title: Cool habitats support darker and bigger butterflies in Australian tropical forests.
abstract: Morphology mediates the relationship between an organism's body temperature and its environment. Dark organisms, for example, tend to absorb heat more quickly than lighter individuals, which could influence their responses to temperature. Therefore, temperature-related traits such as morphology may affect patterns of species abundance, richness, and community assembly across a broad range of spatial scales. In this study, we examined variation in color lightness and body size within butterfly communities across hot and cool habitats in the tropical woodland-rainforest ecosystems of northeast Queensland, Australia. Using thermal imaging, we documented the absorption of solar radiation relative to color lightness and wingspan and then built a phylogenetic tree based on available sequences to analyze the effects of habitat on these traits within a phylogenetic framework. In general, darker and larger individuals were more prevalent in cool, closed-canopy rainforests than in immediately adjacent and hotter open woodlands. In addition, darker and larger butterflies preferred to be active in the shade and during crepuscular hours, while lighter and smaller butterflies were more active in the sun and midday hours-a pattern that held after correcting for phylogeny. Our ex situ experiment supported field observations that dark and large butterflies heated up faster than light and small butterflies under standardized environmental conditions. Our results show a thermal consequence of butterfly morphology across habitats and how environmental factors at a microhabitat scale may affect the distribution of species based on these traits. Furthermore, this study highlights how butterfly species might differentially respond to warming based on ecophysiological traits and how thermal refuges might emerge at microclimatic and habitat scales.
authors.affiliation: School of Biological Sciences The University of Hong Kong Hong Kong China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Xing
authors.affiliation: School of Biological Sciences The University of Hong Kong Hong Kong China.
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Bonebrake
authors.affiliation: School of Science and Technology The Open University of Hong Kong Hong Kong China.
authors.forename: Chin Cheung
authors.initials: CC
authors.lastname: Tang
authors.affiliation: School of Biological Sciences The University of Hong Kong Hong Kong China.
authors.forename: Evan J
authors.initials: EJ
authors.lastname: Pickett
authors.affiliation: School of Biological Sciences The University of Hong Kong Hong Kong China.
authors.forename: Wenda
authors.initials: W
authors.lastname: Cheng
authors.affiliation: College of Marine and Environmental Science James Cook University Townsville QLD Australia.
authors.forename: Sasha E
authors.initials: SE
authors.lastname: Greenspan
authors.affiliation: College of Marine and Environmental Science James Cook University Townsville QLD Australia.
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Williams
authors.affiliation: Department of Wildlife Ecology and Conservation University of Florida Gainesville FL 32611 USA.
authors.forename: Brett R
authors.initials: BR
authors.lastname: Scheffers
keywords: climate change; morphology; trait; tropical forest