title: Benefits associated with escalated begging behaviour of black-billed magpie nestlings overcompensate the associated energetic costs.
abstract: Several experimental results support the existence of costs associated with exaggerated begging behaviour, which are assumed by some theoretical models of honest signalling in parent-offspring communication. However, to understand how honest begging behaviour is evolutionarily maintained in nature, the long-term cost-benefit output associated with exaggerated signals should also be estimated. As far as we know, the net cost-benefit balance of begging display has not previously been explored. Here, we used an appetite stimulant, cyproheptadine hydrochloride, to increase the feeling of hunger in some magpie nestlings. Supporting the use of cyproheptadine to manipulate hunger level and thereby begging behaviour, we found that experimental nestlings increased the frequency of begging and received more food than their control nestmates. Contrary to the expectation that physiological costs per se counteract the associated benefits of escalated begging signals, we found that near-fledging experimental magpies showed a better physical condition than control nestlings. These findings stress the interesting question of why magpie nestlings do not show to adults an escalated level of hunger if it implies an advantage. We discuss the responsibility of inclusive fitness costs and indirect genetic effects for the maintenance of honesty in parent-offspring communication.
authors.affiliation: Departamento de Ecología Evolutiva y Funcional, Estación Experimental de Zonas Áridas (CSIC), 04120 Almería, Spain. dmartin@eeza.csic.es
authors.forename: David
authors.initials: D
authors.lastname: Martín-Gálvez
authors.forename: Tomás
authors.initials: T
authors.lastname: Pérez-Contreras
authors.forename: Manuel
authors.initials: M
authors.lastname: Soler
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Soler
mesh_terms: D000818:Animals; D003533:Cyproheptadine / Q000494:pharmacology; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology*; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology*; D009425:Nesting Behavior / Q000187:drug effects / Q000502:physiology*; D046109:Passeriformes / Q000502:physiology*; D014741:Video Recording
chemical_list: D003533:Cyproheptadine