Courtship behaviour influences social partner choice in male guppies

What is it about?

Whether and how males associate non-randomly with each other is poorly understood in non-human animals. Although male courtship displays have evolved primarily to sexually attract females for mating purposes, they also generate inadvertent public information that may be gleaned by nearby male sexual rivals, who are eavesdropping on the courter’s behaviour, for their future use in behavioural decision making. Here, we tested the hypothesis that males of the Trinidadian guppy (Poecilia reticulata), a small social tropical fish, eavesdrop on the courtship behaviour of rival males and later use this public information to bias their own social partner-choice decisions. In a laboratory experiment, we first presented individual eavesdropping males the opportunity to simultaneously observe two demonstrator males whose courtship behaviour was manipulated experimentally to differ, following which we tested them for their preference to associate socially with either demonstrator males. Test males preferentially associated with the demonstrator male who they had previously observed courting a female over the other (non-courting) demonstrator. By doing so, an eavesdropping male might enhance his own mating success through increased frequency of encounters with receptive females attracted by other courting males compared with searching for females independently. Our novel findings highlight the potential for sexual behaviour to influence male-male social associations in nature.

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