The Aestivation Pattern of a Population of Lymnaea elodes (Say) (Gastropoda:Lymnaeidae)

Abstract

Laboratory and field studies were conducted on the aestivation pattern of a population of the lymnaeid snail, L. elodes from a temporary woodland pond in southern Michigan [USA]. The snails had a 15-mo. life span, 3-4 mo. of which were spent in aestivation during late summer and autumn. It was primarily the juvenile snails which aestivated. In the field they migrated out of the receding pond water and aestivated on dry objects near or above the pond floor. In the laboratory, the juveniles crawled out of the water and aestivated on the aquarium glass. During the field aestivation period, there was an active, terrestrial migration pattern, terminating with the juvenile snails under the leaf litter where they overwintered. There was no evidence that the snails burrowed into the soil. Adult snails, whether they aestivated (rare) or followed the receding water levels (common), succumbed primarily to predation by sciomyzid larvae and possibly terrestrial vertebrates.