title: Using social parasitism to test reproductive skew models in a primitively eusocial wasp.
abstract: Remarkable variation exists in the distribution of reproduction (skew) among members of cooperatively breeding groups, both within and between species. Reproductive skew theory has provided an important framework for understanding this variation. In the primitively eusocial Hymenoptera, two models have been routinely tested: concessions models, which assume complete control of reproduction by a dominant individual, and tug-of-war models, which assume on-going competition among group members over reproduction. Current data provide little support for either model, but uncertainty about the ability of individuals to detect genetic relatedness and difficulties in identifying traits conferring competitive ability mean that the relative importance of concessions versus tug-of-war remains unresolved. Here, we suggest that the use of social parasitism to generate meaningful variation in key social variables represents a valuable opportunity to explore the mechanisms underpinning reproductive skew within the social Hymenoptera. We present a direct test of concessions and tug-of-war models in the paper wasp Polistes dominulus by exploiting pronounced changes in relatedness and power structures that occur following replacement of the dominant by a congeneric social parasite. Comparisons of skew in parasitized and unparasitized colonies are consistent with a tug-of-war over reproduction within P. dominulus groups, but provide no evidence for reproductive concessions.
authors.affiliation: School of Life Sciences, University of Sussex, John Maynard Smith Building, Brighton BN1 9QG, UK jpgreen@liv.ac.uk.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Green
authors.affiliation: Centre for Ecology and Conservation, University of Exeter, Penryn TR10 9EZ, UK.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Cant
authors.affiliation: School of Life Sciences, University of Sussex, John Maynard Smith Building, Brighton BN1 9QG, UK.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Field
mesh_terms: D000818:Animals; D049628:Body Size; D005260:Female; D008297:Male; D008954:Models, Biological; D012098:Reproduction; D012919:Social Behavior; D014863:Wasps / Q000469:parasitology / Q000502:physiology*
keywords: Polistes dominulus; concessions; cooperative breeding; reproductive skew; social parasitism; tug-of-war