Seed preferences of Lumbricus terrestris L.

Abstract

We performed an experiment to determine factors affecting preference in the selection of seeds by Lumbricus terrestris L. Earthworms were given a menu consisting of seeds of nine plant species that were sorted into three size classes and sand particles that were sorted into the same three size classes. The experiment was conducted over a period of 84 days in worm beds under laboratory conditions. Seed and sand particles from the small (0.5–1.0 mm) size class were chosen four to one over seeds and sand in the intermediate (1.0–2.0 mm) size class. Seeds and sand particles in the intermediate size class were chosen 14 to one over seeds and sand particles in the large (2.0–2.5 mm) size class. Seeds were chosen two to one over sand in the small size class, six to one in the intermediate size class, and 15 to one in the large size class. Seeds with smooth surfaces were generally preferred over seeds with rough surfaces. Excavation of the bedding material at the conclusion of the experiment revealed that germination of seeds was occurring beneath the surface in chambers created by the earthworms, and that these seedlings were being grazed by L. terrestris.