Elevated parental reproductive effort decreases immune function in Brown skua (Stercorarius antarcticus) and affects chicks development

IBÁÑEZ, A.E.; GRAÑA GRILLI, M.; FIGUEROA, A.; PARI, M.; MONTALTI, D.

Jornada; XVIII Jornadas Anuales Multidisciplinarias Sociedad Argentina de Biología; 2016

In birds, feeding and caring for chicks have been assumed to be the costliest of the reproductive phases. Life-history theory predicts that increased reproductive effort should lead to a fitness cost and that this cost may be caused by a temporal decrease of body condition and suppression of immune function in hard-working individuals. Brown skuas show a different behaviour during breeding, being males more active in the maintenance of the nest. We used hematological values to assess the nutritional and health status in adult Brown skuas during breeding and its effect on offsprings, in order to understand the physiological background responsible for the trade off between reproductive effort, nutritional and health status. Blood samples were obtained in three different moments from adults: In (incubation), Pi (after egg hatching) and Pii (during chick rearing), and only during Pi and Pii from chicks. Total proteins, serum globulins, A:G ratio, IgY and electrolytes (Na, K, Cl and phophorus) levels were determined. Differences in total proteins, uric acid, IgY and γ-globulin fraction levels were observed in adult males and females through the reproductive stages. In addition, nutritional and immunological consequences (decrease of γ-globulin fraction) were observed in growing chicks. These results indicate that there is a close relationship between the reproductive effort performed by adults in particular by males-, the decrease in body condition during these stages and the health status of the offsprings during development.