Male reproductive success of Schistosoma mansoni-infected Biomphalaria glabrata snails.

Infection of Biomphalaria glabrata by Schistosoma mansoni results in a dramatic reduction in the snail's ability to produce eggs. We studied the ability of such parasitically castrated snails to fertilize the eggs of uninfected snails. Pigmented B. glabrata snails (13141 stock) were infected with S. mansoni miracidia and reared individually until they ceased laying eggs. These infected snails were then given the opportunity to mate with uninfected albino (NMRI) snails. Each of the infected snails was paired with a different albino partner each subsequent week. Sperm transfer by the infected snails was evident from the production of pigmented progeny by the uninfected albino snails. Infected snails successfully acted as males for up to 6 wk after parasitic castration had occurred. The duration of allosperm use by uninfected recipients was lengthy, regardless of the infection status of the pigmented sperm donor.