Blog
About

0
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Expanding the eggshell colour gamut: uroerythrin and bilirubin from tinamou ( Tinamidae) eggshells

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          To date, only two pigments have been identified in avian eggshells: rusty-brown protoporphyrin IX and blue-green biliverdin IXα. Most avian eggshell colours can be produced by a mixture of these two tetrapyrrolic pigments. However, tinamou ( Tinamidae) eggshells display colours not easily rationalised by combination of these two pigments alone, suggesting the presence of other pigments. Here, through extraction, derivatization, spectroscopy, chromatography, and mass spectrometry, we identify two novel eggshell pigments: yellow–brown tetrapyrrolic bilirubin from the guacamole-green eggshells of Eudromia elegans, and red–orange tripyrrolic uroerythrin from the purplish-brown eggshells of Nothura maculosa. Both pigments are known porphyrin catabolites and are found in the eggshells in conjunction with biliverdin IXα. A colour mixing model using the new pigments and biliverdin reproduces the respective eggshell colours. These discoveries expand our understanding of how eggshell colour diversity is achieved. We suggest that the ability of these pigments to photo-degrade may have an adaptive value for the tinamous.

          Related collections

          Most cited references 52

          • Record: found
          • Abstract: found
          • Article: not found

          The evolution of egg colour and patterning in birds.

           R Kilner (2006)
          Avian eggs differ so much in their colour and patterning from species to species that any attempt to account for this diversity might initially seem doomed to failure. Here I present a critical review of the literature which, when combined with the results of some comparative analyses, suggests that just a few selective agents can explain much of the variation in egg appearance. Ancestrally, bird eggs were probably white and immaculate. Ancient diversification in nest location, and hence in the clutch's vulnerability to attack by predators, can explain basic differences between bird families in egg appearance. The ancestral white egg has been retained by species whose nests are safe from attack by predators, while those that have moved to a more vulnerable nest site are now more likely to lay brown eggs, covered in speckles, just as Wallace hypothesized more than a century ago. Even blue eggs might be cryptic in a subset of nests built in vegetation. It is possible that some species have subsequently turned these ancient adaptations to new functions, for example to signal female quality, to protect eggs from damaging solar radiation, or to add structural strength to shells when calcium is in short supply. The threat of predation, together with the use of varying nest sites, appears to have increased the diversity of egg colouring seen among species within families, and among clutches within species. Brood parasites and their hosts have probably secondarily influenced the diversity of egg appearance. Each drives the evolution of the other's egg colour and patterning, as hosts attempt to avoid exploitation by rejecting odd-looking eggs from their nests, and parasites attempt to outwit their hosts by laying eggs that will escape detection. This co-evolutionary arms race has increased variation in egg appearance both within and between species, in parasites and in hosts, sometimes resulting in the evolution of egg colour polymorphisms. It has also reduced variation in egg appearance within host clutches, although the benefit thus gained by hosts is not clear.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Pattern mimicry of host eggs by the common cuckoo, as seen through a bird's eye.

            Cuckoo-host interactions provide classical examples of coevolution. Cuckoos place hosts under selection to detect and reject foreign eggs, while host defences result in the evolution of host-egg mimicry in cuckoos. Despite a long history of research, egg pattern mimicry has never been objectively quantified, and so its coevolution with host defences has not been properly assessed. Here, we use digital image analysis and modelling of avian vision to quantify the level of pattern mimicry in eight host species of the common cuckoo Cuculus canorus and their respective cuckoo host-races. We measure a range of pattern attributes, including marking size, diversity in size, contrast, coverage and dispersion. This new technique reveals hitherto unnoticed sophistication in egg pattern mimicry. We show that various features of host egg pattern are mimicked by the eggs of their respective cuckoo host-races, and that cuckoos have evolved better pattern mimicry for host species that exhibit stronger egg rejection. Pattern differs relatively more between eggs of different host species than between their respective cuckoo host-races. We suggest that cuckoos may have more 'average' markings in order to be able to use subsidiary hosts. Our study sheds new light on cuckoo-host coevolution and illustrates a new technique for quantifying animal markings with respect to the relevant animal visual system.
              Bookmark
              • Record: found
              • Abstract: not found
              • Article: not found

              Why are birds’ eggs speckled?

                Bookmark

                Author and article information

                Contributors
                c.bruckner@uconn.edu
                Journal
                Sci Rep
                Sci Rep
                Scientific Reports
                Nature Publishing Group UK (London )
                2045-2322
                9 July 2020
                9 July 2020
                2020
                : 10
                Affiliations
                [1 ]ISNI 0000 0001 0860 4915, GRID grid.63054.34, Department of Chemistry, , University of Connecticut, ; Unit 3060, Storrs, CT 06269-3060 USA
                [2 ]GRID grid.259180.7, Department of Biology and Environmental Sciences, , Long Island University - Post, ; Brookville, NY 11548 USA
                [3 ]ISNI 0000000419368710, GRID grid.47100.32, Department of Ecology and Evolutionary Biology, Peabody Museum of Natural History, , Yale University, ; New Haven, CT 06520-8105 USA
                Article
                68070
                10.1038/s41598-020-68070-7
                7347609
                © The Author(s) 2020

                Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

                Funding
                Funded by: FundRef http://dx.doi.org/10.13039/100000001, National Science Foundation;
                Award ID: HRD-1400382
                Award ID: CHE-1800361
                Award Recipient :
                Categories
                Article
                Custom metadata
                © The Author(s) 2020

                Uncategorized

                structure elucidation, chemical modification, animal physiology, biosynthesis

                Comments

                Comment on this article