Resource distribution and surface activity of adult Lumbricus terrestris L. in an experimental systemThe 7th international symposium on earthworm ecology · Cardiff · Wales · 2002

Abstract

Lumbricus terrestris L. is noted for activities on the soil surface and descriptions of feeding, movement and mating have previously been recorded. The aim of this study was to investigate the effects of resource availability on these behaviours using an experimental system. The laboratory set-up consisted of an arena with a continuous area of 1 m 2 with soil-filled tubes to a depth of 1 m. Eighteen mature, field-collected L. terrestris were used and fed with dried barley straw on the soil surface, either evenly or in one patch. Both patterns were applied twice over an experimental period of 56 days. An infrared video system was used to provide permanent records of a 12:12 hrs dark : light cycle. Earthworm behaviour was classified into three major groups; foraging/exploration, over-surface movements and mating, with time spent in each activity recorded for all individuals. Seventeen earthworms survived to the end of the experimental period. Surface activity peaked one hour after darkness and diminished steadily until lights up. Foraging activity increased by a factor of 1.6 in a resource-rich area whereas away from the patch it reduced by a factor of 0.8 compared with even straw distribution. Over-surface movement increased by a factor of nine after provision of a patchy straw distribution, with two thirds of movements initiated by individuals in a resource poor area. The majority of matings occurred early in the dark period. During even resource distribution, matings occurred equally in different parts of the arena whereas under patchy distribution, more matings were recorded in the resource-rich area. Presented results suggest that resource availability is an important factor affecting different aspects of surface behaviour in L terrestris .