A trade-off between two resource-demanding functions: post-nuptial moult and immunity during reproduction in male pied flycatchers

摘要: Summary 1 Costs of reproduction might be mediated by a resource-allocation trade-off between immunity and reproductive effort. Recent studies have suggested that the moult–breeding overlap observed mainly in males may affect this trade-off. In order to test whether increased investment onset moult or output species with overlap, we immunized breeding male pied flycatchers Ficedula hypoleuca (Pallas) non-pathogenic antigen (sheep red blood cells) first week post-hatching compared their score, parental effort success shortly before fledging control injected sterile phosphate-buffered saline. 2 Immunized provisioning nestlings delayed post-nuptial primary males. The experimental activation immune defence affected stress levels (heterophile/lymphocyte ratio, heat-shock proteins) on day 13 after chicks hatched. An activated response tended depress output, although design was not efficient enough find significant effect because manipulation performed early nestling period. 3 The results suggest males’ system decreased resources necessary for initiating moult. imply costs cases infection interact immunosuppression overlap. Moult, are locked three-way interaction which markedly avian life histories.