Who's Watching Me: Female Siamese Fighting Fish Alter Their Interactions in Response to an Audience

It is well established that interactions between conspecifics are often influenced by the presence of passive bystanders. Individuals have been found to alter their behavior in a variety of contexts, from foraging to aggression, based on the presence, sex, or identity of an audience. This audience effect may influence not only the nature of a signaling event but also the evolution of signal structure as signals may have to convey information across a distance. Additionally, audience individuals may use information obtained by watching in later encounters with these individuals, which may act as a selection pressure on communication. Communication networks in Siamese fighting fish, Betta splendens, are particularly well studied, with audience effects influencing both male–male interactions and male–female interactions. However, the effects of an audience on female–female interactions have not been examined in this species or any other. This study examined the interactions of pairs of females in three different audience conditions (male, female, and no audience). The results suggest that female–female interactions are affected by the presence of an audience as interactant‐directed gill flaring, the most commonly performed behavior, was performed more with an audience present. Additionally, the sex of the audience seemed to be influential, reflected by a difference in the frequency of interactant‐directed behaviors when a female vs. a male audience was present. This study is one of the first to demonstrate that females modify their behavior as a result of being watched and stresses the importance of examining audience effects in a variety of social contexts.