Does the Silvopastoral System Alter Hymenopteran Fauna (Insecta: Hymenoptera) inBrachiaria decumbensMonocultures?

Abstract

ABSTRACT The aim of this study was to evaluate whether environmental changes promoted by the conversion from a Brachiaria decumbens monoculture to a silvopastoral system can be measured by the diversity, richness, abundance, and constancy of insects of the order Hymenoptera. A Malaise trap for collecting insects was installed in a B. decumbens area managed as a silvopastoral system, and another was installed in a monoculture system. Hymenoptera richness and abundance were determined based on the number of morphospecies and specimens, respectively. The diversity and constancy indices were calculated using the Shannon-Wiener and Bodenheimer methodologies. Fifteen families of Hymenoptera were collected, seven of which were unique to the monoculture system. The samples from the silvopastoral system were significantly more abundant (3,889) and rich (305) compared with those from the monoculture system, which were much less abundant (1,473) and rich (173). Similar trends were noted for the families Formicidae, ...