Abstract
This study examines co-variance between shape variability of UV-reflectant patterns on wing surfaces of Palearctic butterflies and certain environmental variables - mean annual temperature; mean annual precipitation; net primary productivity (NPP); normalized difference vegetation index (NDVI); and altitude. The shape variability was also studied in relation to the latitude and longitude.
Brimstone (Gonepteryx rhamni) was chosen as a model organism. In males, these patterns were observed on the dorsal forewing surface, while in females the whole ventral side of wings reflects.
Said patterns play a very important role in mating behavior and could be crucial for recognizing the quality of a mate. A two-block PLS analysis discovered a significant relationship between the shape of the wing and ecological variables, especially mean annual temperature, mean annual precipitation, and latitude.
The changes in wing morphospace associated with these variables show a noticeable increase of the pattern's surface in relation to the wing. Specimens from areas with higher UV radiation, i.e. closer to the equator, have a relatively larger UV-reflectant pattern.
The results support the hypothesis that UV-reflectant patterns might serve as a protection from UV light. The question remains whether the shape and relative size of UV-reflectant patterns can also be influenced by e.g. metabolic rate, availability of nutrients, or other factors.