Sexual ornaments, body morphology, and swimming performance in naturally hybridizing swordtails (teleostei: xiphophorus).

Autor: James B Johnson, Danielle C Macedo, Courtney N Passow, Gil G Rosenthal
Jazyk: angličtina
Rok vydání: 2014
Předmět:
Zdroj: PLoS ONE, Vol 9, Iss 10, p e109025 (2014)
Druh dokumentu: article
ISSN: 1932-6203
DOI: 10.1371/journal.pone.0109025
Popis: Determining the costs of sexual ornaments is complicated by the fact that ornaments are often integrated with other, non-sexual traits, making it difficult to dissect the effect of ornaments independent of other aspects of the phenotype. Hybridization can produce reduced phenotypic integration, allowing one to evaluate performance across a broad range of multivariate trait values. Here we assess the relationship between morphology and performance in the swordtails Xiphophorus malinche and X. birchmanni, two naturally-hybridizing fish species that differ extensively in non-sexual as well as sexual traits. We took advantage of novel trait variation in hybrids to determine if sexual ornaments incur a cost in terms of locomotor ability. For both fast-start and endurance swimming, hybrids performed at least as well as the two parental species. The sexually-dimorphic sword did not impair swimming performance per se. Rather, the sword negatively affected performance only when paired with a sub-optimal body shape. Studies seeking to quantify the costs of ornaments should consider that covariance with non-sexual traits may create the spurious appearance of costs.
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