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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
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Reduced avian diversity in artificial wetlands

Reduced avian diversity in artificial wetlands

Wetlands are one of the most threatened habitats, but they continue to be destroyed and degraded all over the world. In recent years, various studies have argued that artificial wetlands can compensate for the loss of natural ones, and facilitate conservation of waterbirds. In this study waterbird communities are compared in a set of natural, restored and artificial wetlands within the Doñana Natural Space, which are well known for their birds. Several measures of diversity were used, including the phylogenetic relatedness and the proportion of species that were threatened at national or international levels. Whatever the measure of diversity, artificial wetlands were consistently less diverse than restored or natural wetlands, with hardly any differences between the latter two. Natural wetlands are essential for biodiversity conservation, but restored wetlands can have similar value and assure the maintenance of key ecological processes. In conclusion, when costs are similar, resources for wetland conservation are better invested in restoration than in creating new wetlands. Caution is urged when assuming that artificial wetlands can compensate for the loss of natural ones. informacion[at]ebd.csic.es: Sebastián-González & Green (2016) Reduction of avian diversity in created versus natural and restored wetlands. Ecography DOI: 10.1111/ecog.01736


http://onlinelibrary.wiley.com/doi/10.1111/ecog.01736/abstract