Social Bats : The Males' Perspective

Abstract

Almost all bat species worldwide are, despite pronounced differences in ecology and life history, social. This makes them ideal organisms for studying the diversity and evolution of sociality. However, almost all work has focused on maternity colonies and most studies have been done on temperate species. Although simple density-dependent factors such as thermoregulatory benefits to the offspring or limited availability of roost sites have been refuted as the main driving forces behind sociality, it remains often impossible to disentangle factors associated with breeding from other potential actors on social organization. The study of multimale associations, a hitherto neglected social organization in bats, could provide a solution to this dilemma. Using data from male colonies of particolored bats (Vespertilio murinus, Linnaeus, 1758) in Switzerland I explain how sociality for male particolored bats is likely to be the best of a bad job and that competition over future matings determines when individuals leave the colony. Although multimale associations could potentially yield important insight into the mechanisms shaping social organization, we currently lack information about many aspects of such associations, which we need in order to understand social organization in its full detail.