An immune challenge induces a decline in parental effort and compensation by the mate.

Immune defense is fundamental to diminish the negative effects of the attack of infectious agents, yet the activation of the immune system entails costs and may compromise other life-history traits such as reproduction. In reproductive brown booby pairs (), we experimentally imposed an immune challenge during incubation, by intraperitoneally injecting lipopolysaccharide (LPS), in either the male or the female. We aimed to test whether activation of the immune response results in (1) an increase in oxidative stress parameters, (2) a decline in post-hatching parental care in the treated individual, and (3) a compensation of the post-hatching parental effort by the nontreated mate.

Carotenoid-based skin ornaments reflect foraging propensity in a seabird, .

Carotenoid-based ornaments are common signalling features in animals. It has long been proposed that such ornaments communicate information about foraging abilities to potential mates. However, evidence linking foraging with ornamentation is largely missing from unmanipulated, free-ranging populations.