Mating Interactions between and and Compatibility of Their F1 Progeny with and .

Contrary to the majority of other Trematoda, species are gonochoric. Consequently, in endemic areas where several schistosome species overlap and can co-infect the same definitive host, there may be frequent opportunities for interspecific pairing. Our experimental study provides novel insight on the pairing behavior between and in mixed infections in mice. We used six mate choice experiments to assess mating interactions between the two schistosome species. We show that mating between the two species is not random and that exhibits greater mate recognition compared to . We also performed reciprocal crosses (male × female ) and (female × male ) that produce active swimming miracidia. These miracidia were genotyped by ITS2 sequencing and proposed for mollusc infection. Molecular analyses show that all the miracidia are parthenogenetically produced (i.e., their harbor the mother ITS2 genotype) and as a consequence can only infect the mollusc of the maternal species. Offspring produced by male × female pairing can only infect whereas offspring produced by female × male can only infect snails. Evolutionary and epidemiological consequences are discussed.