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1.
BMC Ecol Evol ; 21(1): 14, 2021 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-33509089

RESUMO

BACKGROUND: Exploring hybrid zone dynamics at different spatial scales allows for better understanding of local factors that influence hybrid zone structure. In this study, we tested hypotheses about drivers of introgression at two spatial scales within the Saltmarsh Sparrow (Ammospiza caudacuta) and Nelson's Sparrow (A. nelsoni) hybrid zone. Specifically, we evaluated the influence of neutral demographic processes (relative species abundance), natural selection (exogenous environmental factors and genetic incompatibilities), and sexual selection (assortative mating) in this mosaic hybrid zone. By intensively sampling adults (n = 218) and chicks (n = 326) at two geographically proximate locations in the center of the hybrid zone, we determined patterns of introgression on a fine scale across sites of differing habitat. We made broadscale comparisons of patterns from the center with those of prior studies in the southern edge of the hybrid zone. RESULTS: A panel of fixed SNPs (135) identified from ddRAD sequencing was used to calculate a hybrid index and determine genotypic composition/admixture level of the populations. Another panel of polymorphic SNPs (589) was used to assign paternity and reconstruct mating pairs to test for sexual selection. On a broad-scale, patterns of introgression were not explained by random mating within marshes. We found high rates of back-crossing and similarly low rates of recent-generation (F1/F2) hybrids in the center and south of the zone. Offspring genotypic proportions did not meet those expected from random mating within the parental genotypic distribution. Additionally, we observed half as many F1/F2 hybrid female adults than nestlings, while respective male groups showed no difference, in support of Haldane's Rule. The observed proportion of interspecific mating was lower than expected when accounting for mate availability, indicating assortative mating was limiting widespread hybridization. On a fine spatial scale, we found variation in the relative influence of neutral and selective forces between inland and coastal habitats, with the smaller, inland marsh influenced primarily by neutral demographic processes, and the expansive, coastal marsh experiencing higher selective pressures in the form of natural (exogenous and endogenous) and sexual selection. CONCLUSIONS: Multiple drivers of introgression, including neutral and selective pressures (exogenous, endogenous, and sexual selection), are structuring this hybrid zone, and their relative influence is site and context-dependent.


Assuntos
Hibridização Genética , Pardais , Animais , Feminino , Genótipo , Masculino , Reprodução , Seleção Genética , Pardais/genética
2.
Viruses ; 13(1)2021 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-33477379

RESUMO

Porcine deltacoronavirus (PDCoV) strain OH-FD22 infects poultry and shares high nucleotide identity with sparrow-origin deltacoronaviruses (SpDCoV) ISU73347 and HKU17 strains. We hypothesized that the spike (S) protein or receptor-binding domain (RBD) from these SpDCoVs would alter the host and tissue tropism of PDCoV. First, an infectious cDNA clone of PDCoV OH-FD22 strain (icPDCoV) was generated and used to construct chimeric icPDCoVs harboring the S protein of HKU17 (icPDCoV-SHKU17) or the RBD of ISU73347 (icPDCoV-RBDISU). To evaluate their pathogenesis, neonatal gnotobiotic pigs were inoculated orally/oronasally with the recombinant viruses or PDCoV OH-FD22. All pigs inoculated with icPDCoV or OH-FD22 developed severe diarrhea and shed viral RNA at moderate-high levels (7.62-10.56 log10 copies/mL) in feces, and low-moderate levels in nasal swabs (4.92-8.48 log10 copies/mL). No pigs in the icPDCoV-SHKU17 and icPDCoV-RBDISU groups showed clinical signs. Interestingly, low-moderate levels (5.07-7.06 log10 copies/mL) of nasal but not fecal viral RNA shedding were detected transiently at 1-4 days post-inoculation in 40% (2/5) of icPDCoV-SHKU17- and 50% (1/2) of icPDCoV-RBDISU-inoculated pigs. These results confirm that PDCoV infected both the upper respiratory and intestinal tracts of pigs. The chimeric viruses displayed an attenuated phenotype with the loss of tropism for the pig intestine. The SpDCoV S protein and RBD reduced viral replication in pigs, suggesting limited potential for cross-species spillover upon initial passage.


Assuntos
Infecções por Coronavirus/patologia , Intestinos/patologia , Sistema Respiratório/patologia , Glicoproteína da Espícula de Coronavírus/genética , Tropismo Viral/genética , Motivos de Aminoácidos , Animais , Doenças das Aves/virologia , Linhagem Celular , Intestinos/virologia , Proteínas Recombinantes/genética , Sistema Respiratório/virologia , Pardais , Suínos , Doenças dos Suínos/virologia , Virulência/genética
3.
Ecotoxicol Environ Saf ; 208: 111755, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396078

RESUMO

Air pollution constitutes potential threats to wildlife and human health; therefore, it must be monitored accurately. However, little attention has been given to understanding the toxicological effects induced by air pollution and the suitability of bird species as bioindicators. The Eurasian tree sparrow (Passer montanus), a human commensal species, was used as a study model to examine toxic metal accumulation, retention of particulate matter (PM), immunological and antioxidant capacities, and hematological parameters in birds inhabiting those areas with relatively higher (Shijiazhuang city) or lower (Chengde city) levels of PM2.5 and PM10 in China. Our results showed that Shijiazhuang birds had significantly more particle retention in the lungs and toxic metal (including aluminum, arsenic, cadmium, iron, manganese, and lead) accumulation in the feathers relative to Chengde birds. They also had lower superoxide dismutase, albumin, immunoglobulin M concentrations in the lung lavage fluid, and total antioxidant capacity (T-AOC) in the lungs and hearts. Furthermore, although they had higher proportions of microcytes, hypochromia, and polychromatic erythrocytes in the peripheral blood (a symptom of anemia), both populations exhibited comparable body conditions, white cell counts, heterophil and lymphocyte ratios, and plasma T-AOC and corticosterone levels. Therefore, our results not only confirmed that Shijiazhuang birds experienced a greater burden from environmental PM and toxic metals but also identified a suite of adverse effects of environmental pollution on immunological, antioxidative, and hematological parameters in multiple tissues. These findings contribute to our understanding of the physiological health consequences induced by PM exposure in wild animals. They suggest that free-living birds inhabiting urban areas could be used as bioindicators for evaluating the adverse effects induced by environmental pollution.


Assuntos
Poluição do Ar/estatística & dados numéricos , Exposição Ambiental/estatística & dados numéricos , Poluição Ambiental/estatística & dados numéricos , Pardais/fisiologia , Poluentes Atmosféricos , Animais , Animais Selvagens , Antioxidantes , Cádmio , China , Cidades , Biomarcadores Ambientais , Poluição Ambiental/análise , Plumas , Humanos , Material Particulado , Pardais/sangue
4.
Sci Total Environ ; 747: 141402, 2020 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-32771794

RESUMO

Heavy metals affect male reproductive function by impairing reproductive organs, disturbing reproductive hormone levels or directly affecting sperm quality. However, little attention has been given to the effect of environmental heavy metals on reproductive function in wild male birds. The present study investigated the alterations of reproductive function in male tree sparrows (Passer montanus) exposed to environments contaminated by heavy metals in terms of testis parameters, reproductive hormone levels and sperm movement characteristics. Two plots, Baiyin (BY, mainly polluted by copper, zinc, lead and cadmium) and Liujiaxia (LJX, a relatively unpolluted area) were selected as sampling sites. The results showed that tree sparrows from BY (1) accumulated higher levels of cadmium in the testes, (2) showed lower superoxide dismutase (SOD) activity and malondialdehyde level, with higher total antioxidant capacity and apoptosis level in the testes, (3) showed higher plasma levels of estrogen, follicle stimulating hormone and luteinizing hormone (LH), and (4) had better sperm movement performance. Additionally, we found that testis size, SOD activity in testes and LH levels were decisive factors in sperm movement performance in tree sparrows. Heavy metal concentrations in testes negatively correlated with testis size, SOD activity in testes, and estrogen levels in tree sparrows. The present study indicates that heavy metals accumulating in testes of tree sparrows adversely affected some key indicators of male reproductive function. However, testicular function, reproductive hormone levels and sperm quality showed adaptive responses that tended to partially compensate for the negative effects in the heavy metal polluted area. This study further indicated that the regulation of testicular function and reproductive hormone levels was the main factor for better sperm quality in tree sparrows exposed to environments contaminated by heavy metals.


Assuntos
Metais Pesados , Pardais , Animais , Cádmio , Poluição Ambiental/análise , Humanos , Masculino , Metais Pesados/análise , Metais Pesados/toxicidade , Motilidade Espermática
5.
Proc Natl Acad Sci U S A ; 117(35): 21673-21680, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32817554

RESUMO

Behavioral evolution relies on genetic changes, yet few behaviors can be traced to specific genetic sequences in vertebrates. Here we provide experimental evidence showing that differentiation of a single gene has contributed to the evolution of divergent behavioral phenotypes in the white-throated sparrow, a common backyard songbird. In this species, a series of chromosomal inversions has formed a supergene that segregates with an aggressive phenotype. The supergene has captured ESR1, the gene that encodes estrogen receptor α (ERα); as a result, this gene is accumulating changes that now distinguish the supergene allele from the standard allele. Our results show that in birds of the more aggressive phenotype, ERα knockdown caused a phenotypic change to that of the less aggressive phenotype. We next showed that in a free-living population, aggression is predicted by allelic imbalance favoring the supergene allele. Finally, we identified cis-regulatory features, both genetic and epigenetic, that explain the allelic imbalance. This work provides a rare illustration of how genotypic divergence has led to behavioral phenotypic divergence in a vertebrate.


Assuntos
Agressão/fisiologia , Receptor alfa de Estrogênio/genética , Pardais/genética , Animais , Comportamento Animal , Inversão Cromossômica/genética , Estrogênios/genética , Estrogênios/metabolismo , Feminino , Genótipo , Masculino , Fenótipo , Receptores Estrogênicos/genética , Comportamento Social
6.
Proc Biol Sci ; 287(1933): 20201259, 2020 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-32811312

RESUMO

Recent studies have emphasized the role of social learning and cultural transmission in promoting conformity and uniformity in animal groups, but little attention has been given to the role of negative frequency-dependent learning in impeding conformity and promoting diversity instead. Here, we show experimentally that under competitive conditions that are common in nature, social foragers (although capable of social learning) are likely to develop diversity in foraging specialization rather than uniformity. Naive house sparrows that were introduced into groups of foraging specialists did not conform to the behaviour of the specialists, but rather learned to use the alternative food-related cues, thus forming groups of complementary specialists. We further show that individuals in such groups may forage more effectively in diverse environments. Our results suggest that when the benefit from socially acquired skills diminishes through competition in a negative frequency-dependent manner, animal societies will become behaviourally diverse rather than uniform.


Assuntos
Comportamento Animal , Comportamento Social , Conformidade Social , Aprendizado Social , Pardais/fisiologia , Animais , Sinais (Psicologia) , Aprendizagem
7.
PLoS One ; 15(8): e0237170, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32813710

RESUMO

In the last decade, house sparrow populations have shown a general decline, especially in cities. Avian malaria has been recently suggested as one of the potential causes of this decline, and its detrimental effects could be exacerbated in urban habitats. It was initially thought that avian malaria parasites would not have large negative effects on wild birds because of their long co-evolution with their hosts. However, it is now well-documented that they can have detrimental effects at both the primo- and chronical infection stages. In this study, we examined avian malaria infection and its physiological and morphological consequences in four populations of wild house sparrows (2 urban and 2 rural). We did not find any relationship between the proportions of infected individuals and the urbanisation score calculated for our populations. However, we observed that the proportion of infected individuals increased during the course of the season, and that juveniles were less infected than adults. We did not detect a strong effect of malaria infection on physiological, morphological and condition indexes. Complex parasite dynamics and the presence of confounding factors could have masked the potential effects of infection. Thus, longitudinal and experimental studies are needed to understand the evolutionary ecology of this very common, but still poorly understood, wild bird parasite.


Assuntos
Doenças das Aves/parasitologia , Malária Aviária/diagnóstico , Parasitemia/diagnóstico , Plasmodium/genética , População Rural , Pardais/parasitologia , População Urbana , Animais , Cidades , Feminino , França , Malária Aviária/parasitologia , Malária Aviária/fisiopatologia , Masculino , Reação em Cadeia da Polimerase , Estações do Ano , Urbanização
8.
Mol Ecol ; 29(20): 3809-3811, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32860449

RESUMO

Parasites are recognized to be some of the strongest agents of natural selection, sometimes causing major changes in the phenotypes of their hosts. Understanding the genomic determinants leading to these adaptive processes is key to understand host-parasite interactions. However, dissecting the genetic architecture of host resistance in natural systems is difficult because of the multiple factors affecting these complex traits in the wild. In this issue of Molecular Ecology, Lundregan et al. (2020) use an impressive long-term data set to analyse the genomic architecture of host resistance to gapeworm in a metapopulation of house sparrows. The authors elegantly combine different approaches (variance component analyses, genome partitioning and genome-wide associations) to reveal that resistance to gapeworm is under polygenic control and can have both a significant additive genetic and dominance variance. This study is one of the first to simultaneously determine genomic architecture and assess additive genetic and dominance genetic variance in parasite resistance in natural populations.


Assuntos
Parasitos , Pardais , Animais , Genoma , Genômica , Modelos Genéticos , Fenótipo , Pardais/genética
9.
PLoS One ; 15(6): e0234008, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32530950

RESUMO

Urbanization fragments landscapes and can impede the movement of organisms through their environment, which can decrease population connectivity. Reduction in connectivity influences gene flow and allele frequencies, and can lead to a reduction in genetic diversity and the fixation of certain alleles, with potential negative effects for populations. Previous studies have detected effects of urbanization on genetic diversity and structure in terrestrial animals living in landscapes that vary in their degree of urbanization, even over very short distances. We investigated the effects of low-intensity urbanization on genetic diversity and genetic structure in Song Sparrows (Melospiza melodia). We captured 208 Song Sparrows at seven sites along a gradient of urbanization in and around Blacksburg, VA, USA, then genotyped them using a panel of fifteen polymorphic microsatellite loci. We found that genetic diversity was comparable among the seven study sites, and there was no evidence of genetic structuring among sites. These findings suggest that over a gradient of urbanization characterized by low density urban development, Song Sparrows likely exist in a single panmictic population.


Assuntos
Interação Gene-Ambiente , Variação Genética , Pardais/genética , Animais , Fluxo Gênico , Frequência do Gene , Repetições de Microssatélites , Urbanização
10.
Proc Natl Acad Sci U S A ; 117(25): 14584-14592, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32513746

RESUMO

Inbreeding may increase the extinction risk of small populations. Yet, studies using modern genomic tools to investigate inbreeding depression in nature have been limited to single populations, and little is known about the dynamics of inbreeding depression in subdivided populations over time. Natural populations often experience different environmental conditions and differ in demographic history and genetic composition, characteristics that can affect the severity of inbreeding depression. We utilized extensive long-term data on more than 3,100 individuals from eight islands in an insular house sparrow metapopulation to examine the generality of inbreeding effects. Using genomic estimates of realized inbreeding, we discovered that inbred individuals had lower survival probabilities and produced fewer recruiting offspring than noninbred individuals. Inbreeding depression, measured as the decline in fitness-related traits per unit inbreeding, did not vary appreciably among populations or with time. As a consequence, populations with more resident inbreeding (due to their demographic history) paid a higher total fitness cost, evidenced by a larger variance in fitness explained by inbreeding within these populations. Our results are in contrast to the idea that effects of inbreeding generally depend on ecological factors and genetic differences among populations, and expand the understanding of inbreeding depression in natural subdivided populations.


Assuntos
Aptidão Genética/fisiologia , Depressão por Endogamia/fisiologia , Pardais/fisiologia , Animais , Feminino , Masculino , Linhagem , Dinâmica Populacional , Análise Espaço-Temporal
11.
PLoS One ; 15(4): e0232282, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32352998

RESUMO

The magnitude and distribution of genetic diversity through space and time can provide useful information relating to evolutionary potential and conservation status in threatened species. In assessing genetic diversity in species that are of conservation concern, several studies have focused on the use of Toll-like receptors (TLRs). TLRs are innate immune genes related to pathogen resistance, and polymorphisms may reflect not only levels of functional diversity, but may also be used to assess genetic diversity within and among populations. Here, we combined four potentially adaptive markers (TLRs) with one mitochondrial (COI) marker to evaluate genetic variation in the endangered Sierra Madre Sparrow (Xenospiza baileyi). This species offers an ideal model to investigate population and evolutionary genetic processes that may be occurring in a habitat restricted endangered species with disjunct populations (Mexico City and Durango), the census sizes of which differ by an order of magnitude. TLRs diversity in the Sierra Madre Sparrow was relatively high, which was not expected given its two small, geographically isolated populations. Genetic diversity was different (but not significantly so) between the two populations, with less diversity seen in the smaller Durango population. Population genetic structure between populations was due to isolation and different selective forces acting on different TLRs; population structure was also evident in COI. Reduction of genetic diversity in COI was observed over 20 years in the Durango population, a result likely caused by habitat loss, a factor which may be the main cause of diversity decline generally. Our results provide information related to the ways in which adaptive variation can be altered by demographic changes due to human-mediated habitat alterations. Furthermore, our findings may help to guide conservation schemes for both populations and their restricted habitat.


Assuntos
Polimorfismo Genético/genética , Pardais/genética , Animais , Evolução Biológica , Conservação dos Recursos Naturais/métodos , Ecossistema , Espécies em Perigo de Extinção , Genética Populacional/métodos , Repetições de Microssatélites/genética , Filogenia
12.
Sci Rep ; 10(1): 7301, 2020 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-32350395

RESUMO

The performances of different social groups can depend on various characteristics, such as familiarity among their members or the presence of individuals with specific traits. However, it has rarely been investigated how groups perform during an encounter with other conspecifics, even if in the natural environment social groups often run into each other and compete for resources. We investigated whether a certain characteristic of the group (i.e., familiarity) could benefit its members when they are confronted with another group. We designed a novel experimental set-up, creating triads of captive house sparrows (Passer domesticus) and examining whether in a situation of competition for limited resources one triad could gain benefits over the other (consume more mealworms, Tenebrio molitor). While we did not find an effect of previous familiarity among triad members on the triads' performances, we discovered a group-based difference in the number of mealworms eaten per capita. Group-mates of the very first individual to eat a mealworm (first feeder) ate more mealworms than those in the opposing triad. First feeder individuals also foraged sooner and more than other birds in a subsequent prey consumption assay. Our results suggest that individual performances were influenced by group membership, even when groups were exploiting the same resource simultaneously.


Assuntos
Comportamento Exploratório , Comportamento Alimentar , Comportamento Social , Pardais/fisiologia , Animais
13.
Aust Vet J ; 98(7): 338-344, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32430906

RESUMO

CASE REPORT: An outbreak of systemic isosporosis caused mortalities in greenfinches (Carduelis chloris) and goldfinches (Carduelis carduelis) kept in an aviary in the western suburbs of Melbourne. The following year, a further outbreak in the same aviary occurred in a different flock of goldfinches. At the time of the second outbreak, dead and sick common sparrows (Passer domesticus) discovered near the aviary were also found to have systemic isosporosis. METHOD: The systemic isosporosis was investigated and described using histopathology, electron microscopy and sequence analysis of the 18s gene. RESULTS: Isospora spp. infecting the greenfinch and the goldfinch caused significant thickening of the duodenal lamina propria. Measurements in the goldfinches showed an inverse correlation coefficient between the thickening of the duodenum and the weightof the birds. Electron microscopy confirmed the presence of Isospora spp. within lymphocytes migrating into the lamina propria of the duodenum. Analysis of the 18s sequence discovered two different gene sequences across the three species of birds that didn't completely match any sequences previously deposited in GenBank. CONCLUSION: Although the sparrows were found to have died from causes other than systemic Isospora, molecular studies of samples from their liver revealed the presence of an Isospora with 18s gene sequence identical to that found in the captive greenfinches.


Assuntos
Doenças das Aves/epidemiologia , Isospora , Pardais , Animais , Surtos de Doenças
14.
Braz. J. Vet. Res. Anim. Sci. (Online) ; 57(2): e164867, mai. 2020. tab
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1122178

RESUMO

The objective of this study was to detect the presence of anti-Toxoplasma gondii antibodies in serum samples from 100 house sparrows (Passer domesticus Linnaeus, 1758) that were caught in the municipality of Pelotas, Rio Grande do Sul, Brazil. The modified agglutination test (MAT) was used to investigate anti-T. gondii antibodies and samples with a cut-off dilution > 5 were considered positive. Among the 100 serum samples analyzed, 80 (80%) were reactive. These results demonstrate that P. domesticus may play an important role in the epidemiological chain of T. gondii, since it is widely distributed throughout Brazil, and may act as a source of infection to domestic and wild felids.(AU)


O objetivo deste estudo foi detectar a presença de anticorpos anti-Toxoplasma gondii em amostras de soro de 100 pardais (Passer domesticus Linnaeus, 1758) capturados na área urbana do município de Pelotas, Rio Grande do Sul, Brasil. Para a pesquisa de anticorpos anti-T. gondii foi utilizado o teste de aglutinação modificado (MAT) e foram consideradas positivas as amostras que apresentaram título > 5. Das 100 amostras de soro analisadas, 80 (80%) foram reagentes. Esses resultados demonstram que P. domesticus, por ser amplamente distribuído em todo país, pode desempenhar um papel importante na cadeia epidemiológica de T. gondii, podendo atuar como fonte de infecção para felinos domésticos e silvestres.(AU)


Assuntos
Animais , Toxoplasma/isolamento & purificação , Toxoplasmose Animal/epidemiologia , Pardais/virologia , Soros Imunes , Brasil , Área Urbana , Passeriformes/virologia , Saúde Pública Veterinária
15.
Int J Biometeorol ; 64(8): 1285-1293, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32328788

RESUMO

Increasing evidence suggests that the environment encountered by migrating landbirds during the nonbreeding season, including temperature and precipitation, may influence individuals and population processes in subsequent seasons. However, to date, most studies have focused on linkages between factors encountered during the wintering and breeding periods in long-distance, primarily insectivorous landbirds. Here, we take advantage of a long-term (23 breeding seasons) data set on the arrival and breeding ecology of female field sparrows (Spizella pusilla), a granivorous, short-distance species that winters in the southeastern USA, to look for time periods (windows) over the preceding winter and spring migratory periods when average daily precipitation or temperature may have influenced when a female arrived at breeding grounds in northeastern Pennsylvania and correlates of seasonal reproductive performance. We employed a sliding window analysis approach using weather data obtained from the south of our site (to evaluate effects of weather experienced during the nonbreeding period) and, separately, near our site (to evaluate effects of weather experienced during the breeding period), finding windows in which temperature and precipitation during the nonbreeding period were associated with arrival timing and clutch initiation day and a window in which temperature experienced during the breeding period was associated with clutch initiation day. We did not, however, find evidence that temperature or precipitation, either during the nonbreeding period or breeding period, was associated with clutch size nor total egg volume. Finally, early arriving females initiated clutches early, produced larger clutches, more nests, and more total eggs than later arriving females. Our findings contribute to the growing body of evidence that events experienced prior to the breeding season may influence individuals and population processes in subsequent seasons.


Assuntos
Migração Animal , Pardais , Animais , Cruzamento , Feminino , Pennsylvania , Reprodução , Estações do Ano , Tempo (Meteorologia)
16.
Ecotoxicol Environ Saf ; 197: 110622, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32311616

RESUMO

Sperm morphology and performance traits are key determinants of male fertilization success, particularly when females copulate with multiple males. Such sperm traits have been reported to be influenced by environmental pollutants in various animals; however, such studies remain rare in free-living birds exposed to heavy metal pollution. In the present study, we selected tree sparrow (Passer montanus) as the study object to explore the effect of long-term environmental heavy metal pollution on sperm morphology (assessed mainly by using the dimensions of different sperm components and the sperm abnormality rates) and sperm performance (indicated by sperm velocity), and to elucidate potential relationships between variations in sperm morphology and performance. Sperm ATP concentration was also assessed considering sperm morphology and performance could be linked via energy availability. According to our results, tree sparrows from heavy metal polluted area (1) accumulated cadmium at a higher level in their testes; (2) produced longer sperm with lower abnormality rates, in addition to sperm with longer flagella and smaller head/flagellum ratios; (3) their sperm swam faster compared to those from the relatively unpolluted area, while no differences were observed in sperm ATP concentrations. We also found that the levels of lead and cadmium in testes affected the sperm nucleus length, and the level of copper in testes was negatively related to the proportions of abnormal sperm. Furthermore, the present study showed that sperm velocity was negatively correlated with sperm head lengths, head/flagellum ratios and ATP concentrations. Our study results reveal that sperm morphology and performance in tree sparrows show positive variations to maximize male fertility ability under long-term environmental heavy metal pollution, where males increase sperm flagellum lengths to decrease head/flagellum ratios, as opposed to varying sperm energy production, to achieve higher sperm velocity.


Assuntos
Poluentes Ambientais/toxicidade , Metais Pesados/toxicidade , Pardais/crescimento & desenvolvimento , Espermatozoides/efeitos dos fármacos , Animais , Cádmio/toxicidade , Feminino , Fertilidade/efeitos dos fármacos , Masculino , Motilidade Espermática/efeitos dos fármacos , Espermatozoides/patologia
17.
Sci Total Environ ; 720: 137583, 2020 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-32325582

RESUMO

In marine species, the transcriptomic response to Deepwater Horizon (DWH) oil implicated many biochemical pathways, with corresponding adverse outcomes on organ development and physiological performance. Terrestrial organisms differ in their mechanisms of exposure to polycyclic aromatic hydrocarbons (PAHs) and their physiological challenges, and may reveal either distinct effects of oil on biochemical pathways or the generality of the responses to oil shown in marine species. Using a cross-species hybridization microarray approach, we investigated the transcriptomic response in the liver of Seaside Sparrows (Ammospiza maritima) exposed to DWH oil compared with birds from a control site. Our analysis identified 295 genes differentially expressed between birds exposed to oil and controls. Gene ontology (GO) and canonical pathway analysis suggested that the identified genes were involved in a coordinated response that promoted hepatocellular proliferation and liver regeneration while inhibiting apoptosis, necrosis, and liver steatosis. Exposure to oil also altered the expression of genes regulating energy homeostasis, including carbohydrate metabolism and gluconeogenesis, and the biosynthesis, transport and metabolism of lipids. These results provide a molecular mechanism for the long-standing observation of hepatic hypertrophy and altered lipid biosynthesis and transport in birds exposed to crude oil. Several of the activated pathways and pathological outcomes shown here overlap with the ones altered in fish species upon exposure to oil. Overall, our study shows that the path of oil contamination from the marine system into salt marshes can lead to similar responses in terrestrial birds to those described in marine organisms, suggesting similar adverse outcomes and shared machinery for detoxification.


Assuntos
Pardais , Animais , Perfilação da Expressão Gênica , Golfo do México , Petróleo , Poluição por Petróleo , Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água
18.
Ecotoxicology ; 29(8): 1148-1160, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32124146

RESUMO

Here we report on the results of a long-term study of mercury exposure in a songbird species, the saltmarsh sparrow (Ammodramus caudacutus). We measured total mercury concentrations in blood (n = 840) and feathers (n = 560) of adult saltmarsh sparrows at six locations between 2000 and 2017: Rachel Carson National Wildlife Refuge (RCNWR) in Wells, Maine; Scarborough Marsh State Wildlife Management Area in Scarborough, Maine; Parker River National Wildlife Refuge on Plum Island, Massachusetts; Pine Neck Preserve in Southampton, Long Island, New York; and North Cinder and North Green Sedge Islands off the coast of Long Island, New York. During the 12-17 year sampling periods, we found that mercury exposure differed by site and year but there was no consistent temporal trend across sites. Blood mercury concentrations declined only at RCNWR in Maine. We also found seasonal variation in blood mercury concentrations and a positive relationship between mercury concentrations of blood and innermost primary feather, but not between blood and tail feather.


Assuntos
Monitoramento Ambiental , Poluentes Ambientais , Mercúrio , Pardais/metabolismo , Animais , Plumas/química , Maine , Massachusetts , New York , Áreas Alagadas
19.
Sci Total Environ ; 721: 137674, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32163734

RESUMO

Anthropogenic metal pollution is known to adversely affect bird reproduction; however, few systematic studies are available on the effects of metal pollution on breeding performance and parental investment in a common resident songbird, the tree sparrow (Passer montanus). We conducted this study in two sites, a long-term heavy metal polluted site (Baiyin [BY]) and a relatively unpolluted site at approximately 110 km distance (Liujiaxia [LJX]), to assess the potential effects of environmental metal contamination on breeding parameters (clutch size, hatching success, fledging success, and growth of nestlings) and parental investment. The results showed smaller clutch size, lower fledging success, and differences in incubation behaviors of tree sparrows in BY than in LJX. Although there was no difference in parental body condition (residual body mass) between the two study sites, the parents responded differently with respect to reproduction due to varying metal levels in their habitats and bodies. Higher Cd levels in the primary feathers of females in BY were associated with lower clutch sizes. Parental investment including incubation duration and feeding rates showed no significant difference between the two sites during the incubation and nestling periods, but the frequencies of incubation visits were higher in BY. Parental behavior during the incubation period was also negatively affected by the parental Pb and Cd levels. Although the nestling growth patterns were relatively similar between the two sites, the nestlings were smaller, had lower body weight, and fledged later and fledging rate was also lower in BY than in LJX. Metal concentrations were higher in nestling organs and feces in BY. Taken together, metal pollution might adversely affect nestling growth condition. Our results suggest a negative response in the reproduction of tree sparrows to long-term environmental metal pollution.


Assuntos
Metais Pesados/análise , Pardais , Animais , Cruzamento , Poluição Ambiental/análise , Feminino , Reprodução
20.
Environ Pollut ; 263(Pt B): 114396, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32222667

RESUMO

Genetic diversity is the bedrock of evolution. The "Genetic Erosion" hypothesis posits that environmental pollution could cause reduced genetic diversity. To explore the effects of heavy metal pollution on genetic diversity in natural populations, we selected an area with more than sixty years of heavy metal contamination (Baiyin, BY) and a relatively unpolluted one (Liujiaxia, LJX), and tree sparrow (Passer montanus) as study models. Five tree sparrow populations were sampled in BY at sites differing in heavy metal pollution level. Lower genetic diversity based on seven microsatellite loci was observed in the five tree sparrow populations from BY compared with those from LJX. Analysis of molecular variance indicated no significant genetic differentiation between BY and LJX. However, the observed heterozygosity and allelic richness were negatively correlated to the lead and cadmium concentrations in the primary feathers of tree sparrow. Our results indicated the genetic diversity might have a negative response to long-term environmental heavy metal pollution in tree sparrow, supporting the "Genetic Erosion" hypothesis. Therefore, the findings shed lights on the possible effects of heavy metal pollution on genetic diversity of wild bird populations.


Assuntos
Metais Pesados/análise , Pardais , Animais , Cádmio , Poluição Ambiental/análise , Variação Genética
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