The Amarillo (Girardinichthys multiradiatus) a fish model to study geographic variation in mate recognition systems

• Published in: Journal of fish biology 2003-12, Vol.63 (s1), p.251-252
• Main Authors: Gonzalez-Zuarth, C., Avila, E., Macías Garcia, C.
• Format: Article
• Language: English
• Subjects: Freshwater; Girardinichthys multiradiatus
• ISSN: 0022-1112; 1095-8649
• DOI: 10.1111/j.1095-8649.2003.216be.x

The existence of a species‐specific mate recognition system (MRS) enables a fluid interchange of genes within species, while promoting the evolution of barriers to hybridization across sibling species. This is because MRS's can diverge in allopatry as a consequence of random events such as drift, or because different ecological conditions impose different optima on sexually‐selected characters such as may be part of the MRS’s. As freshwater habitats are frequently fragmented and re‐merged following long‐term climatic changes and river piracy across catchments, there is ample scope for fish populations’ MRS's to diverge in allopatry to the point of generating pre‐mating barriers. Based on former records of population differences in sexually‐dimorphic traits in the Amarillo fish (Girardinichthys multiradiatus), we investigated 1) whether courtship by males is quantifiably different between populations, and 2) whether these differences are due to difference in the way females respond to specific elements of the courtship sequence (thus prompting males to court in a population‐specific style). Using five populations representing the whole of the Amarillo's geographic range, we found that, when confronted to homogametic females, males exhibited substantial and significant differences in the tendency to perform particular courtship patterns, in spite of males form all populations having equal repertoires. We also found that heterogametic courtship neither resembled that of the populations of origin of the male, nor of the female. We infer that the interpretation of the courtship signals is diverging across Amarillo populations, in a manner akin to the evolution of languages in bird songs.