Long-and short-term changes in social wasp community structure in an urban area IntroductionThe social wasps are widely distributed throughout all continents, except Antarctica. In Brazil, they are represented primarily by the Polistinae (Carpenter & Marques, 2001). Brazilian paper wasps inhabit various environments, but show high degrees of association with urban areas, often constructing nests under or inside the walls of buildings (Wenzel, 1998;Alvarenga et al., 2010;Torres et al., 2014;Michelutti et al., 2013).The importance of studying social wasps and their diversity is emphasized by their ecological roles. For instance, social wasps may act as pollinators when visiting flowers (Clemente et al., 2012), detritivores when foraging on decaying fruits and animal carcasses (Moretti et al., 2011), and predators when foraging on agricultural pests (e.g., caterpillars) (Elisei et al., 2010). As a result, social wasps are part of a complex intra and interspecific ecological web that is yet to be fully comprehended (Menezes et al., 2014; Virgínio et al., 2016). AbstractThe success of social wasps in anthropic environments is related to their ability to nest both in vegetation and human constructions, and, as humans modify their own environments, wasps community structure may shift as well. Our aim was to assess the diversity of social wasps and their interactions with nesting substrates seasonally in an urban squares area in Southeastern Brazil, 15 years after the first diversity study in this area. We actively searched for nests in the rainy season between 2014 and 2015 and in the dry season of 2015. Although social wasp species richness did not change since the 2000 assessment (13 species in 5 genera), the abundance decreased substantially. Additionally, wasps showed a general trend of nesting on the man-made materials Metal (n = 115, 60%) and Concrete (n = 106, 36%), especially by the two most common species sampled: Mischocyttarus cassununga and Polistes versicolor. We suggest that abundance decrease may correspond to the reduction of green areas in the assayed locations. These results support the well-known importance of maintaining green areas in urban environments to promote the growth and conservation of diverse social wasp communities.

As vespas sociais são pouco utilizadas como controladores biológicos, em parte por desconhecimento e má fama, e também por que não se sabe como as espécies reagem à transferência de seus ninhos. Assim, nosso estudo visou a transferência de colônias da vespa Polistes versicolor para uma área urbana, acompanhando sua aceitação e desenvolvimento neste ambiente. Colônias de P. versicolor foram transferidas para abrigos artificiais compostos por potes plásticos fixados a uma haste de madeira. Foi feito um acompanhamento da população através de observação direta, três vezes por semana, durante 14 semanas. Houve 75% de aceitação para os abrigos artificiais, contudo verificou-se estresse da transferência pela perda de adultos e por comportamento de larvifagia nos primeiros dias após a transferência. A partir da segunda semana, os ninhos tiveram um evidente crescimento populacional até a formação de agregados de inverno quase 4 meses depois. Este é o primeiro estudo que registra a transferência bem sucedida de P. baixo custo e com potencial para prover serviços ecológicos e econômicos a longo prazo sem a necessidade de atenção ou manutenção intensa.