Assemblages of social wasps (hymenoptera, Vespidae, Polistinae) in the veredas of central Brazil

Abstract

Social wasps are widely distributed in Brazil, and their distribution is closely related to the type of habitat and vegetation structure. Veredas (palm swamps) occur on moist soils and are characterized by an almost total predominance of buriti palms (Mauritia flexuosa). The insect fauna of these environments is poorly known, especially in Central Brazil. Some data on the diversity of the social wasps are available for the state of Mato Grosso, although its Veredas have not been surveyed up to now. In the present study, we investigated the wasp species composition in six Vereda environments over a 24-month sampling period, between August 2017 and July 2019. The specimens were collected using a sweep net, which was deployed along 200-m transects that were subdivided into 10 plots of 3 m2. To attract the wasps, we used a backpack sprayer to spray each plot with insect attractant made from five spoonfuls of granulated sugar and one spoonful of salt, dissolved in 5 liters of water. After spraying the plot, we waited 10 minutes before initiating the surveys, which lasted 10 minutes per plot, for a total of 200 minutes of sampling per palm swamp. A total of 1072 social wasp specimens were collected, representing 11 genera and 37 different species. The most abundant species were Polybia cf. ruficeps xantops (Richards, 1978), Agelaia pallipes (Olivier, 1792); Polybia rejecta (Lepeletier, 1836), and Mischocyttarus mattogrossoensis Zikán, 1935, which together accounted for 57% of the specimens collected over the 24 months of the study period. The total species richness estimated for the Vereda environments was 39.88 ± 0.627, approximately 41% of the 88 wasp species of the subfamily Polistinae found in the Cerrado of eastern Mato Grosso.