The dark side of Lepidoptera: Colour lightness of geometrid moths decreases with increasing latitude

作者：Lea Heidrich, Nicolas Frieß, Konrad Fiedler, Martin Brändle, Axel Hausmann, Roland Brandl, Dirk Zeuss · 发表于：Global Ecology and Biogeography · 年份：2018 · DOI：10.1111/geb.12703 · 被引用次数：76 · 研究领域：Plant and animal studies、Animal and Plant Science Education、Neurobiology and Insect Physiology Research

Abstract Aim The observed decrease in insect colour lightness with increasing latitude has been explained in earlier macroecological studies by the increased solar absorption of dark coloration, which allows extended periods of activity. However, melanin‐based dark coloration also protects against pathogens and ultraviolet radiation, which select for dark coloration at low latitudes where these selection pressures intensify. In nocturnal insects, the relative importance of these protective functions of dark coloration is expected to surpass thermoregulatory functions, as nocturnal species cannot benefit from extended periods of activity during the daytime. Hence, we expected that diurnal and nocturnal insects show contrasting geographical patterns of colour lightness. We tested these predictions using geometrid moths, which comprise both diurnal and nocturnal species. Location Western Palearctic. Time period Contemporary. Major taxa studied Geometridae (Lepidoptera). Methods We used digital image analysis to assess the colour lightness of 637 species, compiled their distribution across 3,777 grid cells of 50 km × 50 km and calculated the assemblage‐based average colour lightness. We used multiple regressions, autoregressive error models and randomizations to test for relationships between colour lightness and environmental variables associated with the thermal environment, putative pathogen pressure and ultraviolet radiation. Results We found a clear decrease in colour lightn...