Qualitative and quantitative methods show stability in patterns of <i>Cepaea nemoralis</i> shell polymorphism in the Pyrenees over five decades

Over the past century, study of animal color has been critical in establishing some founding principles biology, especially genetics and evolution. In this regard, one emerging strengths working with land snail genus Cepaea is that historical collections can be compared against modern-day samples, for instance, to understand impact changing climate habitat upon shell morph frequencies. However, potential limitation prior studies scored ground by eye into three discrete colours yellow, pink, or brown. This incurs both error bias comparative surveys. study, we therefore aimed use a quantitative method score evaluated it comparing patterns C. nemoralis polymorphism Pyrenees, using methods on present-day data gathered 1960s traditional method. The main finding was while measures reduced possibility standardized procedure, same altitudinal trends were recovered, irrespective results also showed there general stability local over five decades, including clines, just exceptions. Therefore, although subject human scoring remains valuable, if persons have appropriate training. comparison, are benefits taking laboratory, several practical disadvantages, mainly terms throughput accessibility. future, anticipate genomic may used role selection maintaining clines. addition, photographs generated citizen scientists conducting field surveys deep learning-based survey patterns.