Sex differences in host defence interfere with parasite-mediated selection for outcrossing during host-parasite coevolution.

ABSTRACT: The Red Queen hypothesis proposes that coevolving parasites select for outcrossing in the host. Outcrossing relies on males, which often show lower immune investment due to, for example, sexual selection. Here, we demonstrate that such sex differences in immunity interfere with parasite-mediated selection for outcrossing. Two independent coevolution experiments with Caenorhabditis elegans and its microparasite Bacillus thuringiensis produced decreased yet stable frequencies of outcrossing male hosts. A subsequent systematic analysis verified that male C. elegans suffered from a direct selective disadvantage under parasite pressure (i.e. lower resistance, decreased sexual activity, increased escape behaviour), which can reduce outcrossing and thus male frequencies. At the same time, males o

SUBMITTER: Masri L 

PROVIDER: S-EPMC3655609 | biostudies-literature | 2013 Apr

REPOSITORIES: biostudies-literature