Subtle effect of Xenos vesparum (Xenidae, Strepsiptera) on the reproductive apparatus of its male host: Parasite or parasitoid?

L. Beani*, D. Marchini, F. Cappa, I. Petrocelli, M. Gottardo, F. Manfredini, F. Giusti, R. Dallai

*Corresponding author for this work

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Parasitic castration is an adaptive strategy where parasites usurp the hosts' reproductive physiology to complete their life cycle. The alterations in the host traits vary in their magnitude, from subtle changes in the host morphophysiology and behaviour to the production of complex aberrant phenotypes, which often depend on the host gender. The strepsipteran macroparasite Xenos vesparum induces dramatic behavioural and physiological changes in its female host, the paper wasp Polistes dominula, while its effect on the male phenotype is largely unknown.

In this study we investigated how a single X. vesparum parasite influences the functional morphology of P. dominula male reproductive apparatus. We performed morphometry and ultrastructure characterization of corpora allata, testes, seminal vesicles and accessory glands in parasitized and unparasitized males, and also in young and old males to control for the effect of age on the natural deterioration of these organs. Our results show that age significantly affects the development of male reproductive apparatus. A low parasite load one parasite per host is the common prevalence in the field has only a marginal impact on the reproductive morphology of P. dominula males, affecting quantitatively but not qualitatively the protein content of male accessory glands. Thus, in male P. dominula wasps, X. vesparum appears to behave as a true "parasite", in clear opposition to the role of "parasitoid" that it takes in female hosts where castration causes the reproductive death.

Original languageEnglish
Pages (from-to)22-30
Number of pages9
JournalJournal of Insect Physiology
Volume101
Early online date13 Jun 2017
DOIs
Publication statusPublished - Aug 2017

Keywords

  • Polistes dominula
  • Parasitic castration
  • Functional morphology
  • Male reproductive apparatus
  • Age effect
  • Accessory gland secretion
  • PRIMITIVELY EUSOCIAL WASP
  • JUVENILE-HORMONE
  • PAPER WASPS
  • ACCESSORY-GLANDS
  • GENE-EXPRESSION
  • CERITHIDEA-CALIFORNICA
  • PHENOTYPIC PLASTICITY
  • POLISTES-DOMINULUS
  • IMMUNE FUNCTION
  • SEX-DIFFERENCES

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