The sexual attractiveness of the corpse bride : unusual mating behaviour of Helicops carinicaudu s (Serpentes: Dipsadidae)

Natural history studies on Neotropical snake fauna are still scarce. Even though reproductive data for the aquatic snake Helicops carinicaudus is available, the lack of information on courtship, copula and reproductive behaviour in the field is noteworthy. Copulation of H. carinicaudus and necrophilia in snakes in nature is reported for the first time. Data was collected during a fieldwork survey on the herpetofauna at the Sao Camilo environmental station, Atlantic Forest area along the coast in Sao Paulo State. We observed a young male copulating, with the hemipenis fully inserted into a headless female. Specimens were collected, dissected and measured. Histological sections of male and female genital tract and male kidney were prepared in order to assess reproductive status. The observation was made during the vitellogenic period of females of H. carinicaudus , which occurs from July to December, and is probably associated to the production of sex pheromones. Spermatogenesis was observed in male, with testosterone production characterized by the hypertrophy of the SSK. In this case, vitellogenic condition of the female H. carinicaudus favoured necrophilia, as chemical cues, trails and pheromone were still being released, permitting courtship and copulation by the young reproductive male.