Divergent melanism strategies in Andean butterfly communities structure diversity patterns and climate responses

Aim: Geographic distributions are driven by a combination of species sensitivity and exposure to climate. We quantified colour lightness, a trait that mediates the interaction between sensitivity and exposure, of diverse butterfly communities to test whether colour lightness is associated with community assembly across climate-elevation gradients. Location: Ecuadorian Andes Methods: We used a long-term dataset of museum specimens for two of the most speciose genera of Pieridae butterflies in Ecuador, Catasticta and Leptophobia. Within a phylogenetic framework we examined how communities assemble based on four traits across elevation: colour lightness, species-specific heating rate, maximum temperature (under experimental solar exposure), and elevation breadth. Results: We found that colour lightness in both genera was related to elevation, but the two genera exhibited opposite patterns; Catasticta are darker and Leptophobia are lighter with increasing elevation. The two genera have oppo...