Conservation Genetics

, Volume 7, Issue 3, pp 427–437 | Cite as

Inbreeding and promiscuity in the endangered grand skink



The inbreeding avoidance hypothesis predicts that organisms that often encounter relatives as potential mates should evolve behaviours to avoid incestuous matings. Avoidance behaviours have practical importance for small populations because deleterious genetic processes may be less imminent than otherwise expected from genetic models that assume random mating. I used genetic techniques to investigate the extent of inbreeding and inbreeding avoidance behaviours in rare lizards from southern New Zealand. Grand skinks, Oligosoma grande, live in small patchily distributed groups, and have low rates of inter-group dispersal (ca. 3–20% disperse). I used data from 15 microsatellite loci to test the hypothesis that adults are likely to encounter kin as potential mates and will inbreed. These data showed that adult skinks usually inhabited rock outcrops with adult relatives of the opposite sex – up to 35% of potential mates were of equivalent relatedness as half-sibs and 17% were equivalent to full sibs. However, skinks did not preferentially breed with less related mates, and 18.2% of matings were between individuals of equivalent relatedness as full-sibs. Instead, skinks mated with partners of all levels of relatedness, and were promiscuous – almost half of adult females and nearly three quarters of adult males reproduced with multiple partners. In addition, inbreeding had no effect on survival of offspring in their first year. Two other putative mechanisms of inbreeding avoidance, sex-biased and natal dispersal, were not pronounced in this species. This study adds to a growing list of species that inbreed despite the risks.


habitat fragmentation inbreeding offspring survival Oligosoma grande skink 


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I thank Jeroen Spitzen, Annemarieke van der Sluijs, and Amanda Smale for assistance with skink catching. Dave Houston and Graeme Loh provided valuable skink-related discussions. Stephen Sarre, Dianne Gleeson, and Tash Lebas provided helpful comments on the manuscript, as did two anonymous referees. Thanks also to Paul Sunnucks for the Mac SE/30, Keith Goodnight for advice on the use of likelihood ratios, and Bill Amos for the IR macro.


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Copyright information

© Springer Science+Business Media, Inc. 2005

Authors and Affiliations

  1. 1.School of Animal BiologyUniversity of Western AustraliaPerthAustralia

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