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To be able to protect biodiversity in coming decades, conservation strategies need to consider what sites will be important for species not just today but also in the future. Different methods have been proposed to identify places that will be important for species in the future. Two of the most frequently used methods, ecological niche modeling and climate resilience, have distinct aims. The former focuses on identifying the suitable environmental conditions for species, thus protecting the "actor," namely, the species, whereas the latter seeks to safeguard the "stage," or the landscape in which species occur. We used the two methods to identify climate refugia for 258 forest vertebrates under short- and long-term climatic changes in a biodiversity hotspot, the Appalachian ecoregion of the United States. We also evaluated the spatial congruence of the two approaches for a possible conservation application, that of protecting 30% of the Appalachian region, in line with recent national and international policy recommendations. We detected weak positive correlations between resilience scores and baseline vertebrate richness, estimated with ecological niche models for historical (baseline) climatic conditions. The correlations were stronger for amphibians and mammals than for birds and reptiles. Under climate change scenarios, the correlations between estimated vertebrate richness and resilience were also weakly positive; a positive correlation was detected only for amphibians. Locations with estimated future gain of suitable climatic conditions for vertebrates showed low correlation with resilience. Overall, our results indicate that climate resilience and ecological niche modeling approaches capture different characteristics of projected distributional changes of Appalachian vertebrates. A climate resilience (the stage) approach could be more effective in safeguarding species with low dispersal abilities, whereas an ecological niche modeling (the actor) approach could be more suitable for species with long-distance dispersal capacity because they may be more broadly impacted by climate and less sensitive to geophysical features captured by a climate resilience approach.
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Mudança Climática , Conservação dos Recursos Naturais , Animais , Conservação dos Recursos Naturais/métodos , Biodiversidade , Ecossistema , Vertebrados , Anfíbios , MamíferosRESUMO
The Asian giant hornet (Vespa mandarinia) was recently detected in western British Columbia, Canada and Washington State, United States. V. mandarinia are an invasion concern due to their ability to kill honey bees and affect humans. Here, we used habitat suitability models and dispersal simulations to assess potential invasive spread of V. mandarinia We show V. mandarinia are most likely to establish in areas with warm to cool annual mean temperature, high precipitation, and high human activity. The realized niche of introduced populations is small compared to native populations, suggesting introduced populations could spread into habitats across a broader range of environmental conditions. Dispersal simulations also show that V. mandarinia could rapidly spread throughout western North America without containment. Given its potential negative impacts and capacity for spread, extensive monitoring and eradication efforts throughout western North America are warranted.
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Ecossistema , Vespas/fisiologia , Distribuição Animal , Animais , Espécies Introduzidas/estatística & dados numéricos , América do Norte , Dinâmica Populacional , Temperatura , Vespas/crescimento & desenvolvimentoRESUMO
This study investigated the Pleistocene history of a semi-aquatic bug, Microvelia douglasi douglasi Scott, 1874 (Hemiptera: Veliidae) in East Asia. We used M. douglasi douglasi as a model species to explore the effects of historical climatic fluctuations on montane semi-aquatic invertebrate species. Two hypotheses were developed using ecological niche models (ENMs). First, we hypothesized that M. douglasi douglasi persisted in suitable habitats in southern Guizhou, southern Yunnan, Hainan, Taiwan and southeast China during the LIG. After that, the populations expanded (Hypothesis 1). As the spatial prediction in the LGM was significantly larger than in the LIG, we then hypothesized that the population expanded during the LIG to LGM transition (Hypothesis 2). We tested these hypotheses using mitochondrial data (COI+COII) and nuclear data (ITS1+5.8S+ITS2). Young lineages, relatively deep splits, lineage differentiation among mountain ranges in central, south and southwest China and high genetic diversities were observed in these suitable habitats. Evidence of mismatch distributions and neutrality tests indicate that a population expansion occurred in the late Pleistocene. The Bayesian skyline plot (BSP) revealed an unusual population expansion that likely happened during the cooling transition between LIG and LGM. The results of genetic data were mostly consistent with the spatial predictions from ENM, a finding that can profoundly improve phylogeographic research. The ecological requirements of M. douglasi douglasi, together with the geographical heterogeneity and climatic fluctuations of Pleistocene in East Asia, could have shaped this unusual demographic history. Our study contributes to our knowledge of semi-aquatic bug/invertebrate responses to Pleistocene climatic fluctuations in East Asia.
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Ecossistema , Evolução Molecular , Heterópteros/genética , Modelos Biológicos , Animais , Teorema de Bayes , Mudança Climática , DNA Mitocondrial/genética , DNA Espaçador Ribossômico/genética , Ásia Oriental , Variação Genética , Haplótipos , Dados de Sequência Molecular , FilogeografiaRESUMO
The COI gene as the core of the DNA barcoding system for animals has received significant attention. The observed wide overlap between intraand interspecific sequence variability has led researchers to envisage the primary COI-based method. The sequences of 16S rDNA, COI, and Cyt b genes of Nezara virudula (L.) (Hemiptera: Pentatomidae) from 13 countries and the same sequences of N. antennata Scott were chosen as molecular markers to analyze the intraand interspecific relationships between the closely related species in this study. The results support that Cyt b gene may be a good candidate alongside COI, when the combined factors of geographic variation and closely related species are taken into account.
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Citocromos b/genética , Código de Barras de DNA Taxonômico , Complexo IV da Cadeia de Transporte de Elétrons/genética , Hemípteros/genética , RNA Ribossômico 16S/genética , Animais , FilogeografiaRESUMO
Parastrachiidae is a small stinkbug family containing only one genus and two species, Parastrachia japonensis (Scott) (Hemiptera: Heteroptera: Pentatomoidea) and Parastrachia nagaensis Distant. The geographic distribution of the genus has been poorly studied. Niche conservatism refers to that idea that closely related species are more ecologically similar than would be expected, whereas niche divergence predicts they occupy distinct niche spaces. The existence of only two species within one genus suggests niche conservatism or differentiation might exist among them. Herein, the distribution of the genus was mapped, potential distributions were predicted using ecological niche modeling, and climate spaces occupied by the two species were identified and compared. Our outlined map supports the general spreading route proposed by Schaefer et al. The potential distributions suggest that the genus' range could extend beyond its presently known distribution, and further investigation into this area could aid in their conservation, particularly P. nagaensis. The niche space inferred by ecological niche modeling suggests the two species do not occupy identical habitat, but the differences between their models could simply be due to the differential availability of habitat in the different regions that they occupy.
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Distribuição Animal , Conservação dos Recursos Naturais , Ecossistema , Heterópteros/fisiologia , Animais , Modelos Biológicos , Análise de Componente Principal , Especificidade da EspécieRESUMO
The Japanese beetle, Popillia japonica (Newman, 1841) (Coleoptera: Scarabaeidae), was first detected in southern Washington State in 2020. Widespread trapping efforts ensued, and over 23,000 individuals were collected in both 2021 and 2022 in this region known for specialty crop production. The invasion of Japanese beetle is of major concern as it feeds on over 300 plant species and has shown an ability to spread across landscapes. Here, we created a habitat suitability model for Japanese beetle in Washington and used dispersal models to forecast invasion scenarios. Our models predict that the area of current establishment occurs in a region with highly suitable habitat. Moreover, vast areas of habitat that are likely highly suitable for Japanese beetle occur in coastal areas of western Washington, with medium to highly suitable habitat in central and eastern Washington. Dispersal models suggested that the beetle could spread throughout Washington within 20 years without management, which justifies quarantine and eradication measures. Timely map-based predictions can be useful tools to guide management of invasive species while also increasing citizen engagement to invaders.
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Besouros , Animais , Washington , Plantas , Espécies Introduzidas , QuarentenaRESUMO
BACKGROUND: How parasitoids distinguish hosts from non-hosts remains an unknown question. Chouioia cunea Yang (Eulophidae) is an important fall webworm parasitoid that attacks many forest and agricultural pests. To study the differences in the chemical clues used by C. cunea to distinguish host and non-host plants, we used gas chromatography-mass spectrometry (GC-MS) to identify volatile compounds of two C. cunea hosts (Hyphantria cunea and Helicoverpa armigera) and two non-hosts (Spodoptera exigua and Spodoptera frugiperda). Additionally, we used behavioral assays to compare the attraction of C. cunea to various compounds. RESULTS: The two natural host species were more attractive than the two non-host species, in the following order: Hyphantria cunea > Helicoverpa armigera > S. exigua = S. frugiperda. The pupae of the natural hosts contained 1-dodecene, which was not produced by the two natural non-hosts. When the 'attractants' based on the difference between the species-specific blend emitted by pupae and the optimal blend were sprayed onto the natural non-host pupae, they significantly improved the attraction of C. cunea to the non-host pupae. CONCLUSION: These results revealed that specific host-produced volatile compounds guide C. cunea to distinguish between natural hosts and non-hosts. Overall, this study provides a foundation for developing a behavior-modifying strategy to re-direct C. cunea attacks to control important non-host pests. © 2023 Society of Chemical Industry.
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The Anthocoris nemorum group belongs to the Anthocoridae (Hemiptera), and is an important group of predators of agricultural pests. A phylogeny was constructed in conjunction with dispersal-vicariance analysis of the Anthocoris nemorum group species in order to discern the relationships between the phylogeographical structuring of A. nemorum group species, and the effects of the Qinghai-Tibet plateau uplift. The divergence times were estimated using Bayesian inference as implemented in BEAST. A portion of the mitochondrial COI gene (1406 bp) and 16S rDNA (932 bp) were chosen as molecular markers to reconstruct evolutionary relationships among 10 species in this group. The combined approach, based on phylogeny, estimation of node dates, and dispersal-vicariance analyses, indicated that the phylogeographical structuring of A. nemorum has been primarily shaped by the two main periods of the Qinghai-Tibet plateau uplift. The DIVA optimal reconstructions suggest that A. nemorum diversified from the Miocene to the Pleistocene from a center of origin in the Hengduan Mountains. The rapid uplift of Mountain ranges associated with the uplift of the entire Qinghai-Tibet plateau may have promoted rapid divergence in the A. nemorum group. Vicariance and dispersal were both essential in shaping the present distribution patterns of A. nemorum.
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Evolução Molecular , Hemípteros/classificação , Hemípteros/genética , Distribuição Animal , Animais , Teorema de Bayes , Complexo IV da Cadeia de Transporte de Elétrons/genética , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Especiação Genética , Variação Genética , Hemípteros/metabolismo , Filogenia , Filogeografia , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo , Alinhamento de Sequência , Análise de Sequência de DNARESUMO
BACKGROUND: Invasive species threaten the productivity and stability of natural and managed ecosystems. Predicting the spread of invaders, which can aid in early mitigation efforts, is a major challenge, especially in the face of climate change. While ecological niche models are effective tools to assess habitat suitability for invaders, such models have rarely been created for invasive pest species with rapidly expanding ranges. Here, we leveraged a national monitoring effort from 543 sites over 3 years to assess factors mediating the occurrence and abundance of brown marmorated stink bug (BMSB, Halyomorpha halys), an invasive insect pest that has readily established throughout much of the United States. RESULTS: We used maximum entropy models to estimate the suitable habitat of BMSB under several climate scenarios, and generalized boosted models to assess environmental factors that regulated BMSB abundance. Our models captured BMSB distribution and abundance with high accuracy, and predicted a 70% increase in suitable habitat under future climate scenarios. However, environmental factors that mediated the geographical distribution of BMSB were different from those driving abundance. While BMSB occurrence was most affected by winter precipitation and proximity to populated areas, BMSB abundance was influenced most strongly by evapotranspiration and solar photoperiod. CONCLUSION: Our results suggest that linking models of establishment (occurrence) and population dynamics (abundance) offers a more effective way to forecast the spread and impact of BMSB and other invasive species than simply occurrence-based models, allowing for targeted mitigation efforts. Implications of distribution shifts under climate change are discussed. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Ecossistema , Heterópteros , Animais , Mudança Climática , Espécies Introduzidas , Dinâmica Populacional , Estados UnidosRESUMO
BACKGROUND: Chouioia cunea Yang (Hymenoptera: Eulophidae) is a parasitic wasp and natural enemy of several lepidopteran pests during their pupal stage. The volatiles from pupae of three hosts, Hyphantria cunea (Arctiidae), Antheraea pernyi (Saturniidae) and Lymantria dispar (Erebidae), were analyzed and compared to elucidate the chemical cues used by C. cunea to locate its hosts. RESULTS: The attraction of C. cunea to H. cunea pupae has no obvious association with the types of plant leaves consumed by H. cunea before pupation. C. cunea exhibited the strongest attraction to the pupae of H. cunea, followed by those of A. pernyi and L. dispar based on behavioral experiments. Gas chromatography-mass spectrometry and GC-electroantennography (GC-EAD) analyses showed that these three host pupae consisted of essentially the same active volatile components but at different relative amounts. Active components derived from these pupae by GC-EAD were alkanes from C12 to C27, and C. cunea showed different levels of attraction to different single compounds. CONCLUSION: Host location by C. cunea primarily depends on common compounds emanating from the pupae of several host species. The relative amount of each component varies across host species, guiding host preferences by C. cunea. Optimal blends of several components were identified. Understanding the chemical cues used by C. cunea to locate its host could increase the possibility of developing attractants for parasitic wasps and subsequently increasing the parasitism rate of C. cunea on various hosts. © 2019 Society of Chemical Industry.
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Mariposas , Vespas , Animais , Cromatografia Gasosa-Espectrometria de Massas , PupaRESUMO
Although the Masson pine moth, Dendrolimus punctatus, is one of the most destructive forest pest insects and is an endemic condition in China, we still do not fully understand the patterns of how its distribution range varies in response to Quaternary climatic oscillations. Here, we sequenced one maternally inherited mitochondrial gene (COI) and biparentally inherited nuclear data (ITS1 and ITS2) among 23 natural populations across the entire range of the species in China. A total of 51 mitotypes and 38 ribotypes were separately obtained using mtDNA and ITS1 data. Furthermore, significant phylogeographical structure (N ST > G ST, p < 0.01) were detected. The spatial distribution of mitotypes implied that two distinct groups existed in the species: one in the southwest distribution, including 10 locations, and the other located in the northeast region of China. It is suggested, therefore, that each group was derived from ancestors that occupied different isolated refugia during previous periods, possibly last glacial maximum. Mismatch distribution and Bayesian population dynamics analysis suggested the population size underwent sudden expansion, which is consistent with the results of ecological niche modeling. As a typical phytophagous insect, the history of population expansion was in accordance with the host plants, providing abundant food resources and habitat. Intraspecific success rate of barcoding identification was lower than interspecific ones, indicating a level of difficulty in barcoding individuals from different populations. However, it still provides an early insight into the pattern of genetic diversity within a species. OPEN RESEARCH BADGES: This article has been awarded an Open Data and Open Materials. All materials and data are publicly accessible via the Open Science Framework at https://doi.org/10.5061/dryad.2df87g2. Learn more about the Open Practices badges from the Center for Open Science: https://osf.io/tvyxz/wiki.
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Biomphalaria straminea is native to Brazil but has established a population in Guangdong Province, China. Its potential of expanding and transmitting Schistosoma mansoni is of great concern. We seek to map S. mansoni transmission potential by predicting ecological dimensions and potential distributions of B. straminea using state-of-the-art ecological niche model approaches. Two environmental datasets were selected to fit individual and ensemble niche models, together with the evaluation of niche conservatism during B. straminea invasion in China. A small area is still occupied by the introduced population compared to that in Brazil. A vast space with suitable climate remains unfilled and might be available to B. straminea. Contrasting results of niche conservatism evaluation were attained based on the two environmental datasets. The coastal areas in southern China, together with south-western Yunnan and southern Hainan and Taiwan were consistent supported by multiple model approaches, showing high climate suitability for B. straminea. Attention should be paid to the possibility of S. mansoni epidemic in these identified areas, as high pressure due to propagation and future climate change may further complicate conditions. Our results call for rigorous monitoring and supervising along these areas in China.
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Biomphalaria/crescimento & desenvolvimento , Clima , Esquistossomose/epidemiologia , Análise Espacial , Animais , China/epidemiologia , Humanos , Modelos Estatísticos , Medição de RiscoRESUMO
BACKGROUND: The South-to-North Water Diversion (SNWD) project is designed to channel fresh water from the Yangtze River north to more industrialized parts of China. An important question is whether future climate change and dispersal via the SNWD may synergistically favor a northward expansion of species involved in hosting and transmitting schistosomiasis in China, specifically the intermediate host, Oncomelania hupensis. METHODOLOGY/ PRINCIPAL FINDINGS: In this study, climate spaces occupied by the four subspecies of O. hupensis (O. h. hupensis, O. h. robertsoni, O. h. guangxiensis and O. h. tangi) were estimated, and niche conservatism tested among each pair of subspecies. Fine-tuned Maxent (fMaxent) and ensemble models were used to anticipate potential distributions of O. hupensis under future climate change scenarios. We were largely unable to reject the null hypothesis that climatic niches are conserved among the four subspecies, so factors other than climate appear to account for the divergence of O. hupensis populations across mainland China. Both model approaches indicated increased suitability and range expansion in O. h. hupensis in the future; an eastward and northward shift in O. h. robertsioni and O. h. guangxiensis, respectively; and relative distributional stability in O. h. gangi. CONCLUSIONS/SIGNIFICANCE: The southern parts of the Central Route of SNWD will coincide with suitable areas for O. h. hupensis in 2050-2060; its suitable areas will also expand northward along the southern parts of the Eastern Route by 2080-2090. Our results call for rigorous monitoring and surveillance of schistosomiasis along the southern Central Route and Eastern Route of the SNWD in a future, warmer China.
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Mudança Climática , Schistosoma japonicum , Esquistossomose Japônica/epidemiologia , Caramujos/fisiologia , Caramujos/parasitologia , Distribuição Animal , Animais , China/epidemiologia , Fatores de Risco , Esquistossomose Japônica/transmissãoRESUMO
Subtropical China is a centre of speciation and well known for its high biological diversity and endemism. To understand the impact of historical, geographical and ecological factors on the intraspecific lineage divergence of invertebrates, we examined these processes in a semiaquatic bug, Microvelia horvathi (Hemiptera: Veliidae). Three hypotheses were developed using ecological niche models (ENM). We tested these hypotheses using mitochondrial (COI + COII) and nuclear data (ITS1 + 5.8S + ITS2). The phylogenic analysis revealed a shallow divergence in mitochondrial data. Clade I was mostly confined to the northern region and clade II was nearly restricted to the southern region. The historical process of Pleistocene climatic fluctuations during the LGM promoted divergence, along with such geographical barriers as the Wuyi, Nanling and Xuefeng mountains and ecological factors of temperature and vegetation type, contributed to these shallow genetic divergences and helped maintain them. The north-south population differentiation probably occurred during the transition from LIG to LGM, with post-LGM population expansion. The results of genetic data were mostly consistent with the spatial predictions from ENM. Our study emphasizes the multiple effects influencing genetic population differentiation, and also contributes to our knowledge of the phylogeography of other aquatic organisms in subtropical China.
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Hemípteros/genética , Animais , Biodiversidade , China , Clima , DNA Mitocondrial/genética , Ecossistema , Evolução Molecular , Genes de Insetos , Variação Genética , Haplótipos , Hemípteros/classificação , Filogenia , FilogeografiaRESUMO
Potential distributions of endemic relic shrubs in western Ordos were poorly mapped, which hindered our implementation of proper conservation. Here we investigated the applicability of ecological niche modeling for endangered relic shrubs to detect areas of priority for biodiversity conservation and analyze differences in ecological niche spaces used by relic shrubs. We applied ordination and niche modeling techniques to assess main environmental drivers of five endemic relic shrubs in western Ordos, namely, Ammopiptanthus mongolicus, Amygdalus mongolica, Helianthemum songaricum, Potaninia mongolica, and Tetraena mongolica. We calculated niche overlap metrics in gridded environmental spaces and compared geographical projections of ecological niches to determine similarities and differences of niches occupied by relic shrubs. All studied taxa presented different responses to environmental factors, which resulted in a unique combination of niche conditions. Precipitation availability and soil quality characteristics play important roles in the distributions of most shrubs. Each relic shrub is constrained by a unique set of environmental conditions, the distribution of one species cannot be implied by the distribution of another, highlighting the inadequacy of one-fits-all type of conservation measure. Our stacked habitat suitability maps revealed regions around Yellow River, which are highly suitable for most species, thereby providing high conservation value.
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Conservação dos Recursos Naturais , Ecossistema , Magnoliopsida/fisiologia , China , Espécies em Perigo de Extinção , Geografia , Chuva , SoloRESUMO
Chouioia cunea Yang is an endoparasitic wasp that attacks pupae of Hyphantria cunea (Drury), an invasive moth species that severely damages forests in China. Chemosensory systems of insects are used to detect volatile chemical odors such as female sex pheromones and host plant volatiles. The antennae of parasite wasps are important for host detection and other sensory-mediated behaviors. We identified and documented differential expression profiles of chemoreception genes in C. cunea antennae. A total of 25 OBPs, 80 ORs, 10 IRs, 11 CSP, 1 SNMPs, and 17 GRs were annotated from adult male and female C. cunea antennal transcriptomes. The expression profiles of 25 OBPs, 16 ORs, and 17 GRs, 5 CSP, 5 IRs and 1 SNMP were determined by RT-PCR and RT-qPCR for the antenna, head, thorax, and abdomen of male and female C. cunea. A total of 8 OBPs, 14 ORs, and 8 GRs, 1 CSP, 4 IRs and 1 SNMPs were exclusively or primarily expressed in female antennae. These female antennal-specific or dominant expression profiles may assist in locating suitable host and oviposition sites. These genes will provide useful targets for advanced study of their biological functions.
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Antenas de Artrópodes/metabolismo , Regulação da Expressão Gênica/fisiologia , Proteínas de Insetos/biossíntese , Transcriptoma/fisiologia , Vespas/metabolismo , Animais , Feminino , Masculino , Olfato/fisiologiaRESUMO
Invasive species' Pleistocene history contains much information on its present population structure, dispersability and adaptability. In this study, the Pleistocene history of a global invasive pest (Brown Marmorated Stink Bug BMSB, Halyomorpha halys) was unveiled using the coupled approach of phylogeography and ecological niche modelling. Rangewide molecular data suggests that the Taiwan and other native populations had diverged in mid-Pleistocene. In mainland China, the native BMSB did not experience population contraction and divergence during last glacial, but persisted in interconnected populations. Combined Bayesian Skyline Plot (BSP) and niche modelling revealed a rapid expansion occurred during the transition of Last Inter Glacial (LIG) to Last Glacial Maximum (LGM). High genetic diversity and multi-reticular haplotypes network exist in the original sources populations of BMSB invasion in northern China. They were speculated to be colonized from the central China, with many derived haplotypes evolved to adapt the novel environment. The ENM future prediction suggest that BMSB may expand northward to higher latitudes in the US and Europe, because of its high invasive ability, together with the available suitable climate space there.
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Heterópteros/genética , Espécies Introduzidas , Distribuição Animal , Animais , Teorema de Bayes , China , DNA Mitocondrial/genética , Evolução Molecular , Genes de Insetos , Variação Genética , Espécies Introduzidas/tendências , Japão , Modelos Genéticos , Tipagem Molecular , Filogenia , Filogeografia , Densidade Demográfica , Análise de Componente Principal , República da Coreia , TaiwanRESUMO
BACKGROUND: In late March 2013, a new avian-origin influenza virus emerged in eastern China. This H7N9 subtype virus has since infected 240 people and killed 60, and has awakened global concern as a potential pandemic threat. Ecological niche modeling has seen increasing applications as a useful tool in mapping geographic potential and risk of disease transmission. METHODOLOGY/PRINCIPALS: We developed two datasets based on seasonal variation in Normalized Difference Vegetation Index (NDVI) from the MODIS sensor to characterize environmental dimensions of H7N9 virus. One-third of well-documented cases was used to test robustness of models calibrated based on the remaining two-thirds, and model significance was tested using partial ROC approaches. A final niche model was calibrated using all records available. CONCLUSIONS/SIGNIFICANCE: Central-eastern China appears to represent an area of high risk for H7N9 spread, but suitable areas were distributed more spottily in the north and only along the coast in the south; highly suitable areas also were identified in western Taiwan. Areas identified as presenting high risk for H7N9 spread tend to present consistent NDVI values through the year, whereas unsuitable areas show greater seasonal variation.
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Subtipo H7N9 do Vírus da Influenza A , Influenza Humana/epidemiologia , China/epidemiologia , Surtos de Doenças , Meio Ambiente , Mapeamento Geográfico , Geografia Médica , Humanos , Influenza Humana/transmissão , Modelos Estatísticos , Reprodutibilidade dos Testes , Estações do AnoRESUMO
BACKGROUND: Manipulative studies of the behavioral response of soil-dwelling insects to insecticides and other antagonists are stymied by the difficulties of observing and interpreting interactions played out below ground. Six experiments were carried out using X-ray radiography to quantify the movement of the European chafer, Amphimallon majale (Razoumowsky), larvae in response to imidacloprid and how this was affected by host plant cues and cold temperature. RESULTS: The movement of third instars was arrested in imidacloprid-treated soil at ≥ 0.6 ppm concentration. At ≥ 0.8 ppm, the arrestant effect of imidacloprid was stronger than the attraction cue posed by germinating grass seed. There was a less disruptive effect on dispersal distance in vertical versus lateral panels. In vertical panels, there was a less disruptive effect on downward movement under a cold temperature treatment that simulated overwintering conditions. CONCLUSION: Larvae of A. majale do not remotely detect imidacloprid in the soil; they neither evade contact, nor are repelled after contact. Imidacloprid thereby acts as a contact arrestant to disrupt grub movement. This finding might help to explain the synergistic effect of imidacloprid in combination with other biological agents for white grub control, and its effects on grub overwintering behavior.
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Comportamento Animal/efeitos dos fármacos , Besouros/efeitos dos fármacos , Imidazóis/toxicidade , Repelentes de Insetos/análise , Inseticidas/toxicidade , Nitrocompostos/toxicidade , Animais , Temperatura Baixa , Larva/efeitos dos fármacos , Neonicotinoides , Poaceae , RadiografiaRESUMO
BACKGROUND: The Bean plataspid (Megacopta cribraria) (Hemiptera: Pentatomidae), native to Asia, is becoming an invasive species in North America; its potential spread to soybean producing areas in the US is of great concern. Ecological niche modelling (ENM) has been used increasingly in predicting invasive species' potential distribution; however, poor niche model transferability was sometimes reported, leading to the artifactual conclusion of niche differentiation during species' invasion. METHODOLOGY/PRINCIPALS: We aim to improve the geographical transferability of ENM via environmental variable selection to predict the potential distribution of Bean plataspid invasion. Sixteen environmental dimensions between native and introduced Bean plataspid populations were compared, and classified into two datasets with different degrees of discrepancy by the interquartile range (IQR) overlap in boxplot. Niche models based on these two datasets were compared in native model prediction and invading model projection. Classical niche model approaches (i.e., model calibrated on native range and transferred outside) were used to anticipate the potential distribution of Bean plataspid invasion. CONCLUSIONS/SIGNIFICANCE: Niche models based on the two datasets showed little difference in native model predictions; however, when projecting onto the introduced area, models based on the environmental datasets showing low discrepancy among ranges recovered good model transferability in predicting the newly established population of Bean plataspid in the US. Recommendations were made for selecting biological meaningful environmental dimensions of low discrepancy among ranges to improve niche model transferability among these geographically separated areas. Outside of its native range, areas with invasion potential include the southeastern US in North America, southwestern Europe, southeastern South America, southern Africa, and the eastern coastal Australia.