Impacts of soil type, rainfall, and population density on habitat choice and surfacing behavior in the Canadian nightcrawler, Lumbricus terrestris.

Abstract

This study examined environmental factors, such as soil type, rainfall, and population density, which influence where the Canadian nightcrawler, Lumbricus terrestris, dwells. It was predicted that the nightcrawlers would prefer loam when presented with a choice of soil substrate. However, nightcrawlers preferred potting soil to loam or sand. When the amount of rainfall was doubled, flooding and destroying the burrows, an increase in the number of nightcrawlers surfacing was observed. It was expected that increasing the population density would increase the number of surfaced nightcrawlers. No significant difference was found when testing the effects of population density on surfacing after application of intermediate amounts of rainfall. These results suggest that nightcrawlers prefer neutral soils rich in organic matter and respond to varying amounts of rain.