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Craig W. Benkman - One of the best experts on this subject based on the ideXlab platform.
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Character displacement of a learned behaviour and its implications for ecological speciation.
Proceedings of The Royal Society B: Biological Sciences, 2019Co-Authors: Cody K. Porter, Craig W. BenkmanAbstract:Cultural evolution may accelerate population divergence and speciation, though most support for this hypothesis is restricted to scenarios of allopatric speciation driven by random cultural drift. By contrast, the role of cultural evolution in non-allopatric speciation (i.e. speciation with gene flow) has received much less attention. One clade in which cultural evolution may have figured prominently in speciation with gene flow includes the conifer-seed-eating finches in the red crossbill (Loxia curvirostra) complex. Here we focus on Cassia crossbills (Loxia sinesciuris; an ecotype recently split taxonomically from red crossbills) that learn social contact calls from their parents. Previous work found that individuals modify their calls throughout life such that they become increasingly divergent from a closely related, sympatric red crossbill ecotype. This open-ended modification of calls could lead to character displacement if it causes population-level divergence in call structure that, in turn, reduces (maladaptive) heterospecific flocking. Heterospecific flocking is maladaptive because crossbills use public information from flockmates to assess resource quality, and feeding rates are depressed when flockmates differ in their ability to exploit a shared resource (i.e. when flockmates are heterospecifics). We confirm the predictions of character displacement by documenting substantial population-level divergence in Cassia crossbill call structure over just two decades and by using field experiments to demonstrate that Cassia and red crossbills differentially respond to these evolved differences in call structure, reducing heterospecific flock formation. Moreover, because crossbills choose mates from within flocks, a reduction in heterospecific flocking should increase assortative mating and may have been critical for speciation of Cassia crossbills in the face of ongoing gene flow in as few as 5000 years. Our results provide evidence for a largely neglected yet potentially widespread mechanism by which reproductive isolation can evolve between sympatric lineages as a byproduct of adaptive cultural evolution.
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Crossbills were unlikely resident in the Bahamas; thus, there was no population to be extirpated.
Proceedings of the National Academy of Sciences of the United States of America, 2017Co-Authors: Craig W. BenkmanAbstract:In PNAS, Steadman and Franklin (1) make the argument that the large reduction in land area and shift in vegetation in the Bahamian Archipelago from ∼15–9 ka caused declines and extirpation of two bird species, the Eastern bluebird ( Sialia sialis ) and Hispaniolan crossbill ( Loxia megaplaga ). Their evidence for L. megaplaga resides in fossil bones from the Bahamian island of Abaco, representing eight individuals from >9 ka. Two of three qualitative traits from the only mandible recovered provided a better match for L. megaplaga than for red crossbills ( Loxia curvirostra ) from North America. However, their measurements of the postcranial bones for their other specimens do not allow one to eliminate the possibility that they represent L. curvirostra (Fig. 1). Fig. 1. Plots showing means and ranges of measurements of crossbill ( Loxia … [↵][1]1Email: cbenkman{at}uwyo.edu. [1]: #xref-corresp-1-1
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VARIABLE RESOURCE AVAILABILITY WHEN RESOURCE REPLENISHMENT IS CONSTANT: THE COUPLING OF PREDATORS AND PREY
The Auk, 2012Co-Authors: Craig W. Benkman, Trevor Fetz, Matthew V. TallutoAbstract:ABSTRACT. Although food resources are thought to limit many populations, the extent to which the population dynamics of predators and prey are coupled is rarely known. We examined a sedentary population of Red Crossbills (Loxia curvirostra L. complex) that relies on seeds in cones that accumulate in the canopy of Rocky Mountain Lodgepole Pine (Pinus contorta latifolia Engelm.). Nearly constant annual seed production and gradual weathering over many years of initially impenetrable cones in the tree canopy results in a continuous and perhaps roughly constant replenishment of accessible seeds. However, seed availability varies seasonally. We estimated the seasonal variation in the energy demands of the study population. Our results demonstrate that seed predation by these sedentary Red Crossbills potentially drives the seasonal variation in seed availability and likely causes the Red Crossbill population to be regulated. The results are also consistent with a nearly constant replenishment of accessible seeds...
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Mate choice based on a key ecological performance trait
Journal of Evolutionary Biology, 2009Co-Authors: L. K. Snowberg, Craig W. BenkmanAbstract:Mate preference for well-adapted individuals may strengthen divergent selection and thereby facilitate adaptive divergence. We performed mate choice experiments in which we manipulated male red crossbill (Loxia curvirostra complex) feeding rates. Using association time as a proxy for preference, we found that females preferred faster foragers, which reinforces natural selection because poorly adapted males would be less likely to obtain a mate as well as less likely to survive. Although theoretical models predict direct preference for adaptation and performance, to the best of our knowledge this experiment provides the first evidence of individuals directly assessing feeding performance in mate choice. In species where assessing the ecological adaptation of potential mates is possible, females may gain fitness benefits from choosing a well-adapted mate directly or indirectly, promoting the use of information about ecological adaptation in mate choice.
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a new species of the red crossbill fringillidae Loxia from idaho
The Condor, 2009Co-Authors: Craig W. Benkman, Thomas L Parchman, Julie W. Smith, Patrick C Keenan, Leonard SantistebanAbstract:Abstract. The Red Crossbill (Loxia curvirostra complex) endemic to the South Hills and Albion Mountains in southern Idaho has coevolved in a predator-prey arms race with the lodgepole pine (Pinus contorta latifolia). The resulting divergent selection has favored a sedentary, locally adapted crossbill population whose size and vocalizations differ from those of co-occurring Red Crossbills of other call types. It has also led to high levels of reproductive isolation between the “South Hills crossbill” and nomadic taxa with different vocalizations that move in and out of the area yearly. Genetic analyses of amplified fragment length polymorphisms (AFLP) indicate that about 5% of the loci in the South Hills Crossbill have diverged in spite of the potentially homogenizing influence of gene flow. Given these differences in genetics, morphology, and behavior, and the high level of reproductive isolation in sympatry with other call types (99% of South Hills Crossbills pair assortatively), we recommend that this c...
Ron W Summers - One of the best experts on this subject based on the ideXlab platform.
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how important are different non native conifers in britain to common crossbills Loxia curvirostra curvirostra
Bird Study, 2019Co-Authors: Eilidh Mcnab, Ron W Summers, Gavin Harrison, Kirsty J ParkAbstract:ABSTRACTCapsulePines physically defend their seeds against seed-eating birds and mammals more than spruces or larches. Cone characteristics reflect the rate at which Common Crossbills Loxia curviro...
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Associations between crossbills and North American conifers in Scotland
Forest Ecology and Management, 2012Co-Authors: Ron W Summers, Alice BroomeAbstract:Abstract Understanding the habitat requirements of the Scottish crossbill Loxia scotica is fundamental to the conservation of this endemic bird which, like other crossbills, specialises in feeding on conifer seeds extracted from cones. Habitat associations of Scottish crossbills and common crossbills Loxia curvirostra were determined from a systematic survey of conifer woodland within the range of the Scottish crossbill during January to April 2008. All the commonly planted conifers were producing cones. Scottish crossbills were associated with the amount of coning lodgepole pine Pinus contorta, whilst common crossbills were associated with coning Sitka spruce Picea sitchensis, lodgepole pine and to a small extent with larches Larix spp. The Scottish crossbill’s association with lodgepole pine is interesting in view of the notion that Scottish crossbills are adapted to Scots pine Pinus sylvestris. Likewise, there was no evidence that common crossbills in the study area during January to April 2008 had an association with Norway spruce Picea abies, the tree with which they are normally associated in continental Europe. Lodgepole pine and Sitka spruce cones have thinner scales than those of Scots pine and Norway spruce, respectively, so are probably easier to exploit for seeds than the conifers to which they are assumed to be adapted. This may explain the associations we found. North American crossbills that specialise on lodgepole pine and Sitka spruce have smaller bills than even common crossbills (the smallest of the western Palearctic crossbills, apart from the two-barred crossbill Loxia leucoptera bifasciata). Adaptation to Sitka spruce by common crossbills is unlikely because common crossbills in Scotland largely arrive during irruptions from continental Europe, after which they return in a subsequent season. Therefore, their association with North American conifers in Scotland is temporary. For the resident Scottish crossbills, there is a greater possibility of adaptation to lodgepole pine. However, given the difficulties in identification of old specimens in museums, it was not possible to examine trends in bill size; the prediction is that bill size should decline. Future research needs to distinguish which conifer Scottish crossbills are adapted to as opposed to those which may be temporarily preferred when most profitable.
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temporal variation in breeding and cone size selection by three species of crossbills Loxia spp in a native scots pinewood
Journal of Avian Biology, 2010Co-Authors: Ron W Summers, Robert J G Dawson, Robert ProctorAbstract:The breeding biology and cone size selection of crossbills was studied mainly during 1995 to 2002 at Abernethy Forest, Scotland, an ancient native Scots pine Pinus sylvestris wood, where only a single crossbill species, the Scottish crossbill Loxia scotica, was assumed to occur and to be adapted to feed on seeds in Scots pine cones. However, three crossbill species (common Loxia curvirostra, Scottish and parrot crossbills Loxia pytyopsittacus) nested in some years, with the parrot crossbill being the most abundant. Most nests were in old large pines, with the three crossbill species not differing in their use of tree size or stand density for nesting. The mean clutch and brood sizes were 3.8 and 2.9, and their mean survivals were 86 and 74%, respectively, with no significant differences among species. The timing of breeding differed between species, with parrot crossbills breeding earliest (median date 21 March, including second attempts) and common crossbills breeding last (median date 21 April), probably in response to the differing accessibility of Scots pine seeds to these species. The difference in the time of breeding may reduce mixed mating. Crossbills foraged preferentially on trees with small cones when the cones were closed. Small cones had thinner scales than large cones, suggesting that the preference for small cones was related to higher feeding rates on these cones when cones are closed. Such a preference was also found for captive crossbills with the Scottish crossbill showing a more pronounced preference for smaller cones than the larger-billed parrot crossbill. However, crossbills selected larger cones within trees and trees with larger cones once the cones opened in April. Such a shift occurred presumably because variation in scale thickness has little impact on seed accessibility once cones open, and larger cones have larger and more seeds. The greater ability of parrot crossbills to exploit seeds in closed Scots pine cones allowed parrot crossbills to start breeding earlier and to have young when seeds were most accessible. Only after the cones opened were the smaller-billed common crossbills able to easily access seeds and to start breeding. The time of breeding of Scottish crossbills was intermediate between common and parrot crossbills, and they probably had an intermediate ability to exploit Scots pine cones. The reason why there were few Scottish crossbills nesting in Abernethy Forest remains a puzzle, considering that native pine wood is assumed to be the ancestral habitat to which the Scottish crossbill is adapted. The breeding season for all crossbills ended in June, when most of the seed from a given cone cohort was shed. This is when starved broods were found, not associated with bad weather.
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vocal similarities between mediterranean and north european pine crossbills Loxia spp
2005Co-Authors: Ron W Summers, David C JardineAbstract:SUMMARY.—Vocal similarities between Mediterranean and north European Pine Crossbills Loxia spp. Aims: To make a comparative study of the flight and excitement calls of Common Crossbills Loxia curvirostra in the Mediterranean region. Given that different call types (distinguished by combinations of flight and excitement calls) are recognised within the nominate race in northern Europe, we expected that the subspecies endemic to the Mediterranean region would each have a different call type, whilst Pyrenean birds might share calls with one of the call types already described in northern Europe. Location: Calls of Crossbills were recorded in Mallorca, Cyprus and Morocco, where three Mediterranean subspecies of the Common Crossbill occur. Recordings were also made in the Pyrenees, inhabited by the nominate subspecies. Methods: Calls were recorded on a Sony Walkman Professional tape recorder using a Pro-sound directional microphone (model YU-36) or a parabolic reflector. The CANARY system was used to make sonograms. Results: Although different combinations of flight and excitement calls were detected, all four groups of crossbills shared either flight or excitement calls. In particular, the similarity between the flight and excitement calls of crossbills from Mallorca and the Pyrenees suggests that these populations may not be separate. Further, many of the calls of the Mediterranean crossbills were similar to calls of Scottish and Parrot Crossbills in Scotland, rather than Common Crossbills. One individual recorded in Mallorca had flight and excitement calls that matched a call type of the nominate race from northern Europe, confirming that some migrants reach the Mediterranean islands. Conclusions: The results followed our expectation that the endemic subspecies of Crossbills in the Mediterranean region each have different combinations of flight and excitement calls. However, the sharing of flight or excitement calls adds to the debate about the relations among Mediterranean crossbills and their relationship with crossbills on the Spanish mainland. Further, the similarity in calls between Mediter
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the distribution and habitats of crossbills Loxia spp in britain with special reference to the scottish crossbill Loxia scotica
Ibis, 2002Co-Authors: Ron W Summers, David C Jardine, Mick MarquissAbstract:A study was carried out, primarily in northern Scotland, to relate bill and wing measurements to diagnostic calls of crossbill species, and thereby use the calls to describe the distributions and habitats of the different species. Bill depth and wing length measurements from museum specimens and live-trapped birds were used to describe the size categories. Almost all measurements of crossbills from England were similar to measurements of Common Crossbills from Fennoscandia. Museum specimens showed that crossbills in northern Scotland between 1822 and 1990 were a combination of Common Crossbills, birds which were intermediate between Common and Parrot Crossbills (Scottish Crossbills), and perhaps a few Parrot Crossbills. However, catches of crossbills between 1995 and 2000 showed that Parrot Crossbills (based on bill and wing measurements) were present at some sites in the Highlands. Recordings of flight calls and excitement calls of birds of known bill sizes allowed a classification of crossbills according to call types. Four different flight calls (referred to here as types 1–4) and five excitement calls (types A–E) were recognized. A sample of small-billed birds, thereby identified as Common Crossbills, indicated that there were three groups of Common Crossbills: those giving type 1 flight calls and type A excitement calls (1A), type 2 flight calls and type B excitement calls (2B), and type 4 flight calls and type E excitement calls (4E). Large-billed birds identified as Parrot Crossbills gave mainly type 2 flight calls and type D excitement calls. Birds with intermediate bill depths (Scottish Crossbills) gave type 3 flight calls and type C excitement calls. Distributions based on calls showed that 1A Common Crossbills were widespread in Scotland but the other types of Common Crossbill were rare. Parrot Crossbills were found in a few localities in the Highlands, and Scottish Crossbills (defined as those giving type 3 flight calls and type C excitement calls) were restricted to the northern and eastern Highlands. Scottish Crossbills and 1A Common Crossbills had overlapping distributions, and overlapped greatly in the types of forests they used between January and March when the Scots Pine cones were still closed. However, Scottish Crossbills were more frequently associated with stands containing Scots Pine compared with Common Crossbills.
B Bellardi - One of the best experts on this subject based on the ideXlab platform.
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carotenoids in bird plumage the pattern in three Loxia species and in pinicola enucleator
Comparative Biochemistry and Physiology B, 1996Co-Authors: Riccardo Stradi, Elisabetta Rossi, Giuseppe Celentano, B BellardiAbstract:Abstract We studied the carotenoid pigments in the plumage of Loxia curvirostra, Loxia polygina, Loxia leucoptera and Pinicola enucleator . The pigments were extracted under mild conditions and the extract analysed by high-performance liquid chromatography coupled with mass and ultraviolet-vis spectroscopy. In adult females and young males of Loxia, two major carotenoids, all-trans e, e-carotene-3,3′-dione and e-hydroxy-e,e-carotene-3′-one, were responsible for the yellow colour of feathers. Minor amounts of lutein and 3′-dehydrolutein were detected. With sexual maturation, males turn red. The red colour of feathers was attributed to 3-hydroxyechinenone (3-hydroxy-β, β-caroten-4-one); small amounts of other orange-red carotenoids such as astaxanthin (3,3′-dihydroxy-β,β-carotene-4,4'-dione), adonirubin (3-hydroxy-β,β-carotene-4,4′-dione) and canthaxanthin β,β-carotene-4,4′-dione) were also detected. Varying amounts of the yellow carotenoids found in females and young males were present. The same red pigments are observed in the adult males of P. enucleator . In contrast, in adult female and in young male pinicola , lutein and 3'-dehydrolutein were the major carotenoids. Two other carotenoids, not previously observed in bird plumage, were tentatively assigned to 3-hydroxy-β, Ψ-caroten-4-one and 3-hydroxy-β, Ψ-caroten-4-one (5′- cis ).
Thomas L Parchman - One of the best experts on this subject based on the ideXlab platform.
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a new species of the red crossbill fringillidae Loxia from idaho
The Condor, 2009Co-Authors: Craig W. Benkman, Thomas L Parchman, Julie W. Smith, Patrick C Keenan, Leonard SantistebanAbstract:Abstract. The Red Crossbill (Loxia curvirostra complex) endemic to the South Hills and Albion Mountains in southern Idaho has coevolved in a predator-prey arms race with the lodgepole pine (Pinus contorta latifolia). The resulting divergent selection has favored a sedentary, locally adapted crossbill population whose size and vocalizations differ from those of co-occurring Red Crossbills of other call types. It has also led to high levels of reproductive isolation between the “South Hills crossbill” and nomadic taxa with different vocalizations that move in and out of the area yearly. Genetic analyses of amplified fragment length polymorphisms (AFLP) indicate that about 5% of the loci in the South Hills Crossbill have diverged in spite of the potentially homogenizing influence of gene flow. Given these differences in genetics, morphology, and behavior, and the high level of reproductive isolation in sympatry with other call types (99% of South Hills Crossbills pair assortatively), we recommend that this c...
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COEVOLUTION BETWEEN HISPANIOLAN CROSSBILLS AND PINE: DOES MORE TIME ALLOW FOR GREATER PHENOTYPIC ESCALATION AT LOWER LATITUDE?
Evolution, 2007Co-Authors: Thomas L Parchman, Craig W. Benkman, Eduardo T. MezquidaAbstract:Crossbills (Aves: Loxia) and several conifers have coevolved in predator‐prey arms races over the last 10,000 years. However, the extent to which coevolutionary arms races have contributed to the adaptive radiation of crossbills or to any other adaptive radiation is largely unknown. Here we extend our previous studies of geographically structured coevolution by considering a crossbill‐conifer interaction that has persisted for a much longer time period and involves a conifer with more variable annual seed production. We examined geographic variation in the cone and seed traits of two sister species of pines, Pinus occidentalis and P. cubensis, on the islands of Hispaniola and Cuba, respectively. We also compared the Hispaniolan crossbill (Loxia megaplaga) to its sister taxa the North American white-winged crossbill (Loxia leucoptera leucoptera). The Hispaniolan crossbill is endemic to Hispaniola whereas Cuba lacks crossbills. In addition and in contrast to previous studies, the variation in selection experienced by these pines due to crossbills is not confounded by the occurrence of selection by tree squirrels (Tamiasciurus and Sciurus). As predicted if P. occidentalis has evolved defenses in response to selection exerted by crossbills, cones of P. occidentalis have scales that are 53% thicker than those of P. cubensis. Cones of P. occidentalis, but not P. cubensis, also have well-developed spines, a known defense against vertebrate seed predators. Consistent with patterns of divergence seen in crossbills coevolving locally with other conifers, the Hispaniolan crossbill has evolved a bill that is 25% deeper than the white-winged crossbill. Together with phylogenetic analyses, our results suggest that predator‐prey coevolution between Hispaniolan crossbills and P. occidentalis over approximately 600,000 years has caused substantial morphological evolution in both the crossbill and pine. This also indicates that cone crop fluctuations do not prevent crossbills and conifers from coevolving. Furthermore, because the traits at the phenotypic interface of the interaction apparently remain the same over at least several hundred thousand years, divergence as a result of coevolution is greater at lower latitude where crossbill‐conifer interactions have been less interrupted by Pleistocene events.
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patterns of genetic variation in the adaptive radiation of new world crossbills aves Loxia
Molecular Ecology, 2006Co-Authors: Thomas L Parchman, Craig W. Benkman, Seth C BritchAbstract:Incipient species groups or young adaptive radiations such as crossbills (Aves: Loxia ) present the opportunity to investigate directly the processes occurring during speciation. New World crossbills include white-winged crossbills ( Loxia leucoptera ), Hispaniolan crossbills ( Loxia megaplaga ), and red crossbills ( Loxia curvirostra complex), the last of which is comprised of at least nine morphologically and vocally differentiated forms (‘call types’) where divergent natural selection for specialization on different conifer resources has been strongly implicated as driving diversification. Here we use amplified fragment length polymorphism (AFLP) markers to investigate patterns of genetic variation across populations, call types, and species of New World crossbills. Tree-based analyses using 440 AFLP loci reveal strongly supported clustering of the formally recognized species, but did not separate individuals from the eight call types in the red crossbill complex, consistent with recent divergence and ongoing gene flow. Analyses of genetic differentiation based on inferred allele frequency variation however, reveal subtle but significant levels of genetic differentiation among the different call types of the complex and indicate that between call-type differentiation is greater than that found among different geographic locations within call types. Interpreted in light of evidence of divergent natural selection and strong premating reproductive isolation, the observed genetic differentiation suggests restricted gene flow among sympatric call types consistent with the early stages of ecological speciation.
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Reciprocal Selection Causes a Coevolutionary Arms Race between Crossbills and Lodgepole Pine
The American Naturalist, 2003Co-Authors: Craig W. Benkman, Thomas L Parchman, Amanda Favis, Adam M. SiepielskiAbstract:Abstract: Few studies have shown both reciprocal selection and reciprocal adaptations for a coevolving system in the wild. The goal of our study was to determine whether the patterns of selection on Rocky Mountain lodgepole pine (Pinus contorta spp. latifolia) and red crossbills (Loxia curvirostra complex) were concordant with earlier published evidence of reciprocal adaptations in lodgepole pine and crossbills on isolated mountain ranges in the absence of red squirrels (Tamiasciurus hudsonicus). We found that selection (directional) by crossbills on lodgepole pine where Tamiasciurus are absent was divergent from the selection (directional) exerted by Tamiasciurus on lodgepole pine. This resulted in divergent selection between areas with and without Tamiasciurus that was congruent with the geographic patterns of cone variation. In the South Hills, Idaho, where Tamiasciurus are absent and red crossbills are thought to be coevolving with lodgepole pine, crossbills experienced stabilizing selection on bill s...
Riccardo Stradi - One of the best experts on this subject based on the ideXlab platform.
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Carotenoids in bird plumage: the complement of red pigments in the plumage of wild and captive bullfinch (Pyrrhula pyrrhula).
Comparative Biochemistry and Physiology B, 2001Co-Authors: Riccardo Stradi, Elena Pini, Giuseppe CelentanoAbstract:Abstract We have studied the carotenoid pigments in the red plumage of male bullfinch ( Pyrrhula pyrrhula ) immediately following capture and after the completion of the moult in captivity under dietary control. Astaxanthin, adonirubin, and α-doradexanthin, as well as papilioeritrinone and canthaxanthin (in lower amounts) are in every case the dominant carotenoids in the plumage pigment of wild individuals. α-Doradexanthin is responsible for the reddish-rose colour, which captive individuals adopt after a diet consisting mainly of lutein as disposable carotenoid. The red pigmentation biogenesis of captive bullfinch is compared with those of other red pigmented Carduelinae in which male individuals usually lose the red colour in captivity, namely Carpodacus roseus, Carpodacus rubricilloides, Uragus sibiricus, Carduelis cannabina, Carduelis flammea, Loxia curvirostra and Pinicola enucleator.
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carotenoids in bird plumage the pattern in three Loxia species and in pinicola enucleator
Comparative Biochemistry and Physiology B, 1996Co-Authors: Riccardo Stradi, Elisabetta Rossi, Giuseppe Celentano, B BellardiAbstract:Abstract We studied the carotenoid pigments in the plumage of Loxia curvirostra, Loxia polygina, Loxia leucoptera and Pinicola enucleator . The pigments were extracted under mild conditions and the extract analysed by high-performance liquid chromatography coupled with mass and ultraviolet-vis spectroscopy. In adult females and young males of Loxia, two major carotenoids, all-trans e, e-carotene-3,3′-dione and e-hydroxy-e,e-carotene-3′-one, were responsible for the yellow colour of feathers. Minor amounts of lutein and 3′-dehydrolutein were detected. With sexual maturation, males turn red. The red colour of feathers was attributed to 3-hydroxyechinenone (3-hydroxy-β, β-caroten-4-one); small amounts of other orange-red carotenoids such as astaxanthin (3,3′-dihydroxy-β,β-carotene-4,4'-dione), adonirubin (3-hydroxy-β,β-carotene-4,4′-dione) and canthaxanthin β,β-carotene-4,4′-dione) were also detected. Varying amounts of the yellow carotenoids found in females and young males were present. The same red pigments are observed in the adult males of P. enucleator . In contrast, in adult female and in young male pinicola , lutein and 3'-dehydrolutein were the major carotenoids. Two other carotenoids, not previously observed in bird plumage, were tentatively assigned to 3-hydroxy-β, Ψ-caroten-4-one and 3-hydroxy-β, Ψ-caroten-4-one (5′- cis ).
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Separation and identification of carotenoids in bird's plumage by high-performance liquid chromatography--diode-array detection.
Journal of Chromatography B: Biomedical Sciences and Applications, 1995Co-Authors: Riccardo Stradi, Giuseppe Celentano, Donatella NavaAbstract:The coloured feathers of Carduelis spinus (Siskin), C. flammea (Redpoll), Serinus serinus (Serin), Loxia curvirostra (Crossbill), Pinicola enucleator (Grossbeak), Carpodacus roseus (Pallas Rosefinch) and Pyrrhula pyrrhula (Bullfinch) have been extracted with a new procedure using mild conditions (a few minutes at room temperature). After the separation of melanines and proteins, the extracts were analyzed by HPLC-MS and HPLC-UV-Vis. The main components of the pigments were identified in all the species examined; moreover, UV-Vis and MS data were collected also for the minor components. These data suggest that minor components are generally cis isomers accompanying the predominant all-trans isomers.
