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Biology and Fertility of Soils

, Volume 35, Issue 5, pp 390–392 | Cite as

Relatedness does not affect the mating effort of Eisenia fetida Sav. (Oligochaeta) despite evidence for outbreeding depression

  • Shinichi Nakagawa
  • Terry D. Bannister
  • Fiona R. Jensen
  • Donald A. McLean
  • Joseph R. Waas
Short Communication

Abstract.

Animals that can distinguish kin from non-kin may enhance their breeding success through "optimal outbreeding". Although relatedness can influence the breeding success of earthworms, no studies of kin discrimination have been conducted in any Oligochaeta species. We determined whether Eisenia fetida Sav. would discriminate kin and change breeding effort with them. The number of cocoons produced (fecundity), viable cocoons, and hatchlings produced by full sibling (inbreeding) and non-sibling (outbreeding) pairs, from different populations, were compared; in this species, fecundity is a reliable indicator of the occurrence and frequency of mating. There were no significant differences in fecundity between inbreeding and outbreeding pairs, so we obtained no evidence for differential investment based on kinship. However, sibling pairs hatched a significantly greater proportion of their cocoons than non-sibling pairs, suggesting that outbreeding depression may reduce reproductive success. We also provide the first evidence for the possibility of parthenogenesis in this species.

Earthworms Kin discrimination Inbreeding Outbreeding Parthenogenesis 

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Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  • Shinichi Nakagawa
    • 1
  • Terry D. Bannister
    • 1
  • Fiona R. Jensen
    • 1
  • Donald A. McLean
    • 1
  • Joseph R. Waas
    • 1
  1. 1.Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton, New Zealand

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