Is bill colouration in wild male Blackbirds (Turdus merula) related to biochemistry parameters and parasitism?
Studies of signalling and sexual selection in birds are increasingly focussing on the regulation of the expression of carotenoid-based ornaments. Brighter col- oured ornaments are preferred during mate choice and are thought to signal resistance to parasites, immune capacity and health status. As th...
| Autores: | , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2011 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/44515 |
| Acceso en línea: | http://hdl.handle.net/10261/44515 |
| Access Level: | acceso abierto |
| Palabra clave: | Carotenoids Blackbird Bill Parasites Birds Colouration Health Biochemistry |
| Sumario: | Studies of signalling and sexual selection in birds are increasingly focussing on the regulation of the expression of carotenoid-based ornaments. Brighter col- oured ornaments are preferred during mate choice and are thought to signal resistance to parasites, immune capacity and health status. As the colouration of integuments is a dynamic trait, changes in colouration potentially reflect changes in individual condition. The bill of the male Common Blackbird (or Blackbird, Turdus merula) has become a model for studying the implications of caroten- oid-coloured integuments in birds, and Blackbird bill col- ouration has been found to be related to reproductive ability and immune capacity. However, the relationship between bill colouration and parasites and health in this species remains unclear. We have analysed the association between bill colouration, parasites (blood and intestinal parasites) and health status indicators (standard haemato- logical and plasma biochemistry variables) in free-ranging male Blackbirds during the breeding season. Bill colour- ation was found to be related to body condition, health status, stress and hydration and nutritional status, but the presence or load of the parasite groups studied was not found to be related to bill colouration. Moreover, parasites showed no clear aggregation patterns. Our results suggest that certain physiological constraints—rather than parasite infection—are the main cause of variability in the colour- ation of male Blackbird bills. |
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