Kin discrimination by asocial Franklin's ground squirrels (Spermophilus franklinii): is there a relationship between kin discrimination and ground squirrel sociality?

Abstract

Social discrimination among conspecifics allows the expression of beneficent behaviour toward certain individuals including kin, neighbours, colony members, mates or other allies such that the fitness of the actor, recipient or both parties are enhanced. I tested for behavioural discrimination among juvenile Franklin's ground squirrels by staging dyadic interactions among pairs of littermates, neighbours and non-neighbouring colony members in a neutral arena. Franklin's ground squirrel juveniles interacted less frequently and showed fewer recognitive contacts with littermates than with neighbouring or non-neighbouring non-littermates. They did not discriminate neighbouring from non-neighbouring non-littermates in any way. Thus, juvenile Franklin's ground squirrels manifest kin discrimination in the absence of any broader level of social discrimination. Taken together with comparative data from congeners, it is apparent that kin discrimination is not unique to highly social ground squirrels, and that strict kin discrimination may give way to broader social inclusivity with advancing sociality in the genus Spermophilus. It remains unclear, however, whether kin discrimination in Franklin's ground squirrels promotes nepotism, or ultimately serves in the context of mate choice.