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81.
Prodiplosis longifila Gagné (Diptera: Cecidomyiidae) is an insect pest that attacks various types of crops, including tomato, Solanum lycopersicum L. (Solanaceae), a vegetable with substantial economic significance worldwide. Prodiplosis longifila is a widely distributed pest in Colombia, Ecuador, and Peru, countries characterized by the presence of significant geographic barriers like the Andes Mountains. It has been reported that geographic barriers affect the dynamics and genetic differentiation of insect populations. Therefore, the aim of this study was to assess the diversity, genetic structure, and demographic history of P. longifila through the analysis of sequences within the mitochondrial region of cytochrome oxidase I (COI) and rDNA‐ITS2 in 27 populations located in Colombia and Ecuador. Analyses were performed on populations distributed in three geographic groups separated by the presence of the Andes Mountains. A total of 11 haplotypes were identified with the COI gene and only one haplotype in the rDNA‐ITS2 was found. Analyses of population structure and demographic history revealed that there is a structure associated with the Andes, which is reflected in an uneven distribution of the haplotype frequencies between regions, but even so, gene flow between populations was detected which produces low genetic differentiation. Because P. longifila has a short‐range dispersion that determines its territorial nature, it would be expected that other factors are producing the genetic exchange between populations. We suggest that the anthropogenic effect produced by farming practices, such as the use of seedlings as seed, which may carry P. longifila larvae, cause passive dispersal of pest throughout the Andes, particularly in Colombia.  相似文献   
82.
现有基于地点的校园环境安全研究主要以客观的案件数据为研究对象,未能揭示学生安全感与特定地点环境因素的内在联系。利用Maptionnaire问卷平台,以广州大学城为例,通过公众参与地理信息系统分析学生对校园交通、事故和人身财产方面的环境安全感评价及其空间分布。研究发现学生整体安全感评价较低,评价低的地点集中在高校周边公园绿地、城中村、体育场馆,评价高的地点主要位于高校用地范围内。结合对评价低的地点进行实地调研,基于环境设计预防犯罪(crime prevention through environmental design,简称CPTED)理论分析影响学生安全感的环境因素,针对相关问题提出对应的提升学生安全感的环境设计优化建议。  相似文献   
83.
The importance of phenolic compounds for responding to various environmental conditions has been widely emphasized. However, the role of interactions between polyphenols and ecological factors, especially C, N, and P stoichiometry was little studied. Here, 15 sites across five provinces of Pinus bungeana in temperate regions of China were studied. The results showed that the higher values of total phenolic contents (TPC) of leaf and litter were distributed among the north distribution area of P. bungeana, lower values were in the south, whereas soil TPC were contrary to leaf and litter TPC. The stepwise regression, path analysis and decision index of path analysis for leaf TPC and ecological factors showed that altitude had the most direct impact on leaf TPC. Moreover, the principal determinants of leaf, litter and soil TPC were soil C/P ratios, longitude, and soil N/P ratios, respectively. In addition, the leaf, litter and soil TPC of P. bungeana were limited by soil C/N ratios, mean annual temperature, and soil P, respectively. Overall, our study provided evidence that ecological factors affected strongly the leaf, litter and soil TPC of P. bungeana.  相似文献   
84.
菊方翅网蝽Corythucha marmorata(Uhler,1878)是我国新近发现的外来入侵害虫,研究明确菊方翅网蝽在我国的潜在分布范围对其监测预警及科学防控具有重要意义。本研究根据菊方翅网蝽的地理分布数据及相关环境变量,运用Maxent生态位模型与ArcGIS预测了菊方翅网蝽在中国的潜在地理分布范围。预测结果表明:菊方翅网蝽在我国的适生区主要分布于100°~125°E,20°~40°N的亚热带、暖温带区域,其中高适生区主要集中在长江中下游地区,包括浙江、江苏、湖南、上海大部分地区、安徽南部、湖北南部、江西西部及南部、贵州东部、福建东部、广西北部、山东中部、河南南部以及重庆、台湾局部;此外,极端气温、平均气温、最干月份降雨量对菊方翅网蝽的潜在分布影响较大。菊方翅网蝽已在我国成功入侵并迅速蔓延成灾,应在疫区边缘地带加强监测,并采取措施防止其进一步扩散。  相似文献   
85.
Understanding speciation and biodiversity patterns in plants requires knowledge of the general role of climate in allowing polyploids to escape competition and persist with their diploid progenitors. This is a particularly interesting issue in widespread species that present multiple ploidy levels and occur across a heterogeneous environment. Chrysolaena (Vernonieae, Asteraceae) is a cytogenetically very diverse genus, with significant interspecific and intraspecific ploidy level variation and with continuous distribution across South America. No previous studies have summarized chromosome count data of Chrysolaena or addressed the cytogeography of the genus. Ploidy level of Chrysolaena species was determined by chromosome counting during mitosis and/or meiosis; the geographic distribution of cytotypes was examined and the correlations between the distribution of particular cytotypes and current ecological conditions were evaluated. A total of 43 new chromosome counts and five ploidy levels (2x, 4x, 6x, 7x, 8x) were reported. The chromosome number of C. cordifolia (2n = 7x = 70) and a new cytotype for C. propinqua var. canescens (2n = 4x = 40) are reported for the first time. Three geographic areas with high diversity of cytotypes and species were detected. The results obtained do not suggest a clear distribution pattern that depends on climatic factors for Chrysolaena populations. However, a geographic pattern was identified in the distribution of ploidy levels, with diploid species presenting a more restricted distribution than polyploid species.  相似文献   
86.
To analyze and promote resource efficiency in urban areas, it is important to characterize urban metabolism and particularly, material flows. Material flow analysis (MFA) offers a means to capture the dynamism of cities and their activities. Urban‐scale MFAs have been conducted in many cities, usually employing variants of the Eurostat methodology. However, current methodologies generally reduce the study area into a “black box,” masking details of the complex processes within the city's metabolism. Therefore, besides the aggregated stocks and flows of materials, the movement of materials—often embedded in goods or commodities—should also be highlighted. Understanding the movement and dispersion of goods and commodities can allow for more detailed analysis of material flows. We highlight the potential benefits of using high‐resolution urban commodity flows in the context of understanding material resource use and opportunities for conservation. Through the use of geographic information systems and visualizations, we analyze two spatially explicit datasets: (1) commodity flow data in the United States, and (2) Global Positioning System‐based commercial vehicle (truck) driver activity data in Singapore. In the age of “big data,” we bring advancements in freight data collection to the field of urban metabolism, uncovering the secondary sourcing of materials that would otherwise have been masked in typical MFA studies. This brings us closer to a consumption‐based, finer‐resolution approach to MFA, which more effectively captures human activities and its impact on urban environments.  相似文献   
87.
When males fight for access to females, such conflict rarely escalates into lethal fight because the risks and costs involved, that is, severe injury or death, are too high. The social spider mite, Stigmaeopsis miscanthi, does exhibit lethal male fights, and this male–male aggressiveness varies among populations. To understand the evolution of lethal fighting, we investigated aggressiveness in 42 populations and phylogenetic relationships in 47 populations along the Japanese archipelago. By analysis of the male weapon morph, a proxy for aggressiveness, we confirmed the existence of a mildly aggressive (ML) form, besides the low aggression (LW) and high aggression (HG) forms reported earlier. To evaluate demographic history of these three forms, we employed the approximate Bayesian computation approach using mtCOI sequences and taking into consideration the postlast glacial expansion history of the host plant, Miscanthus sinensis. As results, hierarchical split models are more likely to explain the observed genetic pattern than admixture models, and the ML form in the subtropical region was considered the ancestral group. The inferred demographic history was consistent with the one reconstructed for the host plant in a previous study. The LW form was split from the ML form during the last glacial period (20,000–40,000 years BP), and subsequently, the HG form was split from the ML form at the end of or after the last glacial period (5,494–10,988 years BP). The results also suggest that the mite invaded Japan more than once, resulting in the present parapatric distribution of LW and HG forms in eastern Japan.  相似文献   
88.
Information on the spatial distribution of cytotypes and karyotype variation in plants is critical for studies of the origin and evolution of polyploid complexes. Here, the spatial distribution of cytological races and intraspecific variation in the karyotype of Lycoris radiata, an endemic species to East Asia, is investigated. Conventional karyotype analysis methods were used to determine ploidy level and karyotypical characteristics in 2,420 individuals from 114 populations of Lradiata nearly covering the whole distribution areas in China. Of 114 populations studied, 52 (45.61%), 58 (50.88%), and 4 (3.51%) are diploid, triploid, and mixoploid populations, respectively, with 1,224, 1,195, and 1 individuals being diploid, triploid, and tetraploid, respectively. The triploid possesses a much wider distribution range than the diploid, with the former almost occupying the entire range of this complex species in East Asia and the latter distributing in the middle and east regions of China. Triploids tend to occur at high altitudes, and the relationship between the ploidy and altitude is significantly positive but low (r= 0.103, p < 0.01). About 98.6% of examined bulbs have a common karyotype consisting of 22 or 33 acrocentric (A) chromosomes. Some aberrant chromosomes which should be generated from A‐type chromosome have been found including metacentrics (m), small metacentrics (m′), and B‐type chromosome. The results can provide a fundamental cytogeographic data for further studies on the evolutionary origins and adaptive divergences of polyploids, especially the triploid, within Lradiata using molecular and/or ecological methods in the future.  相似文献   
89.
In this work, we report the predicted distribution of the threatened fluminense swallowtail butterfly, Parides ascanius (Cramer 1775), and correlate it to the presence of urban and protected areas within its range. The distribution was modeled using a genetic algorithm. The predicted distribution of the fluminense swallowtail shows high agreement within Rio de Janeiro state, in a near-continuous strip of 2,038,253 ha along the coastal lowlands, 17.8 percent of which is within urban areas. Only 8.7 percent (178,187 ha) of the remaining (nonurban) predicted model overlapped at least partially with protected areas (19 in all). Almost half of these protected areas also overlapped with urban areas, resulting in an additional loss of 58,751 ha. In seven of 19 protected areas, the distribution of P. ascanius was predicted by less than 50 percent of the models; five of the remaining protected areas are less restrictive reserves. Despite the wide distribution predicted by the models, only two of the observed occurrence points matched the predicted distribution within protected areas. Modeling threatened species distribution is a useful tool for highlighting gaps in networks of protected areas and should aid in planning to fill these gaps. However, in several developing countries with high biodiversity, there is insufficient basic biological information for many threatened species. In these cases, prospecting field studies are urgently needed.  相似文献   
90.
BACKGROUND: Although many birth defects surveillance programs incorporate georeferenced records into their databases, practical methods for routine spatial surveillance are lacking. We present a macroprogram written for the software package R designed for routine exploratory spatial analysis of birth defects data, the Automated Spatial Surveillance Program (ASSP), and present an application of this program using spina bifida prevalence data for metropolitan Atlanta. METHODS: Birth defects surveillance data were collected by the Metropolitan Atlanta Congenital Defects Program. We generated ASSP maps for two groups of years that correspond roughly to the periods before (1994-1998) and after (1999-2002) folic acid fortification of flour. ASSP maps display census tract-specific spina bifida prevalence, smoothed prevalence contours, and locations of statistically elevated prevalence. We used these maps to identify areas of elevated prevalence for spina bifida. RESULTS: We identified a large area of potential concern in the years following fortification of grains and cereals with folic acid. This area overlapped census tracts containing large numbers of Hispanic residents. CONCLUSIONS: The potential utility of ASSP for spatial disease monitoring was demonstrated by the identification of areas of high prevalence of spina bifida and may warrant further study and monitoring. We intend to further develop ASSP so that it becomes practical for routine spatial monitoring of birth defects.  相似文献   
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