Research Interests
Ecological drivers of a social transition
A current project on the invasive social wasp, Vespula pensylvanica, addresses how ecological interactions with another introduced species, the European honeybee, influence the transition to a novel social phenotype in Hawaii. We will also determine the role this species plays in vectoring diseases found in honeybees and other ecologically and economically important bees.
collaborators: Erin Wilson Rankin |
Nestmate recognition in invasive wasps
The huge perennial colonies of invasive Vespula likely only occur because colonies adopt secondary queens late in the season. A surprising number of these queens appear to be from foreign colonies, suggesting weak nestmate recognition, at least in invasive populations. We are looking to see if the porous colony boundaries associated with this invasion, in some ways convergent with the unicolonial societies of several invasive ants and termites, results from a loss of nestmate recognition in association with the transition, or if instead this species is ancestrally permissive of non-relatives. If weak nestmate recognition is ancestral, such species could be especially prone to social transitions in novel environments. In parallel, we are investigating the diversity of chemical cues and the colony-level information content of cuticular chemical profiles in native and invasive populations.
collaborators: Erin Wilson Rankin, Jocelyn Millar |
The evolution of matricide in a highly social wasp
As a part of my PhD, I tested hypotheses regarding the adaptive basis of queen killing in a social wasp, Dolichovespula arenaria (the aerial yellowjacket). Queen killing was anectodally reported in a variety of species of annual wasps and bees, and Andrew Bourke made a nice model predicting when it should occur. Observations and experiments suggest that workers decide to kill queens only in colonies with high worker-worker relatedness, though they don't seem to pay attention to the sex ratio of the queen-laid brood.
|
The evolution of multiple mating in the Vespinae
The mating behavior of social insect queens is important for the evolution of cooperation and conflict within societies, as it determines the relatedness among workers within a colony. It also has important consequences for genetic diversity within colonies, which may be important for pathogen resistance and the division of labor. Using a comparative approach, I've shown that within the Vespinae wasps, colony size is strongly positively associated with the number of times a queen mates, and negatively associated with the degree to which queens skew paternity among their mates, which also influences the average genetic diversity among her daughter workers. This is a pattern also reported in other groups of social insects, but I believe the Vespinae (the yellowjacket wasps and hornets) are particularly well-suited to understanding the evolution of multiple mating, given the range of mating behaviors across species that are otherwise quite similar in their ecology and behavior.
|
The mating biology of a social parasite
In another project focusing on the evolution of mating behavior in wasps, we have recently discovered that the inquiline social parasite Dolichovespula arctica has reverted to single mating from a facultatively polyandrous ancestor. This parasite invades young colonies of Dolichovespula arenaria, the species I used to study matricide behavior. While something like 70% of D. arenaria colonies have multiply-mated queens, none of the analysed D. arctica females were multiply mated. This suggests that the benefits that maintain polyandry must stem from the production of workers, since polyandry is lost upon loss of worker production in the social parasite. This parallels the reversion to single mating found in a social parasite ant that invades colonies of fungus growing ants (Sumner et al. 2004 Nature). Photo by Bob Jeanne.
collaborator: Federico Lopez-Osorio |