Attempted copulatory behaviour between two phylogenetically unrelated alien species (Coypu, Myocastor coypus, and Pond slider, Trachemys scripta): first evidence

We report the first case of sexual interaction between two phylogenetically unrelated species (coypu Myocastor coypus and pond slider Trachemys scripta, a freshwater pond turtle), both of them non-native in the study area, a remnant coastal wetland of Tyrrhenian, central Italy (41°57'34.0''N 12°02'58.0''E). We inductively propose two different hypotheses (masturbatory act due to intense sperm competition, or behaviour induced by female pheromones) to explain this peculiar observation.