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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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Bees not the be-all and end-all to pollination

Bees not the be-all and end-all to pollination

Bees are well-documented as the most effective pollinators of crops world-wide.  However, the contributions by pollinators other than bees play a significant role in crop production and stability in the face of environmental change. "Non-bee" insects such as flies, beetles, moths, butterflies, wasps and ants were researched in 39 different field studies, across five continents to directly measure their pollination services in comparison to bees. Non-bees performed 25–50% of the total number of flower visits. Although non-bees were less effective pollinators than bees per flower visit, they provided slightly more visits; so these two factors compensated for each other resulting in similar pollination services. This paper suggests that both non-bee and bee insects are required for optimal fruit production, the non-bee insects providing a unique benefit to fruit crops.  This research indicates that non-bee insect pollinators play a significant role in global crop production and respond differently than bees to the presence of natural vegetation in the landscape, a finding which has implications for changes in land use. Non-bee insects provide a valuable service and potential insurance against bee population declines. informacion[at]ebd.csic.es: Rader et al (2015) Non-bee insects are important contributors to global crop pollination. PNAS doi: 10.1073/pnas.1517092112


http://www.pnas.org/content/early/2015/11/24/1517092112.abstract