Do queen cuticular hydrocarbons inhibit worker reproduction in Bombus impatiens?

Social insect colonies are organized by a reproductive division of labor, in which non-reproductive workers cooperate to rear the offspring of the queen. Queen pheromones, chemical compounds produced by queens that regulate worker fertility, have been identified in a handful of bees, ants, wasps, and termites. However, recent studies on bumblebee (Bombus spp.) queen signals have yielded conflicting findings. Here we provide an independent investigation of experiments to test the hypothesis that queen-produced non-volatile cuticular compounds influence worker's reproductive behavior. We exposed small groups of Bombus impatiens workers to extracted cuticular compounds from queens collected from either mid-season (pre-reproductive) or late-season (reproductive) colonies and tracked worker reproduction and ovary development. We observed no difference in worker's ovarian development or egg production when comparing among the mid-season queen extract, late-season queen extract and the solvent control treatments. Our data replicate the finding that body size positively correlates with ovarian development in workers. These results are consistent with recent studies showing that queen cuticular compounds do not inhibit worker reproduction in B. impatiens.