Habituation underpins preference for mates with novel phenotypes in the guppy

Populations harbor enormous genetic diversity in ecologically important traits. Understanding the processes that maintain this variation is a long-standing challenge in evolutionary biology. Recent evidence indicates that a mating preference for novel sexual signals can be a powerful force maintaining genetic diversity. However, the proximate underpinnings of this preference, and its generality, remain unclear. Here, we test the hypothesis that preference for novel sexual signals is underpinned by habituation, a nearly ubiquitous form of learning whereby individuals become less responsive to repetitive stimuli. We use the Trinidadian guppy (Poecilia reticulata), in which male colour patterns are diverse yet heritable. We show that repeated exposure to males with a given colour pattern reduces female interest in males with that pattern, and that interest recovers following brief isolation. These results fulfil two core criteria of habituation: responsiveness decline, and spontaneous reco...