The effects of habitat and current on the shell morphology of the freshwater snail, Elimia livescens, in northern Michigan streams.

Abstract

Snail shell morphology is a salient property of snail adaptations that is dependent on a variety of environmental factors. The purpose of this study was to observe the differences in snail shell thickness, size, and length-to-width ratio, or apex proportion, in both riffle, or higher current, and pool, or little to no current, environments of streams, and to understand how these differences were dependent on current levels in the freshwater snail, Elimia livescens. To test these factors, snails were collected in riffle and pool sites within two streams and snail shell thickness at the aperture, length, and width were recorded. Thickness was found to be significantly greater in riffle environments than pool environments, and shell thickness was positively correlated with current level. The apex proportion and shell size did not appear to be affected by current. Overall, of the aspects of shell morphology studied, thickness appeared to be the most influenced by current.