Journal article

Climate is a strong predictor of nearinfrared reflectance but a poor predictor of colour in butterflies

JT Munro, I Medina, K Walker, A Moussalli, MR Kearney, AG Dyer, J Garcia, KJ Rankin, D Stuart-Fox

Proceedings of the Royal Society B Biological Sciences | ROYAL SOC | Published : 2019

Abstract

Colour variation across climatic gradients is a common ecogeographical pattern; yet there is long-standing contention over underlying causes, particularly selection for thermal benefits. We tested the evolutionary association between climate gradients and reflectance of near-infrared (NIR) wavelengths, which influence heat gain but are not visible to animals. We measured ultraviolet (UVA), visible (Vis) and NIR reflectance from calibrated images of 372 butterfly specimens from 60 populations (49 species, five families) spanning the Australian continent. Consistent with selection for thermal benefits, the association between climate and reflectance was stronger for NIR than UVA-Vis wavelength..

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