Site Selection and Foraging in the Eresid Spider Stegodyphus tentoriicola

Habitat selection has profound consequences for survival and reproductive success. We investigated web relocation behaviour in relation to plant structure and body condition as well as the plasticity of foraging behaviour of the spider Stegodyphus tentoriicola. Spiders inhabiting thorny vegetation were larger, built larger webs than spiders in thornless plants and relocated their webs less frequently. Web relocation affected reproductive success through a delay of oviposition. Spiders supplemented with extra food improved body condition and built smaller webs than control spiders implying a crucial role of food in limiting fitness of S. tentoriicola. Reduced investment in webs suggests a trade-off between the benefit of more food against the cost of web-construction. We propose that S. tentoriicola exhibit a “silk and energy saving” strategy when saturated.