News Release

How much sex is enough?

Peer-Reviewed Publication

BMC (BioMed Central)

Society has long debated the contrasting advantages of monogamy and promiscuity and, in western society at least, the long term benefits of monogamy have in general won out. However new research published in BioMed Central's open access journal BMC Evolutionary Biology shows that sperm from polygamous mice are better competitors in the race for fertilisation.

Dr Renée Firman at the Centre for Evolutionary Biology, University of Western Australia, has used house mice to show that sperm from rival males compete to fertilise females and that, over several generations, polygamy can select for mice who produce more sperm, with stronger motility, than monogamous males.

After 12 generations of competitive selection (polygamous) or relaxed selection (monogamous) female mice were mated twice, in succession, with males from both groups. While 53% of the litters had mixed paternity, 33% of litters were fathered by the polygamous males compared to 14% by monogamous males. Polygamous males retained this advantage regardless of whether they were mated first or second, demonstrating that the increased fitness applies to both offensive and defensive competition. The selection procedure had no obvious effect on male size or behaviour, nor did it affect female fertility.

So in the age old debate about the merits of monogamy versus polygamy is seems that, for male mice at least, the more partners you have the more fertile your offspring will be.

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Dr Hilary Glover
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Notes to Editors

1. Experimental evolution of sperm competitiveness in a Mammal
Renée C. Firman and Leigh W. Simmons
BMC Evolutionary Biology (in press)

Please name the journal in any story you write. If you are writing for the web, please link to the article. All articles are available free of charge, according to BioMed Central's open access policy.

Article citation and URL available on request at press@biomedcentral.com on the day of publication.

2. BMC Evolutionary Biology is an Open Access, peer-reviewed online journal that considers articles on all aspects of molecular and non-molecular evolution of all organisms, as well as phylogenetics and palaeontology.

3. BioMed Central (http://www.biomedcentral.com/) is an STM (Science, Technology and Medicine) publisher which has pioneered the open access publishing model. All peer-reviewed research articles published by BioMed Central are made immediately and freely accessible online, and are licensed to allow redistribution and reuse. BioMed Central is part of Springer Science+Business Media, a leading global publisher in the STM sector.


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