A70: Grixti, J., Zayed, A., and L. Packer. 2004. Behavioral interactions among females of Acamptopoeum submetallicum (Spinola) and Nolanomelissa toroi Rozen (Hymenoptera: Andrenidae). Journal of Hymenoptera Research (in press).
Abstract: We present the results of circle tube experiments performed upon a solitary panurgine bee Acamptopoeum submetallicum (Spinola) and the enigmatic Nolanomelissa toroi Rozen. As expected for a solitary species, females of A. submetallicum generally avoided one another. In contrast, N. toroi exhibited high levels of aggression, as generally found among bees with a reproductive division of labor. However, dissection and phenological data on N. toroi are incompatible with either eusocial or semisocial behaviors. Furthermore, no acts of cooperation were observed in the behavioral experiments suggesting that N. toroi is not communal. The extremely female biased sex ratio and low levels of mandibular wear among mated, reproductively active females in this species remain difficult to explain.