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1.
Zootaxa ; 5004(3): 447-464, 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34811298

RESUMO

The species of the damselfly genus Wahnesia Frster, 1900 occurring in the DEntrecasteaux Islands, Louisiade Archipelago, and on Woodlark Island are reviewed, and four new species are described: W. muyuw from Woodlark Island, W. misima from Misima Island, W. tagula from Tagula (Sudest) Island, and W. rossel from Rossel Island, these latter three islands all lying in the Louisiade Archipelago. In addition, new information is presented on the identification and distribution of the two previously described species from the DEntrecasteaux islands: W. annulipes (Lieftinck, 1956) from Goodenough, Fergusson, and Normanby islands, and W. armeniaca (Lieftinck, 1956) from Goodenough and Fergusson islands. Illustrations are provided for the male abdominal terminalia and genital ligula of the four new species, as well as the wings and a color photograph of a live male of W. muyuw, and the ligula of W. armeniaca, accompanied by updated distribution maps for all species treated.


Assuntos
Odonatos , Passeriformes , Animais , Masculino , Papua Nova Guiné
2.
Zootaxa ; 5016(3): 441-447, 2021 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-34810437

RESUMO

Myrsidea danielalfonsoi new species is described and illustrated from the Austral thrush (Turdus falcklandii magellanicus King, 1831) in Chile.


Assuntos
Amblíceros , Doenças das Aves , Passeriformes , Animais , Chile , Insetos
3.
Zootaxa ; 5016(1): 1-55, 2021 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-34810465

RESUMO

Investigation of the diversity and taxonomy of feather mites of the subfamily Pterodectinae (Astigmata: Proctophyllodidae) on passerines (Passeriformes) and kingfishers (Coraciiformes: Alcedinidae) in Manitoba revealed 19 species in 5 genera. Of them, eight new species are described, seven of these from passerines and one from a kingfisher: Alaudicola eremophila sp. n. from Eremophila alpestris (Alaudidae), Amerodectes icteri sp. n. from Icterus galbula (Icteridae), A. pheucticus sp. n. from Pheucticus ludovicianus (Cardinalidae), A. tiffanyluiae sp. n. from Oporornis agilis (Parulidae), A. tretiakae sp. n. from Molothrus ater (Icteridae), Tyrannidectes sealyi sp. n. from Tyrannus tyrannus (Linnaeus, 1758) (type host) and Tyrannus verticalis Say, and T. empidonicus sp. n. from Empidonax minimus (Tyrannidae), and Proterothrix megaceryle sp. n. from Megaceryle alcyon (Alcedinidae). Additionally, nine pterodectine species are reported for the first time in the fauna of Canada. Based on re-evaluation of diagnostic charcters, new diagnoses are proposed for the genera Amerodectes, Tyrannidectes, and Metapterodectes, and species contents of these genera are revised. Four species are transferred from the genus Amerodectes to Tyrannidectes with the new combinations proposed: T. caribaeus (Mironov and Gonzlez-Acua, 2011) comb. n., T. charitomenos (Hernandes, 2018) comb. n., T. pitangi (Mironov, 2008) comb. n., T. vireonis (Hernandes and Pedroso, 2016) comb. n. Six species are transferred from the genus Tyrannidectes to Metapterodectes with the new combinations: M. amaurochalinus (Hernandes and Valim, 2006) comb. n., M. cinclodes (Mironov and Gonzlez-Acua, 2011) comb. n., M. crassus (Trouessart, 1885) comb. n., M. falcklandicus (Mironov and Gonzlez-Acua, 2011) comb. n., M. fissuratus (Hernandes and Valim, 2005) comb. n., and M. pteroptochi (Mironov and Gonzlez-Acua, 2015) comb. n.


Assuntos
Ácaros , Passeriformes , Aves Canoras , Animais , Canadá
4.
Zootaxa ; 5060(3): 333-352, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34810662

RESUMO

Four new species of Guimaraesiella Eichler, 1949 are described and illustrated based on specimens collected in South China. They are: Guimaraesiella (Cicchinella) citreisoma new species ex Leiothrix lutea kwangtungensis Whistler, 1943 (Leiothrichidae); Guimaraesiella (Cicchinella) corrugata new species ex Alcippe hueti hueti David, 1874 (Leiothrichidae); Guimaraesiella (Cicchinella) petilorica new species ex Alcippe nipalensis nipalensis (Hodgson, 1837) (Leiothrichidae); and Guimaraesiella (Cicchinella) yuhinae new species from Yuhina flavicollis rouxi (Oustalet, 1896) (Zosteropidae); this is the first species of the Brueelia-complex recorded from a member of the Zosteropidae.


Assuntos
Doenças das Aves , Iscnóceros , Infestações por Piolhos , Passeriformes , Ftirápteros , Animais , China
5.
J Avian Med Surg ; 35(3): 313-324, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34677030

RESUMO

Birds are among the most visually proficient group of animals on the planet; however, their inability to visualize and discriminate translucent glass structures results in an extreme number of deaths worldwide from high-speed collisions. Despite reports of avian glass collisions in North America, only a few studies have been developed to understand this problem in South America, and none evaluated radiographic and postmortem findings. One hundred cadavers were examined radiographically and postmortem, and data from 186 collision reports were analyzed for seasonality (website and manual reports and cadavers). A total of 34 different species of birds within 22 families were evaluated for this study, with the rufous-bellied thrush (Turdus rufiventris; n = 12), eared dove (Zenaida auriculata; n = 12), and ruddy ground dove (Columbina talpacoti; n = 10) being the most common species. Only 6 (27.7%) migratory species were reported: Sick's swift (Chaetura meridionalis), small-billed elaenia (Elaenia parvirostris), Black Jacobin (Florisuga fusca), Great kiskadee (Pitangus sulphuratus), Double-collared seedeater (Sporophila caerulescens), and Creamy-bellied thrush (Turdus amaurochalinus). Males (51) were more frequently reported than females (5), and 50.1% of the males had active gonads. Sex was unable to be determined in 44 birds. The most common radiographic lesion, noted in 16 of 82 (19.5%) animals, was loss of coelomic definition, suggestive of hemorrhage. Prevalent postmortem findings included skull hemorrhages (58/75, 77.3%) and encephalic contusions (47/73, 64.4%), followed by coelomic hemorrhages (33/81, 40.7%). Most of the window collisions (61/186, 32.8%) occurred during spring, the most common breeding season of avian species in Brazil. Cranioencephalic trauma was identified as the primary cause of mortality associated with birds flying into glass windows. Migration does not appear to be the main predisposing factor for window collisions by birds in Brazil. Increased activity and aggression related to breeding season, especially in males, may be a more important predisposing factor for window collision accidents.


Assuntos
Passeriformes , Aves Canoras , Animais , Brasil , Fatores Epidemiológicos , Feminino , Vidro , Masculino
6.
Elife ; 102021 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-34677128

RESUMO

Eurasian jays fail to take into account the point of view and desire of other jays when hiding food they can eat later.


Assuntos
Passeriformes , Aves Canoras , Animais , Comportamento Alimentar , Alimentos
7.
Oecologia ; 197(3): 599-614, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34636981

RESUMO

Seasonal variation in immune function can be attributed to life history trade-offs, and to variation in environmental conditions. However, because phenological stages and environmental conditions co-vary in temperate and arctic zones, their separate contributions have not been determined. We compared immune function and body mass of incubating (female only), chick-feeding (female and male), and non-breeding (female and male) red-capped larks Calandrella cinerea breeding year-round in three tropical equatorial (Kenya) environments with distinct climates. We measured four immune indices: haptoglobin, nitric oxide, agglutination, and lysis. To confirm that variation in immune function between breeding (i.e., incubating or chick-feeding) and non-breeding was not confounded by environmental conditions, we tested if rainfall, average minimum temperature (Tmin), and average maximum temperature (Tmax) differed during sampling times among the three breeding statuses per location. Tmin and Tmax differed between chick-feeding and non-breeding, suggesting that birds utilized environmental conditions differently in different locations for reproduction. Immune indices did not differ between incubating, chick-feeding and non-breeding birds in all three locations. There were two exceptions: nitric oxide was higher during incubation in cool and wet South Kinangop, and it was higher during chick-feeding in the cool and dry North Kinangop compared to non-breeding birds in these locations. For nitric oxide, agglutination, and lysis, we found among-location differences within breeding stage. In equatorial tropical birds, variation in immune function seems to be better explained by among-location climate-induced environmental conditions than by breeding status. Our findings raise questions about how within-location environmental variation relates to and affects immune function.


Assuntos
Passeriformes , Animais , Clima , Feminino , Imunidade , Masculino , Reprodução , Estações do Ano
8.
Exp Appl Acarol ; 85(2-4): 305-318, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34668142

RESUMO

Birds are important hosts for various tick species, playing a significant role in their biological life cycle and dispersion. In this study, we investigated tick infestations on birds trapped in an urban remnant of Atlantic Forest in Pernambuco state, Brazil. From February 2015 to March 2017, 541 birds belonging to 52 species were trapped with mist nets and examined for ectoparasites. Birds trapped in the late successional forest were significantly more infested than birds trapped in the early successional forest. In the same way, ectoparasite infestation varied significantly according to bird weight and collection plot. Overall, 198 birds (36.6%) belonging to 27 species were parasitized by ectoparasites (i.e., ticks, lice and/or mites). Ectoparasites were effectively collected from 111 birds, of which 99 belonging to 20 species were infested by ticks (n = 261), namely, Amblyomma longirostre (13 nymphs), Amblyomma nodosum (21 nymphs), Amblyomma varium (one nymph), and Amblyomma spp. (five nymphs and 221 larvae). Most of the ticks (> 90%) were collected from Passeriformes. This study provides the second record of A. varium in Pernambuco state and confirms that birds, especially Passeriformes, are important hosts for larvae and nymphs of Amblyomma spp. in the Atlantic Forest biome of Pernambuco.


Assuntos
Doenças das Aves , Ixodidae , Passeriformes , Infestações por Carrapato , Animais , Doenças das Aves/epidemiologia , Brasil/epidemiologia , Florestas , Ninfa , Infestações por Carrapato/epidemiologia , Infestações por Carrapato/veterinária
9.
Philos Trans R Soc Lond B Biol Sci ; 376(1836): 20200246, 2021 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-34482720

RESUMO

Socially guided vocal learning, the ability to use contingent reactions from social partners to guide immature vocalizations to more mature forms, is thought to be a rare ability known to be used only by humans, marmosets and two unrelated songbird species (brown-headed cowbirds and zebra finches). However, this learning strategy has never been investigated in the vast majority of species that are known to modify their vocalizations over development. We propose a novel, preliminary evolutionary modelling approach that uses ecological, reproductive and developmental traits to predict which species may incorporate social influences as part of their vocal learning system. We demonstrate our model using data from 28 passerines. We found three highly predictive traits: temporal overlap between sensory (memorization) and sensorimotor (practice) phases of song learning, song used for mate attraction, and social gregariousness outside the breeding season. Species with these traits were distributed throughout the clade, suggesting that a trait-based approach may yield new insights into the evolution of learning strategies that cannot be gleaned from phylogenetic relatedness alone. Our model suggests several previously uninvestigated and unexpected species as likely socially guided vocal learners and offers new insight into the evolution and development of vocal learning. This article is part of the theme issue 'Vocal learning in animals and humans'.


Assuntos
Aprendizagem , Passeriformes , Vocalização Animal , Animais , Masculino , Aves Canoras
10.
Biol Lett ; 17(9): 20210377, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34520683

RESUMO

Yellow warblers (Setophaga petechia) use referential 'seet' calls to warn mates of brood parasitic brown-headed cowbirds (Molothrus ater). In response to seet calls during the day, female warblers swiftly move to sit tightly on their nests, which may prevent parasitism by physically blocking female cowbirds from inspecting and laying in the nest. However, cowbirds lay their eggs just prior to sunrise, not during daytime. We experimentally tested whether female warblers, warned by seet calls on one day, extend their anti-parasitic responses into the future by engaging in vigilance at sunrise on the next day, when parasitism may occur. As predicted, daytime seet call playbacks caused female warblers to leave their nests less often on the following morning, relative to playbacks of both their generic anti-predator calls and silent controls. Thus, referential calls do not only convey the identity or the type of threat at present but also elicit vigilance in the future to provide protection from threats during periods of heightened vulnerability.


Assuntos
Parasitos , Passeriformes , Aves Canoras , Animais , Feminino , Comportamento de Nidação
11.
An Acad Bras Cienc ; 93(suppl 3): e20191458, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34550197

RESUMO

Tawny-bellied Seedeater (Sporophila hypoxantha) is an endangered (in Brazil) grassland dependent species, whose breeding success remains poorly known hampering conservation measures on its breeding grounds. Here we analyze the nest survival of the species in relation to temporal and environmental variables over three breeding seasons in hilly dry grasslands in southern Brazil. The apparent nest success was 40%, and MARK survival 20%. Predation was the main cause of failure, affecting 55% of the unsuccessful nests, followed by desertion, infestation by Philornis fly larvae, cattle trampling and burning. The productivity was 1.77 young per pair. Best models include time-specific factors (nest age and time of breeding season), reflected by a gradual reduction in nest survival over the nesting cycle, accompanied by an increase in temperature, subcutaneous larvae infestation, and predation. Nest site characteristics did not influence nest survival. Predation is more prevalent in the nestling rearing period than during incubation. This tendency may be caused by an increase in the activity in the nests, as is predicted by the Skutch hypothesis. The conclusion that time-specific factors influence nest survival more than ecological variables is important to plan on seasonally dependent conservation and management measures.


Assuntos
Comportamento de Nidação , Passeriformes , Animais , Bovinos , Ecossistema , Melhoramento Vegetal , Comportamento Predatório
12.
Am Nat ; 198(4): 551-560, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34559605

RESUMO

AbstractPredicting the impact of climate change on biodiversity requires understanding the adaptation potential of wild organisms. Evolutionary responses depend on the additive genetic variation associated with the phenotypic traits targeted by selection. We combine 5 years of cross-fostering experiments, measurements of resting metabolic rate (RMR) on nearly 200 wild collared flycatcher (Ficedula albicollis) nestlings, and animal models using a 17-year pedigree to evaluate the potential for an evolutionary response to changing environmental conditions. Contrary to other avian studies, we find no significant heritability of whole-organism, mass-independent, or mass-specific RMR, but we report a strong effect of nest environment instead. We therefore conclude that variation in nestling RMR is explained by variation in the early-life environment provided by the parents. We discuss possible underlying specific parental effects and the importance of taking different mechanisms into account to understand how animals phenotypically adapt (or fail to adapt) to climate change.


Assuntos
Passeriformes , Aves Canoras , Animais , Metabolismo Basal , Evolução Biológica , Passeriformes/genética , Fenótipo , Aves Canoras/genética
13.
J Exp Biol ; 224(20)2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34553762

RESUMO

Vertebrates confronted with challenging environments often experience an increase in circulating glucocorticoids, which result in morphological, physiological and behavioral changes that promote survival. However, chronically elevated glucocorticoids can suppress immunity, which may increase susceptibility to disease. Since the introduction of avian malaria to Hawaii a century ago, low-elevation populations of Hawaii Amakihi (Chlorodrepanis virens) have undergone strong selection by avian malaria and evolved increased resilience (the ability to recover from infection), while populations at high elevation with few vectors have not undergone selection and remain susceptible. We investigated how experimentally elevated corticosterone affects the ability of high- and low-elevation male Amakihi to cope with avian malaria by measuring innate immunity, hematocrit and malaria parasitemia. Corticosterone implants resulted in a decrease in hematocrit in high- and low-elevation birds but no changes to circulating natural antibodies or leukocytes. Overall, leukocyte count was higher in low- than in high-elevation birds. Malaria infections were detected in a subset of low-elevation birds. Infected individuals with corticosterone implants experienced a significant increase in circulating malaria parasites while untreated infected birds did not. Our results suggest that Amakihi innate immunity measured by natural antibodies and leukocytes is not sensitive to changes in corticosterone, and that high circulating corticosterone may reduce the ability of Amakihi to cope with infection via its effects on hematocrit and malaria parasite load. Understanding how glucocorticoids influence a host's ability to cope with introduced diseases provides new insight into the conservation of animals threatened by novel pathogens.


Assuntos
Malária Aviária , Passeriformes , Plasmodium , Animais , Corticosterona , Hawaii , Humanos , Imunidade Inata , Masculino
14.
Behav Processes ; 192: 104493, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34487830

RESUMO

Few avian species use tools in the wild. Yet, several birds build nests of great complexity and many aspects of tool use may also apply to nest building. It has long been hypothesised that tool use may select for specialised cognitive adaptations or even general cognitive skills. This might similarly pertain to species that build complex nests. In this study, we investigated the problem-solving capacity of a complex nest builder, a weaverbird species, in a foraging context that either required or did not require the use of tools. First, we tested the capacity of yellow-crowned bishops (Euplectes afer ssp. afer) to use a tool for retrieving an out-of-reach reward during three problem-solving tasks offering different nest/non-nest materials (Experiment 1). Next, subjects were confronted with two problem-solving tasks that required no tools (Experiment 2). No subject was able to use a tool in Experiment 1. However, 11 out of 12 subjects succeeded in using their beak in the first problem-solving task, and 9 in the second problem-solving task of Experiment 2. These results suggest that weaverbirds showed flexible problem-solving if the use of tools was not required.


Assuntos
Passeriformes , Resolução de Problemas , Animais , Humanos , Comportamento de Nidação , Recompensa
15.
Am J Bot ; 108(9): 1716-1730, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34590308

RESUMO

PREMISE: Pollinators are thought to exert selective pressures on plants, mediating the evolution of convergent floral shape often recognized as pollination syndromes. However, little is known about the accuracy of using petal shape for inferring convergence in pollination mode without a priori pollination information. Here we studied the genus Erythrina L. as a test case to assess whether ornithophyllous pollination modes (hummingbirds, passerines, sunbirds, or mixed pollination) can be inferred based on the evolutionary analysis of petal shape. METHODS: We characterized the two-dimensional dissected shape of standard, keel, and wing petals from 106 Erythrina species using geometric morphometrics and reconstructed a phylogenetic tree of 83 Erythrina species based on plastid trnL-F and nuclear ribosomal ITS sequences. We then used two phylogenetic comparative methods based on Ornstein-Uhlenbeck models, SURFACE and l1OU, to infer distinct morphological groups using petal shape and identify instances of convergent evolution. The effectiveness of these methods was evaluated by comparing the groups inferred to known pollinators. RESULTS: We found significant petal shape differences between hummingbird- and passerine-pollinated Erythrina species. Our analyses also revealed that petal combinations generally provided better inferences of pollinator types than individual petals and that the method and optimization criterion can affect the results. CONCLUSIONS: We show that model-based approaches using petal shape can detect convergent evolution of floral shape and relatively accurately infer pollination modes in Erythrina. The inference power of the keel petals argues for a deeper investigation of their role in the pollination biology of Erythrina and other bird-pollinated legumes.


Assuntos
Erythrina , Passeriformes , Animais , Flores , Filogenia , Polinização
16.
J Morphol ; 282(11): 1587-1603, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34369611

RESUMO

Cowbirds are a successful group of obligate brood parasites in the Neotropical passerine family Icteridae that offer an interesting model to explore the factors behind the evolution of the bird craniomandibular complex. The Giant Cowbird, Molothrus oryzivorus, stands out from its congeners, among other features, in diet (feeds mostly on fruit, nectar, and arthropods, instead on seeds), its larger body size, and longer, more robust beak with a much broader bony casque than in other cowbirds. In turn, Giant Cowbirds show a remarkable resemblance in these features to the distantly related caciques and oropendolas (some are its breeding hosts). However, the causes behind the latter resemblance and the distinctiveness among cowbirds have not yet been elucidated. We aim to explore the factors involved in the diverging morphology of the Giant Cowbird from its congeners and the convergence with caciques and oropendolas, surveying their skull and lower jaw under an explicit evolutionary framework. Using geometric morphometrics and comparative methods, we assessed the signal of phylogeny, convergence, feeding ecology, and size in skull shape. Our results indicated that evolution of the craniomandibular complex of icterids in general, and of the beak morphology in the Giant Cowbird in particular, are shaped by multiple factors, with phylogeny being largely overridden by changes in size (evolutionary allometry), primarily, and feeding ecology, secondarily. However, the evolution of a broad bony casque in the Giant Cowbird, otherwise a hallmark of caciques and oropendolas, does not appear to have primarily been ruled by evolutionary allometry. Instead, taking into account the unique extreme convergence between Giant Cowbirds and some of its caciques hosts, it might be consequence of selective regimes associated with parasite-host interactions acting on top of other evolutionary processes. This suggests chick mimicry as a reasonable explanation for this peculiar morphology that would require further investigation.


Assuntos
Parasitos , Passeriformes , Animais , Bico , Filogenia , Crânio
17.
Viruses ; 13(7)2021 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-34372564

RESUMO

Avian bornaviruses were first described in 2008 as the causative agents of proventricular dilatation disease (PDD) in parrots and their relatives (Psittaciformes). To date, 15 genetically highly diverse avian bornaviruses covering at least five viral species have been discovered in different bird orders. Currently, the primary diagnostic tool is the detection of viral RNA by conventional or real-time RT-PCR (rRT-PCR). One of the drawbacks of this is the usage of either specific assays, allowing the detection of one particular virus, or of assays with a broad detection spectrum, which, however, do not allow for the simultaneous specification of the detected virus. To facilitate the simultaneous detection and specification of avian bornaviruses, a multiplex real-time RT-PCR assay was developed. Whole-genome sequences of various bornaviruses were aligned. Primers were designed to recognize conserved regions within the overlapping X/P gene and probes were selected to detect virus species-specific regions within the target region. The optimization of the assay resulted in the sensitive and specific detection of bornaviruses of Psittaciformes, Passeriformes, and aquatic birds. Finally, the new rRT-PCR was successfully employed to detect avian bornaviruses in field samples from various avian species. This assay will serve as powerful tool in epidemiological studies and will improve avian bornavirus detection.


Assuntos
Bornaviridae/genética , Bornaviridae/isolamento & purificação , Reação em Cadeia da Polimerase Multiplex/métodos , Animais , Doenças das Aves/virologia , Aves/genética , Aves/virologia , Primers do DNA/genética , Genoma Viral , Infecções por Mononegavirales/veterinária , Papagaios/genética , Papagaios/virologia , Passeriformes/genética , Passeriformes/virologia , Filogenia , RNA Viral/genética , Sequenciamento Completo do Genoma/métodos
18.
Viruses ; 13(7)2021 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-34372622

RESUMO

The mosquito-borne flaviviruses USUV and WNV are known to co-circulate in large parts of Europe. Both are a public health concern, and USUV has been the cause of epizootics in both wild and domestic birds, and neurological cases in humans in Europe. Here, we explore the susceptibility of magpies to experimental USUV infection, and how previous exposure to USUV would affect infection with WNV. None of the magpies exposed to USUV showed clinical signs, viremia, or detectable neutralizing antibodies. After challenge with a neurovirulent WNV strain, neither viremia, viral titer of WNV in vascular feathers, nor neutralizing antibody titers of previously USUV-exposed magpies differed significantly with respect to magpies that had not previously been exposed to USUV. However, 75% (6/8) of the USUV-exposed birds survived, while only 22.2% (2/9) of those not previously exposed to USUV survived. WNV antigen labeling by immunohistochemistry in tissues was less evident and more restricted in magpies exposed to USUV prior to challenge with WNV. Our data indicate that previous exposure to USUV partially protects magpies against a lethal challenge with WNV, while it does not prevent viremia and direct transmission, although the mechanism is unclear. These results are relevant for flavivirus ecology and contention.


Assuntos
Proteção Cruzada/imunologia , Transmissão de Doença Infecciosa/veterinária , Infecções por Flavivirus/veterinária , Flavivirus/imunologia , Passeriformes/virologia , Febre do Nilo Ocidental/transmissão , Febre do Nilo Ocidental/veterinária , Vírus do Nilo Ocidental/imunologia , Animais , Anticorpos Antivirais/sangue , Doenças das Aves/virologia , Infecções por Flavivirus/imunologia , Espanha , Febre do Nilo Ocidental/prevenção & controle
19.
Mol Ecol ; 30(19): 4833-4844, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34347907

RESUMO

Geographic contact between sister lineages often occurs near the final stages of speciation, but its role in speciation's completion remains debated. Reproductive isolation may be essentially complete prior to secondary contact. Alternatively, costly interactions between partially reproductively isolated species - such as maladaptive hybridization or competition for resources - may select for divergence, increasing reproductive isolation and driving speciation toward completion. Here, we use coalescent demographic modelling and whole-genome data sets to show that a period of contact and elevated hybridization between sympatric eastern North American populations of two cryptic bird species preceded a major increase in reproductive isolation between these populations within the last 10,000 years. In contrast, substantial introgression continues to the present in a western contact zone where geographic overlap is much narrower and probably of more recent origin. In the sympatric eastern region where reproductive isolation has increased, it is not accompanied by character displacement in key morphometric traits, plumage coloration, or ecological traits. While the precise trait and underlying mechanism driving increased reproductive isolation remains unknown, we discuss several possibilities and outline avenues for future research. Overall, our results highlight how demographic models can reveal the geographic context in which reproductive isolation was completed, and demonstrate how contact can accelerate the final stages of speciation.


Assuntos
Passeriformes , Aves Canoras , Animais , Especiação Genética , Passeriformes/genética , Isolamento Reprodutivo , Aves Canoras/genética , Simpatria
20.
J R Soc Interface ; 18(181): 20210252, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34343456

RESUMO

The diverse colours of bird feathers are produced by both pigments and nanostructures, and can have substantial thermal consequences. This is because reflectance, transmittance and absorption of differently coloured tissues affect the heat loads acquired from solar radiation. Using reflectance measurements and heating experiments on sunbird museum specimens, we tested the hypothesis that colour and their colour producing mechanisms affect feather surface heating and the heat transferred to skin level. As predicted, we found that surface temperatures were strongly correlated with plumage reflectivity when exposed to a radiative heat source and, likewise, temperatures reached at skin level decreased with increasing reflectivity. Indeed, nanostructured melanin-based iridescent feathers (green, purple, blue) reflected less light and heated more than unstructured melanin-based colours (grey, brown, black), as well as olives, carotenoid-based colours (yellow, orange, red) and non-pigmented whites. We used optical and heat modelling to test if differences in nanostructuring of melanin, or the bulk melanin content itself, better explains the differences between melanin-based feathers. These models showed that the greater melanin content and, to a lesser extent, the shape of the melanosomes explain the greater photothermal absorption in iridescent feathers. Our results suggest that iridescence can increase heat loads, and potentially alter birds' thermal balance.


Assuntos
Plumas , Passeriformes , Animais , Cor , Iridescência , Pigmentação
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