The strepsipteran endoparasite Xenos vesparum alters the immunocompetence of its host, the paper wasp Polistes dominulus

It is unexplained how strepsipteran insects manipulate the physiology of their hosts in order to undergo endoparasitic development without being entrapped by the innate immune defences of the host. Here we present pioneering work that aimed to explore for the first time several components of the cellular and humoral immune response among immature stages of the paper wasp Polistes dominulus, in both unparasitized insects and after infection by the strepsipteran endoparasite Xenos vesparum. We carried out hemocyte counts, phagocytosis assays in vitro and antibacterial response in vivo. On the whole, hemocyte load does not seem to be drastically affected by parasitization: a non-significant increase in hemocyte numbers was observed in parasitized wasps as respect to control, while the two dominant hemocyte types were present with similar proportions in both groups. On the other hand, phagocytosis was significantly reduced in hemocytes from parasitized wasps while the antibacterial response seemed to be less effective in control. These somewhat unexpected results are discussed, along with the implications of a multiple approach in immune response studies. \uc2\ua9 2009 Elsevier Ltd. All rights reserved

Erratum to: Examining the "evolution of increased competitive ability" hypothesis in response to parasites and pathogens in the invasive paper wasp Polistes dominula

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Preference of Polistes dominula wasps for trumpet creepers when infected by Xenos vesparum : A novel example of co-evolved traits between host and parasite

Acknowledgments The authors are grateful to Marta Mariotti, Laura Maleci, Claudia Giuliani and Corrado Tani for fruitful discussions on Campsis radicans identification and morphology. We also thank two anonymous reviewers and Francesco Dessı`-Fulgheri for their helpful suggestions; Marco Vannini and Leonardo Dapporto for their support in the statistical analyses; Alessandro Pagnini for his help in the search of Campsis radicans bushes in Tuscany; Rita Cervo, Stefano Turillazzi and the members of the Florence Group for the Study of Social Wasps for their assistance during this study, both in the field and in the laboratory.Peer reviewedPublisher PD

Social wasps desert the colony and aggregate outside if parasitized: parasite manipulation?

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Parasitic castration by Xenos vesparum depends on host gender

Host castration represents a mechanism used by parasites to exploit energy resources from their hosts by interfering with their reproductive development or to extend host lifespan by removing risks associated with reproductive activity. One of the most intriguing groups of parasitic castrators is represented by the insects belonging to the order Strepsiptera. The macroparasite Xenos vesparum can produce dramatic phenotypic alterations in its host, the paper wasp Polistes dominula. Parasitized female wasps have undeveloped ovaries and desert the colony without performing any social task. However, very little attention has been given to the parasitic impact of X. vesparum on the male phenotype. Here, we investigated the effects of this parasite on the sexual behaviour and the morpho-physiology of P. dominula males. We found that, differently from female wasps, parasitized males are not heavily affected by Xenos: they maintain their sexual behaviour and ability to discriminate between female castes. Furthermore, the structure of their reproductive apparatus is not compromised by the parasite. We think that our results, demonstrating that the definition of X. vesparum as a parasitoid does not apply to infected males of P. dominula, provide a new perspective to discuss and maybe reconsider the traditional view of strepsipteran parasites