Aspects of Lumbricus Terrestris L. dispersal, distribution and intraspecific interactions in field and laboratory investigations

Abstract

Earthworms are considered very important soil organisms, greatly influencing soil function through their feeding, burrowing and casting activities, e.g. comminution and incorporation of litter into soil, building and maintenance of soil structural porosity and aggregation, promoting changes in microbial communities and activities and influencing plant growth.
Although research on earthworms is increasing rapidly, there is still inadequate knowledge of the basic biology and ecology of even common species, such as Lumbricus terrestris. This study aimed to examine aspects of adult, immature and hatchling L. terrestris dispersal, distribution and intraspecific interactions through a number of laboratory and field experiments. Results demonstrated that population density can significantly affect dispersal in L. terrestris. Intraspecific competition for food resources and space in combination with the need to secure mating opportunities interact to produce regular patterns in the horizontal distribution of individuals, observed at the scale of I m 2. Burrow reuse by offspring and other conspecifics was observed, in addition to permanence in distribution of L. terrestris over short periods (1 year). Intraspecific competition between adults (parents or not) and hatchlings/juveniles intensified as the latter grew in size. However, observations of cocoon deposition by adults in distinct locations within side burrows, could represent a form of "parental investment". Results from this study could assist in identifying some of the factors that influence L. terrestris population dynamics, however further research is required to fully understand how their combined effect may influence the behaviour of this species in natural environments.