Female biased sex-ratio in Schistosoma mansoni after exposure to an allopatric intermediate host strain of Biomphalaria glabrata

- An allopatric and a sympatric strain of B.glabrata were used as intermediate host for S.mansoni.
- The simple fact to change the intermediate host led to a 1.2-2 fold enrichment of females S.mansoni.
- Sex-ratio goes back to normal after sexual reproduction of S. mansoni (miracidia population).
- The allopatric host effect is probably based on higher phenotypic plasticity of females.