Carotenoid availability affects the development of a colour-based mate preference and the sensory bias to which it is genetically linked.
Regardless of their origins, mate preferences should, in theory, be shaped by their benefits in a mating context. Here we show that the female preference for carotenoid colouration in guppies (Poecilia reticulata) exhibits a phenotypically plastic response to carotenoid availability, confirming a key prediction of sexual selection theory. Earlier work indicated that this mate preference is genetically linked to, and may be derived from, a sensory bias that occurs in both sexes: attraction to orange objects. The original function of this sensory bias is unknown, but it may help guppies find orange-coloured fruits in the rainforest streams of Trinidad. We show that the sensory bias also exhibits a phenotypically plastic response to carotenoid availability, but only in females. The sex-specificity of this reaction norm argues against the hypothesis that it evolved in a foraging context. We infer instead that the sensory bias has been modified as a correlated effect of selection on the mate preference. These results provide a new type of support for the hypothesis that mate preferences for sexual characters evolve in response to the benefits of mate choice--the alternatives being that such preferences evolve entirely in a non-mating context or in response to the costs of mating.
Grether
Gregory F
GF
Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA. ggrether@ucla.edu
Kolluru
Gita R
GR
Rodd
F Helen
FH
de la Cerda
Jennifer
J
Shimazaki
Kaori
K
D000704:Analysis of Variance; D000818:Animals; D001824:Body Constitution; D049628:Body Size; D002338:Carotenoids / Q000378:metabolism*; D003118:Color Perception / Q000502:physiology*; D005260:Female; D010858:Pigmentation / Q000502:physiology*; D011036:Poecilia / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D012641:Selection, Genetic; D012737:Sex Factors; D012726:Sexual Behavior, Animal / Q000502:physiology*; D014300:Trinidad and Tobago
D002338:Carotenoids