Polygynandry, extra‐group paternity and multiple‐paternity litters in European badger (Meles meles) social groups

Abstract

The costs and benefits of natal philopatry are central to the formation and maintenance of social groups. Badger groups, thought to form passively according to the resource dispersion hypothesis (RDH), are maintained through natal philopatry and delayed dispersal; however, there is minimal evidence for the functional benefits of such grouping. We assigned parentage to 630 badger cubs from a high-density population in Wytham Woods, Oxford, born between 1988 and 2005. Our methodological approach was different to previous studies; we used 22 microsatellite loci to assign parent pairs, which in combination with sibship inference provided a high parentage assignment rate. We assigned both parents to 331 cubs at > or = 95% confidence, revealing a polygynandrous mating system with up to five mothers and five fathers within a social group. We estimated that only 27% of adult males and 31% of adult females bred each year, suggesting a cost to group living for both sexes. Any strong motivation or selection to disperse, however, may be reduced because just under half of the paternities were gained by extra-group males, mainly from neighbouring groups, with males displaying a mixture of paternity strategies. We provide the strongest evidence to date for multiple-paternity litters, and for the first time show that within-group and extra-group males can sire cubs in the same litter. We investigate the factors that may play a role in determining the degree of delayed dispersal and conclude that the ecological constraints hypothesis, benefits of philopatry hypothesis, and life history hypothesis may all play a part, as proposed by the broad constraints hypothesis.

Alloparental behaviour and long-term costs of mothers tolerating other members of the group in a plurally breeding mammal

“…We assigned both parents to all 24 cubs in the filmed groups, and we assigned both 168 parents to 595 (94%) of the 630 cubs born 1988-2005, with 80% confidence, or 331 (53%) 169 cubs with 95% confidence (Dugdale et al 2007). We assessed whether breeding females 170 could confidently be assigned as full-siblings or mother-offspring rather than unrelated using 171 KINSHIP 1.3.1 (Goodnight & Queller 1999).…”

“…Group size was estimated using trapping data, assuming that badgers last caught as a 94 cub were present for one extra year, and badgers last caught as yearlings or adults were 95 present for two years (Dugdale et al 2007). We assigned group membership on the basis of 96 rules described by Dugdale et al (2007), such that badgers trapped successively in different 97 social groups were recorded as resident in both groups for the intervening period, with theexception that badgers caught in more than one group were divided fractionally between 99 these groups. 100…”

How many Eurasian badgers Meles meles L. are there in the Republic of Ireland?

“…Though social, badgers are shy and nocturnal, living much of their lives underground in large setts (burrows). Furthermore, badgers move frequently and such movements appear to have significant consequences at population level Carter et al 2007;Pope et al 2007;Dugdale et al 2007;McDonald et al population is important to assist in their management including potential vaccination projects (Collins et al 1994;O'Keeffe 2006;Kelly et al 2007).…”

Estimating offspring production using capture‐mark‐recapture and genetic methods in red squirrels

“…In several studies only parents assigned with a 95% probability were considered (e.g., Aars et al 2006;Dugdale et al 2007;Lane et al 2008). In our study system it was impossible to exclude the candidate mothers (CPs) assigned with a 80% confidence (see also Telfer et al 2003).…”