title: Desiccation resistance reflects patterns of microhabitat choice in a Central American assemblage of wandering spiders.
abstract: The lowland rainforest of northeastern Costa Rica harbours an assemblage of large wandering spider species belonging to three habitat subguilds: (1) semi-aquatic, (2) forest ground dwelling and (3) vegetation dwelling. We hypothesized that desiccation resistance should differ among species preferring different microhabitats and the associated microclimate. Desiccation resistance was assessed by: (1) measuring water loss rates of the spiders under relatively dry experimental conditions, and (2) recording desiccation susceptibility, i.e. the reactions of the spiders to a relatively dry environment. High water loss rates and desiccation susceptibility of the semi-aquatic and forest-ground-dwelling subguilds clearly mirrored the relatively humid microclimate of the understory. Significantly lower water loss rates and desiccation susceptibility of the vegetation-dwelling species reflected the highly variable, often dry and hot conditions of the rainforest canopy and forest edge habitats. Vegetation-dwelling wandering spiders are therefore physiologically better adapted to dry conditions than the semi-aquatic and forest-ground-dwelling species. The results illustrate the significance of physiological characteristics for explaining both species-specific habitat use and, in a larger context, niche partitioning within a community.
authors.affiliation: Institute of Experimental Ecology, University of Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany Witold.Lapinski@uni-ulm.de Marco.Tschapka@uni-ulm.de.
authors.forename: Witold
authors.initials: W
authors.lastname: Lapinski
authors.affiliation: Institute of Experimental Ecology, University of Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa Ancón, Republica de Panamá Witold.Lapinski@uni-ulm.de Marco.Tschapka@uni-ulm.de.
authors.forename: Marco
authors.initials: M
authors.lastname: Tschapka
mesh_terms: D000818:Animals; D003364:Costa Rica; D003890:Desiccation; D017753:Ecosystem; D008834:Microclimate; D065947:Rainforest; D013112:Spiders / Q000502:physiology*; D014870:Water Loss, Insensible / Q000502:physiology*
keywords: Canopy; Ctenidae; Ecology; Physiology; Rainforest; Trechaleidae