Molecular and morphological insights into the origin of the invasive greater white-toothed shrew (Crocidura russula) in Ireland

Abstract

Identifying routes of invasion is a critical management strategy in controlling the spread of invasive species. This is challenging however in the absence of direct evidence. Therefore, indirect methodologies are used to infer possible invasion sources and routes, such as comparisons of genetic and morphological data from populations from invasive ranges and putative source areas. The greater white-toothed shrew (Crocidura russula) was first discovered in Ireland from skeletal remains in the pellets of birds of prey collected in 2007 and is it is now sufficiently established that the species has a detrimental impact on Ireland's small mammal community. In this study, we address the uncertain origin(s) of the Irish population of C. russula. The cytochrome b gene of mitochondrial DNA was analysed from 143 individuals from throughout its range within a phylogenetic and approximate Bayesian computation framework. These analyses revealed that the Irish population stemmed from Europe as opposed to North Africa. Additionally, mandibles from 523 individuals from Ireland and 28 other European populations were subjected to multivariate and distance-based analyses, which demonstrated an association between the Irish population and those in France, Switzerland and Belgium. When the genetic and morphological analyses were considered together, an origin stemming from France was deemed the most likely scenario for the source of the invasive Irish population. This study has demonstrated the importance of utilising a multidisciplinary approach when attempting to identify the origins and invasion routes of invasive species

Emerging Infectious Disease Implications of Invasive Mammalian Species: The Greater White-Toothed Shrew (Crocidura russula) Is Associated With a Novel Serovar of Pathogenic Leptospira in Ireland

“…This pathogen has not previously been identified in Ireland, or Europe, and never before been cultured from a mammalian host. Whilst there have been numerous accidental or deliberate introductions of mammalian and avian species into Europe[50], the GWTS population established in Ireland is most likely sourced from within Europe[3]. Regardless, invasive species have unique attributes to facilitate the dissemination of emerging infectious diseases[51]: firstly, invasive species may be more efficient at transmitting pathogens and, as in the case of our study, novel and as yet undescribed, pathogens.…”

“…According to recent studies, this species is rapidly spreading with radial expansion estimates of approximately 5.5 km/yr[2]. The source of this invasive population is from Europe as opposed to North Africa[3], and evidence suggests that the greater white-toothed shrew is associated with the local extinction of indigenous populations of the pygmy shrew ( Sorex minutus )[2]. However, a comprehensive investigation on the One Health implications of this invasive species has yet to be performed.…”

Insularity induces changes on body and mandible morphology in a Mediterranean population of the greater white-toothed shrew Crocidura russula (Hermann, 1780)

“…This crocidurine is widespread across Western Europe (except Italy) and Northern Maghreb, including some Atlantic and Mediterranean islands (Cornette et al, 2012 and references therein). Moreover, C. russula has been recently reported as a highly invasive species with rapid adaptation to new territories and high potential to displace other shrews, disrupting autochthonous small mammals communities (McDevitt et al, 2014;Montgomery et al, 2015;Gargan et al, 2016). Mainland and island populations of C. russula have been considered largely undifferentiated; nevertheless, recent studies do have detected metabolic and morphological differences (Magnanou et al, 2005;Cornette et al, 2012Cornette et al, , 2015.…”

“…Mainland and island populations of C. russula have been considered largely undifferentiated; nevertheless, recent studies do have detected metabolic and morphological differences (Magnanou et al, 2005;Cornette et al, 2012Cornette et al, , 2015. Specifically, while morphological studies have analysed mandible form in populations of C. russula from Atlantic islands (Cornette et al, 2012(Cornette et al, , 2015Gargan et al, 2016), similar information regarding Mediterranean populations is very scarce. Since evolutionary causes prompting morphological change in insular populations can differ depending on ecological and geographic features of the islands (Lomolino et al, 2012), the study of populations of C. russula from Mediterranean islands can bring important information of this widely distributed and highly invasive small mammal species (McDevitt et al, 2014;Montgomery et al, 2015;Gargan et al, 2016).…”

“…Specifically, while morphological studies have analysed mandible form in populations of C. russula from Atlantic islands (Cornette et al, 2012(Cornette et al, , 2015Gargan et al, 2016), similar information regarding Mediterranean populations is very scarce. Since evolutionary causes prompting morphological change in insular populations can differ depending on ecological and geographic features of the islands (Lomolino et al, 2012), the study of populations of C. russula from Mediterranean islands can bring important information of this widely distributed and highly invasive small mammal species (McDevitt et al, 2014;Montgomery et al, 2015;Gargan et al, 2016). In this context, the general aim of this study is to gain insight into the evolutionary and ecological processes involved in morphological differentiation of island populations of C. russula.…”