Sex,snails, and schistosomes: the influence of compatibility genotype on reproductive strategy

Summary

The impact of current parasitic infection status on mate choice and reproductive strategies has been widely reported, particularly amongst vertebrate host-parasite systems. However, evidence is lacking as to whether animals discriminate between mates on the basis of their potential infection status, in terms of host resistance or susceptibility genotype (i.e., compatibility). In a series of experiments, Biomphalaria glabrata snail strains were artificially selected for either resistance or susceptibility to Schistosoma mansoni infection. Individual snails from each line were then paired with a partner of matched compatibility status and the proportion of outcrossed to selfed offspring produced identified by RAPD-PCR. Individual unselected snails, either infected or uninfected, were then given a choice of partners artificially selected for either resistance or susceptibility to infection, and their behaviour analysed. The results demonstrate that compatibility genotype can influence reproductive strategy and are discussed in terms of their implications regarding the maintenance of sex and the evolution of recognition systems.