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Advisor(s)
Abstract(s)
Social status in lek-breeding species is highly correlated with mating success. Reproductive failure of
subordinates may be caused either by direct aggression by dominant males or by induced physiological
changes. We hypothesized that recent social status (winning or losing an encounter with another male)
affects the production of courtship sounds in male Mozambique tilapia, Oreochromis mossambicus, in the
absence of dominant males. We staged dyadic encounters between males and subsequently allowed full
access to a female to either the winner or the loser (one fish per dyad). We minimized possible effects of
social experience by isolating the subject males before the experiments. All males courted the females but
winners produced more courtship sounds than losers and showed significantly shorter courtship latencies
and longer courtship durations. The sounds of winners had longer pulse durations and lower peak
frequencies. Male size and condition factor, fighting latency and duration, and number of escalated
agonistic acts were not correlated with number of sounds or any of the courtship parameters measured.
Differences between winners and losers in courtship were probably related to transient physiological
changes induced by the encounter outcome, such as changes in levels of circulating monoamines, cortisol
and androgens, which can modulate courtship behaviour including sound production. We suggest that in
nature the outcome of recent social interactions between males may affect the production of courtship
sounds and courtship behaviour in general from the early stages of hierarchy formation.
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Keywords
Citation
Animal Behaviour, 69, 595-601
Publisher
Elsevier