Population genetics analysis of the origin of the Oriental fruit fly, Bactrocera dorsalis Hendel (Diptera: Tephritidae), in northern Yunnan Province, China

We examined genetic variation in the Oriental fruit fly, Bactrocera dorsalis (Hendel), using six populations in two regions of Yunnan Province, China, to determine the distribution and likely mechanism for the dispersal of this fly. A 501‐bp portion of the mitochondrial cytochrome oxidase gene was sequenced from a minimum of eight individuals from each population, and 43 haplotypes were observed in the six Bactrocera dorsalis populations. When comparing the genetic diversity of populations in the northern and southern regions, which differ with respect to elevation, climate and plant phenology, we found a significantly greater haplotype diversity in the southern region (permutation test; P < 0.05), suggesting that the northern populations, those at Kunming and Qujing, probably originated from somewhere in the southern region. F_ST and number of pairwise differences revealed a high level of differentiation between the Panxi population and the other populations (permutation test; P < 0.05). Although the difference was marginally insignificant, the Shuitang population seemed to have differentiated from both northern populations. The Mantel test did not detect any isolation due to geographic distance. An amova analysis found that 2.56% of the variance was caused by the Panxi population. Haplotype network analysis showed that none of the six populations had a specific genetic lineage. Together, these analyses suggest that long‐distance dispersal has occurred for this species, and the species most probably took advantage of both a mountain pass and prevailing air currents. The Panxi population was significantly isolated from the others, probably because of its distinguishing habitat features, host plants or the recent reduction of the population size.     

云南桔小实蝇五个地理种群的遗传分化研究

对云南省瑞丽、景洪、化念、元江、河口的桔小实蝇5个地理种群共27个个体的线粒体细胞色素氧化酶Ⅰ(COⅠ) 基因进行了部分序列测定。序列的碱基变化中转换明显多于颠换、无碱基的插入和缺失。5个地理种群中共有27个多态位点和23种单倍型,其中2种为共享单倍型。桔小实蝇5个地理种群的Fst值在0.0364～0.1364之间(P>0.05), Nm值在3.88～13.25之间。对其所有单倍型聚类分析发现,单倍型在系统树中的分布散乱、混杂,没有显示出明显的地理分布族群。分析认为5个地理种群间已存有一定程度的遗传分化,但分化的程度还比较低。造成5个种群这种遗传分化的因素主要与地理隔离有关,而种群间低程度的遗传 分化估计与桔小实蝇在云南的发展历史及生态适应有关。     

基于线粒体COI基因的桔小实蝇种群遗传分化研究

【目的】推测桔小实蝇Bactrocera dorsalis在中国的扩散路径和新发生地区的入侵来源。【方法】本研究测序获得来自中国、泰国、日本、老挝、孟加拉国和美国等地31个种群的192头桔小实蝇个体的COI序列（1 496 bp,占COI基因全长97.3%）,并以软件DnaSP 5.0, MEGA 6.0和Arlequin 3.5等完成各种群的遗传多样性、种群间的遗传分化以及单倍型分析。【结果】所测31个桔小实蝇种群总体表现出较高水平的核苷酸多样性（0.00663）和高水平的单倍型多样性（0.98069）。以F-统计法度量种群间遗传分化程度, 结果显示中国桔小实蝇地理种群间遗传分化较弱, 中国种群与泰国、日本、老挝、孟加拉国、美国种群间的遗传分化程度不同, 中国种群与美国种群及日本种群的遗传分化最大。而Mantel检验发现,中国、泰国、日本、老挝、孟加拉国和美国种群间的遗传分化与空间距离有关（R=0.670, P<0.0001）, 中国种群间的遗传分化不是地理隔离所造成的（R=0.038, P=0.534）。中国种群与泰国、日本、老挝、孟加拉国和美国种群间不存在共享单倍型。根据种群系统发育树,可将中国原发生地区种群划分为西南、东南两大分支。中性检验和错配分析结果均表明桔小实蝇曾存在大规模的扩张。【结论】桔小实蝇以东南地区和西南地区为源头向中国内陆扩散,其中广东、福建、广西和贵州种群为中国内陆种群较为有影响力的源头。根据遗传多样性、遗传分化、单倍型分析,推测新发生地区桔小实蝇的来源, 例如安徽合肥桔小实蝇种群主要来源于福建长乐、广东珠海和上海。     

Population structure and colonization history of the olive fly, Bactrocera oleae (Diptera, Tephritidae)

The olive fly, Bactrocera oleae, is the major pest of olives in most commercial olive-growing regions worldwide. The species is abundant in the Mediterranean basin and has been introduced recently into California and Mexico, creating problems for quarantine protection and international trade. Here, we use nuclear microsatellite markers and mitochondrial sequences to examine the history of olive fly range expansion and colonization. Sampled populations span the current distribution of the olive fly worldwide, including South and Central Africa, Pakistan, Mediterranean Europe and Middle East, California, and Mexico. The Pakistani populations appear to be genetically well differentiated from the remaining populations, though rooting the origins of the species is problematic. Genetic similarity and assignment tests cluster the remaining populations into two genetic groups--Africa and a group including the Mediterranean basin and the American region. That Africa, and not the Mediterranean, is the origin of flies infesting cultivated olive is supported by the significantly greater genetic diversity at microsatellite loci in Africa relative to the Mediterranean area. The results also indicate that the recent invasion of olive flies in the American region most likely originated from the Mediterranean area.     

Genetic structure and demographic history of the melon fly Zeugodacus cucurbitae (Coquillet) (Diptera: Tephritidae) in Thailand

相似文献   

Genetic relationship of the melon fly,Bactrocera cucurbitae (Diptera: Tephritidae) inferred from mitochondrial DNA

Abstract The melon fruit fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae), has been the subject of worldwide quarantine and management efforts due to its widespread agricultural impact and potential for rapid range expansion. From its presumed native distribution in India, this species has spread throughout the hot‐humid regions of the world. We provide information that reveals population structure, invasion history and population connectivity from 23 locations covering nine countries based on DNA sequences of the mitochondrial cytochrome oxidase I (COI) gene. Forty‐two polymorphic sites were described among 38 haplotypes. The most common haplotype, H1, was observed in 73% of the samples distributed among all populations. Highest genetic diversity was seen within populations, and no isolation‐by‐distance was detected. The western regions (Nepal, Bangladesh, Thailand, Burma and China‐west) showed higher haplotype diversity than eastern regions (China‐east). China‐Yunnan showed highest levels of genetic diversity in China. Haplotype diversity decreased with longitude from west to east. Together, these analyses suggest that B. cucurbitae has expanded from west to east within a limited geographic scale and recently invaded China through Yunnan Province.     

Detection of the solanum fruit fly, Bactrocera latifrons (Hendel) in Tanzania (Dipt., Tephritidae)

Abstract:  The presence of the Solanum fruit fly, Bactrocera latifrons , in Africa is reported for the first time, based on trapped and reared specimens in Tanzania. Two new host records, Solanum aethiopicum and Solanum macrocarpon , are reported.     

桔小实蝇不同发育阶段过冷却点的测定

对桔小实蝇Bactrocera dorsalis (Hendel)不同发育阶段的过冷却点进行了测定。结果表明：同一虫期个体间的过冷却点出现不同程度的变异,但均服从正态分布。不同虫期的过冷却点差异显著,其中蛹的过冷却点最低（-12.2℃～-15.0℃）。老熟幼虫的过冷却点为-8.1℃。成虫的过冷却点最低值为7日龄雄虫（-10.5℃）和雌虫（-10.1℃）,最高值为60日龄雄虫（-5.9℃）和雌虫（-6.4℃）,但同一发育时期的雌、雄成虫之间的过冷却点没有差异。测定结果提示蛹期最有可能是该虫在温带地区越冬的虫态。     

橘小实蝇交配行为观察

在实验室内对橘小实蝇Bactrocera dorsalis（Hendel）的交配行为进行了观察。描述了橘小实蝇交配中雄虫的“求偶场”,雄雄相遇、雌雌相遇、雌雄相遇时的相互反应,雌雄虫的交配行为与交配后行为。     

Population genetic structure and demographic history of the black fly vector,Simulium nodosum in Thailand

An understanding of the genetic structure and diversity of vector species is crucial for effective control and management. In this study, mitochondrial DNA sequences were used to examine the genetic structure, diversity and demographic history of a black fly vector, Simulium nodosum Puri (Diptera: Simuliidae), in Thailand. A total of 145 sequences were obtained from 10 sampling locations collected across geographical ranges in the country. Low genetic diversity was found in populations of S. nodosum that could be explained by the recent population history of this species. Demographic history analysis revealed a signature of demographic expansion dating back to only 2600–5200 years ago. Recent population expansion in S. nodosum possibly followed an increase in agriculture that enabled its hosts', humans and domestic animals, densities to increase. Alternatively, the Thai populations could be a derivative of an older expansion event in the more northern populations. Mitochondrial DNA genealogy revealed no genetically divergent lineages, which agrees with the previous cytogenetic study. Genetic structure analyses found that only 27% of the pairwise comparisons were significantly different. The most likely explanation for the pattern of genetic structuring is the effect of genetic drift because of recent colonization.     

Mitotic and polytene chromosomes analysis of the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae)

The Oriental fruit fly, Batrocera dorsalis s.s. (Hendel) is one of the most destructive agricultural pests, belonging to a large group of difficult to distinguish morphologically species, referred as the B. dorsalis complex. We report here a cytogenetic analysis of two laboratory strains of the species and provide a photographic polytene chromosome map from larval salivary glands. The mitotic complement consists of six chromosome pairs including a heteromorphic sex (XX/XY) chromosome pair. Analysis of the polytene complement has shown a total of five polytene chromosomes (10 polytene arms) that correspond to the five autosomes. The most important landmarks of each polytene chromosome and characteristic asynapsis at a specific chromosomal region are presented and discussed. Chromosomal homology between B. dorsalis and Ceratitis capitata has been determined by comparing chromosome banding patterns. The detection of chromosome inversions in both B. dorsalis strains is shown and discussed. Our results show that the polytene maps presented here are suitable for cytogenetic analysis of this species and can be used for comparative studies among species of the Tephritidae family. They also provide a diagnostic tool that could accelerate species identification within the B. dorsalis complex and could shed light on the ongoing speciation in this complex. Polytene chromosome maps can facilitate the development of biological control methods and support the genome mapping project of the species that is currently in progress.     

Population structure and colonization of Bactrocera dorsalis (Diptera: Tephritidae) in China,inferred from mtDNA COI sequences

The oriental fruit fly, Bactrocera dorsalis, is a serious pest of fruits and vegetables in South‐east Asia, and, because of quarantine restrictions, impedes international trade and economic development in the region. Revealing genetic variation in oriental fruit fly populations will provide a better understanding of the colonization process and facilitate the quarantine and management of this species. The genetic structure in 15 populations of oriental fruit fly from southern China, Laos and Myanmar in South‐east Asia was examined with a 640‐bp sequence of the mitochondrial cytochrome oxidase subunit I (COI) gene. The highest levels of genetic diversity were found in Laos and Myanmar. Low to medium levels of genetic differentiation (F_ST ≤ 0.134) were observed among populations. Pooled populations from mainland China differed from those in Laos and Myanmar (F_ST = 0.024). Genetic structure across the region did not follow the isolation‐by‐distance model. The high genetic diversity observed in Laos and Myanmar supports the South‐east Asian origin of B. dorsalis. High genetic diversity and significant differentiation between some populations within mainland China indicate B. dorsalis populations have been established in the region for an extended period of time. High levels of genetic diversity observed among the five populations from Hainan Island and similarity between the Island and Chinese mainland populations indicate that B. dorsalis was introduced to Hainan from the mainland and has been on the island for many years. High genetic diversity in the recently established population in Shanghai (Pudong) suggests multiple introductions or a larger number of founders.     

Population dynamics of the oriental fruit fly, Bactrocera dorsalis （Diptera： Tephritidae） in the Kunming area,southwestern China

Population dynamics of Bactrocera dorsalis Hendel （Diptera： Tephritidae） were studied through pheromone trapping over 4 years （1997, 1999, 2000, 2003） in the Kunming region, a high plateau area in southwestern China. B. dorsalis immigrates from southern Yunnan to Kunming each year, and occurs during early May through November. Annual trap captures recorded an increase in the B. dorsalis populations from May to July, when they peaked in abundance, and a decline until November. No flies were detected from November to April. The fruit flies had two generations. There was considerable overlapping due to the continuous arrival of immigrating flies during the summer months. Annual capture rates were significantly related to numbers of flies caught in July when peak captures were recorded; whereas the peak captures, in turn, positively depended on numbers of flies recorded in May, the first month of fly appearance in the current year. It suggested that the annual population abundance was mainly dependent on the size of the initial emigrating population. A daily average temperature of 18℃ was probably the threshold temperature required for the flies to undertake long-range dispersal, which partially explained the start of the fly in May each year on this high plateau. Under field conditions, the fruit flies can withstand 13℃ as a daily average temperature. No flies were recorded in any of the study years at a daily temperature colder than 10 ℃.     

南亚果实蝇多酚氧化酶的性质研究(英文)

【目的】为揭示南亚果实蝇Bactrocera tau (Walker)不同发育阶段体内多酚氧化酶的活性与性质。【方法】以邻苯二酚为底物, 在415 nm波长下测定了南亚果实蝇1, 2和3龄幼虫、 蛹以及成虫多酚氧化酶的活性和动力学参数。【结果】南亚果实蝇在不同发育阶段, 多酚氧化酶的活性存在明显差异, 通常3龄幼虫中活性最高, 为434.42 U/mg; 蛹中最低, 为231.05 U/mg。在pH 6.5时, 南亚果实蝇不同发育阶段多酚氧化酶的活性分别为265.42, 358.34, 444.42, 210.02和373.99 U/mg, 但当pH值高于7.0或低于5.0时, 多酚氧化酶的活性则明显下降。在温度为34℃和37℃时, 南亚果实蝇各发育阶段多酚氧化酶的活性均较高, 当温度高于40℃或低于27℃时, 活性则明显下降。以邻苯二酚为底物, 2龄幼虫中多酚氧化酶的K_m值（3.10 mmol/min）和V_max（476.19 mmol/L）较大, 说明多酚氧化酶对底物邻苯二酚催化能力强; 蛹中多酚氧化酶的K_m（0.63 mmol/min）和V_max（50.25 mmol/L）较小, 说明多酚氧化酶对底物的亲和力和催化能力弱。当以L-DOPA为底物时, 3龄幼虫中多酚氧化酶的K_m值和V_max较大, 分别为0.49 mmol/min和188.68 mmol/L; 蛹中多酚氧化酶的K_m值和V_max较小, 分别为0.25 mmol/min和21.79 mmol/L。【结论】南亚果实蝇体内多酚氧化酶在不同温度和pH值下的活性和动力学参数与虫体发育阶段密切相关。     

Spatial expansion and population structure of the neotropical malaria vector, Anopheles darlingi (Diptera: Culicidae)

Extensive population structuring is known to occur in Anopheles darlingi , the primary malaria vector of the Neotropics. We analysed the phylogeographic structure of the species using the mitochondrial cytochrome oxidase I marker. Diversity is divided into six main population groups in South America: Colombia, central Amazonia, southern Brazil, south-eastern Brazil, and two groups in north-east Brazil. The ancestral distribution of the taxon is hypothesized to be central Amazonia, and there is evidence of expansion from this region during the late Pleistocene. The expansion was not a homogeneous front, however, with at least four subgroups being formed due to geographic barriers. As the species spread, populations became isolated from each other by the Amazon River and the coastal mountain ranges of south-eastern Brazil and the Andes. Analyses incorporating distances around these barriers suggest that the entire South American range of An. darlingi is at mutation–dispersal–drift equilibrium. Because the species is distributed throughout such a broad area, the limited dispersal across some landscape types promotes differentiation between otherwise proximate populations. Moreover, samples from the An. darlingi holotype location in Rio de Janeiro State are substantially derived from all other populations, implying that there may be additional genetic differences of epidemiological relevance. The results obtained contribute to our understanding of gene flow in this species and allow the formulation of human mosquito health protocols in light of the potential population differences in vector capacity or tolerance to control strategies.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 97 , 854–866.     

Inferences on the population structure and colonization process of the invasive oriental fruit fly, Bactrocera dorsalis (Hendel)

The phytophagous insects of the Tephritidae family offer different case histories of successful invasions. An example is Bactrocera dorsalis sensu stricto, the oriental fruit fly which has been recognized as a key pest of Asia and the Pacific. It is known to have the potential to establish adventive populations in various tropical and subtropical areas. Despite the economic risk associated with a putative stable presence of this fly, the genetic aspects of its invasion process have remained relatively unexplored. Using microsatellite markers we have investigated the population structure and genetic variability in 14 geographical populations across the four areas of the actual species range: Far East Asia, South Asia, Southeast Asia and the Pacific Area. Results of clustering and admixture, associated with phylogenetic and migration analyses, were used to evaluate the changes in population genetic structure that this species underwent during its invasion process and establishment in the different areas. The colonization process of this fly is associated with a relatively stable population demographic structure, especially in an unfragmented habitat, rich in intensive cultivation such as in Southeast Asia. In this area, the results suggest a lively demographic history, characterized by evolutionary recent demographic expansions and no recent bottlenecks. Cases of genetic isolation attributable to geographical factors, fragmented habitats and/or fruit trade restrictions were observed in Bangladesh, Myanmar and Hawaii. Regarding the pattern of invasion, the overall genetic profile of the considered populations suggests a western orientated migration route from China to the West.     

桔小实蝇线粒体基因组全序列及其分析

桔小实蝇Bactrocera dorsalis线粒体基因组全序列对研究实蝇分子系统进化具有重要意义。本研究通过DNA测序和克隆技术,对桔小实蝇mtDNA全序列进行了测定和分析。结果表明：桔小实蝇线粒体基因组全长15 915 bp（GenBank序列号: DQ845759）。基因组碱基组成为39.3%A,16.2%C,10.2%G,34.3%T,由13个蛋白编码基因、22个tRNA基因、2个rRNA基因以及一个非编码的控制区域（A+T-rich区）组成。7个蛋白编码基因和13个tRNA基因从J链编码,其余6个蛋白编码基因和9个tRNA基因从N链编码。位于J链上的蛋白编码基因具有近似的A、T含量,而位于N链上的蛋白编码基因的A的含量明显高于T的含量。以mtDNA COⅠ基因为例,比较了桔小实蝇与其他14种实蝇的亲缘关系,结果显示其与同亚属（果实蝇亚属Bactrocera）内的其他近缘种相互间的同源性很高。     

Nondestructive DNA extraction from blackflies (Diptera: Simuliidae): retaining voucher specimens for DNA barcoding projects

A nondestructive, chemical-free method is presented for the extraction of DNA from small insects. Blackflies were submerged in sterile, distilled water and sonicated for varying lengths of time to provide DNA which was assessed in terms of quantity, purity and amplification efficiency. A verified DNA barcode was produced from DNA extracted from blackfly larvae, pupae and adult specimens. A 60-second sonication period was found to release the highest quality and quantity of DNA although the amplification efficiency was found to be similar regardless of sonication time. Overall, a 66% amplification efficiency was observed. Examination of post-sonicated material confirmed retention of morphological characters. Sonication was found to be a reliable DNA extraction approach for barcoding, providing sufficient quality template for polymerase chain reaction amplification as well as retaining the voucher specimen for post-barcoding morphological evaluation.     

Contrasting patterns of population structure and demographic history in cryptic species of Bostrychia intricata (Rhodomelaceae,Rhodophyta) from New Zealand

Spatial patterns of genetic diversity provide insight into the demography and history of species. Morphologically similar but genetically distinct “cryptic” species are increasingly being recognized in marine organisms through molecular analyses. Such species are, on closer inspection, often discovered to display contrasting life histories or occasionally minor morphological differences; molecular tools can thus be useful indicators of diversity. Bostrychia intricata, a marine red alga, is widely distributed throughout the Southern Hemisphere and comprises many cryptic species. We used mitochondrial cytochrome c oxidase I gene sequences to assess the genetic variation, population genetic structure, and demographic history of B. intricata in New Zealand. Our results supported the existence of three cryptic species of B. intricata (N2, N4, and N5) in New Zealand. Cryptic species N4, which was found throughout New Zealand, showed a higher genetic diversity and wider distribution than the other two species, which were only found in the North Island and northern South Island. Our analyses showed low to moderate genetic differentiation among eastern North Island populations for cryptic species N2, but high differentiation among North and South Island populations for N4, suggesting different population structure between these cryptic species. Data also indicated that N2 has recently undergone population expansion, probably since the Last Glacial Maximum (LGM), while the higher genetic diversity in N4 populations suggests persistence in situ through the LGM. The contrasting population structures and inferred demographic histories of these species highlight that life history can vary greatly even among morphologically indistinguishable taxa.