Reproductive skew and relatedness in European badger social groups

Badgerland online shop
Click here to buy our badger booklets, field guides, posters, PowerPoint presentations  and Teaching Kits!

Journal

Molecular Ecology Volume 17 Issue 7,Pages 1815-1827 Published Online: 27 Feb 2008

Authors

HANNAH L. DUGDALE*†, DAVID W. MACDONALD*, LISA C. POPE†, PAUL J. JOHNSON* and TERRY BURKE†
*Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Tubney House, Abingdon Road, Tubney, Abingdon, Oxfordshire OX13 5QL,
†NERC Molecular Genetics Facility, Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN

Abstract

Reproductive skew is a measure of the proportion of individuals of each sex that breed in a group and is a valuable measure for understanding the evolution and maintenance of sociality. Here, we provide the first quantification of reproductive skew within social groups of European badgers Meles meles, throughout an 18-year study in a high-density population. We used 22 microsatellite loci to analyse within-group relatedness and demonstrated that badger groups contained relatives. The average within-group relatedness was high (R=0.20) and approximately one-third of within-group dyads were more likely to represent first-order kin than unrelated pairs. Adult females within groups had higher pairwise relatedness than adult males, due to the high frequency of extra-group paternities, rather than permanent physical dispersal. Spatial clustering of relatives occurred among neighbouring groups, which we suggest was due to the majority of extra-group paternities being attributable to neighbouring males. Reproductive skew was found among within-group candidate fathers (B=0.26) and candidate mothers (B=0.07), but not among breeding individuals; our power to detect skew in the latter was low. We use these results to evaluate reproductive skew models. Although badger society best fits the assumptions of the incomplete-control models, our results were not consistent with their predictions. We suggest that this may be due to female control of paternity, female–female reproductive suppression occurring only in years with high food availability resulting in competition over access to breeding sites, extra-group paternity masking the benefits of natal philopatry, and/or the inconsistent occurrence of hierarchies that are linear when established.

Keywords

binomial skew index • European badger Meles meles • kinship • microsatellite • reproductive suppression • within-group relatedness

Web site

• http://www3.interscience.wiley.com/journal/117989598/home

Badger by Tim Roper
This reference work is packed with detail about the badger - great for studious readers - there is no better book in print.  Click here to buy: Paperback edition or Hardback edition Kindle edition