Conspicuous Coloration in Males of the Damselfly Nehalennia irene Zygoptera: Coenagrionidae: Do Males Signal Their Unprofitability to Other MalesReportar como inadecuado




Conspicuous Coloration in Males of the Damselfly Nehalennia irene Zygoptera: Coenagrionidae: Do Males Signal Their Unprofitability to Other Males - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

In damselflies, sexual colour dimorphism is commonly explained as a consequence of selection on traits that increase male attractiveness to females. However, while many species in the damselfly family Coenagrionidae Insecta: Odonata are sexually dimorphic, the males do not engage in displays, and male competition for mates resembles a -scramble-. An alternative explanation for the sexual differences in coloration within these species is that sexual dimorphism has evolved as a sex-related warning signal, with males signalling their uprofitability as mates to other males, thereby avoiding harassment from conspecifics. We evaluated an underlying assumption of the theory that male-male harassment rate is influenced by colour by comparing harassment of males of the species Nehalennia irene that had been painted to make them appear: i similar to an unaltered male blue, ii different from a male orange and iii more similar to a female black. When caged together we found that blue-painted males experienced significantly lower harassment than black-painted males. When unpainted males were caged with each type of painted male we found that blue-painted males and the unpainted males housed in the same cages experienced lower rates of harassment than males housed in cages where some males were painted black, suggesting that a single, reliable signal of unprofitability may benefit the individuals that carry it. While our results do not in themselves demonstrate that sexual colour dimorphism originally evolved as an intra-specific warning signal, they do show that harassment is influenced by coloration, and that such selection could conceivably maintain male coloration as a warning signal.



Autor: Christopher D. Beatty , José A. Andrés, Thomas N. Sherratt

Fuente: http://plos.srce.hr/



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