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The feeding behaviour of the European hedgehog (Erinaceus europaeus L.) has been investigated in a pastoral environment. Sampling methods that caused the minimum interference to the natural population were used. The relative importance of the various prey species in the diet were analysed by occurrence, relative volume and direct counting techniques. Problems often associated with the use of direct counting were successfully overcome. It was established that the main animal food items in the hedgehog diet were earwigs, lepidopteran larvae, beetles, harvestmen, dung flies, slugs, and earthworms. Small quantities of a large number of other species were also consumed. Several variations in the diet were found to be related to changes in the availability of food species. Although hedgehogs are capable of consuming large numbers of grass grub beetles (Costelytra zealandica) during the flight season it is concluded that they are unlikely to provide any effective measure of biological control of this pasture pest. Hedeghog diet was not influenced significantly by the sex of the animal, or by pasture irrigation. It was demonstrated that the feeding rhythm of captive animals, fed under laboratory conditions, was similar to that observed in the field. Observation showed that hedgehogs were active for an average of eight hours per night, with a period of maximum activity between 9 p.m. and 11 p.m. Animals tended to follow relatively fixed routes on successive nights. Excluding nestlings, the population density in an irrigated clover-ryegrass pasture was found to vary from four (winter) to eight (summer) animals per hectare. The average minimum feeding range of these animals was 2.4 hectares, although their feeding ranges overlapped considerably.

Polymorphism in coding regions and regions controlling gene expression is the major determinant of adaptive differences in natural populations. Genes of the major histocompatibility complex (MHC) possess a high level of genetic variation, which is maintained by selection over long coalescence times. MHC genes encode antigen-presenting molecules in the adaptive immune system, which protects the host from infectious diseases. However, MHC molecules may also present self-peptides and for most autoimmune diseases there is a genetic factor associated with the MHC. MHC genes have been used to learn about the interplay of selection and historical population events. In domestic dogs and their progenitor, the wolf, I explored factors associated with domestication and breed formation and their influence not only on MHC coding regions but also on the haplotypic structure of the class II region. Polymorphism and strong selection was demonstrated in the proximal promoters of MHC genes in dogs and wolves. Hence, genetic variation associated with MHC gene expression may have at least equal importance for a well functioning immune system. Associations between promoter sequences and particular coding alleles suggested allele-specific expression patterns. SNP haplotypes of the MHC class II region revealed ancestral as well as convergent haplotypes, in which combinations of alleles are kept by selection. Interestingly, weaker allelic associations were found between different genes and between coding regions and promoters in dogs compared to wolves. Potentially, this could cause insufficient defense against infections and predispose dogs to autoimmune diseases. For example, I identified a site in the promoter region that showed a consistent difference between haplotypes conferring susceptibility and protection to diabetes in dogs, which should be investigated further. Furthermore, I investigated how selection and demographic changes associated with glacial and inter-glacial periods have affected MHC variation in European hedgehogs and extended the prevailing knowledge concerning their population history.