Non-crop plant communities conserve spider populations in chili pepper agroecosystems

Abstract

Habitat management enhances heterogeneity in agroecosystems and also has the potential to increase recruitment of spiders, which can improve the biological control services afforded by these important predators. A paucity of studies has documented the associations of spiders with plant communities or the efficacy of non-crop plants for increasing the density and diversity of spider populations. Here we examined natural associations of spiders with native non-crop plants within Brazilian chili pepper agroecosystems. Following this characterization, a manipulative experiment was undertaken at two locations to identify the effects of non-crop plant strips and borders on spider community structure. The composition of native plants altered the community of spiders. The abundance of these predatory spiders was highest on Asteraceae. Spatial Analyses by Distance Indices (SADIE) determined that there was significant aggregation of spiders in chili pepper fields under these plant management strategies. Although incorporating this habitat management approach reduced the overall cropping area, the corresponding increase in generalist predator abundance could offset costs by improving the natural control of pests. This study revealed associations between native plants and spider communities, and how these help to conserve predator biodiversity. Targeted management of native non-crop plants promote the abundance of natural enemies and enhances biological control in chili pepper agroecosystems.