News News

Impairment of mixed melanin-based pigmentation in parrots

Parrots and allies (Order Psittaciformes) have evolved an exclusive capacity to synthesize polyene pigments called psittacofulvins at feather follicles, which allows them to produce a striking diversity of pigmentation phenotypes. Melanins are polymers constituting the most abundant pigments in animals, and the sulphurated form (pheomelanin) produces colors that are similar to those produced by psittacofulvins. However, the differential contribution of these pigments to psittaciform phenotypic diversity has not been investigated. Given the color redundancy, and physiological limitations associated to pheomelanin synthesis, this study assumed that the latter would be avoided by psittaciform birds. This hypothesis was tested by using Raman spectroscopy to identify pigments in feathers exhibiting colors suspicious of being produced by pheomelanin (i.e., dull red, yellow and grey- and green-brownish) in 26 species from the three main lineages of Psittaciformes. The non-sulphurated melanin form (eumelanin) were detected in black, grey and brown plumage patches, and psittacofulvins in red, yellow and green patches, but no evidence of pheomelanin was found. As natural melanins are assumed to be composed of eumelanin and pheomelanin in varying ratios, these results represent the first report of impairment of mixed melanin-based pigmentation in animals. Given that psittaciforms also avoid the uptake of circulating carotenoid pigments, these birds seem to have evolved a capacity to avoid functional redundancy between pigments, likely by regulating follicular gene expression. The study provides the first vibrational characterization of different psittacofulvin-based colors and thus helps to determine the relative polyene chain length in these pigments, which is related to their antireductant protection activity. informacion[at]ebd.csic.es: Neves et al (2020) Impairment of mixed melanin-based pigmentation in parrots. J Experim Biol. DOI 10.1242/jeb.225912


https://jeb.biologists.org/content/early/2020/05/08/jeb.225912
Average (0 Votes)

Latest News Latest News

Back

The functional connectivity network of wintering gulls links seven habitat types, acting ricefields as the central node

The functional connectivity network of wintering gulls links seven habitat types, acting ricefields as the central node

The lesser black-backed gull is now the second most abundant wintering waterbird in Andalusian wetlands. Many birds are fitted with GPS loggers on their breeding grounds in northern Europe, and using 42 tagged individuals we studied the connectivity network between different sites and habitats in Andalusia. Thirty seven principal sites (nodes) from seven different habitats (ricefields, landfills, natural lakes, reservoirs, fish ponds, coastal marshes and ports) were identified. By analysing nearly 6,000 gull flights, it was found that Doñana ricefields are the most important node in the network, but that 90% of flights are made between a wetland and a landfill. The 37 nodes are split into 10 functional units (modules) in which gulls tend to fly daily and up to 60 km between a wetland roost site, and a landfill feeding site. This network allows to predict how gulls contribute to seed dispersal, wetland eutrophication, and the spread of pathogens such as antibiotic resistant bacteria. informacion[at]ebd.csic.es: Martín-Vélez et al (2019) Functional connectivity network between terrestrial and aquatic habitats by a generalist waterbird, and implications for biovectoring. Science Total Environm 107: 135886 DOI 10.1016/j.scitotenv.2019.135886


https://www.sciencedirect.com/science/article/pii/S0048969719358814?via%3Dihub#ab0005