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| 5. |
- Andersson, Staffan, 1959, et al.
(författare)
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Quantifying Colors
- 2006
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Ingår i: Bird Coloration, Vol. 1: Mechanisms and measurements (Hill GE & McGraw KJ, eds). - Cambridge, USA : Harvard University Press. - 9780674018938 ; , s. 41-89
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Isaksson, Caroline, 1976, et al.
(författare)
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Sex and age differences in reflectance and biochemistry of carotenoid-based colour variation in the great tit Parus major
- 2008
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Ingår i: Biological Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4066 .- 1095-8312. ; 95:4, s. 758-765
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Tidskriftsartikel (refereegranskat)abstract
- The plumage coloration in great tits (Parus major) is the subject of much behavioural and ecophysiological research, yet there is a lack of analyses of the natural colour variation and its mechanisms. We used reflectance spectrometry and high-performance liquid chromatography to explore individual, sexual and age-related variation in carotenoid coloration and pigmentation, paramount to the often presumed, but rarely substantiated, costs and 'honesty' of carotenoid displays. In adults, we found that sex was the strongest predictor of 'brightness' (higher in males) and of 'hue' (longer wavelength in females). There was no sex difference in 'carotenoid chroma' or carotenoid content of feathers which also was unrelated to adult age (1 or 2+ years) and condition. Similar patterns were revealed for nestlings. Regarding the biochemical 'signal content', 'carotenoid chroma', but not 'hue', was significantly related to the carotenoid content (lutein and zeaxanthin) of feathers. These results refute the previously assumed exaggeration of carotenoid pigmentation in male great tits, and question the condition-dependence of carotenoid coloration in this species. However, the sexual dimorphism in total reflectance or 'brightness', most likely due to melanins rather than carotenoids, may have implications for signalling or other adaptive explanations that need to be explored.
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| 7. |
- Kullman, Lars, 1974, et al.
(författare)
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Universitetsrankning
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)
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| 8. |
- Minguillo Brehaut, David, 1981, et al.
(författare)
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Universitetsrankning: Rapport 2014
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med rankningsrapporten är att ge en djup inblick i Chalmers prestation under det senaste året i de tre stora internationella rankinglistorna THE, QS, ARWU (Shanghai), samt CWTS (Leiden) som enbart fokuserar på bibliometriska mått. Chalmers placeringsmässiga prestation i 2014 varierade beroende på listornas olika aggregat på multidimensionella parametrar. Däremot uppvisar vår samlade bild av medelmåttiga och lågrankade placeringar att det behövs extra insatser och förbättringar för att bli placerad bland elitgruppen i Europa.THE visar en oförändrad prestation (från plats 277 till 276) som resultat av fortsatt begränsade forskningsgenomslag och blygsamt internationellt anseende. Den mest oroväckande trenden ligger inom citeringar där vi har kontinuerligt sjunkit de senaste tre åren och ligger på plats 380 av 400. Till nästa år blir dock det svårt att förutse Chalmers utveckling eftersom THE ska börja använda Scopus citeringsdata. QS listan rankar Chalmers som 175. En markant förbättring med 27 placeringar baserad på högre akademiskt anseende och ökad lärartäthet. Denna positiva trend förstärker den fortsatta förbättringen av industriellt anseende sedan 2012 vilket tyder på goda förutsättningar och möjligheter att närma sig topp 150 de närmaste åren. I elitinriktade listan ARWU får vi vår sämsta placering (349). Nedgången med 49 placeringar är orsakat av en metodologisk ändring där listan Highly Cited Researchers håller på att bli ersatt. Att inga Chalmersforskare finns på den nya listan ska leda till en fortsatt nedgång till 2015 och risken att hamna i bottenblocket är stor. Förutom vår andraplats i fråga om andel samförfattarskap med industrin, tydliggör den bibliometriska listan (CWTS Leiden) att vår nuvarande forskningsmiljö och produktionstakt inte är tillräcklig anpassad för att klara konkurrensen på en alltmer prestationsbaserad internationell arena. Vi har sjunkit cirka 100 placeringar bland citeringsbaserade indikatorer och därmed blir forskningsverksamheten Chalmers svagaste gren. Förväntningarna till nästa år är negativa. Utifrån Chalmers tre övergripande mål blir nyttiggörande (genom samförfattarskap, anseende, intäkter) vår starkaste gren, följd av utbildning tack vare sina senaste positiva trender och bidrag till en poängmässig ökning de senaste åren. Låg prestation bland indikatorer inom excellent forskning tyder dock att omfattande förändringar är nödvändiga för att förstärka vår konkurrenskraft internationellt.
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| 9. |
- Nilsson, R. Henrik, 1976, et al.
(författare)
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Introducing guidelines for publishing DNA-derived occurrence data through biodiversity data platforms
- 2022
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Ingår i: Metabarcoding and Metagenomics. - : Pensoft Publishers. - 2534-9708. ; 6, s. 239-244
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Tidskriftsartikel (refereegranskat)abstract
- DNA sequencing efforts of environmental and other biological samples disclose unprecedented and largely untapped opportunities for advances in the taxonomy, ecology, and geographical distributions of our living world. To realise this potential, DNA-derived occurrence data (notably sequences with dates and coordinates) – much like traditional specimens and observations – need to be discoverable and interpretable through biodiversity data platforms. The Global Biodiversity Information Facility (GBIF) recently headed a community effort to assemble a set of guidelines for publishing DNA-derived data. These guidelines target the principles and approaches of exposing DNA-derived occurrence data in the context of broader biodiversity data. They cover a choice of terms using a controlled vocabulary, common pitfalls, and good practices, without going into platform-specific details. Our hope is that they will benefit anyone interested in better exposure of DNA-derived occurrence data through general biodiversity data platforms, including national biodiversity portals. This paper provides a brief rationale and an overview of the guidelines, an up-to-date version of which is maintained at https://doi.org/10.35035/doc-vf1a-nr22. User feedback and interaction are encouraged as new techniques and best practices emerge.
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| 10. |
- Pointer, M. A., et al.
(författare)
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A novel method for screening a vertebrate transcriptome for genes involved in carotenoid binding and metabolism
- 2012
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Ingår i: Molecular Ecology Resources. - : Wiley. - 1755-098X .- 1755-0998. ; 12:1, s. 149-159
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Tidskriftsartikel (refereegranskat)abstract
- Carotenoid-based colour signals are widespread in the animal kingdom and common textbook examples of sexually selected traits. Carotenoid pigments must be obtained through the diet as all animals lack the enzymatic machinery necessary to synthesize them from scratch. Once ingested, carotenoids are metabolized, stored, transported and deposited, and some or all of these processes may be limiting for signal production and thus subjected to social or sexual selection on phenotypic coloration. Very little is known about which genes and physiological pathways are involved in carotenoid pigmentation which is unfortunate, as genetic information would allow us to investigate the biochemical consequences of sexual selection. In this study, we present a transcriptome-screening technique and apply it to a carotenoid-signalling bird species, the southern red bishop Euplectes orix, to uncover the gene(s) responsible for the conversion of dietary beta-carotene (orange) to canthaxanthin (bright red). The transcriptome, extracted from the liver of a male entering his breeding moult, is expressed within bacterial cells genetically modified to synthesize beta-carotene. Effects of expressed E. orix proteins on the structure or amount of beta-carotene are initially detected by eye (based on colour change) and subsequently confirmed by high-performance liquid chromatography. Here, we demonstrate the validity of the technique and provide a list of candidate genes involved in the carotenoid pigmentation pathway. We believe that this method could be applied to other species and tissues and that this may help researchers uncover the genetic basis of carotenoid coloration in vertebrates.
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| 11. |
- Prager, Maria, 1973, et al.
(författare)
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A molecular phylogeny of the African widowbirds and bishops, Euplectes spp. (Aves: Passeridae: Ploceinae)
- 2008
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Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 46:1, s. 290-302
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Tidskriftsartikel (refereegranskat)abstract
- The elaborate male displays and plumage ornaments in the African widowbirds and bishops (Euplectes spp.) have inspired classic studies on mating systems and sexual selection. In order to study the extreme divergence in ornament design and expression in this group, we present and discuss a well-supported molecular phylogeny of the genus and its placement within the Ploceinae subfamily. Parsimony and Bayesian analyses were performed on 2557 bp of mitochondrial DNA (ATP6, Cyt b, ND2 and ND3) and a nuclear intron (G3PDH). All 17 Euplectes species, and 31 of 51 suggested subspecies, were included, as well as eight Ploceinae outgroups from four genera (Amblyospiza, Ploceus, Quelea and Foudia). Our results show monophyly of Euplectes, but not of the intrageneric groupings of bishops and widowbirds. Most notably, the Red-collared Widowbird E. ardens belongs to a subclade of bishops, and not to the sister subclade of ‘true’ widowbirds. Furthermore, the two bishops E. afer and E. aureus represent lineages that branched off before this basal split, which also refutes the proposed superspecies of E. afer and E. diadematus. Also somewhat surprisingly, and despite the striking plumage similarities among the red bishops, E. franciscanus is not closely related to either E. nigroventris or E. orix (of which it until recently was considered a subspecies). Finally, the Mountain Marsh Widowbird E. psammocromius is likely closest to the Long-tailed Widowbird E. progne, and not, as previously thought, to the Marsh Widowbird E. hartlaubi.
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| 12. |
- Prager, Maria, et al.
(författare)
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ASV portal : an interface to DNA-based biodiversity data in the Living Atlas
- 2023
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Ingår i: BMC Bioinformatics. - : BioMed Central (BMC). - 1471-2105. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: The Living Atlas is an open source platform used to collect, visualise and analyse biodiversity data from multiple sources, and serves as the national biodiversity data hub in many countries. Although powerful, the Living Atlas has had limited func-tionality for species occurrence data derived from DNA sequences. As a step toward integrating this fast-growing data source into the platform, we developed the Ampli-con Sequence Variant (ASV) portal: a web interface to sequence-based biodiversity observations in the Living Atlas.Results: The ASV portal allows data providers to submit denoised metabarcoding output to the Living Atlas platform via an intermediary ASV database. It also enables users to search for existing ASVs and associated Living Atlas records using the Basic Local Alignment Search Tool, or via filters on taxonomy and sequencing details. The ASV portal is a Python-Flask/jQuery web interface, implemented as a multi-container docker service, and is an integral part of the Swedish Biodiversity Data Infrastructure. Conclusion: The ASV portal is a web interface that effectively integrates biodiversity data derived from DNA sequences into the Living Atlas platform.
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| 13. |
- Prager, Maria, 1973, et al.
(författare)
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Convergent evolution of red carotenoid coloration in widowbirds and bishops (Euplectes spp.)
- 2010
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Ingår i: Evolution. - 0014-3820. ; 64:12, s. 3609-3619
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Tidskriftsartikel (refereegranskat)abstract
- Avian carotenoid-based signals are classic examples of sexually selected, condition-dependent threat displays or mate choice cues. In many species, male dominance or mating success is associated with redder (i.e., longer wavelength) color hues, suggesting that red colors are either more efficient or more reliable signals than yellow colors. Few studies, however, have investigated selection for redness in a macroevolutionary context. Here, we phylogenetically reconstruct the evolution of carotenoid coloration in the African widowbirds and bishops (Euplectes spp.), for which agonistic selection for redder hues, as well as pigmentary mechanisms, is well documented. Using reflectance spectrometry for objective color quantification, and accounting for phylogenetic uncertainty, we find that yellow plumage color is a retained ancestral state in Euplectes, and that red color hues have convergently evolved two or three times. Results are discussed in relation to a known diversity in pigment mechanisms, supporting independent origins of red color, and suggesting that agonistic selection and physiological constraints have interacted to generate color diversity in Euplectes.
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| 14. |
- Prager, Maria, 1973, et al.
(författare)
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Differential ability of carotenoid C4-oxygenation in yellow and red bishop species (Euplectes spp.)
- 2009
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Ingår i: Comparative Biochemistry And Physiology B-Biochemistry & Molecular Biology. - : Elsevier BV. ; 154, s. 373-380
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Tidskriftsartikel (refereegranskat)abstract
- Male breeding plumages of African widowbirds and bishops (Euplectes spp.) show striking variation in carotenoid-based plumage coloration, with saturated yellow or orange-red patches of different size. Yet, from observations and experiments, agonistic signaling appears to have been a generalized sexual selection pressure for redness in the genus. Recent results show that yellow and red widowbird colors derive from distinctly different pigment profiles, and suggest that species vary in their ability to metabolize ingested carotenoids. We used reflectance spectrometry and High Performance Liquid Chromatography (HPLC) to describe the species-specific colors and plumage carotenoids of the congeneric yellow-crowned bishop (E. afer) and southern red bishop (E. orix). Results show that the yellow rump color of E. afer primarily derives from direct-deposited, dietary yellow pigments, i.e. lutein and zeaxanthin. In the red breast of E. orix, these are complemented by smaller amounts of derived red C4-keto-carotenoids: mainly α-doradexanthin, but also β-doradexanthin, canthaxanthin, astaxanthin and adonirubin. We also performed a diet supplementation experiment to investigate the relative importance of nutritional and metabolic constraints in determining the differential occurrence of C4-keto-carotenoids, and thus red plumage color, in the two species. Our results indicate that E. orix, but not E. afer, can manufacture red C4-keto-carotenoids (α-doradexanthin and canthaxanthin) from yellow dietary precursors (lutein and β-carotene).
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- Prager, Maria, 1973, et al.
(författare)
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Phylogeny and evolution of sexually selected tail ornamentation in widowbirds and bishops (Euplectes spp.)
- 2009
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Ingår i: J Evol Biol. - : Wiley. ; 22, s. 2068-2076
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Tidskriftsartikel (refereegranskat)abstract
- Despite similar ecology, mating systems and female preferences for supernormal tails, the 17 species of African widowbirds and bishops (Euplectes spp.) show astonishing variation in male tail ornamentation. Whereas bishops retain their brown nonbreeding tails in nuptial plumage, widowbirds grow black nuptial tails, varying in length from a few centimetres in E. axillaris to the extreme half metre train of E. progne. Here, we phylogenetically reconstruct the evolution of the discrete trait, nuptial tail and the continuous trait, tail length, using a molecular phylogeny of 33 Euplectes subspecies. Unlike many recent findings of labile evolution of plumage ornaments, our results suggest that the nuptial tail of Euplectes is a derived and phylogenetically conserved ornamental trait that, once gained, shows directional evolution in its expression. Directionality is demonstrated in the trivial sense of a short-tailed ancestor, and by contingency and randomization tests suggesting that branches with increasing tail length are overrepresented. This supports an early origin and strong retention of directional female mate choice in widowbirds and bishops, as previously indicated by empirical and experimental results, and provides a less labile, yet rapid scenario of sexually selected diversification.
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| 19. |
- Prager, Maria, 1973
(författare)
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Phylogeny and Signal Diversity in Widowbirds and Bishops (Euplectes spp.)
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Although sexual selection for elaborate signals is well documented in numerous species, the extreme diversity in signal design and expression in many taxa is largely unexplained. This thesis explores phylogenetic, mechanistic and ontogenetic explanations for divergence in two classic condition-dependent signal traits in the African widowbirds and bishops (Euplectes spp.); elongated black tails (in widowbirds) and patches of bright yellow or red carotenoid coloration (most prominent in bishops). A molecular phylogeny of 33 Euplectes subspecies (representing all 17 species) was derived using parsimony and Bayesian analyses of mitochondrial and nuclear DNA sequences. A consensus tree, or a sample of the most probable Bayesian trees, was then used in parsimony, likelihood and Bayesian reconstructions of ancestral signal states. Specifically, the discrete presence of a nuptial tail (i.e. prenuptial tail moult), continuous tail length, and discrete as well as continuous reflectance-based measures of carotenoid colour hue were analysed. The proximate basis of interspecific colour variation was investigated using High Performance Liquid Chromatography (HPLC) analyses of feather and plasma pigments in five Euplectes species. Finally, the relative importance of nutritional and metabolic constraints behind differential occurrence of C4-keto-carotenoids, and thus red plumage color, in Euplectes, was tested by diet manipulation in a yellow and a red bishop species. Results show monophyly of the genus Euplectes, but not of ‘widowbirds’ or ‘bishops’. Most notably, the red-collared widowbird E. ardens belongs to a clade of short-tailed bishops and not to the ‘true’ widowbirds. Extant Euplectes furthermore derive from ancestors in which breeding males had short (not prenuptially moulted) tails and yellow colour signals. Nuptial tail elongation and red coloration have since evolved at least twice in distinct lineages, possibly as convergent responses to early established and directional sexual selection for increasingly exaggerated quality advertisements. This provides an interesting contrast to several recent findings of labile ornament evolution in birds and other animals. Three different pigment profiles were identified in Euplectes feathers. Yellow colours primarily depend on dietary yellow carotenoids, while red hues result either from addition of metabolically derived red C4-keto-carotenoids, or from high concentrations of dietary and derived yellow pigments. A possible genetic constraint on colour evolution was also identified, as the southern red bishop E. orix, but not the yellow-crowned bishop E. afer, can manufacture red C4-keto-carotenoids (α-doradexanthin and canthaxanthin) from yellow dietary precursors (lutein and β-carotene). Combined with previous work on adaptive signal functions in Euplectes, the phylogenetic and proximate analyses in this thesis provide an unusually complete picture of avian plumage diversification, and a useful framework for further exploration of both genetics and ecology of avian colour signalling.
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| 21. |
- Sattler, Claudia, et al.
(författare)
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Participatory research in times of COVID-19 and beyond: Adjusting your methodological toolkits
- 2022
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Ingår i: One Earth. - : Elsevier BV. - 2590-3330 .- 2590-3322. ; 5:1, s. 62-73
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Tidskriftsartikel (refereegranskat)abstract
- Solving grand environmental societal challenges calls for transdisciplinary and participatory methods in social- ecological research. These methods enable co-designing the research, co-producing the results, and co-creating the impacts together with concerned stakeholders. COVID-19 has had serious impacts on thechoice of research methods, but reflections on recent experiences of ‘‘moving online’’ are still rare. In this perspective, we focus on the challenge of adjusting different participatory methods to online formats used in five transdisciplinary social-ecological research projects. The key added value of our research is the lessons learned from a comparison of the pros and cons of adjusting a broader set ofmethods to online formats. We conclude that combining the adjusted online approaches with well-established face-to-face formats intomore inclusive hybrid approaches can enrich and diversify the pool of available methods for postpandemic research. Furthermore, a more diverse group of participants can be engaged in the research process.
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| 23. |
- Twyman, H., et al.
(författare)
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Expression of a carotenoid-modifying gene and evolution of red coloration in weaverbirds (Ploceidae)
- 2018
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 27:2, s. 449-458
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Tidskriftsartikel (refereegranskat)abstract
- Red carotenoid colours in birds are widely assumed to be sexually selected quality indicators, but this rests on a very incomplete understanding of genetic mechanisms and honesty-mediating costs. Recent progress was made by the implication of the gene CYP2J19 as an avian carotenoid ketolase, catalysing the synthesis of red C4-ketocarotenoids from yellow dietary precursors, and potentially a major mechanism behind red coloration in birds. Here, we investigate the role of CYP2J19 in the spectacular colour diversification of African weaverbirds (Ploceidae), represented by five genera and 16 species: eight red, seven yellow and one without carotenoid coloration. All species had a single copy of CYP2J19, unlike the duplication found in the zebra finch, with high expression in the retina, confirming its function in colouring red oil droplets. Expression was weak or undetected in skin and follicles of pigment-depositing feather buds, as well as in beaks and tarsi, including those of the red-billed quelea. In contrast, the hepatic (liver) expression of CYP2J19 was consistently higher (>14-fold) in seven species with C4-ketocarotenoid coloration than in species without (including one red species), an association strongly supported by a phylogenetic comparative analysis. The results suggest a critical role of the candidate ketolase, CYP2J19, in the evolution of red C4-ketocarotenoid colour variation in ploceids. As ancestral state reconstruction suggests that ketocarotenoid coloration has evolved twice in this group (once in Euplectes and once in the Quelea/Foudia clade), we argue that while CYP2J19 has retained its ancestral role in the retina, it has likely been co-opted for red coloration independently in the two lineages, via increased hepatic expression.
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