endler-colourchange-2016.pdf (559.86 kB)
Colour change on different body regions provides thermal and signalling advantages in bearded dragon lizards
journal contribution
posted on 2016-06-08, 00:00 authored by K R Smith, V Cadena, John EndlerJohn Endler, W P Porter, M R Kearney, D Stuart-FoxMany terrestrial ectotherms are capable of rapid colour change, yet it is unclear how these animals accommodate the multiple functions of colour, particularly camouflage, communication and thermoregulation, especially when functions require very different colours. Thermal benefits of colour change depend on an animal's absorptance of solar energy in both UV–visible (300-700 nm) and near-infrared (NIR; 700-2600 nm) wavelengths, yet colour research has focused almost exclusively on the former. Here, we show that wild-caught bearded dragon lizards (Pogona vitticeps) exhibit substantial UV–visible and NIR skin reflectance change in response to temperature for dorsal but not ventral (throat and upper chest) body regions. By contrast, lizards showed the greatest temperature-independent colour change on the beard and upper chest during social interactions and as a result of circadian colour change. Biophysical simulations of heat transfer predicted that the maximum temperature-dependent change in dorsal reflectivity could reduce the time taken to reach active body temperature by an average of 22 min per active day, saving 85 h of basking time throughout the activity season. Our results confirm that colour change may serve a thermoregulatory function, and competing thermoregulation and signalling requirements may be met by partitioning colour change to different body regions in different circumstances.
History
Journal
Proceedings of the Royal Society B: biological sciencesVolume
283Issue
1832Pagination
1 - 9Publisher
The Royal Society PublishingLocation
London, Eng.Publisher DOI
Link to full text
ISSN
0962-8452eISSN
1471-2954Language
engPublication classification
C Journal article; C1 Refereed article in a scholarly journalCopyright notice
2016, The AuthorsUsage metrics
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