo-
.
V- :
' pe rio d s i n i t i a t e th e p roduction ,of apterous progeny, w h ile decreasing :.
photoperiods cause the p roduction o f a ! a t e o f f s p r i n g .
If,
as was sug-.
gested by th e corpus a lla tu m s tu d y , th e production o f apterous progeny
i s under th e c o n tr o l o f j u v e n i l e hormone, then lo n g e r photoperiods
■ must, in.some manner, a c t i v a t e th e corpus a ll a t u m .
It
is s t i l l
a mat­
t e r o f d e b a t e , . however, whether the photoperiod a c ts d i r e c t l y on the
aphid d r i n d i r e c t l y through n u t r i t i o n a l
changes in the ap h id s'
.
host
p l a n t to produce t h i s response.
V a r i a b l e p h o to p e rio d s , as w ell, as o th e r environm ental
s t i m u l i , may
b rin g about changes in th e l e v e l s o f hormones i n , t h e host p l a n t .
Treatm ent w ith the p l a n t hormones GAg 6 m g / L . d i s t i l l e d HgO and ABA 60
mg/L d i s t i l l e d
HgO e l i c i t e d a s i g n i f i c a n t e f f e c t a t th e
g e n e ra tio n
in th e 16-hour p h o to p e rio d , suggesting t h a t these hormones, a f f e c t wing
dimorphism in H., p a d i .
The tre a tm e n ts ABA 60 and GAg 6 appear to
i n f l u e n c e wing dimorphism towards ah a l ate. course o f development, w h ile
GAg 60. seems to cause an a p te r iz i.n g e f f e c t . . Thus,, th e tre a tm e n t w ith .
ABA 60 and GAg 6 caused a r e v e r s a l
in wing form p r o d u c t i o n . t h a t was
o b ta in e d under th e i n f l u e n c e o f photoperiod a lo n e .
T h i S' suggests, t h a t
these p l a n t hormones i n t e r f e r r e d w ith th e normal response to photop e r io d .
This i n t e r f e r e n c e could be achieved in s ev e ral ways; I )
low
c o n c e n tr a tio n s o f GA and high c o n c e n tr a tio n s o f ABA may mimic the p l a n t
c o n d itio n s .u n d e r s h o r t e r p h o to p e rio d s , thus e l i c i t i n g
th e p roduction o f
29
a l a t e progeny, 2) these p l a n t hormones may i n h i b i t th e .p h o to p e r io d
response, o r 3) the s tim u lu s provided to the aphid by these p la n t hor­
mones may be s tr o n g e r than t h a t provided by ph o to p erio d .
ABA occur n a t u r a l l y in the host p l a n t , and t h e i r t i t e r s
to p h o to p e rio d , i t
may b e . li n k e d
seems u n l i k e l y t h a t these p l a n t hormones would s i g ­
n i f i c a n t l y a l t e r th e photoperiod response.
p e r io d s ,
Since GA and
In response to s h o rt photo­
however, GA may occur a t low c o n c e n tr a tio n s , w h i le ABA may be
a t h ig h e r c o n c e n tr a tio n s in the p l a n t ,
so t h a t i t
t h i s c o n d itio n mimics t h a t o f a s h o rt ph o to p erio d .
seems l i k e l y t h a t
In any case, i t
seems' apparent t h a t because these p l a n t hormones can re v e rs e the
response o f p h o to p e rio d , t h a t th e photo period response must be mani­
f e s te d in the aphids through changes in i t s
M ittle r
host p l a n t .
(1 9 72 ) suggested t h a t a y e t unknown aptero u s-p ro m o tin g
p r i n c i p l e e x is t e d which was o f a chemical n a tu r e and pro b a b ly in g e s te d .
I t could be p o s tu la te d from th e p re s e n t re se a rch t h a t GA in r e l a t i v e l y
high c o n c e n tr a tio n s e i t h e r produces i n th e p l a n t a substance, or is
i t s e l f th e "a p te ro u s-p ro m o tin g p r i n c i p l e " .
This "a p terous-prom oting
p r i n c i p l e " must a c t in tu r n to a c t i v a t e th e corpus a l latum gland to
s e c r e te j u v e n i l e hormone.
R e l a t i v e l y high c o n c e n tra tio n s o f ABA on
the o th e r hand, e l i c i t a response in the. aphid t h a t i s o p p o s ite to t h a t
obta ine d w ith high c o n c e n tr a tio n s o f GA.
I t may be p o s tu la te d t h a t ABA
i t s e l f i n h i b i t s o r produces in the p l a n t a substance.which i n h i b i t s
30
s e c r e t i o n 'b y th e corpus a lla tu m gland o r th e a c t i v i t y o f th e j u v e n i l e
hormone.
F u r th e r i n v e s t i g a t i o n i n t o th e r o l e o f p la n t hormones on the
d e te r m in a tio n o f wing dimorphism in aphids seems w a rra n te d .
SUMMARY
In c r e a s in g photoperiods in Rhopalosiphum padi
( L i n n . ) were found
to d i r e c t wing dimorphism towards an apterous c o u rse , w h ile d ecreasing
photoperiods d i r e c t e d wing fo rm a tio n o f o f f s p r i n g towards an a l a t e .
course o f development.
As p l a n t hormones can re v e rs e the response o f
p h o to p e rio d , th e photo period response must be m a n ifes te d in the aphids
through changes in i t s
host p l a n t .
The study o f th e e f f e c t s o f p l a n t hormones on wing dimorphism e l i ­
c i t e d a s i g n i f i c a n t tr e a tm e n t e f f e c t in th e
hour photoperiod regimen.
g e n e ra tio n in th e 16-
ABA-60 and GAj 6 appear to cause th e produc­
t i o n o f a l a t e progeny, w h ile GAg-60 seems to i n i t i a t e th e pro d u c tio n o f
apterous o f f s p r i n g .
The c o r r e l a t i o n o b ta in e d in t h i s paper between th e corpus a l latum
s iz e o f the mother and form p roduction in th e o f f s p r i n g suggests t h a t
t h e r e may be p r e n a ta l d e te r m in a tio n o f wing form in jt, p a d i .
Since
s iz e o f the corpus a ll a t u m has been suggested to i n d i c a t e i t s a c t i v i t y ,
the apterous p ro d u c tio n o f progeny may be fa vored by high t i t r e s o f
j u v e n i l e hormone in th e mother.
.
APPENDIX
33
MODIFICATIONS OF TECHNIQUES FOR THE ADAPTATION TO APHID TISSUES
Double Embedding w it h Methyl Benzoate C e l l i o d i n (Humason, 1962)
80% ETOH
5 minutes
95% ETOH
2 changes 5 minutes each
100% ETOH
2 changes 5 minutes each
Toluene
2 changes 15 minutes each
Methyl Benzoate C e l l o i d i n
24 hours
Toluene
2 changes, I hour each
% p a r a f f i n and % Toluene
2 changes, I hour each
Embed in p a r a f f i n .
Ewen's Aldehyde-Fuchsin S ta in in g Technique
T o l uene
5 minutes
Toluene
5 minutes
% Toluene and % 100% ETOH
5 minutes
100%
I minute
100%
I minute
95%
I minute
80%
I minute
70%
I minute
50%
I minute
D is t.
HgO
Oxidize in acid permaganate
I minute
2 h minutes
34
Rinse in d i s t .
HgO
D e c o l o r i z e , i n 2%% NaHS
Rinse in d i s t .
40 seconds
HgO
30% Rinse
70% Rinse
Aldehyde-Fuchsin
15 minutes
95%
Wash
D iffe re n tia te
in a c id a lcohol
70%
Rinse
30%
Rinse
D is t.
HgO
Rinse
Mordant
90 minutes
D is t.
Rinse
HgO
C o u n ters ta in
20 hours
0.2% a c e t i c a c id
Rinse
Hydrate
Take through Toluene.
•Mount in Adam's H is to c la d
Sections must be s ta in e d as soon as p o s s ib le a f t e r th e y a re c u t.
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G23%
cop.2
OATE
G a u d e t , Michelle D
Factors infl u e n c i n g
the d e t e r m i n a t i o n of
wing formation in the
aphid
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