Nelson, B.F., Daunt, F., Monaghan, P., Wanless, S., Butler, A., Heidinger, B.J., Newell, M. and Dawson, A.
General and Comparative Endocrinology 210, 38-45. Elsevier, London, UK.
Elsevier, London, UK
Prolactin, Physiology, Parental care, Reproduction, Black-legged kittiwake, Rissa tridactyla
||Determining the physiological mechanisms underpinning life-history decisions is essential for understanding
the constraints under which life-history strategies can evolve. In long-lived species, where
the residual reproductive value of breeders is high, adult survival is a key contributor to lifetime reproductive
success. We therefore expect that when adult survival is compromised during reproduction,
mechanisms will evolve to redirect resources away from reproduction, with implications for reproductive
hormones, adult body mass, nest attendance behaviour and breeding success. We investigated whether
manipulating corticosterone, to simulate exposure to an environmental stressor, affected the secretion of
prolactin and breeding success in the black-legged kittiwake Rissa tridactyla. We used implanted Alzet[symbol]
osmotic pumps to administer corticosterone to incubating kittiwakes at a constant rate over a period of
approximately 8 days. Manipulated birds were compared with sham implanted birds and control birds,
which had no implants. There was no significant difference in the body mass of captured individuals
at the time of implantation and implant removal. Corticosterone-implanted males showed lower nest
attendance during the chick rearing period compared to sham-implanted males; the opposite pattern
was found in females. Corticosterone treated birds showed a marginally significant reduction in breeding
success compared to sham-implanted individuals, with all failures occurring at least 1 week after implant
removal. However, prolactin concentrations at implant removal were not significantly different from
initial values. We were unable to measure the profile of change in corticosterone during the experiment.
However, our results suggest a delayed effect of elevated corticosterone on breeding success rather than
an immediate suppression of prolactin concentrations causing premature failure.