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The Function of Anal Fin Egg-Spots in the Cichlid Fish Astatotilapia burtoni

Color and pigmentation patterns of animals are often targets of sexual selection because of their role in communication. Although conspicuous male traits are typically implicated with intersexual selection, there are examples where sex-specific displays play a role in an intrasexual context, e.g. wh...

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Detalles Bibliográficos
Autores principales: Theis, Anya, Salzburger, Walter, Egger, Bernd
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3252332/
https://www.ncbi.nlm.nih.gov/pubmed/22242184
http://dx.doi.org/10.1371/journal.pone.0029878
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author Theis, Anya
Salzburger, Walter
Egger, Bernd
author_facet Theis, Anya
Salzburger, Walter
Egger, Bernd
author_sort Theis, Anya
collection PubMed
description Color and pigmentation patterns of animals are often targets of sexual selection because of their role in communication. Although conspicuous male traits are typically implicated with intersexual selection, there are examples where sex-specific displays play a role in an intrasexual context, e.g. when they serve as signals for aggression level and/or status. Here, we focus on the function of a conspicuous male ornament in the most species-rich tribe of cichlid fishes, the haplochromines. A characteristic feature of these ca. 1500 species are so-called egg-spots in form of ovoid markings on the anal fins of males, which are made up of carotenoid based pigment cells. It has long been assumed that these yellow, orange or reddish egg-spots play an important role in the courtship and spawning behavior of these maternal mouth-brooding fishes by mimicking the eggs of a conspecific female. The exact function of egg-spots remains unknown, however, and there are several hypotheses about their mode of action. To uncover the function of this cichlid-specific male ornament, we used female mate choice experiments and a male aggression test in the haplochromine species Astatotilapia burtoni. We manipulated the number and arrangement of egg-spots on the anal fins of males, or removed them entirely, and tested (1) female preference with visual contact only using egg-traps, (2) female preference with free contact using paternity testing with microsatellites and (3) male aggression. We found that females did not prefer males with many egg-spots over males with fewer egg-spots and that females tended to prefer males without egg-spots over males with egg-spots. Importantly, males without egg-spots sired clutches with the same fertilization rate as males with egg-spots. In male aggression trials, however, males with fewer egg-spots received significantly more attacks, suggesting that egg-spots are an important signal in intrasexual communication.
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spelling pubmed-32523322012-01-12 The Function of Anal Fin Egg-Spots in the Cichlid Fish Astatotilapia burtoni Theis, Anya Salzburger, Walter Egger, Bernd PLoS One Research Article Color and pigmentation patterns of animals are often targets of sexual selection because of their role in communication. Although conspicuous male traits are typically implicated with intersexual selection, there are examples where sex-specific displays play a role in an intrasexual context, e.g. when they serve as signals for aggression level and/or status. Here, we focus on the function of a conspicuous male ornament in the most species-rich tribe of cichlid fishes, the haplochromines. A characteristic feature of these ca. 1500 species are so-called egg-spots in form of ovoid markings on the anal fins of males, which are made up of carotenoid based pigment cells. It has long been assumed that these yellow, orange or reddish egg-spots play an important role in the courtship and spawning behavior of these maternal mouth-brooding fishes by mimicking the eggs of a conspecific female. The exact function of egg-spots remains unknown, however, and there are several hypotheses about their mode of action. To uncover the function of this cichlid-specific male ornament, we used female mate choice experiments and a male aggression test in the haplochromine species Astatotilapia burtoni. We manipulated the number and arrangement of egg-spots on the anal fins of males, or removed them entirely, and tested (1) female preference with visual contact only using egg-traps, (2) female preference with free contact using paternity testing with microsatellites and (3) male aggression. We found that females did not prefer males with many egg-spots over males with fewer egg-spots and that females tended to prefer males without egg-spots over males with egg-spots. Importantly, males without egg-spots sired clutches with the same fertilization rate as males with egg-spots. In male aggression trials, however, males with fewer egg-spots received significantly more attacks, suggesting that egg-spots are an important signal in intrasexual communication. Public Library of Science 2012-01-05 /pmc/articles/PMC3252332/ /pubmed/22242184 http://dx.doi.org/10.1371/journal.pone.0029878 Text en Theis et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Theis, Anya
Salzburger, Walter
Egger, Bernd
The Function of Anal Fin Egg-Spots in the Cichlid Fish Astatotilapia burtoni
title The Function of Anal Fin Egg-Spots in the Cichlid Fish Astatotilapia burtoni
title_full The Function of Anal Fin Egg-Spots in the Cichlid Fish Astatotilapia burtoni
title_fullStr The Function of Anal Fin Egg-Spots in the Cichlid Fish Astatotilapia burtoni
title_full_unstemmed The Function of Anal Fin Egg-Spots in the Cichlid Fish Astatotilapia burtoni
title_short The Function of Anal Fin Egg-Spots in the Cichlid Fish Astatotilapia burtoni
title_sort function of anal fin egg-spots in the cichlid fish astatotilapia burtoni
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3252332/
https://www.ncbi.nlm.nih.gov/pubmed/22242184
http://dx.doi.org/10.1371/journal.pone.0029878
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