The effects of light and temperature on grazing patterns of Douglas Lake snails.

Abstract

The purpose of this study was to determine if varying light or temperature conditions influence the grazing rates of Elimia livescens. We expected to see increased grazing rates with greater temperatures and with greater light exposure. E. livescens were collected from the littoral zone in South Fishtail Bay of Douglas Lake near Pellston, Michigan, and individually placed into pint sized jars with lake water and one algae-covered rock. We used environmental chambers to simulate six 24-hour light and temperature treatments. Statistical tests between the mean area grazed in light treatments, as well as temperature treatments, showed significant results. Additional tests also yielded significant results, showing that E. livescens were more likely to be found grazing at the end of the 24-hour period in longer light periodicities and higher temperatures. From these results, we were able to conclude that E. livescens grazed the most in settings with longer light exposure and higher temperatures. We were also able to determine that in darker and colder conditions E. livescens are less likely to graze.