Nests of Monobia angulosa Saussure were obtained at Santa Cariota Farm, Cajuru, São Paulo (n=10), and at the Ecological Station of Jatai, Luis Antônio, São Paulo (n=3). The wasps nested in segments of bamboo canes, 158 to 194 mm in length and 9.5 to 15 mm in internal diameter. Nests consisted of a linear series of 1 to 6 cells, separated by mud partitions followed or not by a vestibular cell and final-closure mud plug, generally inside of the tube entrance. Intercalary cells were observed in 33.3% of nests. Brood cells were provisioned with caterpiliars and eggs were attached to the ceiling of the cells by a thin filament. More females than males were produced with females being reared of cells from the interior end of the nest. Females were larger than males, as well as the lengths of their respective cells. Natural enemies were: Chrysis intrincata Dahibom (Chrysididae), Anthrax sp. (Bombyliidae), and a Tachinidae fly. M. angulosa presented at least two generations/year, during both the hot and wet seasons.
Insecta; wasps; trap-nests; nest structure; natural enemies
