Visual habitat geometry predicts relative morph abundance in the colour-polymorphic ornate rainbowfish

Daniel Hancox, Robbie S Wilson, C.R. White

Research output: Contribution to journalArticleResearchpeer-review

6 Citations (Scopus)


During colour signalling in aquatic environments, the colour of the ambient light, the background against which signals are viewed and signal transmission through the environment can all have profound impacts on the efficacy of a given signal. In colour-polymorphic species, where alternative morphs persist owing to a balance in the natural and sexual selection for each, changes to the visual context can have large effects on the local success and relative abundance of competing phenotypes. The ornate rainbowfish, Rhadinocentrus ornatus, is composed of populations that vary in the relative frequency of red and blue individuals, and inhabit sites that vary in water transmittance from clear (white) to heavily tannin-stained (red-shifted). Using spectroradiometry, we measured the downwelling and sidewelling irradiance, bank radiance and water transmittance of 10 R. ornatus habitats. We found that the relative local abundance of each morph was predicted not by water transmittance but by chromatic differences between the vertical (downwelling light) and horizontal (bank colour) components of the habitat. This visual habitat geometry should increase contrast between the colour signal and background, with large potential to influence the strength of natural and sexual selection in this system.
Original languageEnglish
Pages (from-to)1-7
Number of pages7
JournalProceedings of the Royal Society B: Biological Sciences
Issue number1752
Publication statusPublished - 2013
Externally publishedYes


  • Bluefin killifish
  • Colour signalling
  • Guppy
  • Phenotypic divergence
  • Water transmittance

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