Exploitation of host mechanism for parental care by avian brood parasites
Parasitic birds and their hosts engage in a coevolutionary arms race in which hosts have evolved fine egg disenmination that has in turn selected for sophisticated egg mimicry in many parasites. Paradoxically, however, very few have evolved chick mimicry. This has been traditionally interpreted as e...
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 1993 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/36748 |
| Acceso en línea: | http://hdl.handle.net/10261/36748 |
| Access Level: | acceso abierto |
| Palabra clave: | Brood parasitism Parental care Evolution Reproduction Ayes |
| Sumario: | Parasitic birds and their hosts engage in a coevolutionary arms race in which hosts have evolved fine egg disenmination that has in turn selected for sophisticated egg mimicry in many parasites. Paradoxically, however, very few have evolved chick mimicry. This has been traditionally interpreted as evidence that hosts fail to discriminate between chicks baus of the existence of an evolutionary lag or equilibrium (costs) in the host-parasite arms race. Here, I show that none of these hypotheses can satisfactorily explain the nearly total lack of chick mimicry. Alternatively, parasitic chicks may be highly constrained to evolve mimicry of host young when both belong to phylogenetically-distant taxa with very different developmental pathways. Data on genomic divergence from DNA hybridization studies support this possibility. I suggest that nonmimetic parasites prevent rejection by exploiting a set of “imperfect’ behavioural mechanisms in hosts. First, perceptual and developmental constraints, among other factors, limit the efficiency of chick-recognition mechanisms, particularly prior to fledging. The scarce evidence available on chick discrimimition across different bird groups is consistent with this assumption. Second, nonmimctic parasites might evolve manipulative signals that elicit preferential care by hosts to compensate for their odd appearance, in order to decouple the recognition and rejection mechanisms. Some experimental and observational data suggest that hosts may favour parasitic chicks over conspecific young of similar characteristics. Thus, unless we take into consideration the proximate mechanisms involved, it will not be possible to obtain a comprehensive view of this problem from an evolutionary |
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