Host sex and ectoparasites choice: preference for, and higher survival on female hosts

Authors

  • PHILIPPE CHRISTE,

    1. Department of Ecology and Evolution, Le Biophore, University of Lausanne, CH-1015 Lausanne, Switzerland; Musée cantonal de zoologie, Place de la Riponne 6, CH-1014 Lausanne, Switzerland; and
    Search for more papers by this author
  • OLIVIER GLAIZOT,

    1. Department of Ecology and Evolution, Le Biophore, University of Lausanne, CH-1015 Lausanne, Switzerland; Musée cantonal de zoologie, Place de la Riponne 6, CH-1014 Lausanne, Switzerland; and
    Search for more papers by this author
  • GUILLAUME EVANNO,

    1. Department of Ecology and Evolution, Le Biophore, University of Lausanne, CH-1015 Lausanne, Switzerland; Musée cantonal de zoologie, Place de la Riponne 6, CH-1014 Lausanne, Switzerland; and
    Search for more papers by this author
  • NADIA BRUYNDONCKX,

    1. Department of Ecology and Evolution, Le Biophore, University of Lausanne, CH-1015 Lausanne, Switzerland; Musée cantonal de zoologie, Place de la Riponne 6, CH-1014 Lausanne, Switzerland; and
    Search for more papers by this author
  • GODEFROY DEVEVEY,

    1. Department of Ecology and Evolution, Le Biophore, University of Lausanne, CH-1015 Lausanne, Switzerland; Musée cantonal de zoologie, Place de la Riponne 6, CH-1014 Lausanne, Switzerland; and
    Search for more papers by this author
  • GLENN YANNIC,

    1. Department of Ecology and Evolution, Le Biophore, University of Lausanne, CH-1015 Lausanne, Switzerland; Musée cantonal de zoologie, Place de la Riponne 6, CH-1014 Lausanne, Switzerland; and
    Search for more papers by this author
  • PATRICK PATTHEY,

    1. Zoological Institute – Conservation Biology, University of Bern, Baltzerstrasse 6, CH-3012 Bern, Switzerland
    Search for more papers by this author
  • ARNAUD MAEDER,

    1. Department of Ecology and Evolution, Le Biophore, University of Lausanne, CH-1015 Lausanne, Switzerland; Musée cantonal de zoologie, Place de la Riponne 6, CH-1014 Lausanne, Switzerland; and
    Search for more papers by this author
  • PETER VOGEL,

    1. Department of Ecology and Evolution, Le Biophore, University of Lausanne, CH-1015 Lausanne, Switzerland; Musée cantonal de zoologie, Place de la Riponne 6, CH-1014 Lausanne, Switzerland; and
    Search for more papers by this author
  • RAPHAËL ARLETTAZ

    1. Zoological Institute – Conservation Biology, University of Bern, Baltzerstrasse 6, CH-3012 Bern, Switzerland
    Search for more papers by this author

Philippe Christe, Department of Ecology and Evolution, Le Biophore, University of Lausanne, CH-1015 Lausanne, Switzerland. Tel.: +41 21 692 41 57. Fax: +41 21 692 41 65. E-mail: philippe.christe@unil.ch

Summary

  • 1Sex differences in levels of parasite infection are a common rule in a wide range of mammals, with males usually more susceptible than females. Sex-specific exposure to parasites, e.g. mediated through distinct modes of social aggregation between and within genders, as well as negative relationships between androgen levels and immune defences are thought to play a major role in this pattern.
  • 2Reproductive female bats live in close association within clusters at maternity roosts, whereas nonbreeding females and males generally occupy solitary roosts. Bats represent therefore an ideal model to study the consequences of sex-specific social and spatial aggregation on parasites’ infection strategies.
  • 3We first compared prevalence and parasite intensities in a host–parasite system comprising closely related species of ectoparasitic mites (Spinturnix spp.) and their hosts, five European bat species. We then compared the level of parasitism between juvenile males and females in mixed colonies of greater and lesser mouse-eared bats Myotis myotis and M. blythii. Prevalence was higher in adult females than in adult males stemming from colonial aggregations in all five studied species. Parasite intensity was significantly higher in females in three of the five species studied. No difference in prevalence and mite numbers was found between male and female juveniles in colonial roosts.
  • 4To assess whether observed sex-biased parasitism results from differences in host exposure only, or, alternatively, from an active, selected choice made by the parasite, we performed lab experiments on short-term preferences and long-term survival of parasites on male and female Myotis daubentoni. When confronted with adult males and females, parasites preferentially selected female hosts, whereas no choice differences were observed between adult females and subadult males. Finally, we found significantly higher parasite survival on adult females compared with adult males.
  • 5Our study shows that social and spatial aggregation favours sex-biased parasitism that could be a mere consequence of an active and adaptive parasite choice for the more profitable host.

Ancillary