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Advisor(s)
Abstract(s)
In many territorial species androgens respond to social interactions.
This response has been interpreted as a mechanism for
adjusting aggressive motivation to a changing social environment.
Therefore, it would be adaptive to anticipate social challenges and
reacting to their clues with an anticipatory androgen response to
adjust agonistic motivation to an imminent social challenge. Here
we test the hypothesis of an anticipatory androgen response to
territorial intrusions using classical conditioning to establish an
association between a conditioned stimulus (CS = light) and an
unconditioned stimulus (US = intruder male) in male cichlid fish
(Oreochromis mossambicus). During the training phase conditioned
males (CS US paired presentations) showed a higher decrease
in latency for agonistic response toward the intruder than
unconditioned males (CS–US unpaired presentations). In the test
trial, conditioned males showed an increase in androgen levels
(i.e., testosterone and 11-ketotestosterone) relative to baseline, in
response to the CS alone. This increase was similar to that of
control males exposed to real intruders after CS, whereas unconditioned
males showed a decrease in androgen levels in response
to the CS. Furthermore, conditioned males were significantly more
aggressive than unconditioned males during the post-CS period on
test trial, even though the intruder male was not present during
this period. These results reveal the occurrence of a conditioned
androgen response that may give territorial males an advantage in
mounting a defense to upcoming territorial intrusions, if the ability
to readily elevate androgens does not co-vary with other traits that
bear costs.
Description
Keywords
Aggression Androgens Associative learning Social challenge
Citation
Proceedings of the National Academy of Sciences of The United States of America, 106, 15985-15989
Publisher
National Academy of Sciences