Submitted to: Pan-Pacific Entomologist
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/24/2004
Publication Date: 12/1/2005
Citation: Reed, H.C., Landolt, P.J. 2005. Late season polygynous Vespula pensylvanica (Hymenoptera: Vespidae) colonies in a northern temperate area. Pan-Pacific Entomologist. 81(3/4): 164-170 Interpretive Summary: Because of increasing concern with adverse environmental and human health effects of many pesticides in use, new methods are needed to control insect pests of agricultural crops. Researchers at the USDA-ARS Yakima Agricultural Research Laboratory are studying chemical attractants for several insect pests of tree fruit and vegetable crops, including yellowjacket wasps that are pests on Pacific Northwest fruit at harvest. This work resulted in the discovery of a new chemical attractant for yellowjacket wasps that is being developed as a trap lure and bait for controlling wasp populations. It was recently discovered that population levels of these wasps in late summer may be prolonged by a process of requeening of nests, a phenomenon previously thought to occur only in subtropical and tropical wasps. Nests were found that possessed multiple new queens that had probably been laying eggs and were contributing to reproduction in the nest after the original foundress queen had died. This new information on wasp colony dynamics will be useful when devising efficient trapping and baiting programs to reduce wasp numbers because the success of such programs relies in part on understanding and predicting wasp reproductive rates and seasonal population patterns.
Technical Abstract: Two colonies of the western yellowjacket, Vespula pensylvanica (Saussure), were active later in the fall and early winter than expected for eastern Washington State. Nest analyses revealed that both colonies were not perennial and were within the size range for typical colonies in the area, but contained multiple queens with developed eggs. Monogynous colonies are the rule in the vespine wasps, and when polygyny occurs it is usually in large perennial colonies in mild temperate or tropical regions. This report is only the second case of polygyny in any Vespula colony in a northern temperate distribution. It is suggested that polygyny may provide an occasional, alternative reproductive strategy for the western yellowjacket.