Space-time variation in the composition, richness and abundance of social wasps (Hymenoptera: Vespidae: Polistinae) in a forest-agriculture mosaic in Rio Grande do Sul, Brazil

Resumo

Wasps, important agents for the control of insect population, have been scantily studied in the Brazilian State of Rio Grande do Sul. Current study investigates monthly variations of social wasps in microhabitats within a forest-agriculture mosaic. Samples were collected between February 2013 and February 2014, through active search and baited traps made from 2 L transparent PET bottles, in five microhabitats, namely, forest, monoculture, polyculture and the edges between the forest fragment and monoculture and polyculture, in the municipality of Doutor Maurício Cardoso. Statistical tests, similarity indices, dominance and constancy as well as PCoA were used for data analysis to group the collection. A total of 953 specimens were collected, distributed across 15 species and seven genera. Abundance differed between microhabitats and the monoculture cultivation was least similar to the other microhabitats. PCoA identified three different groups. Abundance was positively correlated with temperature, negatively correlated with air humidity and was not correlated with wind velocity. Social wasps are able to utilize resources outside the forest fragments, but monocultures may create barriers for their dispersal.