The use of artificially coloured stimuli, especially to test hypotheses about sexual selection and anti-predator defence, has been common in behavioural ecology since the pioneering work of Tinbergen. To investigate the effects of colour on animal behaviour, many researchers use paints, markers and dyes to modify existing colours or to add colour to synthetic models. Because colour perception varies widely across species, it is critical to account for the signal receiver's vision when performing colour manipulations. To explore this, we applied 26 typical coloration products to different types of avian feathers. Next, we measured the artificially coloured feathers using two complementary techniques-spectrophotometry and digital ultraviolet-visible photography-and modelled their appearance to mammalian dichromats (ferret, dog), trichromats (honeybee, human) and avian tetrachromats (hummingbird, blue tit). Overall, artificial colours can have dramatic and sometimes unexpected effects on the reflectance properties of feathers, often differing based on feather type. The degree to which an artificial colour differs from the original colour greatly depends on an animal's visual system. 'White' paint to a human is not 'white' to a honeybee or blue tit. Based on our analysis, we offer practical guidelines for reducing the risk of introducing unintended effects when using artificial colours in behavioural experiments.
Bibliographical noteFunding Information:
plementary material. Authors’ contributions. M.C.S., A.E.M., H.N.E. and D.A. conceived and planned the study, collected and analysed the data and produced figures and tables. M.C.S. wrote the manuscript, to which all authors contributed. Competing interests. We declare we have no competing interests. Funding. Funding to M.C.S. was provided by Princeton University and a Sloan Research Fellowship. Acknowledgements. We thank the Editor and three anonymous reviewers for constructive suggestions. We are grateful to Ben Hogan for assistance in creating figures. We also thank members of the Stoddard Laboratory for discussion and feedback.
© 2018 The Author(s) Published by the Royal Society. All rights reserved.
- Animal coloration
- Animal vision
- Artificial stimuli
- Sensory ecology
- Ultraviolet digital photography
ASJC Scopus subject areas
- Biomedical Engineering