Interações entre vespas e bromélias em um fragmento urbano de Floresta Atlântica

Abstract

Social wasps are among the insect groups associated to the bromeliads. Studies dealing with the potential of plants be a suitable substrate to nesting of social wasps are scarce. Such studies contribute to the comprehension of the choice of nesting site, which is a very important element in defense by hiddenness, in order to protect the offspring against predation. Besides, these insects present a growing interest as pollinating agents, acting as floral visitors and overlapping the bees in the exploitation of resources in tropical areas. Despite the high ecological importance, little is know about the aspects involving the association between wasps and bromeliads. So, the present dissertation is structured in two topics, and the studies were conducted in an urban fragment of Atlantic Forest of the municipality of Juiz de Fora (MG), Southeastern Region of Brazil. The first topic aimed to identify the species of wasps that nest in the bromeliads Billbergia horrida Regel and Portea petropolitana (Wawra) Mez and verify if these plants represent a good substrate to the nests. A total of 34 nests of wasps were found below the leaves of P. petropolitana and B. horrida. The most frequent species were Mischocyttarus drewseni (De Sausurre) and unidentified specimens of the subfamily Eumeninae with seven nests, each. Among the bromeliad species, P. petropolitana was considered a good nesting substrate to the wasps, taking in account the analysis of success of the nests. The second topic deals with the identification of the species of wasps that visit the bromeliad P. petropolitana and describes the exhibited behavior during the visitation. Two species of wasps were recorded using floral resources of P. petropolitana: Polybia platycephala (Richards) and Agelaia vicina (De Sausurre), besides ants and bees. Five behavioral acts were observed during the visitation of the wasps: landing on flower, searching for the nectar source, removal of the resource, self cleaning and leave the flower. In summary, this study can be a base to new studies that approach a larger number of records in order to enhance the knowledge about aspects of the biology of bromeliads and mainly about the behavior of the wasps, suggesting its conservation, which are important part for the maintenance of the environment where live.