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Carotenoid scarcity, synthetic pteridine pigments and the evolution of sexual coloration in guppies (Poecilia reticulata)

Version 2 2024-06-03, 13:16
Version 1 2016-09-02, 16:35
journal contribution
posted on 2024-06-03, 13:16 authored by GF Grether, J Hudon, John EndlerJohn Endler
Carotenoid-based sexual coloration is the classic example of an honest signal of mate quality. Animals cannot synthesize carotenoid pigments and ultimately depend on dietary sources. Thus, in carotenoid-poor environments, carotenoid coloration may be a direct indicator of foraging ability and an indirect indicator of health and vigour. Carotenoid coloration may also be affected, more directly, by parasites in some species. Carotenoids are not, however, the only conspicuous pigments available to animals. Pteridine pigments, with similar spectral properties, are displayed in the exoskeletons and wings of insects, the irides of birds and the skins of fishes, lizards and amphibians. Unlike carotenoids, pteridines are synthesized de novo by animals. We report that the orange spots that male guppies (Poecilia reticulata) display to females contain red pteridine pigments (drosopterins) in addition to carotenoids. We also examined the relationship between drosopterin production by males and carotenoid availability in the field. The results contrasted sharply with the hypothesis that males use drosopterins to compensate for carotenoid scarcity: males used more, not less, drosopterins in streams with higher carotenoid availability. The positive association between drosopterin use and carotenoid availability could reflect the costs of drosopterin synthesis or it could be a consequence of females preferring a particular pigment ratio or hue. Male guppies appear to use drosopterin pigments in a manner that dilutes, but does not eliminate, the indicator value of carotenoid coloration.

History

Journal

Royal Society of London : proceedings B : biological sciences

Volume

268

Pagination

1245-1253

Location

London, Eng.

ISSN

0962-8452

Language

eng

Publication classification

C Journal article, C1.1 Refereed article in a scholarly journal

Copyright notice

2001, The Royal Society

Issue

1473

Publisher

Royal Society Publishing