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1.
Nat Commun ; 12(1): 1019, 2021 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-33589637

RESUMO

Genome-wide variation in introgression rates across hybrid zones offers a powerful opportunity for studying population differentiation. One poorly understood pattern of introgression is the geographic displacement of a trait implicated in lineage divergence from genome-wide population boundaries. While difficult to interpret, this pattern can facilitate the dissection of trait genetic architecture because traits become uncoupled from their ancestral genomic background. We studied an example of trait displacement generated by the introgression of head plumage coloration from personata to alba subspecies of the white wagtail. A previous study of their hybrid zone in Siberia revealed that the geographic transition in this sexual signal that mediates assortative mating was offset from other traits and genetic markers. Here we show that head plumage is associated with two small genetic regions. Despite having a simple genetic architecture, head plumage inheritance is consistent with partial dominance and epistasis, which could contribute to its asymmetric introgression.


Assuntos
Introgressão Genética , Genoma , Passeriformes/genética , Pigmentação/genética , Característica Quantitativa Herdável , Animais , Quimera , Cor , Epistasia Genética , Plumas/anatomia & histologia , Plumas/metabolismo , Feminino , Masculino , Passeriformes/anatomia & histologia , Passeriformes/classificação , Sibéria , Uzbequistão
2.
Oecologia ; 195(1): 37-49, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33389017

RESUMO

Using measurements of naturally occurring stable isotopes in feathers to determine avian origin and migratory patterns is well established. However, isotopically determining nutritional origins of lipids, a major migratory fuel, has not been attempted. This study explores isotopic links between diet and stored lipids in captive white-throated sparrows (Zonotrichia albicollis) by providing isotopically distinct mixtures of carbohydrates/oils and drinking water and assessing the δ13C and δ2H values of stored lipid, breath CO2 (δ13C) and breath water vapour (δ2H). Stored lipid δ13C and δ2H values correlated with the isotopic values found in dietary carbohydrates/oils and drinking water treatments, respectively, indicating a clear traceable transfer of environmental dietary isotopic signals into body lipids. Dietary oils and carbohydrates contributed 80-82% of carbon and 44-46% of hydrogen, respectively, to stored lipids. Drinking water contributed 18-28% of hydrogen to stored lipids. Isotopic relationships were quantifiable using linear calibration algorithms which provide the basis for the construction of tissue isoscapes for migratory passerines. Breath CO2 δ13C values and breath water vapour δ2H values for fed and fasted birds reflected dietary sources. Breath CO2 δ13C values were higher for fasted birds than for fed birds by an average of 4.5‰ while breath water vapour δ2H values were lower for fasted birds by an average of 48.9‰. These results indicate that lipids and metabolites from their subsequent breakdown for fuel isotopically reflect dietary sources but complicate interpretation of such data, especially for wild migrating birds. Applications and limitations of these findings to the creation of "liposcapes" are examined.


Assuntos
Carbono , Passeriformes , Animais , Isótopos de Carbono , Hidrogênio , Isótopos , Lipídeos
3.
Oecologia ; 195(2): 355-365, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33439358

RESUMO

Climatic factors act on populations at multiple timescales leading to the separation of long-term climate and shorter-term weather effects. We used passerine counts from 1995 to 2019 in subarctic Alaska (Denali National Park, USA) to assess the impacts of the prior breeding season's weather on breeding season abundance and the impacts of climate measured through shifts in elevational distribution. Weather and climate appear to have had opposing effects on the abundance of some shrub-associated species as evidenced by a positive response to nesting phase temperature over a 1-year lag and a negative response to warming-induced shifts in shrub-dominated habitats over the long term. The latter response was indicated by declines in abundance which occurred in some part through portions of these populations shifting upslope of our fixed sampling frame. Overall, the abundance of species was related to one or more of the lagged effects of weather and the effects of weather alone drove nearly twofold variation in annual abundance in most species. The effect of nesting phase temperature was a strong positive predictor at both community and individual species levels, whereas arrival phase temperature had weak support at both levels. The effects of total precipitation during the nesting phase and snowmelt timing shared mixed support at community and species levels, but generally indicated higher abundance following seasons that were drier and had earlier snowmelt. Together, our findings of opposing effects of climatic variables at different timescales have implications for understanding the mechanisms of population and distributional change in passerines in the subarctic.


Assuntos
Mudança Climática , Passeriformes , Alaska , Animais , Estações do Ano , Temperatura , Tempo (Meteorologia)
4.
Am Nat ; 197(1): 111-127, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33417527

RESUMO

AbstractWhy do senescence rates of fitness-related traits often vary dramatically? By considering the full aging trajectories of multiple traits, we can better understand how a species' life history shapes the evolution of senescence within a population. Here, we examined age-related changes in sex-specific survival, reproduction, and several components of reproduction using a long-term study of a cooperatively breeding songbird, the superb fairy-wren (Malurus cyaneus). We compared aging patterns between traits by estimating standardized rates of maturation, age of onset of senescence, and rates of senescence while controlling for confounding factors reflecting individual variability in life history. We found striking differences in aging and senescence patterns between survival and reproduction as well as between reproductive traits. In both sexes, survival started to decline from maturity onward. In contrast, all reproductive traits showed improvements into early adulthood, and many showed little or no evidence of senescence. In females, despite senescence in clutch size, number of offspring surviving to independence did not decline in late life, possibly due to improvements in maternal care with age. Superb fairy-wrens have exceptionally high levels of extragroup paternity, and while male within-group reproductive success did not change with age, extragroup reproductive success showed a dramatic increase in early ages, followed by a senescent decline, suggesting that male reproductive aging is driven by sexual selection. We discuss how the superb fairy-wrens' complex life history may contribute to the disparate aging patterns across different traits.


Assuntos
Envelhecimento/fisiologia , Passeriformes/fisiologia , Reprodução/fisiologia , Animais , Território da Capital Australiana , Tamanho da Ninhada , Feminino , Estágios do Ciclo de Vida , Longevidade , Masculino , Fatores Sexuais
5.
Sci Total Environ ; 763: 142957, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33498114

RESUMO

The aim of this study was to estimate the risk posed by imidacloprid (IMI) seed coating to passerine birds of the Pampa Region of Argentina using data specifically generated with the grayish baywing (Agelaioides badius). Median lethal dose (LD50) of the IMI-based formulation tested was 57.11 mg IMI/kg body weight (bw), with intoxication signs starting from 20.6 mg IMI/kg bw. The feed intake rate (FIR) was estimated experimentally as 4.895 g/day per bird, representing 12.43% of bw. It was calculated that the ingestion of 7-10% of the FIR as treated seeds would be enough to achieve the LD50 for sorghum, corn, sunflower, and alfalfa, whereas consumption of 31 and 54% of FIR was necessary for oat and wheat, respectively. Based on spill data values available in the literature, it was calculated that, for most crops, a baywing would have to forage an area of field corresponding to less than 60 m2 to obtain the number of seeds required to reach the LD50. It was also shown that this number of seeds is coherent with the amount of seeds ingested in a bout. In a pilot study, all grayish baywings fed with millet seeds treated with 3 g IMI/kg died within three to five days of exposure. In Tier I risk assessment, the trigger value was achieved for all crops except soybean and a weight-of-evidence risk assessment was performed. All lines of evidence examined are consistent with the view that grayish baywings, and probably other small farmland birds, are exposed to a risk of acute toxicity and mortality under both worst-case and mixed-ration exposure scenarios. The possible impacts on bird species calls for an urgent reconsideration of IMI seed coating practices currently approved in the Pampa Region of Argentina and the various parts of the world where this practice is still in use.


Assuntos
Inseticidas , Passeriformes , Animais , Argentina , Peso Corporal , Fazendas , Inseticidas/análise , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Projetos Piloto , Sementes/química
6.
Ecol Lett ; 24(3): 477-486, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33314573

RESUMO

Animals use acoustic signals for communication, implying that the properties of these signals can be under strong selection. The acoustic adaptation hypothesis predicts that species in dense habitats emit lower-frequency sounds than those in open areas because low-frequency sounds propagate further in dense vegetation than high-frequency sounds. Signal frequency may also be under sexual selection because it correlates with body size and lower-frequency sounds are perceived as more intimidating. Here, we evaluate these hypotheses by analysing variation in peak song frequency across 5,085 passerine species (Passeriformes). A phylogenetically informed analysis revealed that song frequency decreases with increasing body mass and with male-biased sexual size dimorphism. However, we found no support for the predicted relationship between frequency and habitat. Our results suggest that the global variation in passerine song frequency is mostly driven by natural and sexual selection causing evolutionary shifts in body size rather than by habitat-related selection on sound propagation.


Assuntos
Passeriformes , Vocalização Animal , Acústica , Animais , Evolução Biológica , Masculino
7.
Sci Total Environ ; 762: 144160, 2021 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-33373750

RESUMO

The exposure of non-target wildlife to anticoagulant compounds used for rodent control is a well-known phenomenon. Exposure can be primary when non-target species consume bait or secondary via uptake of poisoned animals by mammalian and avian predators. However, nothing is known about the exposure patterns in passerine birds that are commonly present on farms where rodent control is conducted. We used liquid chromatography coupled with tandem mass spectrometry to screen for residues of anticoagulant rodenticides (ARs) in liver tissue of passerine birds that were present during rodent control with a product containing brodifacoum (BR). The 222 birds of 13 species were bycatch of rodent snap trapping in 2011-2013 on 11 livestock farms run synchronously with baiting. During baiting, ARs were detected in about 30% of birds; 28% carried BR. In liver tissue of 54 birds that carried BR, concentrations ranged from 4 to 7809 ng/g (mean 490 ± 169 ng/g). Among common bird species with AR residues, BR was most prevalent in robins (Erithacus rubecula) (44%) and dunnocks (Prunella modularis) (41%). Mean BR concentration was highest in great tits (Parus major) (902 ± 405 ng/g). The occurrence and concentrations of BR residues were about 30% higher in birds collected close to bait stations compared to birds collected further away. The results demonstrate that several ground feeding songbird species are exposed to ARs used on farms. If BR was present in liver tissue, concentrations were variable, which may imply a combination of primary and secondary exposure of songbirds. Exposure was mostly restricted to the immediate surroundings of farms where bait was used, which might limit the transfer to the wider environment. Efforts should be made to reduce the access for birds to AR bait to prevent high exposure.


Assuntos
4-Hidroxicumarinas , Passeriformes , Rodenticidas , Animais , Anticoagulantes , Fazendas , Ratos
8.
Mol Phylogenet Evol ; 154: 106962, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32950682

RESUMO

The stipple-throated antwrens of the genus Epinecrophylla (Aves: Thamnophilidae) are represented by eight species primarily found in the lowlands of the Amazon Basin and the Guiana Shield. The genus has a long and convoluted taxonomic history, with many attempts made to address the taxonomy and systematics of the group. Here we employ massively parallel sequencing of thousands of ultraconserved elements (UCEs) to provide both the most comprehensive subspecies-level phylogeny of Epinecrophylla antwrens and the first population-level genetic analyses for most species in the genus. Most of our results are robust to a diversity of phylogenetic and population genetic methods, but we show that even with thousands of loci we are unable to fully resolve the relationships between some western Amazonian species in the haematonota group. We uncovered phylogenetic relationships between taxa and patterns of population structure that are discordant with both morphology and current taxonomy. For example, we found deep genetic breaks between taxa in the ornata group that are currently regarded as species, and in the haematonota and leucophthalma groups we found paraphyly at the species and subspecies levels, respectively. As has been found in many Amazonian taxa, our phylogenetic results show that the major river systems of the Amazon Basin appear to have an effect on the genetic structure and range limits within Epinecrophylla. Our population genetics analyses showed extensive admixture between some taxa despite their deep genetic divergence. We present a revised taxonomy for the group and suggest areas for further study.


Assuntos
Passeriformes/classificação , Filogenia , Clima Tropical , Animais , Sequência de Bases , Genética Populacional , Genoma Mitocondrial , Geografia , Passeriformes/genética , Polimorfismo de Nucleotídeo Único/genética , Análise de Componente Principal , Especificidade da Espécie
9.
Mol Phylogenet Evol ; 154: 106973, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33059067

RESUMO

The Pernambuco Center of Endemism (PCE) is the northernmost strip of the Atlantic Forest (AF). Biogeographic affinities among avifaunas in the PCE, the southern-central Atlantic Forest (SCAF), and Amazonia (AM) have not been studied comprehensively, and current patterns of genetic diversity in the PCE remain unclear. The interplay between species' ecological attributes and historical processes, such as Pleistocene climate fluctuations or the appearance of rivers, may have affected population genetic structures in the PCE. Moreover, the role of past connections between the PCE and AM and the elevational distribution of species in assembling the PCE avifauna remain untested. Here, we investigated the biogeographic history of seven taxa endemic to the PCE within a comparative phylogeographic framework based on a mean of 3,618 independent single nucleotide polymorphisms (SNPs) extracted from flanking regions of ultraconserved elements (UCEs) and one mitochondrial gene. We found that PCE populations were more closely related to SCAF populations than they were to those in AM, regardless of their elevational range, with divergence times placed during the Mid-Pleistocene. These splits were consistent with a pattern of allopatric divergence with gene flow until the upper Pleistocene and no signal of rapid changes in population sizes. Our results support the existence of a Pleistocene refugium driving current genetic diversity in the PCE, thereby rejecting the role of the São Francisco River as a primary barrier for population divergence. Additionally, we found that connections with Amazonia also played a significant role in assembling the PCE avifauna through subsequent migration events.


Assuntos
Florestas , Passeriformes/classificação , Filogeografia , Animais , Brasil , Demografia , Fluxo Gênico , Variação Genética , Genética Populacional , Haplótipos/genética , Mitocôndrias/genética , Passeriformes/genética , Filogenia , Polimorfismo de Nucleotídeo Único/genética , Especificidade da Espécie
10.
Mol Phylogenet Evol ; 154: 106994, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33250446

RESUMO

Species delimitation has advanced from a purely phenotypic exercise to a branch of science that integrates multiple sources of data to identify independently evolving lineages that can be treated as species. We here test species limits in the avian Lesser Short-toed Lark Alaudala rufesens-Sand Lark A. raytal complex, which has an intricate taxonomic history, ranging from a single to three recognised species, with different inclusiveness in different treatments. Our integrative taxonomic approach is based on a combination of DNA sequences, plumage, biometrics, songs, song-flights, geographical distributions, habitat, and bioclimatic data, and using various methods including a species delimitation program (STACEY) based on the multispecies coalescent model. We propose that four species should be recognised: Lesser Short-toed Lark A. rufescens (sensu stricto), Heine's Short-toed Lark A. heinei, Asian Short-toed Lark A. cheleensis and Sand Lark A. raytal. There is also some evidence suggesting lineage separation within A. cheleensis and A. raytal, but additional data are required to evaluate this. The species delimitation based on STACEY agrees well with the non-genetic data. Although computer-based species delimitation programs can be useful in identifying independently evolving lineages, we stress that whenever possible, species hypotheses proposed by these programs should be tested by independent, non-genetic data. Our results highlight the difficulty and subjectivity of delimiting lineages and species, especially at early stages in the speciation process.


Assuntos
Passeriformes/classificação , Filogenia , Animais , Teorema de Bayes , Comportamento de Escolha , Clima , Citocromos b/genética , Análise Discriminante , Ecossistema , Plumas/anatomia & histologia , Voo Animal/fisiologia , Geografia , Umidade , Passeriformes/anatomia & histologia , Passeriformes/fisiologia , Chuva , Especificidade da Espécie , Temperatura , Vocalização Animal/fisiologia
11.
Zootaxa ; 4878(1): zootaxa.4878.1.4, 2020 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-33311168

RESUMO

Four new species of amblyceran chewing lice of the genus Myrsidea Waterston, 1915 are described from hosts of the babbler families Leiothrichidae, Paradoxornithidae and Timaliidae in China. They are: Myrsidea attenuata n. sp. from Garrulax maesi maesi (Oustalet, 1890), Myrsidea zhangae n. sp. from Ianthocincla berthemyi (Oustalet, 1876), Myrsidea liopari n. sp. from Lioparus chrysotis amoenus (Mayr, 1941) and L. chrysotis swinhoii (Verreaux, 1871), and Myrsidea suthorae n. sp. from Suthora verreauxi verreauxi Sharpe, 1883. A checklist of host-louse associations for identified and unidentified Myrsidea species known from babblers is provided.


Assuntos
Amblíceros , Doenças das Aves , Infestações por Piolhos , Passeriformes , Animais , Humanos
12.
Proc Biol Sci ; 287(1941): 20202428, 2020 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-33323076

RESUMO

It remains poorly understood how effects of anthropogenic activity, such as large-scale habitat fragmentation, impact sociality in animals. In cooperatively breeding species, groups are mostly formed through delayed offspring dispersal, and habitat fragmentation can affect this process in two opposite directions. Increased habitat isolation may increase dispersal costs, promoting delayed dispersal. Alternatively, reduced patch size and quality may decrease benefits of philopatry, promoting dispersal. Here, we test both predictions in a cooperatively breeding bird (placid greenbul, Phyllastrephus placidus) from an Afrotropical cloud forest archipelago. Males born in fragmented forest dispersed about 1 year earlier than those born in continuous forest. Contrary to females, males also started to reproduce earlier and mostly settled within their natal patch. Females only rarely delayed their dispersal for more than 1 year, both in fragmented and continuous forests. Our results suggest that early male dispersal and reproduction is jointly driven by a decrease in the value of the natal territory and an increase in local breeding opportunities in fragmented forest. While plasticity in dispersal strategies of cooperative breeders in response to anthropogenic change is believed to optimize reproduction-survival trade-offs, to what extent it shapes the ability of species to respond to rapid environmental change remains to be studied.


Assuntos
Distribuição Animal , Ecossistema , Passeriformes , Animais , Feminino , Masculino , Reprodução
13.
Proc Biol Sci ; 287(1941): 20201554, 2020 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-33352080

RESUMO

In socially monogamous animals, including humans, pairs can meet and spend time together before they begin reproduction. However, the pre-breeding period has been challenging to study in natural populations, and thus remains largely unexplored. As such, our understanding of the benefits of mate familiarity is almost entirely limited to assessments of repeated breeding with a particular partner. Here, we used fine-scale tracking technology to gather 6 years of data on pre-breeding social associations of individually marked great tits in a wild population. We show that pairs which met earlier in the winter laid their eggs earlier in all years. Clutch size, number of hatched and fledged young, and hatching and fledging success were not influenced by parents' meeting time directly, but indirectly: earlier laying pairs had larger clutches (that also produce higher number of young), and higher hatching and fledging success. We did not detect a direct influence of the length of the initial pairing period on future mating decisions (stay with a partner or divorce). These findings suggest a selective advantage for a new pair to start associating earlier (or for individuals to mate with those they have known for longer). We call for more studies to explore the generality of fitness effects of pair familiarity prior to first breeding, and to elucidate the mechanisms underlying these effects.


Assuntos
Passeriformes/fisiologia , Comportamento Sexual Animal , Animais , Tamanho da Ninhada , Feminino , Masculino , Reprodução , Estações do Ano
14.
BMC Ecol ; 20(1): 70, 2020 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-33334346

RESUMO

BACKGROUND: Earlier breeding is one of the strongest responses to global change in birds and is a key factor determining reproductive success. In most studies of climate effects, the focus has been on large-scale environmental indices or temperature averaged over large geographical areas, neglecting that animals are affected by the local conditions in their home ranges. In riverine ecosystems, climate change is altering the flow regime, in addition to changes resulting from the increasing demand for renewable and clean hydropower. Together with increasing temperatures, this can lead to shifts in the time window available for successful breeding of birds associated with the riverine habitat. Here, we investigated specifically how the environmental conditions at the territory level influence timing of breeding in a passerine bird with an aquatic lifestyle, the white-throated dipper Cinclus cinclus. We relate daily river discharge and other important hydrological parameters, to a long-term dataset of breeding phenology (1978-2015) in a natural river system. RESULTS: Dippers bred earlier when winter river discharge and groundwater levels in the weeks prior to breeding were high, and when there was little snow in the catchment area. Breeding was also earlier at lower altitudes, although the effect dramatically declined over the period. This suggests that territories at higher altitudes had more open water in winter later in the study period, which permitted early breeding also here. Unexpectedly, the largest effect inducing earlier breeding time was territory river discharge during the winter months and not immediately prior to breeding. The territory river discharge also increased during the study period. CONCLUSIONS: The observed earlier breeding can thus be interpreted as a response to climate change. Measuring environmental variation at the scale of the territory thus provides detailed information about the interactions between organisms and the abiotic environment.


Assuntos
Hidrologia , Passeriformes , Animais , Cruzamento , Mudança Climática , Ecossistema
15.
Zootaxa ; 4885(2): zootaxa.4885.2.1, 2020 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-33311274

RESUMO

The species of the chewing louse genus Guimaraesiella Eichler, 1949 parasitic on drongos (Dicruridae) are reviewed and placed in the new subgenus Dicrurobates, which is described herein together with eight new species, including one species from non-dicrurid hosts. The new species are: Guimaraesiella (Dicrurobates) carbonivora n. sp. from Dicrurus bracteatus carbonarius Bonaparte, 1850; Guimaraesiella (Dicrurobates) latitemporalis n. sp. from Dicrurus hottentottus brevirostris (Cabanis, 1851) and Dicrurus hottentottus ssp. (Linnaeus, 1766); Guimaraesiella (Dicrurobates) lurida n. sp. from Dicrurus leucophaeus Vieillot, 1817; Guimaraesiella (Dicrurobates) luzonica n. sp. from Dicrurus balicassius (Linnaeus, 1766); Guimaraesiella (Dicrurobates) nana n. sp. from Dicrurus hottentottus samarensis Vaurie, 1947; Guimaraesiella (Dicrurobates) regis n. sp. from Dicrurus annectans (Hodgson, 1836), Dicrurus paradiseus paradiseus (Linnaeus, 1766) and Dicrurus paradiseus rangoonensis (Gould, 13836); Guimaraesiella (Dicrurobates) transvaalensis n. sp. from Dicrurus adsimilis apivorus Clancey, 1976; and Guimaraesiella (Dicrurobates) campanula n. sp. from Oriolus larvatus rolleti Salvadori, 1864 and Prionops plumatus poliocephalus (Stanley, 1814). Also, Guimaraesiella (Dicrurobates) sexmaculata (Piaget, 1880) and Guimaraesiella (Dicrurobates) dicruri (Ansari, 1955) are redescribed and illustrated. A key to identify adults of all 10 species included in the subgenus is provided.


Assuntos
Doenças das Aves , Iscnóceros , Infestações por Piolhos , Passeriformes , Ftirápteros , Animais
16.
Biol Lett ; 16(12): 20200786, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33321068

RESUMO

Visual attention plays a fundamental role in avian flight but attention is likely limited whenever birds blink. Because blinks are necessary to maintaining proper vision, this study tested the hypothesis that birds strategically inhibit their blinks in flight. The blinks of captive great-tailed grackles (Quiscalus mexicanus) were recorded before, during and after they flew a short distance in an open environment. The grackles spent the least amount of time blinking in flight (take-off, during flight and landing) and the most amount of time blinking at impact. Their blinking behaviour was similar before and after flight. These results suggest that grackles strategically inhibit their blinking behaviour in flight, potentially because blinks impose costs to avian flight.


Assuntos
Passeriformes , Aves Canoras , Animais , Piscadela , Visão Ocular
17.
PLoS One ; 15(10): e0227161, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33052936

RESUMO

Dispersal of whitebark pine (Pinus albicaulis Engelm.), a keystone species of many high-elevation ecosystems in western North America, depends on Clark's nutcracker (Nucifraga columbiana Wilson), a seed-caching bird with an affinity for whitebark seeds. To the extent that this dependence is mutual, declines in whitebark seed production could cause declines in nutcracker abundance. Whitebark pine is in decline across much of its range due to interacting stressors, including the non-native pathogen white pine blister rust (Cronartium ribicola J. C. Fisch.). We used avian point-count data and tree surveys from four national park units to investigate whether trends in whitebark pine can explain trends in Clark's nutcracker. Spatial trends were modeled using recent data from two parks, while temporal trends were modeled using longer time-series of nutcracker and whitebark data from two additional parks. To assess the potential dependence of nutcrackers on whitebark, we linked a model of nutcracker density (accounting for detection probability) with a model of whitebark trends, using a Bayesian framework to translate uncertainty in whitebark metrics to uncertainty in nutcracker density. In Mount Rainier National Park, temporal models showed dramatic declines in nutcracker density concurrent with significant increases in whitebark crown mortality and trees infected with white pine blister rust. However, nutcrackers did not trend with whitebark metrics in North Cascades National Park Service Complex. In spatial models of data from Yosemite National Park and Sequoia-Kings Canyon National Park, nutcracker density varied not only with local cover of whitebark but also with elevation and, in Sequoia-Kings Canyon, with cover of another species of white pine. Our results add support for the hypothesis that the mutualism between whitebark pine and Clark's nutcracker is vulnerable to disruption by blister rust, and our approach integrates data across monitoring programs to explore trends in species interactions.


Assuntos
Passeriformes/crescimento & desenvolvimento , Pinus/crescimento & desenvolvimento , Animais , Teorema de Bayes , América do Norte , Parques Recreativos , Densidade Demográfica , Dinâmica Populacional , Análise Espaço-Temporal , Simbiose
18.
Nat Commun ; 11(1): 4970, 2020 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-33009414

RESUMO

Communicating species identity is a key component of many animal signals. However, whether selection for species recognition systematically increases signal diversity during clade radiation remains debated. Here we show that in woodpecker drumming, a rhythmic signal used during mating and territorial defense, the amount of species identity information encoded remained stable during woodpeckers' radiation. Acoustic analyses and evolutionary reconstructions show interchange among six main drumming types despite strong phylogenetic contingencies, suggesting evolutionary tinkering of drumming structure within a constrained acoustic space. Playback experiments and quantification of species discriminability demonstrate sufficient signal differentiation to support species recognition in local communities. Finally, we only find character displacement in the rare cases where sympatric species are also closely related. Overall, our results illustrate how historical contingencies and ecological interactions can promote conservatism in signals during a clade radiation without impairing the effectiveness of information transfer relevant to inter-specific discrimination.


Assuntos
Comunicação Animal , Evolução Biológica , Passeriformes/fisiologia , Acústica , Animais , Ecossistema , Teoria da Informação , Filogenia , Especificidade da Espécie , Simpatria
19.
Oecologia ; 194(1-2): 75-86, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33025265

RESUMO

Behavioural plasticity during habitat selection plays a key role in determining whether organisms may thrive under human-induced rapid environmental changes. As organisms rely on environmental cues to make decisions, these behavioural responses may be maladaptive. We studied the European stonechat Saxicola torquatus as a model open-habitat bird species breeding in three structurally different land-use types generated by agriculture and forestry activities. In this mosaic landscape, we compared the relative attractiveness and the breeding habitat quality of intensive grassland, Christmas tree plantations and clear-cut patches in plantation forests to test whether habitat selection was adaptive. We examined the settlement pattern of territorial males to evaluate habitat preference. We recorded key parameters reflecting reproductive performances, adult and first-year survival to estimate the individual fitness of the birds and assess the quality of the different land-use types for breeding. Stonechats preferentially settled in clear-cut patches, but their fitness was not found to be markedly different in comparison with the other occupied habitats. Although they produced slightly lower-quality offspring in clear-cut patches, we did not find a negative consequence on first-year survival probabilities or any among-habitat differences in adult survival. With our analysis integrating multiple components of individual fitness, we show that all occupied land-use types are similarly rewarding for the breeding stonechats. Our study shows that some species can benefit from novel land-use types emerging in the landscape as a result of human activities. Flexible habitat selection in the stonechat has most probably contributed to its recent population increase in Western Europe.


Assuntos
Passeriformes , Aves Canoras , Animais , Ecossistema , Europa (Continente) , Humanos , Masculino , Reprodução
20.
Zootaxa ; 4860(1): zootaxa.4860.1.1, 2020 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-33056170

RESUMO

Ten new species of the feather mite genus Trouessartia Canestrini, 1899 (Analgoidea: Trouessartiidae) are described from various passerines of the superfamily Passeroidea in Georgia: Trouessartia americana sp. n. from Setophaga americana (Linnaeus), T. helmitheros sp. n. from Helmitheros vermivorum (Gmelin, JF), T. mniotilta sp. n. from Mniotilta varia (Linnaeus), T. pensylvanica sp. n. from Setophaga pensylvanica (Linnaeus) (type host) and S. palmarum (Gmelin, JF), T. ruticilla sp. n. from S. ruticilla (Linnaeus), T. seiurus sp. n. from Seiurus aurocapilla (Linnaeus), T. tigrina sp. n. from Setophaga tigrina (Gmelin, JF) (Parulidae), T. passerinae sp. n. from Passerina caerulea (Linnaeus) (type host) and P. cyanea (Linnaeus), T. ciris sp. n. from P. ciris (Linnaeus) (Cardinalidae), and T. spizellae sp. n. from Spizella passerina (Bechstein) (Passerellidae). Based on a specific combination of morphological characters, all new species and six previously known species are arranged into a new species group capensis in the genus Trouessartia. The most important diagnostic characters of this species group include: in both sexes, the dorsal hysterosomal apertures are absent; in males, the postgenital plaque is well developed and genital setae g have cylindrical articulation rings; in females, the external copulatory tube is straight, stylet- or finger-like, and situated on the margin of the interlobar membrane, and the head of spermatheca has a semi-ovate extension without indentations. A key to all species referred to the capensis group is provided and host associations of this group with passerines are summarized and briefly discussed. It is hypothesized that this species group originated on the ancestors of New World nine-primaried oscines (Emberizoidea) and diverged in close relation with this group of hosts.


Assuntos
Doenças das Aves , Ácaros , Passeriformes , Aves Canoras , Animais , Feminino , Georgia , Masculino
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