Table of Contents
International Journal of Evolutionary Biology
Volume 2012 (2012), Article ID 161306, 12 pages
http://dx.doi.org/10.1155/2012/161306
Research Article

Species-Specific Relationships between Water Transparency and Male Coloration within and between Two Closely Related Lake Victoria Cichlid Species

1Theoretical Biology Group, Centre for Ecological and Evolutionary Studies (CEES), University of Groningen, P.O. Box 11103, 9700 CC Groningen, The Netherlands
2Department of Fish Ecology and Evolution, Eawag Centre of Ecology, Evolution and Biogeochemistry, Seestraße 79, 6047 Kastanienbaum, Switzerland
3Department of Aquatic Ecology, Institute of Ecology and Evolution, University of Bern, Baltzerstraße 6, CH-3012 Bern, Switzerland
4Sylvius Laboratory, Behavioural Biology, IBL, Leiden University, P.O. Box 9505, 2300 RA Leiden, The Netherlands
5Behavioural Biology Group, Centre for Behaviour and Neurosciences, University of Groningen, P.O. Box 11103, 9700 CC Groningen, The Netherlands

Received 20 January 2012; Revised 28 March 2012; Accepted 12 April 2012

Academic Editor: Kristina M. Sefc

Copyright © 2012 Ruth F. Castillo Cajas et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Environmental variation in signalling conditions affects animal communication traits, with possible consequences for sexual selection and reproductive isolation. Using spectrophotometry, we studied how male coloration within and between populations of two closely related Lake Victoria cichlid species (Pundamilia pundamilia and P. nyererei) covaries with water transparency. Focusing on coloration patches implicated in sexual selection, we predicted that in clear waters, with broad-spectrum light, (1) colours should become more saturated and (2) shift in hue away from the dominant ambient wavelengths, compared to more turbid waters. We found support for these predictions for the red and yellow coloration of P. nyererei but not the blue coloration of P. pundamilia. This may be explained by the species difference in depth distribution, which generates a steeper gradient in visual conditions for P. nyererei compared to P. pundamilia. Alternatively, the importance of male coloration in intraspecific sexual selection may differ between the species. We also found that anal fin spots, that is, the orange spots on male haplochromine anal fins that presumably mimic eggs, covaried with water transparency in a similar way for both species. This is in contrast to the other body regions studied and suggests that, while indeed functioning as signals, these spots may not play a role in species differentiation.