Parasites play a central role in the adaptiveness of sexual reproduction. Sexual selection theory suggests a role for parasite resistance in the context of mate choice, but the evidence is mixed. The parasite-mediated sexual selection (PMSS) hypothesis derives a number of predictions, among which that resistance to parasites is heritable, and that female choice favours parasite resistance genes in males. Here we tested the PMSS hypothesis using the dung beetle Onthophagus taurus, a species that can be heavily parasitised by Macrocheles merdarius mites, which are known to affect adult survival. We investigated the heritability of resistance to M. merdarius, as well as whether female O. taurus impose a mating bias against males susceptible to mite infestation. Female choice for parasite resistance is difficult to disentangle from the possibility that females are simply choosing less parasitised males due to naturally selected benefits of avoiding contracting those parasites. This is especially likely for ectoparasites, such as mites. We tackled this problem by performing a mate choice trial first, and then measuring a male’s resistance to mite infestation. Resistance to mite infestation exhibited significant levels of additive genetic variance. Although we found no relationship between mating success and parasite resistance, males with greater resistance to infestation mated for longer. If females control copula duration, given that short copulations often result in mating failure, female choice could act on parasite resistance.

Buzatto et al 2019 Behav EcolThis data file has two tabs. The first tab contains data for the heritability of mite resistance (to the mite Macrocheles merdarius) in the dung beetle Onthophagus taurus. The first column has the individual ID, the second column the ID of their father, and the third column the ID of their mother, which together comprise the pedigree information for a nested paternal half-sib/full-sib breeding design. The number of mites found on males after experimental exposure and the pronotum width of each male (in mm) are also presented. The second tab has information from another experiment about mate choice and its relationship to a subsequent resistance to parasites (also under experimental exposure). This tab has information on male ID, their latency to court females (seconds between being exposed to a female and starting to court), number of courting bouts (see MS), mating success (1 when mated, 0 when failed to mate), mating latency (seconds between starting to court and mating), and mating duration (in seconds). This information can be used to calculate courtship rate (see MS). Finally, this tab also contains information on the number of mites found on males after the subsequent (after the mate choice trial) experimental exposure to these parasites, and the identity of the block.