Communal Roost Site Selection in a Neotropical Harvestman: Habitat Limitation vs. Tradition

Communal roosting has been studied most extensively in birds and bats, but the behavior is taxonomically widespread (e.g., Reynierse et al. 1969; Cook et al. 1976; Pearson & Anderson 1985; Mallet 1986; Cockerill 1988; Miller 1989; Alcock 1998; Pimenta & Martins 1999; Gomes-Filho 2000; Grether & Switzer 2000). The location of communal roosts often appears to be traditional in that the same sites are used repeatedly while other seemingly suitable sites remain unused (e.g., Rau & Rau 1916; Vaughan & O’Shea 1976; Eiserer 1984; Marzluff et al. 1996; Blanco & Tella 1999; Brooke et al. 2000; Switzer & Grether 2000; Harms & Eberhard 2003). Although the functions of communal roosts have been studied and discussed extensively (e.g., Waltz 1982; Mallet 1986; Rabenold 1987; Miller 1989; Vulinec 1990; Marzluff et al. 1996; Switzer & Grether 2000; Barta & Giraldeau 2001; Dall 2002; Wright et al. 2003), the proximate mechanisms of roost site selection, and the reasons for repeated use of specific sites, have received comparatively little attention. Site fidelity, in general, is favored when the costs (e.g., energy, time, predation) of moving to a new Correspondence Greg Grether, Department of Ecology & Evolutionary Biology, University of California, 621 Charles E. Young Drive South, Los Angeles, CA 90095-1606, USA. E-mail: [email protected]