Variation of visual signal coloration has been predicted among closely related species or populations by the sensory drive hypothesis and tested in fishes, reptiles, or birds. However, despite the tremendous diversity of insect colorations and habitat preferences, sensory drive constrained by habitat transmission through different light environments has not been investigated in this group. Here...

BACKGROUND Plumage coloration is important for bird communication, most notably in sexual signalling. Colour is often considered a good quality indicator, and the expression of exaggerated colours may depend on individual condition during moult. After moult, plumage coloration has been deemed fixed due to the fact that feathers are dead structures. Still, many plumage colours change after moult...

The differential allocation hypothesis predicts that females modify their investment in a breeding attempt according to its reproductive value. One prediction of this hypothesis is that females will increase reproductive investment when mated to high-quality males. In birds, it was shown that females can modulate pre-hatch reproductive investment by manipulating egg and clutch sizes and/or the ...

A prey may achieve camouflage through background matching and through disruptive coloration. Background matching is based on visual similarity between the prey and its background, whereas disruptive coloration emphasizes the use of highly contrasting pattern elements at the body outline to break up the body shape of the prey. Another factor that may influence prey detection, but has been little...

BACKGROUND Shell color polymorphisms of Mollusca have contributed to development of evolutionary biology and population genetics, while the genetic bases and molecular mechanisms underlying shell pigmentation are poorly understood. The Pacific oyster (Crassostrea gigas) is one of the most important farmed oysters worldwide. Through successive family selection, four shell color variants (white, ...

Aposematism is one of the great mysteries of evolutionary biology. The evolution of aposematic coloration is poorly understood, but even less understood is the evolution of polymorphism in aposematic signals. Here, we use a phylogeographic approach to investigate the evolution of color polymorphism in Dendrobates pumilio, a well-known poison-dart frog (family Dendrobatidae), which displays perh...

Trade-offs in resource allocation have been widely stated as the means by which the honesty of ornamental traits is maintained, but an alternative to this resource trade-off hypothesis is that production of ornamentation is linked to the biochemical efficiency of vital cellular processes. Carotenoids are antioxidants, potentially tying carotenoid-based coloration to the oxidative state of an or...

It has been suggested that carotenoid-derived coloration serves as an indicator of parasite levels and (or) the general health of birds. We investigated relationships among spleen size (sometimes considered an indicator of the cellular immune response capacity of birds), carotenoid level, helminth load, and leg and bill coloration of greylag geese, Anser anser (L., 1758), from Doñana National P...

The arms race between predators and prey has led to morphological and behavioral adaptations. Different antipredator strategies can coexist within a population if each strategy is the result of a trade-off with competing demands. Antipredator behavior can be associated with morphological traits, like color patterns, either because in the context of sexual selection, coloration signals the abili...

Allocation rules between ornamental and other functional traits of birds may differ among individuals and vary with environmental conditions. We supplemented roller (Coracias garrulus) nestlings with methionine in a between-nest design to investigate the way in which the sex and position in the hatching hierarchy affect the allocation of resources among growth, immunity, and plumage coloration....