Patch richness affecting patch selection of Pityophantes

Abstract

We observed spiders of the family Linyphiidae and genus Pityohyphantes in two different microhabitats at the University of Michigan Biological Station near Pellston, Michigan. The purpose of this study was to explore the effects of prey distribution on spider foraging behavior in the two microhabitats. The microhabitats were composed of a temperate forest woodland understory and a shoreline habitat along Douglas Lake. Microhabitat richness was measured by observing potential prey abundance, number of prey captured on sheet webs, and biomass of captured prey in both microhabitats. The shoreline microhabitat was found to have a higher abundance of potential prey of the two areas under study. However, the woodland understory was observed to have a higher average prey capture count and biomass per web. Unfortunately, our results conflicted depending on what criteria was used. Though we could not definitively say which was the richer patch, we did find variability in patch richness. Despite the variability in patch richness, an equal distribution of sheet webs was found between the two microhabitats. These results suggest that factors other than prey distribution affect patch selection. Although outside the scope of our study, tradeoffs such as competition or predation likely result in Pityohyphantes spiders preferring a microhabitat with less potential prey.