Projects per year
Abstract
Countershading, the widespread tendency of animals to be darker on the side that receives strongest illumination, has classically been explained as an adaptation for camouflage: obliterating cues to 3D shape and enhancing background matching. However, there have only been two quantitative tests of whether the patterns observed in different species match the optimal shading to obliterate 3D cues, and no tests of whether optimal countershading actually improves concealment or survival. We use a mathematical model of the light field to predict the optimal countershading for concealment that is specific to the light environment, then test this with correspondingly patterned model “caterpillars” exposed to avian predation in the field. We show that the optimal countershading is strongly illumination dependent. A relatively sharp transition in surface patterning from dark to light is only optimal under direct solar illumination; if there is diffuse illumination from cloudy skies or shade, the pattern provides no advantage over homogeneous background-matching coloration. Conversely, a smoother gradation between dark and light is optimal under cloudy skies or shade. The demonstration of these illumination dependent effects of different countershading patterns on predation risk strongly supports the comparative evidence showing that the type of countershading varies with light environment.
Original language | English |
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Pages (from-to) | 13093-13097 |
Number of pages | 5 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 113 |
Issue number | 46 |
Early online date | 2 Nov 2016 |
DOIs | |
Publication status | Published - 15 Nov 2016 |
Keywords
- Camouflage
- Defensive coloration
- Animal coloration
- Shape-from-shading
- Shape perception
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Dive into the research topics of 'Optimizing countershading camouflage'. Together they form a unique fingerprint.Projects
- 1 Finished
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Counter shaded animal patterns: Counter shaded animal patterns: from photons to form
Harris, J. (PI)
12/10/12 → 31/01/16
Project: Standard
Profiles
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Julie Harris
Person: Academic
Datasets
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Data from: Optimizing countershading camouflage
Cuthill , I. (Creator), Sanghera, S. (Creator), Penacchio, O. (Creator), Lovell, P. G. (Creator), Ruxton, G. D. (Creator) & Harris, J. (Creator), Dryad, 18 Nov 2016
DOI: 10.5061/dryad.rd47f
Dataset