Parasitoid Abundance and Community Composition in Desert Vineyards and Their Adjacent Natural Habitats

SIMPLE SUMMARY: Desert agricultural systems are characterized by extreme contrast in environmental conditions between the irrigated fields and their surrounding natural habitats. We compared insect communities between vineyards and their surrounding desert habitats, in a hyper-arid region in Israel. We focused on parasitoid wasps—a highly diverse group with members that are important for the biological control of insect pests. Parasitoids were more abundant outside of the vineyard at the beginning of the vine growth season and became more abundant within the vineyard habitats later in the season. In contrast to our predictions, many parasitoid species were found both within and outside of the vineyards. This highlights the importance of the natural surrounding habitats in maintaining and providing resources for potentially beneficial biological control agents and calls for their preservation. ABSTRACT: Parasitoids are important natural enemies of many agricultural pests. Preserving natural habitats around agricultural fields may support parasitoid populations. However, the success of such an approach depends on the ability of parasitoids to utilize both crop and natural habitats. While these aspects have been studied extensively in temperate regions, very little is known about parasitoid communities in desert agroecosystems. We took one step in this direction by sampling parasitoids in six vineyards and their surrounding natural desert habitat in a hyper-arid region of the Negev Desert Highlands, Israel. We predicted that due to the high contrast in environmental conditions, parasitoid abundance and community composition would differ greatly between the crop and the natural desert habitats. We found that parasitoid abundance differed between the habitats; however, the exact distribution pattern depended on the time of year—with higher numbers of parasitoids in the natural habitat at the beginning of the vine growth season and higher numbers in the vineyard at the middle and end of the season. Although parasitoid community composition significantly differed between the vineyard and desert habitats, this only accounted for ~4% of the total variation. Overall, our results do not strongly support the notion of distinct parasitoid communities in the crop vs. the desert environment, suggesting that despite environmental contrasts, parasitoids may move between and utilize resources in both habitats.