Molecular evidence for multiple introductions of the banded grove snail (Cepaea nemoralis) in North America

Abstract

Global identification and monitoring programs for invasive species aim to reduce imminent impacts to biodiversity, ecosystem services, agriculture, and human health. This study employs a 658 base pair fragment of the cytochrome c oxidase subunit I (COI) gene to identify and categorize clades of the banded grove snail (Cepaea nemoralis (Linnaeus, 1758)) from native (European) and introduced (North American) ranges using a maximum-likelihood phylogeny and haplotype networks. This work corroborates the existence of eight clades within C. nemoralis and further identified three clades that were common to both Europe and North America (A, D, O). Clades A and D were found in eastern Canada, Ontario (Canada), and British Columbia (Canada), whereas clade O was restricted to Ontario, possibly introduced from Poland or central Europe. Haplotype networks suggest clade A was introduced from northern Europe, whereas clade D was introduced from western and central Europe. Networks contained many private haplotypes and a lack of haplotype sharing, suggesting strong genetic structure in this system, possibly resulting from reduced dispersal in this species. This study describes the contemporary distribution of C. nemoralis in Canada and demonstrates the efficacy of DNA barcoding for monitoring the spread of invasive species, warranting its widespread adoption in management policies.

Multiple Introductions of the Pestiferous Land Snail Theba pisana (Müller, 1774) (Gastropoda: Helicidae) in Southern California

“…These results contribute to a growing body of literature that documents repeated introduction of terrestrial gastropod taxa at sites around the world, e.g., Ambigolimax valentianus (Férussac, 1821) in Japan [68], Arion subfuscus (Draparnaud, 1805) in the U.S. [69,70], Cepaea nemoralis (Linnaeus) in North America [71,72], Cornu aspersum (Müller, 1774) in North and South America [73][74][75], Deroceras invadens Reise, Hutchinson, Schunack and Schlitt, 2011 in Europe and North America [76], Helix spp. in Europe [77], and Lissachatina fulica (Bowdich, 1822) in South America [78,79].…”

Deep structure, long‐distance migration and admixture in the colour polymorphic land snail Cepaea nemoralis

“…It is reasonable to suppose that snails of the same lineage could also have been distributed along the western fringes of France. Of use here, an inspection of the data in Layton et al (2019) shows that snails of mtDNA lineage C are found in central and North Western France (see their Figure 1; Deux‐Sevres, Paimpont), whereas previously lineage C was reported from the Pyrenean region and Ireland only (Grindon & Davison, 2013). This finding is, therefore, consistent with the genomic evidence (especially the admixture analyses) that indicates a possible hybrid origin of snails in North‐West France (La Roche; Table S5).…”

“…It is reasonable to suppose that snails of the same lineage could also have been distributed along the western fringes of France. Of use here, an inspection of the data in Layton et al (2019) shows that snails of mtDNA lineage C are found in central and North Western…”

“…Limits of the present‐day distribution of C. nemoralis shown by the red dotted line. Data from Layton et al (2019) indicated by asterisk. Bottom: Some of the C. nemoralis colour and banding morphs, from left: (1) yellow unbanded, white lip; (2) brown mid‐banded, white lip; (3) pink unbanded, normal lip; (4) yellow five‐banded, white lip; (5) brown unbanded, normal lip; (6) pink five‐banded, normal lip; (7) yellow three‐banded (10 305), normal lip.…”

“…In this study, we take advantage of a first draft genome sequence of C. nemoralis (∼3.5 Gb, 28 537 contigs with N50 of 333 kb; Saenko et al, 2021) and restriction site‐associated DNA sequencing methods (ddRAD) to understand the phylogeographic and population genomic structure of C. nemoralis . By combining the genomic data with mtDNA sequences generated from three prior studies (Davison, 2000; Grindon & Davison, 2013; Layton et al, 2019) and new sequences from Italy, the proximate aim is to begin to understand the post‐glacial history of the species. The ultimate aim is to provide context for subsequent studies on the evolutionary origins of the supergene and the relative roles that natural selection and drift may play in the establishment and loss of colour polymorphism in local populations.…”