The foraging niche of different species of linyphiid spider overlaps both spatially and temporally within agroecosystems, potentially reducing their biocontrol potential through competition and competitive exclusion. Within alfalfa, spider communities were monitored to assess the extent to which different subfamilies co-exist in relation to the availability of pest and non-pest prey. In parallel, the web-construction behaviors of linyphiid spiders were examined in the laboratory to test the hypothesis that at high densities intraguild competition would occur but the spatial separation of microhabitat to which different subfamilies locate would reduce intraguild competition, thus allow co-existence. Ultimately, by enhancing the diversity within a guild of generalist predators, biological control can be maximized whilst minimizing competition between species.