Mate choice of an endogeic earthworm revealed by microsatellite markers

Endogeic earthworms are difficult study subjects due to the cryptic medium in which they live; thus, only the behaviour of epigeic and anecic earthworms has been studied before. We used microsatellite markers as a tool to elucidate the mate choice processes of Hormogaster elisae, an endogeic earthworm. It was shown to normally mate with two partners, preferably of the same size that are found in close proximity thereby eliminating the need for long-distance dispersion, which could explain the previously observed high genetic differentiation between populations. The genetic analyses of the sperm within each of its four spermathecae showed a uniform distribution with no signs of differential storage of sperm from different partners.