Mating Behaviour in Two Schistosoma Mansoni Intermediate Hosts (Biomphalaria Pfeifferi and Biomphalaria Camerunensis) in Cameroon

Biomphalaria pfeifferi and B. camerunensis are Schistosoma mansoni intermediate hosts. The knowledge of their mating system and mating behaviour is of high interest in mastering the transmission and evolution of a potential resistant gene introduced in a population. This study was therefore conducted to provide further knowledge on the mating behaviour of these two S. mansoni intermediate hosts in Cameroon. Mating behaviour was observed in three populations, one of B. pfeifferi and two of B. camerunensis. Mature virgin young snails (G1) were paired and followed up daily, from 8 am to 5 pm, during three consecutive days. The courtship behaviour, the number of copulations, as well as the sexual role assumed by individuals were recorded. Snails from both species easily copulated and individuals displayed elaborate stereotyped courtship behaviour. Three distinct phases were observed in the mating behaviour of these two snail species. Mating starts by shell mounting with unilateral intromission, the sexual roles changing after the first mate. In B. camerunensis in particular, simultaneous reciprocal mating, characterized by simultaneous intromission of male organs, was observed in few couples. In these two species, a relation between the mating system and the number of copulations was noticed, as a higher number of copulations were recorded in outcrossing (B. camerunensis) than in selfing (B. pfeifferi) snail species. No preference in the sexual role of mates was observed.