Spatial distribution of genetic relatedness in a moorland population of red grouse (Lagopus lagopus scoticus)

Several aspects of the ecology and biology of red grouse (Lagopus lagopus scoticus) could prevent the complete admixture of genes within and between populations. Male red grouse display a high degree of natal philopatry, are territorial, and show less aggression to kin than to non-kin. Such Factors acting in combination predict limited male-mediated gene flow, which will promote social structure within a population by the formation of stable kin clusters, and facilitate a rapid rise in allelic coancestry and/or inbreeding. In this study we utilize hypervariable microsatellite polymorphisms to examine the extent of social affiliation between relatives in a moorland population of grouse from NE Scotland. Levels of genetic relatedness between individual male red grouse occupying territories at Glas Choille in the spring and autumn of 1995 were examined, and kin clusters delimited, Nine kin groups (mean size = 2.1 individuals) were identified prior to breeding in the spring, which increased to 11 kin groups (mean size =4.0 individuals) when territories were reformed in the autumn. The majority of those individuals that were recruited into the adult population during the autumn already had a first-order male relative established, supporting the hypothesis that recruitment is facilitated by behavioural interactions among relatives. The demographic and population genetic consequences of philopatric recruitment and kin clustering are examined and discussed. (C) 1999 The Linnean Society of London.