Abstract
Geographical patterns in morphology can be the result of divergence among populations due to neutral or selective changes and/or phenotypic plasticity in response to different environments. Marine gastropods are ideal subjects on which to explore these patterns, by virtue of the remarkable intraspecific variation in life‐history traits and morphology often observed across relatively small spatial scales. The ubiquitous N‐Atlantic common whelk (Buccinum undatum) is well known for spatial variation in life‐history traits and morphology. Previous studies on genetic population structure have revealed that it exhibits significant differentiation across geographic distances. Within Breiðafjörður Bay, a large and shallow bay in W‐Iceland, genetic differentiation was demonstrated between whelks from sites separated by just 20 km. Here, we extended our previous studies on the common whelk in Breiðafjörður Bay by quantifying phenotypic variation in shell morphology and color throughout the Bay. We sought to test whether trait differentiation is dependent on geographic distance and/or environmental variability. Whelk in Breiðafjörður Bay displayed fine‐scale patterns of spatial variation in shape, thickness, and color diversity. Differentiation increased with increasing distance between populations, indicating that population connectivity is limited. Both shape and color varied along a gradient from the inner part of the bay in the east to the outer part in the west. Whelk shells in the innermost part of Breiðafjörður Bay were thick with an elongate shell, round aperture, and low color diversity, whereas in the outer part of the bay the shells were thinner, rounder, with a more elongate aperture and richer color diversity. Significant site‐specific difference in shell traits of the common whelk in correlation with environmental variables indicates the presence of local ecotypes and limited demographic connectivity.
Highlights
We extend our previous study (Pálsson et al, 2014) to evaluate whether the common whelk in Breiðafjörður Bay is composed of different populations based on phenotypic variation in shell morphology and color, and whether the differentiation between populations is dependent on geographic distance and/or environmental variability
Aperture shape became increasingly elongate from east to west in the bay (Figure 6), but the trend was not as clear as for the thickness, as results from Tukey HSD showed that the SK and BJ are significantly different from the central sites in the bay (HR, Brjánslækur 1 (B1), and Brjánslækur 2 (B2)), but not from HV and ST
Whelk populations were clearly spatially differentiated, which corroborates the results of previous studies on the species in the bay (Gunnarsson & Einarsson, 1995; Magnúsdóttir, 2010; Woods & Jonasson, 2017) and indicates limited demographic connectivity between populations
Summary
We extend our previous study (Pálsson et al, 2014) to evaluate whether the common whelk in Breiðafjörður Bay is composed of different populations based on phenotypic variation in shell morphology and color, and whether the differentiation between populations is dependent on geographic distance and/or environmental variability. The shell shape and color of whelk within Breiðafjörður Bay was quantified and the association with depth and substrate type analyzed.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
