Receiver-bias implicated in the nonsexual origin of female mate choice in the pentamorphic fish Poecilia parae Eigenmann, 1894

Receiver-bias hypotheses of signal evolution posit that male sexually selected traits evolve via prior selection for other functions. We found support for the hypothesis that the origin of female choice of mates is a linked effect of a receiver-bias for carotenoid coloration favored in the context of efficient food detection. Adult pentamorphic livebearing fish or pentas (P. parae) nibbled significantly more often at orange, red, and yellow discs than at green, blue, white, and black discs, outside a mating context. This innate attraction to carotenoid colored discs was positively correlated with female preferences for red and yellow melanzona males, and for novel red ornaments in fins of an immaculata male tested against typically uncolored immaculata. Furthermore, preference for carotenoid colored discs was absent in one ancestral taxon, and yet mapped onto a poeciliid phylogeny as ancestral. Overall these results suggest a strong association between a potential trigger of a mate choice preference and a sexually selected trait, thereby corroborating the receiver-bias hypothesis for carotenoid coloration independent and dependent of the assumptions of phylogenetic inference.