Behavioral Ecology Advance Access originally published online on December 14, 2007
Behavioral Ecology 2008 19(2):272-278; doi:10.1093/beheco/arm128
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Worker policing in the German wasp Vespula germanica
a Zoological Institute, Catholic University of Leuven, Naamsestraat 59, 3000 Leuven, Belgium b Department of Ecology and Evolution, Bâtiment de Biologie, University of Lausanne, 1015 Lausanne, Switzerland
Address correspondence to W. Bonckaert, who is now at Laboratory of Entomology, Zoological Institute, Catholic University of Leuven, Naamsestraat 59, 3000 Leuven, Belgium. E-mail: wim.bonckaert{at}bio.kuleuven.be.
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Abstract |
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In some ants, bees, and wasps, workers kill or "police" male eggs laid by other workers in order to maintain the reproductive primacy of the queen. Kin selection theory predicts that multiple mating by the queen is one factor that can selectively favor worker policing. This is because when the queen is mated to multiple males, workers are more closely related to the queen's sons than to the sons of other workers. Earlier work has suggested that reproductive patterns in the German wasp Vespula germanica may contradict this theory, because in some colonies a large fraction of the adult males were inferred to be the workers' sons, despite the effective queen mating frequency being greater than 2 (2.4). In the present study, we reexamine the V. germanica case and show that it does support the theory. First, genetic analysis confirms that the effective queen mating frequency is high, 2.9, resulting in workers being more related to the queen's sons than to other workers' sons. Second, behavioral assays show that worker-laid eggs are effectively killed by other workers, despite worker-laid eggs having the same intrinsic viability as queen-laid ones. Finally, we estimate that approximately 58.4% of the male eggs but only 0.44% of the adult males are worker derived in queenright colonies, consistent with worker reproduction being effectively policed.
Key words: reproductive conflict, Vespinae wasps, Vespula germanica, worker policing, worker reproduction.
Received 23 September 2007; revised 25 October 2007; accepted 28 October 2007.