Genetic relatedness and eusociality parasite mediated selection on the genetic composition of groups

  • Shykoff J
  • Schmid-Hempel P
  • 20

    Readers

    Mendeley users who have this article in their library.
  • N/A

    Citations

    Citations of this article.

Abstract

Contrary to the expectations of kin selection theory, intracolony relatedness in eusocial insects is often low. We examined the idea that associations of low relatedness (high genetic variability) may be advantageous because of negative frequency-dependent selection on common host phenotypes by rapidly evolving parasites and pathogens. Using the natural host-parasite system of the bumble bee Bombus terrestris and its intestinal trypanosome Crithidia bombi, we investigated the transmission properties of parasites in host groups. Within naturally infested nests and in artificially constructed groups of workers, prevalence of infestation increased with time of exposure (Table 1). The susceptibility of isolated groups of workers to the parasites to which they were exposed differed with identity and natural infestation of their nest of origin (Table 2). In addition, those workers that were related to the individual introducing an infection to their group were more likely to become infested than were unrelated workers (Table 3). Although the bumble bee workers in experimental boxes appeared to differ in behavior toward kin and non-kin, making more physical contacts with kin, we found no discernible relationship between number of physical contacts and prevalence of infestation in a group. Therefore, we conclude that differences in parasite transmission reflected interactions among different host and parasite phenotypes. This system thus demonstrates the factors necessary for negative frequency-dependent selection by parasites on common host phenotypes - variability for susceptibility and infectiousness in host and parasite populations and similarity for these traits among related individuals. If, as we show here, high genetic relatedness within groups enhances parasite transmission, kin directed altruism may increase the risk of contracting parasites and infectious diseases. Therefore, parasites and pathogens may be an important force moderating the genetic structure of social groups.

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Authors

  • Jacqui A. Shykoff

  • Paul Schmid-Hempel

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free