Variable inter-annual relationships between T-cell mediated immunity and individual traits in White Storks

Aims: The PHA skin-testing technique has become a widespread way of studying the ecological and evolutionary implications of T-cell mediated immunity (CMI) in birds. Several breeding and individual traits have been found to be related to CMI. However, it is not known how consistent these relationships are over the years. A four year study was conducted on the CMI response of White Stork Ciconia ciconia nestlings to evaluate this point.Location: Dehesa de Abajo, Puebla del Rio, Sevilla, Espana.Methods: T-cell mediated immunity was measured by the PHA skin-testing technique in 1999, 2001, 2002, and 2003, as well as seven parental or individual variables for each nestling: laying date, clutch size, brood size, sex, age, brood hierarchy, and body condition.Results: The relationship between CMI and individual traits over the years depended on the studied variable. Some of them, when significantly related, showed a consistent relationship (e.g. body condition), while others did not have any relationship (e.g. age) or even contrary trends (laying date) depending on the year.Conclusions: These results highlight the need of including the temporal scale into ecological immunology for a better understanding of the relationships between CMI and individual traits.

Roger Jovani, Jose Luis Tella, Guillermo Blanco & Marcelo Bertellotti, Ardeola 51(2), 2004, 357-364