SREL Reprint #3174

Novel microsatellite loci for the compost earthworm Eisenia fetida: A genetic comparison of three North American vermiculture stocks

Christopher M. Somers1, Kara Neudorf1, Kenneth L. Jones2, and Stacey L. Lance3

1University of Regina, Department of Biology, Regina, Saskatchewan, Canada S4S 0A2
2Georgia Genomics Facility, University of Georgia, Athens, GA 30602, USA
3Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, SC 29802, USA

Abstract: Earthworms are important components of soil ecosystems worldwide, and have been used extensively as indicator species in ecotoxicology studies. Our understanding of mating systems, population structure, and genetic diversity in earthworms is limited by the current lack of available genetic tools. To address this gap, we developed 16 novel microsatellite markers for the compost earthworm Eisenia fetida, one of the most widely studied earthworm species. We tested the new markers in 3 putative populations of worms from commercial vermiculture operations in Canada and the U.S.A. All 16 loci were variable in at least one population, with the number of alleles per locus ranging from 3 to 10, observed heterozygosity from 0.000 to 0.783, and polymorphic information content from 0.032 to 0.587. One group had significantly reduced heterozygosity compared to the other 2, but overall there were only minor genetic differences among the tested suppliers, suggesting a possible bottleneck for this species in North America. The microsatellite loci we describe here will be extremely useful tools for future field and laboratory studies of E. fetida. Body size and condition in adult worms varied significantly by supplier, and breeding success and cocoon production were significantly higher in breeding pairs from one supplier compared to the other two. In the absence of evidence for genetic divergence among populations, our results suggest that the early rearing environment may be an important factor affecting adult breeding performance. We caution that the source of worms may affect the outcome of laboratory experiments involving growth and reproduction.

Keywords: Eisenia fetida, Microsatellites, Population genetics, Genetic diversity, Body condition, Breeding performance

SREL Reprint #3174

Somers, C. M., K. Neudorf, K. L. Jones, and S. L. Lance. 2011. Novel microsatellite loci for the compost earthworm Eisenia fetida: A genetic comparison of three North American vermiculture stocks. Pedobiologia - International Journal of Soil Biology 54(2011): 111-117.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).