Fire is one of the most common natural harassments and it is characterized as an important component of the systems, although little studied regarding the influence of this event in social wasps communities. One month after the end of the collections, the area of Regenerating Brazilian Savanna of the present study undertook a fire in exactly half of the points sampled, which motivated one further year of sampling. The aim of this study was to compare the social wasps fauna collected before and after the fire, indicating a possible impact on their populations. In the first year of collection, before the fire, 21 species (seven genera) were sampled with a total amount of 297 individuals. In the second year, after the fire, 14 species were collected (reduction of 33,33% in richness) and six genera, with an abundance of 153 wasp individuals of Vespidae (loss of 48,48% of individuals). The area 1 in the first year, presented an abundance of 182 individuals (61,27%) and 16 species (76,19%) and the area 2, 115 (38,73%) and 19 species (90,47%). For the area 1 in the second year, 74 individuals (48,36%) and 12 species (85,71%) were captured and for the area 2 there were 79 individuals (51,64%) distributed among nine species (64,28%). However, we did not find significant values for both the abundance and for the richness among the areas and the years of sampling. Nine species were not registered in the second year, although two presented their registration only after the fire.

Social wasps participate in food webs, act as biological control agents in small crops and the natural environment, and act as potential pollinators. The objective of this study was to carry out an inventory of social wasps in five phytophysiognomies with different degrees of anthropogenic disturbance in São Paulo, Brazil. The collections were performed by active search and attractive traps to survey social wasps. We collected wasp for one year with collection campaigns every other month totaling six campaigns for site. We collected a total of 913 individuals representing 31 species and eight genera. The species with the highest abundances were Agelaia pallipes and Agelaia vicina. The highest richness of social wasps was found in the riparian forest and regenerating Cerrado. We conclude that social wasp richness and diversity varies according to habitat vegetation characteristics and that these effects are likely mediated by resulting differences in the provision of resources and nesting locations among the different environments. The areas in this study have suffered considerable vegetation loss due to common farming practices, however, the existing fragments are still capable of hosting a rich social wasp fauna.

There are different methodologies used to make an inventory of social wasps. In general, these methods are divided into active search and passive collections. Each method has a different performance, depending on the environment in which the collection is being carried out. Thus, the choice for the proper methodology according to the study area will impact the success of sampled species. This study aimed to evaluate the performance of sampling methodologies for social wasps (active search and bait traps) in different phytophysiognomies (Regenerating Cerrado, “Cerradão”, Restored Forest, Semideciduous Forest and Riparian Forest) in the state of São Paulo, Southeastern Brazil. The active search sampled a greater number of species, with the exception of the Regenerating Cerrado. Regarding abundance, the active search was also more efficient, except in “Cerradão”, where there was no difference between the methods, and in Regenerating Cerrado, where the traps sampled a higher number of individuals. The fact that none of the methods collected all the sampled species indicates that it is appropriate to use more than one collection method in order to obtain a sampling closer to the true richness of the studied sites.

O elemento mais característico da morfologia de Odontomachus são as mandíbulas de fechamento rápido, adaptações para capturar presas eficientemente. Embora facilmente encontrada, existem poucos estudos sobre o comportamento predatório de O. bauri. As presas utilizadas neste experimento foram larvas e adultos de H. illucens. Este trabalho comparou a frequência dos comportamentos de predação de O. bauri sobre larvas e adultos de H. illucens e analisou a sequência em que ocorrem. Foram coletados dois ninhos de O. bauri e as formigas foram transferidas para ninhos artificiais. Na arena de forrageamento, ao lado do ninho, foram oferecidas as presas vivas. Os comportamentos foram filmados e as suas frequências foram calculadas para montagem de um etograma e descrição da sequência comportamental. Os cálculos foram feitos separadamente para cada tipo de presa. Registrou-se 81 atos comportamentais agrupados em 14 categorias, sendo “inspecionar” a mais comum. Na predação sobre adultos houve maior variação comportamental do que sobre larvas. Repertório e sequência comportamental de predação de O. bauri não diferem muito de outras espécies do gênero. Operárias tiveram maior interesse em predar adultos, enquanto as larvas não foram utilizadas como alimento. O fechamento rápido das mandíbulas foi utilizado na mutilação de partes do corpo da presa, algo ignorado em estudos anteriores.

Ectatomma opaciventre Roger é uma espécie de formiga cujas presas incluem espécies de moscas, no entanto, não se conhecia os comportamentos empregados pelas operárias em sua predação. Neste trabalho, foi elaborado um etograma da predação sobre larvas e adultos da mosca Hermetia illucens L. por operárias de E. opaciventre. Foram coletados indivíduos de três ninhos de E. opaciventre, sendo posteriormente transferidos para ninhos artificiais. Para cada um deles, foram oferecidas larvas e adultos vivos de moscas. A partir das observações, em um contexto de predação, os comportamentos observados que apresentavam funções semelhantes foram agrupados em categorias, com quatro delas tendo sido observados na predação sobre larvas e todas as oito na predação sobre adultos. As larvas não chegaram a ser predadas de fato (os comportamentos agressivos, realizados pelas formigas, aparentam estar relacionados à defesa do ninho), porém as moscas adultas serviram realmente como alimento.