The Social Structure of the Hazel Dormouse (Muscardinus avellanarius)

Abstract

The maintenance of genetic variation is a general conservation concern for endangered species, such as the British hazel dormouse (Muscardinus avellanarius). The structuring of genetic variation at multiple hierarchical levels, from individual through to the total population, can provide insights into within-population processes, such as inbreeding and social behaviour, and help understand the causes of population partitioning, both current and historical. Investigating the processes that shape and alter levels of genetic variation within hazel dormouse populations will highlight any factors that may influence their continued persistence and inform on appropriate management strategies. The current thesis aimed to address whether a) microbial-mediated odour could be a mechanism for kin discrimination, inbreeding avoidance and social cooperation; b) the hazel dormouse displays social structuring and, as a result, evidence for inbreeding avoidance; c) there is within and among population structuring, resulting from identified physical features that restrict gene flow and d) current patterns of genetic variation inform us about historic dispersal. Captive bred individuals of known pedigree were used to assess the relationship between bacterial community composition and relatedness. Microsatellite markers were used to generate relatedness estimates and analyse levels of genetic variation at the individual, social group and sub-population levels on samples obtained from Sussex and the Isle of Wight. Mitochondrial markers were used to infer patterns of genetic variation at the total population level, including samples obtained from all over the species range. F-statistics were then used to infer any deviations from Hardy-Weinberg equilibrium that could imply for example inbreeding or gene flow. The main findings of the thesis are that 1) microbial composition correlates with genetic relatedness in the hazel dormouse, indicating that microbial-mediated odour could be a mechanism for kin discrimination; 2) inbreeding levels are not significantly high, even though both male and female close relatives are in close proximity, with neither sex exclusively practising natal philopatry or dispersal; 3) no identified habitat features appeared to influence gene flow and levels of genetic variation did not differ between sites, regardless of the habitat features; 4) on the basis of mtDNA, the British dormouse population is likely to have been founded by a relatively recent colonisation event, rather than be a remnant of a more ancient indigenous species. The results of this study contribute to our understanding of how social and dispersal mechanisms determine a population’s composition and hence provide some indicators of how the species has evolved. It is intended that knowledge of the species’ social structure and, in particular, details of their inbreeding avoidance behaviour and tolerance of close relatives, will help optimise population survival in future reintroduction programs.

Date of Award	2017
Original language	English
Awarding Institution	University of Brighton