Advances in studies of sociality in nocturnal prosimians.

Abstract

The evolution of sociality and its differential expression in primate socialorganizations have been a major focus of primatology for several decades. Theprocesses shaping specific mating systems and social relationships (such as sexualselection and life history strategies) and the underlying selective pressures (pre-dation pressure, feeding competition, etc.) have been investigated for a growingnumber of primate species. We know much more about diurnal than nocturnalspecies, however. Recent attempts at synthetic overviews of prosimian social or-ganization generally relegate nocturnal species to single, all-encompassing cat-egories such as “solitary” [Kappeler, 1997], despite evidence of complexity withinand variability between their social organizations [Gursky, 2000]. Several factorscontribute to this over-generalization, not the least of which are observationalchallenges and a dearth of long-term studies on nocturnal prosimians. Fortu-nately, research on nocturnal primates has dramatically increased over the lastdecade in particular [Alterman et al., 1995]. Several volumes have been pro-duced that focus on the ecology, behavior, genetics, and conservation of nocturnalprimates [Charles-Dominique et al., 1980; Alterman et al., 1995]. We still have along way to go toward a comprehensive view of the patterns and processes ofsociality in the order Primates, but the case studies contained in this volumetake us one step closer.Most of the papers in this issue were part of a symposium on Sociality inNocturnal Prosimians held at the XVIIth International Primatological Societymeeting in Antananarivo, Madagascar, in 1998. They address the levels, units,and patterns of sociality within a broad sample of nocturnal species from fourdifferent families that have recently been intensively studied. The data from thiscompendium clearly show that intraspecific relationships and mating systemsare more complex than previously thought.Gursky [2000] shows that spectral tarsiers (