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

Abstract

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 species‐rich 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 opposite configurations of body and body + wings colour lightness but achieve comparable thermoregulation, assessed via their rates of heating under experimental solar exposure. Additionally, we found that the phylogenetic signal for colour lightness was strong, and that patterns between traits and elevation held after correction for phylogeny in Catasticta but not in Leptophobia. Main conclusions The two genera exhibit divergent relationships between elevational and colour lightness patterns, with evidence that these relationships evolved multiple times in Catasticta. Communities from these two genera have likely been shaped by selection on different traits, with Catasticta colour lightness more responsive to temperature than Leptophobia. The observed geographic patterns of colour lightness in both body + wings (Catasticta) and body (Leptophobia) correspond strikingly with the distribution of montane cloud forests. Habitat fragmentation and cloud lifting from climate change documented across the Andes may therefore significantly impact communities through increased exposure to solar radiation, highlighting the complexity of conserving these diverse montane communities.

Mimicry can drive convergence in structural and light transmission features of transparent wings in Lepidoptera

“…Scales can contain pigments or generate structural colours, thereby producing colour patterns across the entire wing. Wing colour patterns are involved in thermoregulation ( Dufour et al, 2018 ; Heidrich et al, 2018 ), sexual selection ( Kemp, 2007 ), and anti-predator defences, such as crypsis ( Cook et al, 2012 ; Endler, 1984 ; Webster et al, 2009 ), masquerade ( Skelhorn et al, 2010 ; Stoddard, 2012 ), disruptive coloration, and deflection of predator attacks ( Vallin et al, 2011 ). Another type of anti-predator defence in Lepidoptera involving wing colour pattern is aposematism, where the presence of secondary defences is advertised by the means of bright and contrasted colour patterns.…”

Mimicry drives convergence in structural and light transmission features of transparent wings in Lepidoptera

“…Scales can contain pigments or generate interferential colours, thereby producing colour patterns across the entire wing. Wing colour patterns are involved in thermoregulation (Dufour et al 2018;Heidrich et al 2018), sexual selection (Kemp 2007) and anti-predator defences, such as camouflage (Arias et al 2019(Arias et al , 2020Endler 1984), masquerade (Skelhorn et al 2010;Stoddard 2012), disruptive coloration, and deflection of predator attacks (Stevens, Stubbins, and Hardman 2008). Another type of anti-predator defence in Lepidoptera involving wing colour pattern is aposematism, where the presence of secondary defences is advertised by the means of bright and contrasted colour patterns.…”

Temperature‐driven color lightness and body size variation scale to local assemblages of European Odonata but are modified by propensity for dispersal

“…Bergmann's rule, dispersal, freshwater insects, habitat-stability-dispersal hypothesis, local assemblages, macrophysiology, Odonata, thermal adaptation, thermal melanism hypothesis strong links between physiological trait and the environment, but these are often limited in spatial extent (Brehm, Zeuss, & Colwell, 2018;Dufour et al, 2018;Peters, Peisker, Steffan-Dewenter, & Hoiss, 2016;Xing et al, 2018). On the other hand, most of the studies conducted so far on the interspecific variation of color lightness and body size in ectothermic species over large geographical ranges are based on expert range maps generated by interpolating species occurrence records across suitable habitats (e.g., Pinkert, Brandl, & Zeuss, 2017;Zeuss, Brandl, Brändle, Rahbek, & Brunzel, 2014;Zeuss, Brunzel, & Brandl, 2017; but see Bishop et al, 2016).…”

“…These macrophysiological inferences based on the assumption that the explanations for large‐scale diversity patterns are found at lower levels of biological organization, as functional traits influence the fundamental physiological rates of individuals and populations whereas the consequences thereof play an important role in determining a species’ fundamental niche (Gaston & Blackburn, 2000). On the one hand, previous physiological studies on few species (Brakefield & Willmer, 1985; Harris, McQuillan, & Hughes, 2013) and local scale studies (e.g., along elevational gradients) have reported strong links between physiological trait and the environment, but these are often limited in spatial extent (Brehm, Zeuss, & Colwell, 2018; Dufour et al, 2018; Peters, Peisker, Steffan‐Dewenter, & Hoiss, 2016; Xing et al, 2018). On the other hand, most of the studies conducted so far on the interspecific variation of color lightness and body size in ectothermic species over large geographical ranges are based on expert range maps generated by interpolating species occurrence records across suitable habitats (e.g., Pinkert, Brandl, & Zeuss, 2017; Zeuss, Brandl, Brändle, Rahbek, & Brunzel, 2014; Zeuss, Brunzel, & Brandl, 2017; but see Bishop et al., 2016).…”