Gut content analysis of earthworms (Lumbricidae) in a beechwood

In a submontane beechwood on limestone near Göttingen (Germany), gut contents of adult earthworms were analysed. Paniculate detritus, non-particulate detritus, and mineral components were differentiated by sieving and ashing; plant remains were bleached and identified microscopically. Lumbricus terrestris (the only anecic species in the study area) was the only earthworm with high amounts of particulate plant remains in the gut (median 38% dry wt). Preferential feeding on non-beech litter could be demonstrated. Median total organic gut content was 76% dry wt. L. castaneus (the dominant epigeic species) had a high proportion of organic gut contents (median 61% dry wt) which was mainly non-particulate detritus. The endogeic species ( Aporrectodea caliginosa, Aporrectodea rosea, Octolasion lacteum, O. cyaneum) had no, or only few particles in the gut. Median organic fractions were 39, 40, 44, and 29% dry wt, respectively. It is concluded that endogeic earthworms preferentially feed on soil compartments with high detritus concentrations, as average soil organic matter contents were ⩽20% dry wt.