University of Groningen
Motivational influences on individual and species differences in response to
conspecifics in three Haplochromis species (Pisces: Cichlidae)
Carlstead, Kathy
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Publication date:
1981
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Citation for published version (APA):
Carlstead, K. (1981). Motivational influences on individual and species differences in response to
conspecifics in three Haplochromis species (Pisces: Cichlidae) Groningen: s.n.
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Download date: 18-06-2017
- 1 3 0SUMMARY
T h i s p a p e r r e p o r t s o n d i f f e r e n c e s i n b e h a v i o r t o c o n s p e c i f i c s a m o n gi n d i v i d u a l s
o f t h e s a m ea n d o f c l o s e l y r e l a t e d s p e c i e s . T h e p u r p o s ei s t o d e t e r n ' i n et h r o u g h
w h i c h m o t ' i v a t i o n a ln T e c h a n i s m
s esl e c t i o n f o r r e s p o n s i v e n e stso s t i m u l i i n t h e
e n v i r o n m e nm
t a y h a v e h a d , i n d i r e c t l y , c o n s e q u e n c eosn t h e e v o l u t i o n a r y d e v e l o p m e n to f a t t a c k a n d d i s p l a y b e h a v i o r .
T h e b e h a v i o ro f t h r e e s p e c i e so f c i c h l i d f i s h , f l c r p L a c h r . o m
e l es a a r t s ,I i ,
a n g u s t i f r o n s , a n d i l . s q u a r L i p i n n i s ,d 1 l e n d e m i ct o L a k e G e o r g e i n U g a n d a ,w a s
studied intensively in the laboratory. The first andmajor part of this study
i s d e v o t e dt o u n r a v e l i n g t h e c a u s a l o r g a n i z a t i o n u n d e r l y i n g t h e r e s p o n s et o a
t e r r i t o r i a l i n t r u d e r . S p a t i a l l j , i s o l a t e dt e r r i t o r i a l m a l e s , p h y s i c a l l y b u t n o t
v i s u a l l y i s o l a t e d f r o m c o n s p e c i f i c s ,w e r e p r e s e n t e dw i t h a n e q u a l i y - s i z e dc o n s p e c i f i c i n t r u d e r , r e s t r a i n e d i n a g l a s s t u b e s r n a l l e n o u g ht o p r e v e n t i t f r o m
r e s p o n d i n gb e h a v i o r a ' l 1 t. o
v the actions of the test fish. Theexperiment hus
e m p l o y sa c o n s t a n t e x t e r n a l s t i m u l u s s i t u a t . i o n i n w h i c h d i f f e r e n c e s i n t h e
b e h a v i o r a l r e s p o n s e sa m o n gi n d i v i d u a l t e s t f j s h , a s w e l l a s c h a n g e so v e r t i m e
i n t h e b e h a v i o rw i t h i n i n d i v i d u a l s , c a n b e a t t r i b u t e d t o c h a n g e si n t h e i n t e r n a . l
c o n t r o l l i n g f a c t o r s f o r t h e b e h a v i o r . V a r i o u sm e a s u r e m e not sf t h e b e h a v i o rv r e r e
taken from video fi.lmsof the experimentsa
, n d l a t e r a n a l y z e du s i n g u n i v a r i a t e
a n d m u l t i v a r i a t e s t a t i s t i c a l t e c h n i q u e s i, n o r d e r t o d e d u c et h e e x i s t e n c ea n d
d e f i n e t h e i n f l u e n c eo f c e r t a i n c a u s a l m e c h a n i s m s .
In a first
e x p e r i m e n t ,p r i n c i p a l c o m p o n e n tasn a l y s i s w a s u s e d t o r e d u c et h e
l a r g e n u m b e ro f b e h a v i o r a l v a r i a b l e s t o a f e w r e s p o n s ed i m e n s i o n sa l o n g v r h i c h
i n d i v i d u a . l sm a i n l y v a r y . F o u r c o m p o n e n twse r e e x t r a c t e d t h a t e x p l a i n 7 7 . 4 %o f
t h e t o t a l v a r i a n c e o f t h e o r i g i n a l v a r . i a b l e s .T h e s ew e r e c o n c l u d e dt o r e f l e c t
paid to the intruder versus
i n d i v i d u a l v a r ia t i o n i n 1 ) t h e r e L a t ' i r e a t t e r - i t ' t o n
o t h e r s t i m u l i , 2 ) c n , o t . d a n ar ees p o n d i n gt o t h e i n t r u d e r , 3 ) r e s p o t t s i l e n e s st c ' l ' t s tu-!b{1/ireof the suz,rout:dl.ngs,
and 4) perstst;-,nceof responding to all
selected
e x t e r n a l s t i m u l i . S c o r e sf o r e a c h i n d i v i d u a l o n e a c ho f t h e s e r e s p o n s ed i m e n s i o n s w e r ec a l c u l a t e ds o t h a t e a c h f i s h c o u l d b e c h a r a c t e r i z e dr e l a t i v e t o t h e
others on these propertiesof the response.
C o r r e l a t i o n so f i n d i v i d u a l c o m p o n e nstc o r e s w i t h a s p e c t so f t h e m o v e m e n t s
a n d s t e r e o t y p e db e h a v i o r p a t t e r n s p e r f o r m e dt o t h e i n t r u d e r w e r e a n a l y z e d .T h e y
i n d i c a t e d t h a t t w o o f t h e c o r n p o n e n at sr e a s s o c i a t e dw i t h a t e n d e n c yt o a p p r o a c h
IJl
.
t h e i n t r u d e r , a n d t w o w i t h a t e n d e n c yt o s t a y o u t o f i t s v j c j n r ' t y . T h e r a t i o o f
m o v e m e n ttso w a r d s a n d a w a y f r o n t h e i n t r u d e r w a s f o u n d t o b e a s s o c i a t e d w j t h
the strength of these two tendencies.
I n t h e s a m ee x p e r i r n e nat n a t t e m p t w a s m a d et o m a n i p u l a t eo n e o r m o r ef a c s y p r e s e n t i n ga f r i g h t e n i n g s t i m u l u s , a b r i g h t
t o r s u n d e r l y i n gt h e c o n p o n e n t b
l i g h t . T h e l ' i g h t w a s p r e s e n t e dh a l f w a y t h r o u g ht h e o b s e r v a t i o np e r i o d w h i l e t h e
r e s p o n s et o t h e i n t r u d e r w a s o n g o i n g . T h e b e h a v j o l i n t h e p e r i o d w i t h t h e l i g h t
o n w a s c o m p a r e tdo t h e b e h a v i o r b e f o r e i t c a m eo n , a n d t o b e h a v i o r i n a s i m i l a r
control period later in time but without the 1ight.
l h e l i g h t i n c r e a s e dt h e s c o r e s o f i n d i v i d u a l f i s h o n t h e c o m p o n e n tfso r
rn:oi4crce and re'sponsiuenessto dlstutbantce, and it removedthe changes in the
s c o r e so n p e r s r s t e n c et h a t h a d o c c u r r e do v e r t i m e . T h e r e s u l t s a l s o i n d i c a t e d
t h a t t h e r e a r e m u t u a l i n f l u e n c e s b e t w e e nt h e c o m p o n e n t sS
. coresin the initjal
p e r i o d o f t h e t e s t f o r r e s p o n s i u e n e s st o d l s t t L t : b a n c e
were found to explain a
s u b s t a n t i a la m o u n o
t f t h e v a r i a n c e i n c r o o i d a r i cl ea t e r i n t i m e w h e t h e rt h e l i g h t
was on or not. Initial
had
scores on auoidarLceand responsi't;enessto tlistttv'bant:a.
a n i n h i b i t o r y e f f e c t o n s c o r e s o n p e r s i s t e n c e\ t h e nt h e l i g h t w a s o n .
I t w a s c o n c l u d e dt h a t t h e l i g h t p o t e n t i a t e s a s y s t e mf o r f e a r , e n c o m p a s s i n g
the ctuoidanceand responsiueness to dtsturbal?d€ components.This fear system
e x e r t s a c o n t r o l o v e r t h e p e r s i s t e n c eo f r e s p o n s et o e x t e r n a l s t i m u l i .
A s e c o n de x p e r i m e n w
t a s p e r f o r m e dt o e x a m i n et h e r e l a t i o n s h i p b e t w e e n
m e a s u r e m e notfs t h e r e s p o n s et o t h e i n t r u d e r a n d t h e r e s p o n s et o a n o t h e r c o n s t a n t
e x t e r n a .sl t i m u l u s .T h e r e s p o n s et o j u v e n i l e f i s h , r e s i d i n g i n t h e s a m ea q u a r i u m
p r e s e n t a t i o n .R e s p o n s et o t h e e x p e r i m e n t e e
r n t e r i n g t h e r o o mt o p l a c e a n d r e m o v et h e i n t r u d e r
v r a sa l s o r e c o r d e d . I n t h e p o s t - i n t r u d e r p e r i o d t h e d e g r e et o w h i c h
w i t h t h e t e s t f i s h , w a s r e c o r d e db e f o r e a n d a f t e r i n t r u d e r
d e c r e m e n tosc c u r r e d i n t h e r e s p o n s i v e n e stso j u v e n i l e s o r t o d i s t u r b a n c ew a s
f o u n d t o b e p o s i t i v e l y r e l a t e d t o t h e a r n o u not f r e s p o n s ee v o k e db y t h e i n t r u d e r .
I t w a sc o n c ' l u d etdh a t a s y s t e me x i s t s w h i c h c o n t r o l s t h e a t t e n t i o n a l m e c h a n i s m s
f o r r e s p o n d i n tgo t e r r i t o r i a l
i n t r u d e r s b y e x c l u d i n gr e s p o n d i n g
to other stimuli.
A n a t t e r n p tw a s m a d et o e x p l a i n t h e s e p h e n o m e ni na a m o d e lf o r t h e a r r a n g e m e n to f s t a t e v a r i a b l e s a n d i n t e g r a t i v e s y s t e m sc o n t r o l l i n g t h i s b e h a v i o r .I t
p r o p O s etsh a t t h e r e s p o n s et o t h e i n t r u d e r a t a n y g i v e n m o r n e ni st c o n t r o l l e d b y
t w o m e c h a n i s mi ns t e g r a t i n g t h e o u t p u t o f t h r e e s y s t e m s :a s y s t e n f o r r e s p o n d i n q
-t32-
t o s t i m u l i t h a t d i s t u r b a s p e c t so f t h e s u r r o u n d i n g s( D ) , a s y s t e mf o r r e s p o n d i n g
t o t e r r i t o r i a ' l i n t r u d e r s ( T I ) , a n d a s y s t e mf o r f e a r r e s p o n s e s( F ) . T h e f o r m e r
t w o s y s t e m sc o m p e t ef o r c o n t r o l o f s e l e c t i v e a t t e n t i o n , a n d e a c h c o n t r o l s t h e
a p p r o p r i a t em o t o r p a t t e r n s f o r r e s p o n d i n gt o t h e s e l e c t e d s t i m u l u s ( i n t h e b e h a v ' i o r a lf i n a l c o m m opna t h ) . A n o t h e r i n p u t t o t h i s c o n t r o l o r i g i n a t e s f r o m t h e
f e a r s y s t e m .T h e m o d e la l s o p o s t u l a t e s a f a c t o r c o n t r o l i i n g i n g e n e r a l t h e p e r s i s t e n c eo f t h e r e s p o n s et o a l l s e l e c t e de x t e r n a l s t i m u l i b y i n f l u e n c i n q t h e
( l u t p u t f r o m s y s t e m sD e n T I .
T h e d i s c u s s i o no f P a r t I d e a l s w i t h t h e m e c h a n ' i s m
t hsr o u g h w h i c h r e s p o n s i v e n e s st o e x t e r n a l s t j r n u l i n i g h t h a v e a n e f f e c t o n t h e f o r m o f a t t a c k a n d d i s p l a y b e h a v i o r ,a n d w ' i t h t h e l i t e r a t u r e o n f e a r b e h a v i o rj n a n i m a l s .
T h e s e c o n dp a r t o f t h i s s t u d y d e a l s w i t h d i f f e r e n c e s i n u n d e r l y i n g m o t i v a t i o n a l f a c t o r s o f t h e r e s p o n s et o e x t e r n a l s t i m u l i a m o n gt h e t h r e e s p e c i e s .
T h e r e s p o n s e sw e r e s t u d j e d o f t w e l v e i n d i v ' i d u a l so f e a c h s p e c i e s t o r e s t r a i n e d
i n t r u d e r s w h i l e a t t h e s a m et i m e t h e e x p e r i m e n t e w
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front of the tank
view of
r . . ! i : . : L t i ,i \i .rio ' i s i s t h e
territorial
s p e c i e sm o s t r e s p o n s i v et o d i s t u r b a n c ea f f o r d e d b y t h e e x p e r i m e n t e r .T h i s h a s
t h e e f f e c t o f r e d u c i n g i t s r e s p o n s i v e n e stso i n t r u d e r s . E . e l e g u n s i s t h e m o s t
r e s p o n s i v et o i n t r u d e r s a n d l e a s t s o t o d i s t u r b a n c e . . 4 ' .s q u c n ' n i p i n : ihsa s t h e
h i g h e s t l e v e l o f a g e n e r a lp e r s i s t e n c ef a c t o r , r e s p o n d i n gp e r s i s t e n t l y t o b o t h
d i s t u r b a n c eo f t h e s u r r o u n d i n gas n d t o t e r r i t o r i a l
i n t r u d e r s . T h e s ed i f f e r e n c e s
a r e d i s c u s s e dc o n c e r n i n gt h e e n v i r o n m e n t aflo r c e s t h a t m i g h t h a v e s e l e c t e d f o r
t h e s em o t i v a t i o n a ls p e c i a l i z a t i o n si n v i e w o f w h a t i s k n o w no f t h e n a t u r a l h a b i t a t o f e a c hs p e c i e s .
D i f f e r e n c e sa m o n gt h e s p e c i e si n t h e d i s p l a y a s s o c i a t e dw i t h s p a w n i n a
gc t i v i t i e s w i t h f e m a l e sw e r e f o u n d t o c o r r e s p o n dt o d i f f e r e n c e s i n t h e d i s p l a y
f o l l o w i n g a n a p p r o a c h / w i t h d r a wcaoln f l i c t t o r e s t r a i n e dn a l e i n t r u d e r s . T h e d ' i vergence
o f c o u r t s h i pd i s p l a y s i n r e l a t i o n t o s e l e c t i o n f o r r e s p o n s i v e n e st os
e n v i r o n n e n t asl t i m u l i i s d i s c u s s e d .