Courtship by subordinate male siamese fighting fish, betta splendens: Their response to eavesdropping and naive females

In a social environment, a communication signal may provide information to individuals other than those interacting with the signaler. Eavesdropping is gathering information without being directly involved in the communication interaction. Female Siamese fighting fish, Betta splendens, choose the winner of male-male aggressive interactions based upon information she extracts from eavesdropping. Naive females, those that have not witnessed the interaction, show no consistent preference for either male. This suggests that losers would be more successful in courting a naive female. We conducted two sets of trials: one set tested the losers' courting preference of eavesdropping females or naive females whereas the other tested the winners' courting preference. We found that losers displayed gill cover erection, a courting behaviour, significantly more towards the naive female than towards the eavesdropping female whereas the winner showed no preference. These results suggest that male B. splendens can moderate their response to an audience in ways more complex than previously appreciated. Our data support the suggestion that communication can serve as a network that reaches beyond the immediate signaler and receiver. Understanding the complexity of communication networks will enable us to broaden our ideas about the mechanisms of sexual selection.