Weak nestmate discrimination behavior in native and invasive populations of a yellowjacket wasp (Vespula pensylvanica)
Kevin J. Loope, Kevin J. Loope , Jocelyn G. Millar , Erin E. Wilson Rankin
Department of Entomology, University of California, Riverside, USA; Department of Entomology, University of California, Riverside, USA ; Department of Entomology, University of California, Riverside, USA ; Department of Entomology, University of California, Riverside, USA
In geographic regions with warm winters, invasive yellowjacket wasp colonies (genus Vespula) often exhibit polygyny (multiple queens) and persist for multiple years, though these phenomena are rare in the native range. Here, we test the hypothesis that polygyny caused by foreign queens being accepted into an existing colony is the result of relaxed nestmate recognition in the invasive range, as has been observed in some supercolonial invasive ants. In bioassays with wild colonies in the field, we found that nestmate discrimination is weak in both invasive (Hawaii) and native (California) populations of Vespula pensylvanica, with significant nestmate discrimination in only ~30% of trials. We also found that the diversity and variability of cuticular hydrocarbons, chemical compounds that mediate nestmate recognition, are not reduced in introduced populations, unlike several supercolonial invasive ant species. Our findings suggest that ancestral weak nestmate discrimination behavior of V. pensylvanica may make this species pre-adapted to transition to polygyny when introduced into environments with benign winters that facilitate foreign queens joining existing colonies in late-season, and extended colony lifespans.