Behavioral Ecology and Sociobiology

, Volume 63, Issue 9, pp 1363–1368

Adult sex ratio affects divorce rate in the monogamous endoparasite Schistosoma mansoni

  • Sophie Beltran
  • Frank Cézilly
  • Jérôme Boissier
Original Paper

Abstract

“Divorce” (mate switching) rate is known to vary largely both between and within socially monogamous species. Although the adult sex ratio can have an important influence on mating patterns, very few studies have investigated the influence of sex ratio on divorce rate in monogamous species, and even less so from an experimental point of view. In addition, most studies on the causes and consequences of divorce have been performed on vertebrate species, whereas data for invertebrate monogamous species remain scarce. Schistosoma mansoni is a monogamous endoparasite with a complex life cycle characterized by asexual reproduction in the intermediate host and sexual reproduction in the definitive host. In the wild, populations of S. mansoni inside their definitive hosts are characterized by a male-biased sex ratio. We studied the influence of experimentally varying the adult sex ratio on divorce rate in S mansoni, using controlled infections of hosts with clonal populations. The more male-biased the sex ratio was, the more the divorce rate increased, whereas no such effect was observed under a female-biased sex ratio. In this study and for the first time, we showed, by handling the sex ratio, that the divorce rate increases in adult male-biased sex ratio conditions in a monogamous species.

Keywords

Adult sex ratio Better option hypothesis Forced divorce hypothesis Monogamy Schistosomes 

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Sophie Beltran
    • 1
  • Frank Cézilly
    • 2
  • Jérôme Boissier
    • 1
  1. 1.Université de Perpignan, Laboratoire de Biologie et d’Ecologie Tropicale et Méditerranéenne, UMR 5244 CNRS–EPHE–UPVDPerpignan CedexFrance
  2. 2.Université de Bourgogne, Equipe Ecologie Evolutive, UMR CNRS 5561 BiogéosciencesDijonFrance

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