Spontaneous egg or chick abandonment in energy-depleted king penguins: A role for corticosterone and prolactin?

• Published in: Hormones and behavior 2008, Vol.53 (1), p.51-60
• Main Authors: Groscolas, René, Lacroix, André, Robin, Jean-Patrice
• Format: Article
• Language: English
• Subjects: Analysis of Variance; Animal behavior; Animal reproduction; Animals; Behavioral psychophysiology; Biodiversity; Biodiversity and Ecology; Biological and medical sciences; Birds; Body Composition - physiology; Brooding; Corticosterone; Corticosterone - blood; Egg/chick abandonment; Energy depletion; Energy Metabolism - physiology; Environmental Sciences; Fasting; Fasting - physiology; Fatty Acids, Nonesterified - blood; Female; Fundamental and applied biological sciences. Psychology; Hormones; Hormones and behavior; Incubation; Life Sciences; Male; Marine; Maternal Behavior - physiology; Nesting Behavior - physiology; Nutritional Status - physiology; Paternal Behavior; Populations and Evolution; Prolactin; Prolactin - blood; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Reproduction - physiology; Spheniscidae - physiology; Statistics, Nonparametric; Uric Acid - blood
• ISSN: 0018-506X; 1095-6867
• DOI: 10.1016/j.yhbeh.2007.08.010

Various exogenous or endogenous factors may induce an emergency response in birds, redirecting current activity towards survival. In fasting, breeding penguins, the achievement of a critical energy depletion was suggested to induce egg abandonment and departure to sea for re-feeding. How such a behavioral shift is hormonally controlled remains unknown. The possible involvement of corticosterone and prolactin was examined by characterizing the nutritional and hormonal states of king penguins at egg abandonment. Further, we tested if these states differ according to whether an egg or a chick is abandoned, and according to the timing of breeding. In every case of abandonment, birds were in phase III fasting characterized by accelerated protein catabolism. However, body condition at egg abandonment was lower in early than in late breeders, suggesting that king penguins are willing to tolerate a larger energy depletion when their potential breeding success is high. At egg and chick abandonment, plasma corticosterone levels were, respectively, increased by 2- and 4-fold, whereas plasma prolactin levels were, respectively, depressed by 3- and 1.4-fold. The increase in plasma corticosterone and the decrease in plasma prolactin could be involved in the control of abandonment by, respectively, stimulating the drive to re-feed and diminishing the drive to incubate or brood. The smaller decrease in prolactin levels and the greater increase in corticosterone levels observed at chick vs egg abandonment suggest that, in addition to nutritionally-related stimuli, tactile or audible stimuli from the egg or chick could intervene in the endocrine control of abandonment.