Secondary reduction of preference for the sword ornament in the pygmy swordtail Xiphophorus nigrensis (Pisces: Poeciliidae)
نویسندگان
چکیده
Female mating preferences can be secondarily lost for a number of reasons. We examined the preference of female pygmy swordtails, Xiphophorus nigrensis, for the sword, a conspicuous extension of the caudal fin in some males. Females failed to show a preference for conspecific males with swords when presented with live males naturally varying in sword length, with live males of manipulated sword length, and with synthetic animations of males expressing natural variation in sword length. Females showed a significant bias against swords when presented with synthetic animations bearing supernormal sword characteristics. The reduced preference for swords, relative to closely related fish, may result from an increase in the cost of choice due to predation risk, selection against mating with heterospecifics, or changes in the spatial and contrast properties of the conspecific signal.
منابع مشابه
Female preference for swords in Xiphophorus helleri reflects a bias for large apparent size.
Swordtail fish (Poeciliidae: genus Xiphophorus) are a paradigmatic case of sexual selection by sensory exploitation. Female preference for males with a conspicuous "sword" ornament is ancestral, suggesting that male morphology has evolved in response to a preexisting bias. The perceptual mechanisms underlying female mate choice have not been identified, complicating efforts to understand the se...
متن کاملAn organizer controls the development of the "sword," a sexually selected trait in swordtail fish.
Male swordtail fish of the genus Xiphophorus (Poeciliidae) possess a "sword" that is composed of several colored elongated ventral fin rays of the caudal fin. The sword is a secondary sexual trait that evolved through sexual selection by female preference. To uncover the developmental mechanisms underlying the metamorphosis from a juvenile caudal fin to the sword, we have devised a transplantat...
متن کاملFemale preference for swords in Xiphophorus helleri reflects a bias for large apparent size (sexual selectionyvisual signalsypreexisting biasyvideo playbackyPoeciliidae)
Swordtail fish (Poeciliidae: genus Xiphophorus) are a paradigmatic case of sexual selection by sensory exploitation. Female preference for males with a conspicuous ‘‘sword’’ ornament is ancestral, suggesting that male morphology has evolved in response to a preexisting bias. The perceptual mechanisms underlying female mate choice have not been identified, complicating efforts to understand the ...
متن کاملFemale disdain for swords in a swordtail fish.
Studies of mate choice evolution tend to focus on how female mating preferences are acquired and how they select for greater elaboration of male traits. By contrast, far less is known about how female preferences might be lost or reversed. In swordtail fish Xiphophorus, female preference for the sword ornament is an ancestral trait. Xiphophorus birchmanni, however, is one species that has secon...
متن کاملAsymmetries in mating preferences between species: female swordtails prefer heterospecific males.
In male swordtails ((Xiphophorus nigrensis)) there are three size classes that derive from allelic variation at the pituitary locus on the Y chromosome. Progeny analysis and preference tests suggest that females prefer to mate with larger males. In the closely related X. pygmaeus, there is no allelic variation at this locus; this species consists of males similar in size only to smaller X. nigr...
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