L. rubellus preference for Quercus spp. demonstrated by isotopic and density analysis in a northern temperate forest.

Abstract

Detritivores by nature, earthworms feed on multiple sources of organic matter. We hypothesized that they exhibit selective foraging habits, which would be reflected in their isotopic composition. We sampled at FASET and Ameriflux at the University of Michigan Biological Station, where we obtained earthworm specimens by using an electro shocking technique. We measured organic soil depth, soil moisture, and mass of leaf litter, and collected leaf and soil samples. We compared the density of worms to the organic soil depths, moisture of soil, and mass of leaf litter and found no significance, although there were definite trends. The composition of the tree species relative to worm densities showed a correlation between oak LAI (leaf area index) and density of L. rubellus worms. Our isotopic analysis of the L. rubellus worm, leaf litter, and soil samples showed that L. rubellus worms have a preference of oak litter.