Lapinski Witold, Tschapka Marco
Institute of Experimental Ecology, University of Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany
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
J Exp Biol. 2014 Aug 1;217(Pt 15):2789-95. doi: 10.1242/jeb.102533. Epub 2014 May 22.
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.
哥斯达黎加东北部的低地雨林中栖息着一群大型游走蜘蛛，它们分属于三个栖息地亚类群：（1）半水生的，（2）栖息于森林地面的，以及（3）栖息于植被中的。我们推测，偏好不同微生境及相关小气候的蜘蛛物种，其抗干燥能力应该有所不同。通过以下方式评估抗干燥能力：（1）在相对干燥的实验条件下测量蜘蛛的失水率，以及（2）记录干燥易感性，即蜘蛛对相对干燥环境的反应。半水生和栖息于森林地面的亚类群的高失水率和干燥易感性，清楚地反映了林下相对潮湿的小气候。栖息于植被中的物种显著较低的失水率和干燥易感性，反映了雨林树冠层和森林边缘栖息地高度多变、通常干燥炎热的条件。因此，栖息于植被中的游走蜘蛛在生理上比半水生和栖息于森林地面的物种更能适应干燥条件。这些结果说明了生理特征对于解释物种特异性栖息地利用以及在更大背景下群落内生态位划分的重要性。
