Data from: Adaptive phenotypic plasticity in a clonal invader

Organisms featuring wide trait variability and occurring in a wide range
of habitats, such as the ovoviviparous freshwater New Zealand snail
Potamopyrgus antipodarum, are ideal models to study adaptation. Since the
mid-19th century, P. antipodarum, characterized by extremely variable
shell morphology, has successfully invaded aquatic areas on four
continents. Because these obligately and wholy asexual invasive
populations harbor low genetic diversity compared to mixed sexual/asexual
populations in the native range, we hypothesized that 1) this phenotypic
variation in the invasive range might be adaptive with respect to
colonization of novel habitats, and 2) that at least some of the variation
might be caused by phenotypic plasticity. We surveyed 425 snails from 21
localities across northwest Europe to attempt to disentangle genetic and
environmental effects on shell morphology. We analysed brood size as proxy
for fitness and shell geometric morphometrics, while controlling for
genetic background. Our survey revealed 10 SNP genotypes nested into two
mtDNA haplotypes and indicated that mainly lineage drove variation in
shell shape but not size. Physicochemical parameters affected both shell
shape and size and the interaction of these traits with brood size. In
particular, stronger stream flow rates were associated with larger shells.
Our measurements of brood size suggested that relatively larger slender
snails with relatively large apertures were better adapted to strong flow
than counterparts with broader shells and relatively small apertures. In
conclusion, the apparent potential to modify shell morphology plays likely
a key role in the invasive success of P.antipodarum; the two main
components of shell morphology, namely shape and size, being
differentially controlled, the former mainly genetically and the latter
predominantely by phenotypic plasticity.