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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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Society perceives the presence of Kramer's parrot worse the more common it becomes

Society perceives the presence of Kramer's parrot worse the more common it becomes

The perceptions of the general public regarding invasive alien species (IAS) are important in the prevention of future invasions and the success of management programmes. A novel visual method was used to investigate the perception of a charismatic IAS, the rose-ringed parakeet, across different stakeholders in Seville, Spain. Respondents were asked to select images of 10 bird species they would like to have present in their surroundings, out of 20 available images, including the parakeet and three other non-natives. This makes the survey easy, fast to take and attractive to potential participants, while prior and potentially biasing information of survey goals is minimised. Although more than 95% of the respondents recognised the parakeet, at least up to family level, only 34.8% selected it. Selection rates were even lower for three other IAS and even more so when the status of non-native species was indicated next to the images, suggesting that a social norm against IAS may be established. To validate this novel visual approach, perception via a traditional questionnaire was also assessed and the results of the two survey methods coincided. Finally parakeet selection differed importantly amongst pre-defined sectors of the public and people who had prior experience with the parakeet selected it less frequently (e.g. farmers, park managers). These results highlight the importance of studying different stakeholders to get the full picture when considering IAS management programmes. This new visual survey method can thus serve as an excellent and user-friendly tool to study people's perceptions regarding charismatic IAS and facilitate well-informed and sensible decision-making. informacion[at]ebd.csic.es: Luna et al (2019) Assessment of social perception of an invasive parakeet using a novel visual survey method. NeoBiota DOI 10.3897/neobiota.42.31017


https://neobiota.pensoft.net/article/31017/