A COMPARISON OF THE DIET COMPOSITION OF 2-SOREX-ARANEUS POPULATIONS UNDER DIFFERENT HEAVY-METAL STRESS

The food composition of two populations of the common shrew Sorex araneus Linnaeus, 1758 was studied. One population lived in the surrounding of a former zinc smelter in the Dutch province of Noord-Brabant, the other in the National Park "Hoge Veluwe". The whole contents of the alimentary tract of 112 specimens were analysed. The analysis was needed in a model study of the transfer of heavy metals in the food chain of this shrew. Qualitative and quantitative analyses both showed major prey types in all seasons were lumbricids, insect larvae (mainly Coleoptera and Lepidoptera), adult Coleoptera and Araneae. Opiliones only in autumn supplied a contribution to the diet. Soft prey animals contributed quantitatively for 40-50% to the total food intake. Significant differences in food choice between the two populations were noticed. This can be a factor of importance in transfer studies of toxic substances. Despite significant differences in heavy metal burden of the prey of contaminated and uncontaminated sites, both populations preferred Lumbricidae as a major prey. It is concluded that for both populations arthropod larvae increased in importance in the winter period, coleopteran larvae being the most important order. Throughout all seasons lumbricid earthworms are quantitatively the most important prey.