Sniff and seek: A preliminary investigation into how brood parasitic bees use chemical cues to find their hosts

Approximately 13% of all bee species are brood parasites, in which the parasitic female lays eggs in the nests of other bees. Despite this incredible diversity little is known regarding how brood parasites locate nests and evade host defenses, beyond the assumption that chemical cues are heavily involved with these interactions. Investigating how brood parasites engage with their hosts requires an integrative approach that combines aspects of chemical ecology and behavior. Using the host-parasite pair Andrena regularis and Nomada imbricata as a model system, we performed four assays in the lab using a y-tube olfactometer and live individuals. We first determined the attractiveness of live hosts and other brood parasites to female N. imbricata. We then examined if the presence of brood parasites acted as a deterrent or attractant to female A. regularis and if hosts were attracted to the presence of conspecifics. Results from this project enable insight into the chemical cues that influence host and parasite behavior in the presence of their partner within a shared environment and ultimately allow for greater understanding of the relationship between brood parasitic bees and their hosts.