Reproduction of the earthworm Lumbricus terrestris Linné after the first mating

Abstract

Mature virgin individuals of the simultaneously hermaphroditic earthworm Lumbricus terrestris Linné were housed in small groups and allowed access to each other under continuous video observation. After copulation, earthworms were isolated and thereafter their mass and the number of cocoons they produced were recorded monthly. Mated individuals produced cocoons for up to 12 months after the mating, while unmated individuals produced no cocoons. Hatchability of cocoons ranged from 76 to 62% over the 5 months following the mating, but decreased to 11% in the sixth month. Cocoons produced beyond that period failed to hatch. The median period of viable cocoon production was 3 months. Monthly cocoon production peaked 2-3 months after the mating, when 2-3 (1-2 viable) cocoons per individual were produced. Median total production of viable cocoons was 5 per individual (range 0-21). There was no discernible relationship between cocoon production and length of copulation, individual longevity, or individual mass at mating. Both partners usually contributed to the production of viable cocoons, but within mating pairs there was a median difference of 4 cocoons. Median survival time after the experimental mating period was 9 and 11 months for mated and unmated earthworms, respectively.