An indicator of maternal stress is correlated with nestling growth in pied flycatchers Ficedula hypoleuca

Abstract:

Reproductive success is frequently associated with factors such as hatching date, presence of ectoparasites or maternal age. Seldom is the stress of parents considered as an important determinant of offspring size and condition. In a population of pied flycatchers Ficedula hypoleuca breeding in a montane area of central Spain, we estimated fledging success as well as measured offspring size and condition in order to evaluate crucial determinants of reproductive success. We also measured the cell-mediated immunocompetence of 12-day old nestlings with the phytohemagglutinin injection assay. Maternal stress was estimated through the heterophil/lymphocyte ratio (H/L ratio) obtained from leukocyte counts in blood smears. Infection by Haemoproteus balmorali and Trypanosoma spp. was also obtained from blood smears. The prevalence and intensity of infestation of nests by mites Dermanyssus gallinoides and fly larvae Protocalliphora azurae were used as estimates of ectoparasitism. Maternal H/L was not significantly related to the presence of mites or infection by haematozoa, while it was positively associated with provisioning rates at the nest and negatively with presence of fly larvae. We examined fledging success and measures of offspring fitness in relation to hatching date, brood size, number of Protocalliphora larvae, presence of mites and maternal age and stress. Fledgling mass and wing length were significantly negatively correlated with maternal H/L ratio and presence of mites, while tarsus length was significantly negatively associated with mite prevalence. The other factors had no significant effects. The models explained 33–40 …

Año de publicación:

2002

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