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

Abstract

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.

Sharing space between native and invasive small mammals: Study of commensal communities in Senegal

“…a preliminary metabarcoding study of the gut and faeces content of C. olivieri individuals provides support for such a hypothesis that would imply active predation, possibly mostly on neonates or nonactive unweaned juveniles, directed primarily against M. musculus (Galan et al, 2023). Rattus rattus, which was very abundant in stock rooms where it probably causes important damage to food stuff (see Dossou et al, 2020, for an example in Cotonou, Benin), presents an average value of niche breadth compared to other species, and high overlap values with other species.…”

“…The habitat niche overlap with rodent species here observed probably relates to the fact that this shrew does not belong to the same ecological guild (sensu Simberloff & Dayan, 1991 ) and, as such, is probably not submitted to competitive interactions with them likely to constrain its ecological distribution. Here, another type of interaction may rather be at work between shrews and rodents, namely a predator–prey relation: a preliminary metabarcoding study of the gut and faeces content of C. olivi eri individuals provides support for such a hypothesis that would imply active predation, possibly mostly on neonates or non‐active unweaned juveniles, directed primarily against M. musculus (Galan et al, 2023 ). Rattus rattus , which was very abundant in stock rooms where it probably causes important damage to food stuff (see Dossou et al, 2020 , for an example in Cotonou, Benin), presents an average value of niche breadth compared to other species, and high overlap values with other species.…”

All-you-can-eat buffet: A spider-specialized bat species (Myotis emarginatus) turns into a pest fly eater around cattle

“…Surprisingly, even the number of Diptera taxa was significantly higher using Galan primers, while Zeale primers were previously considered efficient in retrieving both Diptera and Lepidoptera taxa in bat diets [43,93,95]. This might have been due to the increased use of the efficient Galan adapted primer pair in recent studies of invertebrate and vertebrate diets [76,77,[96][97][98][99][100]. The benefit of Galan primers was also their capacity to amplify host DNA, enabling simultaneous identification of the predator and its prey.…”