Context dependent acquisition of familiarity recognition in Trinidadian guppies

Animals have the cognitive capacity to distinguish between familiar and unfamiliar conspecifics, and gain a range of benefits as a result of behavioural decisions linked to this ability. Familiarity recognition emerges after repeated encounters among individuals. In Trinidadian guppies (Poecilia reticulata), for example, females preferentially shoal with other, familiar females after 12 days of prior association, while the same time frame of familiarity acquisition exits in males when shoaling with other males. In a mating context, however, female guppies preferentially mate with males displaying unfamiliar colour patterns. Similarly, males prefer to court unfamiliar females after spending six weeks in the same tank. Given the different reproductive agendas of the sexes in promiscuous species such as guppies, we predict that context influences the development of familiarity. Specifically, we argue that males, who move between shoals of fish in pursuit of mating opportunities, do not ordinarily need to distinguish between familiar and unfamiliar females. Therefore, we predict that male guppies do not develop short-term familiarity with their mating partners. Here we confirm that shoaling preferences by females emerge within 12 days, but go on to show that familiarity cues are not used by males in mate choice over the equivalent time frame. We argue that it is only after prolonged association, as occurs for example when guppies are confined to isolated pools, that familiarity cues become important in male mating decisions.