The biological effect of Sepedon (Diptera: Sciomyzidae) fly larvae living on Lymnea snails.

The present work was carried out to investigate first, the ecology of the Sepedon flies as well as species of Lymnea snails and secondly, the biological effects of Sepedon fly larvae living on Lymnea. In this regard, the life cycle, death rate and compatibility of Lymnea species, as well as the life cycle of Sepedon tlies in breeding cage and the activity of the new larvae in the same ecological condition were investigated. The results showed that Lymnea truncatula needs more sophisticated ecological and feeding conditions than other species of the snails. Lymnea stagnalis was found sensitive to temperature variation and this may lead to gradual or sudden death. Lymnea pregra and Lymnea palustris could well adapt with laboratory conditions. The killing effect (P 0.001) of the third-stage larvae on snails (3 to 4 weeks) was more than the effect of first- and second-stages larvae. This effect was more in a container with 2 cm water depth than a container with 5 cm depth.