Pathways to elaboration of sexual dimorphism in bird plumage patterns

Abstract

Patterns, such as bars and spots, are common in birds. Some patterns can function in camouflage and/or communication and can benefit both males and females, paving the way for elaboration in sexual dimorphism. Historically, sexual dichromatism was predominantly considered to be a consequence of mating systems. However, the distribution of traits between the sexes is not always indicative of function; genetic correlation may cause traits to evolve in both sexes and traits may serve a social function in males and/or females. In addition, sexual dichromatism in bird plumage patterns can be composed of multiple types of patterns within and/or between the sexes. Therefore, there can be more than one type of dimorphism and some are more elaborate than others. Under classical models of genetic correlation, patterns evolve in both sexes followed by a loss of patterning in one sex. Elaborate types of sexual dimorphism in plumage patterns may be due to selection acting on existing patterns and are perhaps derived. Waterfowl (Anseriformes) and gamebirds (Galliformes) arguably have the most striking plumage patterns. Using 288 species from these orders I reconstructed the evolutionary history of plumage pattern dimorphism. There was little support for genetic correlation but elaborate types of dimorphism are probably derived. Backward and forward evolutionary transitions between different types of dimorphism can occur by loss or elaboration. These results demonstrate that plumage patterns are evolutionary labile and current forms may represent shifting adaptations to a changing environment. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111, 262–273.

Reduced sexual dichromatism, mutual ornamentation, and individual quality in the monogamous Zenaida dove Zenaida aurita

“…Alternatively, similarity in plumage coloration between the two sexes might simply be a genetically correlated response in one sex, male or female, to selection in the other sex (Lande , Roulin and Jensen , but see Gluckman ). In such a case, one would expect to observe a negative relationship between fitness and the intensity of plumage coloration in one sex and a positive one in the other one (Fitzpatrick et al , Roulin et al ), if color entails production or maintenance costs, which may be the case with iridescent colors (Dyck , Eliason and Shawkey , Meadows et al ).…”

A new Early Cretaceous enantiornithine (Aves, Ornithothoraces) from northwestern China with elaborate tail ornamentation

“…observ.). Among modern birds, the most elaborate tail morphologies are phylogenetically derived (Gluckman, 2014); however, Feitianius falls within the large polytomy of basal enantiornithines (Fig. 5), which may suggest that this clade began to experiment with different plumages fairly early in its diversification.…”

“…Although currently enantiornithines do not approach the skeletal diversity encompassed within Neornithes (O'Connor and , the new specimen suggests that the caudal plumages of these archaic birds may have reached levels of complexity comparable to those of extant taxa. This is unsurprising considering a recent study that suggested that plumage is highly evolutionarily labile, as inferred from the number of times that exaggerated features have independently evolved among closely related modern birds (Gluckman, 2014). The O'Connor et al-New enantiornithine Feitianius (e1054035-10) diversity of ornamental tail morphologies within Enantiornithes, which more closely approaches modern complexity and diversity than does the morphology of the skeleton, strongly suggests that sexual selection was a major driver of the diversification of feather and plumage morphologies during the early evolution of Aves.…”

The evolution of pattern camouflage strategies in waterfowl and game birds

“…, ; Roulin and Ducrest ; Nordeide et al. ; Gluckman ). Given that there is a large body of evidence linking pattern type with function, we focus solely on the type of pattern present in each species regardless of the sex.…”