Eavesdropping and mate choice in female fighting fish

Despite the fact that most communication occurs in the context of networks of several individuals, the consequences of considering communication as a network on individuals' capacity for gathering information on congeners has been little investigated. Eavesdropping is the behaviour of a receiver extracting information from an interaction in which it is taking no part. Due to the fact that signals used in aggressive interactions are assumed to be reliable, eavesdropping could be an effective way of evaluating the quality of potential mates. We conducted two experiments designed to discover if female fighting fish (Betta splendens) monitor aggressive interactions between two males and if information gained by eavesdropping is used in the initial stages of subsequent mate choice. We found that females that had seen the interaction visited the winner first more often and spent significantly more time near, looking at and displaying to the winner of the interaction. By contrast females that had not seen the interaction visited the loser first more often and did not behave significantly differently to winner and loser. Overall these results are consistent with the idea that in the initial stages of mate choice females eavesdrop, i.e. use information gathered from male-male displays.