Brood Parasitism of the Resin BeeMegachile campanulae(Robertson) byCoelioxys modestaSmith (Hymenoptera: Megachilidae)

• DOI: 10.2317/0022-8567-89.2.117
• Publication Date: 2016-08-04T16:51:56Z
• Authors: Kevin M. O’Neill; James F. O’Neill
• Keywords: 0106 biological sciences; 01 natural sciences

ABSTRACT: In North America, brood parasitic bees of the genus Coelioxys attack nests of solitary nest-provisioning bees of the genus Megachile. Using trap-nests in central New York State, we found Coelioxys modesta (Smith) in 49% of 72 nests and 27% of 313 cells provisioned by Megachile campanulae (Robertson). Because we had a nearly complete record of the species and sex of individuals developing in nest cells, we were able to use logistic regression to test several hypotheses concerning the risk of brood parasitism, the spatial distribution of infested cells, and the sex and size of C. modesta at different cell positions. The probabilities that a nest was infested or contained multiple C. modesta were higher in nests of larger diameter and in those had been active for longer durations. Cells of the host and cells infested with C. modesta tended to cluster with those of conspecifics within nests, an observation consistent with the hypothesis that individual female C. modesta remain at or frequently revi...