Diet Metabarcoding Reveals Correlations Between the Consumption of Slugs and Hepatic Toxicants in European Hedgehogs (Erinaceus europaeus).

The European hedgehog (Erinaceus europaeus) is currently designated as near threatened by the International Union for the Conservation of Nature. Threats include reduced prey availability, emerging pathogens, and environmental contaminants. Improving knowledge of food preferences and the role of diet in disease and exposure to toxins is important for its conservation. We used fecal DNA metabarcoding to characterize the diet of 209 hedgehogs in Europe. Stylommatophora (slugs and snails) made up the most frequent order in the hedgehog diet (found in 92% of individuals), followed by Haplotaxida (earthworms; 54%), Coleoptera (beetles; 54%), Lepidoptera (moths and butterflies; 48%), and Orthoptera (grasshoppers, locusts, and crickets; 54%). Presumed anthropogenic food, primarily in the form of pet food, was consumed by 29% of hedgehogs. We found no relation between diet and infection with pathogens (Corynebacterium ulcerans or circovirus). However, diet richness was negatively correlated with hepatic concentration in brodifacoum, a widely used rodenticide. Moreover, the relative abundance of Stylommatophora in the hedgehog diet was positively correlated with their hepatic concentration of zinc. Generally, Stylommatophora consumption was most frequent at locations of highest cumulated rainfall. The near-ubiquity of invasive Spanish slugs (Arion vulgaris; found in 80% of individuals) in the diet is concerning for hedgehog conservation, since this species is a known vector of lungworm parasites and accumulates high concentrations of environmental contaminants, such as zinc and rodenticides. Overall, this study provides a novel, high-resolution view of hedgehog diet composition and highlights the need for further research on the role of terrestrial gastropods as toxicant vectors through food webs.