Sex-specific vulnerability to breeding conditions in chicks of the sexually monomorphic Gull-billed Tern

摘要: Environmental conditions during early development may differentially affect male and female offspring, the effects of this sex–environment interaction in chick performance be exaggerated under harsh conditions. In birds, most currently available evidence on sex-biased environmental sensitivity nestlings is derived from species that display sexual size dimorphism, while studies monomorphic or slightly dimorphic are less abundant have produced inconsistent results. We evaluated sex-specific vulnerability to breeding chicks Gull-billed Tern (Gelochelidon nilotica), a semiprecocial with only low dimorphism. compared mass growth fledgling physiological condition (measured through plasma metabolite levels) several colonies differed reproductive parameters. Chicks both sexes grew more slowly fledged lower poorer nutritional state colony worst conditions, i.e., later phenology clutch success. Contrary our expectations, rearing was pronounced for than fledglings. While males faster females middle phase regardless colony, difference disappeared fledging period all but where maintained worse males. These results add that, even species, vary way select allocation parental resources sex ratio adjustments specific