Abstract

DOMINGUEZ, Jorge  and  PEREZ-LOSADA, Marcos. Eisenia fetida (Savigny, 1826) and Eisenia andrei Bouché, 1972 are two different earthworm species. Acta Zool. Mex [online]. 2010, vol.26, n.spe2, pp.321-331. ISSN 2448-8445.

The closely related species Eisenia fetida (Savigny, 1826) and Eisenia andrei Bouché, 1972 are the most commonly used for management of organic wastes, and also in ecotoxicology, physiology and genetic studies. The problem of their taxonomic status remained unresolved for a long time and in much of the current literature both species are still termed indiscriminately as E. fetida or E. foetida, and it is often not clear which of the two species is being referred to. This review article synthesizes two articles already published by our group where we found that they are two different biological species, reproductively isolated and that they are also two different phylogenetic species. The reproductive isolation was confirmed after studying the offspring viability from inter- and intra-specific crosses of both species. Additionally, fully resolved and well supported phylogenetic trees based on mitochondrial (COI) and nuclear DNA sequences (28S) confirmed that they are different phylogenetic species. This evidence implies important considerations: for vermiculture or vermicomposting E. andrei is more recommended since its growth and reproduction rates are higher. In studies on ecotoxicology it is not possible to assume that contaminants will have the same effect on the two species, since their responses to stress factors could be different. The existence of post-copula but not pre-copula isolation in sympatric populations clearly affects the population dynamics by reducing the fitness of the individuals. For this reason, in applied aspects it is important keep the two species separated.

Keywords : Earthworms; reproductive barriers; hybridization; speciation; post-zygotic isolation; DNA; phylogeny; species delimitation.

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