Effect of habitat amount and complexity on social wasps (Vespidae: Polistinae): implications for biological control

Abstract

Agricultural expansions have major negative impacts on terrestrial biodiversity, directly affecting ecosystem services. Social wasps (Hymenoptera: Vespidae: Polistinae) actively participate in trophic balance in natural ecosystems and biological control of agricultural pests. In this work, we evaluated the richness and composition of social wasps in the interior of the native habitat, edge, and adjacent soybean cultivation area. We also evaluated the effect of the amount and complexity of habitat structure on the richness and composition of social wasps, considering two scales (buffer 5000 and 1000 m). We sampled 42 sites distributed in eight municipalities, in the Midwest region of Brazil, using Malaise trap. In total, we collected 288 individuals distributed in 43 species and 10 genera. The richness of social wasps did not differ among the points (interior, edge, and culture) in the three vegetation categories (Forest, Ecotone, and Cerrado). However, species composition differed between edge and crop, only in areas categorized as Forest. The amount of native habitat influenced social wasp richness and composition only in the Forest areas and social wasp richness was positively related to the complexity of the habitat structure at both scales (buffer 5000 and 1000 m), which had no significant effect on species composition. Social wasps are generalists regarding foraging sites but rely on structurally more complex habitats to nest. Thus, the maintenance of native habitats favors the richness of social wasps in adjacent soybean areas.