Affiliation:
1. University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA
Abstract
SUMMARY
Recent advances in portable spectrophotometers have allowed researchers to collect quantitative, objective data on colour. There are few comparisons of the different methods used to summarize and analyse spectrophotometer data,however. Using colour data on over 900 species of birds, we compared three methods of calculating sexual dichromatism using spectrophotometer data. We also compared sexual dichromatism calculated from spectrophotometer data, in both the ultraviolet (UV) and bird-visible range, with human estimates of sexual dichromatism. We found that all three methods, principal component analysis, segment classification and colour discriminability, yielded essentially comparable estimates of dichromatism for our extensive sample of birds. Certain methods may be better suited to a particular study depending on the questions addressed and the specific colours examined. We found that human visual estimates of dichromatism were similar to spectrophotometer estimates of dichromatism in the bird-visible range; however, human visual estimates did not predict the extent of UV dichromatism. Therefore, the conclusions of previous studies that relied on human vision to assess sexual dichromatism should be reliable. It is not possible, however, to predict a prioriwhether a species exhibits UV dichromatism without spectrophotometer measurements.
Publisher
The Company of Biologists
Subject
Insect Science,Molecular Biology,Animal Science and Zoology,Aquatic Science,Physiology,Ecology, Evolution, Behavior and Systematics
Reference46 articles.
1. Andersson, S. and Prager, M. (2006). Quantifying colours. In Bird Coloration. Vol.1 (ed. G. E. Hill and K. J. McGraw), pp.41-89. Cambridge, MA.: Harvard University Press.
2. Andersson, S., Ornborg, J. and Andersson, M.(1998). Ultraviolet sexual dimorphism and assortative mating in blue tits. Proc. R. Soc. Lond. B265,445-450.
3. Armenta, J. K., Dunn, P. O. and Whittingham, L. A.(2008). Effects of specimen age on plumage color. Auk. (in press).
4. Badyaev, A. V. and Hill, G. E. (2003). Avian sexual dichromatism in relation to history and current selection. Annu. Rev. Ecol. Syst.34, 27-49.
5. Bennett, A. and Cuthill, I. C. (1994). Ultraviolet vision in birds: what is its function? Vision Res.34,1471-1478.
Cited by
63 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献