Factors affecting plasma concentrations of prolactin in the common eider Somateria mollissima.

摘要: In the common eider only females incubate while they fast for 25 days. Thus, since rely entirely on their body reserves successful incubation, can be defined as capital incubators. To assess potential effects of initial mass, incubation duration, and depletion in prolactinemia, blood samples eiders were analyzed during breeding cycle an experimental manipulation duration incubation. Levels circulating prolactin increased at onset then reached a high stable level before increasing sharply hatching. The decreased significantly upon Captive deprived from eggs exhibited rapid decrease suggesting that egg stimuli are necessary to secretion. Aunts, i.e., helper caring conspecific young, presented levels higher than nonbreeding captive but not different those Plasma hatch was directly related mass loss. Birds with shortened have masses showed prolactinemia hatching control group, accordance idea circulant is linked condition. Females which underwent extended (and started eat again) displayed low prolactinemia. These data therefore suggest refeeding, albeit risk predation, enhances secretion allows bird continue despite it has poor