The cost of queen loss in the social wasp Polistes dominulus (Hymenoptera: Vespidae)

Loss of the queen is a crisis for a social insect colony. The process of queen succession could cause increased aggression and work inefficiencies, and the new queen, if the colony can produce one, could be slow to develop mature eggs. We evaluated the cost of queen replacement in Polistes dominulus by removing the queen from a set of single-foundress colonies while leaving a control set with their queens. At 2 and 11 days after queen removal, we found that the queenless colonies had increased levels of some dominance behaviors, chewing and climbing, but not of the far more common lunging and biting. However, foraging behavior did not decrease on nests without queens as compared to nests with their original queens. Nest growth diminished as compared to control nests, as would be expected if new queens were not as competent at egg laying or if dominance behavior interfered with nurturing activities. Furthermore, replacement queens did not mate in the first 12 days after queen removal and few had mature eggs in their ovaries, though after a month most had mated and had developed ovaries. The degree of ovarian dominance of the top egg-layer over the others was also diminished at 12 days, but by a month the new queen was as dominant as control queens. The high cost of replacing the queen may indicate that workers are kept reproductively suppressed enough not to be a threat to the existing queen.