Nocturnal foraging patterns of linyphiid spiders: Implications for biological control

Linyphiid spiders are some of the most abundant predators present in agroecosystems, exerting significant pressure on prey population dynamics and thus delaying the exponential increase in pest density. Therefore, knowledge of their foraging strategies is necessary in order to enhance their role in biological control. Despite the potential importance of diel trophic patterns in linyphiid spider food-webs, there is limited information concerning nocturnal activities even though many spiders increase their activity and/or forage almost exclusively during the night. This increase could be explained, in part, as a response to increased prey availability or reduced predation pressure by higher order predators. Previous work has shown that linyphiids choose web-sites to maximize prey capture and forage in microhabitats where prey resources vary according to web placement. We tested the hypothesis that prey availability at web-sites of linyphiid spiders would vary between diurnal and nocturnal periods. To test our hypothesis, prey items were collected from microsite-specific mini-sticky traps and prey compared between nocturnal and diurnal periods. In parallel with the collection of prey at linyphiid webs, we quantified total prey abundance to compare prey resource utilization and falling rate into websites with total prey densities in the agroecosystem. The implications of our results for biological control will be discussed.