Humoral immunocompetence correlates with date of egg-laying and reflects work load in female tree swallows
Because quality differences between individuals affect fitness, much research has attempted, with limited success, to relate physiological condition (e.g., body reserves), to differences in life history between individuals. Recently, it has been suggested that immunocompetence may reflect condition, and it thus may mediate variation in individual quality and reproductive performance and, ultimatel
