The diet of commensal Crocidura olivieri (Soricomorpha: Soricidae): predation on co-existing invasive Mus musculus suggested by DNA metabarcoding data

Crocidura olivieri is a large-sized shrew species showing a clear trend towards commensalism in West Africa, where it co-occurs and interacts with a number of rodent species in indoor small mammal communities. Among the rodents present is the house mouse Mus musculus, a major invasive species worldwide. We here test the hypothesis that M. musculus could be part of the diet of C. olivieri in a number of localities of Senegal where the two species are known to coexist. We use a metabarcoding approach based on the high-throughput sequencing of a 133 bp fragment of the COI gene, on DNA extracted from digestive tracts and faeces of a sample of 108 shrews. Beside insects of various groups (ants, beetles and cockroaches especially) representing usual items of shrew's diet, and traces of domestic mammals and poultry that were probably scavenged, several species of rodents were evidenced. Among them, M. musculus was by far the best represented species, found in 17 of the 54 shrews where at least one prey taxon was identified. This finding tends to confirm the potential role of C. olivieri as predator of house mice, while highlighting the capacity of this species to adapt its diet to environmental conditions.