Male and female fighting fish

The study of communication in a network setting has gained increasing popularity in recent years. While audience effects on aggressive interactions have been studied extensively, male–female interactions have often been overlooked. In addition, little is known about how reproductive status affects the nature of audience effects. Siamese fighting fish, Betta splendens, are a popular subject for communication network studies, but male–female interactions have not been explored in this setting. In this study, pairs of male and female Betta were presented with a male, female or no audience to determine whether the presence of an audience alters the behaviour of the interactants. Within these three audience types, there were four reproductive status conditions with receptivity indicated by nest presence for males and reproductive barring for females. It was predicted that male–female interactions would be affected by the presence of an audience, especially when both interactants are receptive as has been found in male–male interactions in this species. The results suggest that presence of an audience and reproductive status act in combination to influence male–female interactions, but only in interactant-directed behaviours. Not all behaviours were equally affected by these factors. For example, while tail beats to the other interact were greatest when a female audience was present and both the interactants were receptive, this was not true for gill flaring. This study is among the first investigations into audience effects on male–female interactions including the first in Betta and suggests that courtship as well as aggression should be explored in a network setting.