Molecular phylogeny and population structure of the codling moth (Cydia pomonella) in Central Europe: I. Ancient clade splitting revealed by mitochondrial haplotype markers

The codling moth (Cydia pomonella L., Tortricidae, Lepidoptera) is an important pest of pome fruit with global distribution. It has adapted successfully to different habitats by forming various ecotypes and populations, often termed strains, which differ among each other in several morphological, developmental, and physiological features. Many strains of Cydia pomonella have developed resistance against a broad range of chemically different pesticides. Obviously, pesticide-resistant strains must have a genetic basis inherent to the gene pool of codling moth populations, and this deserves our particular attention. The primary intention of the present study was to contribute novel information regarding the evolutionary phylogeny and phylogeography of codling moth populations in Central Europe. In addition, we aimed at testing the hypothesis that differential biological traits and response patterns towards pesticides in codling moth populations may be reflected at a mitochondrial DNA level. In particular, we wanted to test if pesticide resistance in codling moths is associated repeatedly and independently with more than one mitochondrial haplotype. To this end, we analyzed mitochondrial DNA and constructed phylogenetic trees based on three mitochondrial genes: cytochrome oxidase I (COI), the A+T-rich region of the control region (CR), and the nicotinamide adenine dinucleotide dehydrogenase subunit 5 (ND5). The results indicate that Central European populations of Cydia pomonella are clearly divided in two ancient clades. As shown by means of a molecular clock approach, the splitting of the two clades can be dated to a time period between the lower and middle Pleistocene, about 1.29-0.20 million years ago. It is assumed that the cyclic changes of warm and cold periods during Pleistocene may have lead to the geographic separation of codling moth populations due to glaciation, giving rise to the formation of the two separate refugial clades, as already shown for many other European animal species. Due to their inclination towards developing novel detoxification gene variants, codling moth individuals from both clades independently and multifariously may have developed pesticide resistance, and this process may be ongoing. During their more recent evolutionary history, natural events such as the gradual disappearance of climate-specific geographic barriers, as well as human-aided dispersal in recent historic times, may have allowed codling moth haplotypes from the original clades to interbreed and completely merge again, creating a globally successful insect species with a gene pool capable of responding to novel selective challenges by rapid adaptation.     

苹果蠹蛾种群遗传多样性研究进展

苹果蠹蛾是重要的世界性果树害虫,寄主广泛,通过形成各种生态型或种群适应新入侵环境,对当地果品生产造成严重损失。本文综述了国内外有关苹果蠹蛾遗传多样性的研究进展。相关研究表明,寄主植物、地理隔离和杀虫剂等因素影响种群间的遗传多样性和遗传分化。其中,地理隔离是种群间形成遗传分化的主要原因之一,寄主分布格局、气候条件、虫体飞行能力和人为活动等因素都会影响种群间遗传分化的程度。苹果蠹蛾是我国重要的入侵害虫,我国东北地区和西北地区的苹果蠹蛾种群具有不同的遗传多样性水平,并且种群间有一定程度的分化,今后需要进一步研究影响我国苹果蠹蛾种群遗传的重要因素,明确该虫种群间分化情况、入侵来源和扩散路径,这对于延缓苹果蠹蛾在我国的扩散,制定合理有效的综合防治策略具有重要意义。     

Overwintering of codling moth (Lepidoptera: Tortricidae) larvae in apple harvest bins and subsequent moth emergence.

Codling moths, Cydia pomonella (L.), have long been suspected of emerging from stacks of harvest bins in the spring and causing damage to nearby apple and pear orchards. With increased use of mating disruption for codling moth control, outside sources of infestation have become more of a concern for growers using pheromone based mating disruption systems. Studies were designed to provide information on bins as a source of codling moth and the pattern of codling moth emergence from stacks of bins. In these studies, codling moth larvae colonized wood harvest bins at a much higher frequency than harvest bins made of injection molded plastic (189 moths emerged from wood compared with five from plastic). There was no statistical difference in the number of moths infesting bins that had been filled with infested fruit compared with bins left empty at harvest. This suggests that codling moth enter the bins during the time that the bins are in the orchard before harvest. Emergence of laboratory reared adult codling moth from wood bins placed in stacks was found to be prolonged compared with field populations. Temperature differences within the bin stacks accounted for this attenuated emergence pattern. Covering bin stacks with clear plastic accelerated codling moth development in the upper levels of the stack. Codling moth emergence patterns from plastic-covered stacks more closely coincided with male flight in field populations. This information could be important in developing a technique for neutralizing codling moth-infested bins, and in understanding how infested bins may influence pest management in fruit orchards that are located near bin piles. Implications for control of codling moth in conventional orchards and in those using mating disruption as the principal component of an integrated pest management system include increased numbers of treatments directed at areas affected by infested bins.     

Quality of mass-reared codling moth (Lepidoptera: Tortricidae) after long-distance transportation: 1. Logistics of shipping procedures and quality parameters as measured in the laboratory

The sterile insect technique (SIT) is a proven effective control tactic against lepidopteran pests when applied in an areawide integrated pest management program. The construction of insect mass-rearing facilities requires considerable investment and moth control strategies that include the use of sterile insects could be made more cost-effective through the importation of sterile moths produced in other production centers. For codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), this is an attractive option because mating studies have confirmed the absence of mating barriers between codling moth populations from geographically different areas. To assess the feasibility of long-distance transportation of codling moths, pupae and adult moths were transported in 2004 from Canada to South Africa in four shipments by using normal commercial transport routes. The total transport time remained below 67 h in three of the consignments, but it was 89 h in the fourth consignment. Temperature in the shipping boxes was fairly constant and remained between -0.61 and 0.16 degrees C for 76.8-85.7% of the time. The data presented indicate that transporting codling moths as adults and pupae from Canada to South Africa had little effect on moth emergence, longevity, and ability to mate, as assessed in the laboratory. These results provide support to the suggestion that the STT for codling moth in pome fruit production areas might be evaluated and implemented by the importation of irradiated moths from rearing facilities in a different country or hemisphere.     

Population genetic structure of codling moth (Lepidoptera: Tortricidae) from apple orchards in central Chile

Codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is the main pest of pome fruits worldwide. Despite its economic importance, little is known about the genetic structure and patterns of dispersal at the local and regional scale, which are important aspects for establishing a control strategy for this pest. An analysis of genetic variability using microsatellites was performed for 11 codling moth populations in the two major apple (Malus domestica Borkh) cropping regions in central Chile. Despite the geographical distances between some populations (approximately 185 km), there was low genetic differentiation among populations (F(ST) = 0.002176), with only slight isolation by distance. Only approximately 0.2% of the genetic variability was found among the populations. Geographically structured genetic variation was independent of apple orchard management (production or abandoned). These results suggest a high genetic exchange of codling moth between orchards, possibly mediated by human activities related to fruit production.     

Costs of insecticide resistance in Cydia pomonella (Lepidoptera: Tortricidae)

The obvious benefits associated with insecticide resistance for pest species may come at a cost to other life-history traits. In this study, we compared the larval and pupal developmental times, pupal mass wing surface area and wing fluctuating asymmetry (FA) in insecticide resistant and control strains of codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), collected from apple (Malus spp.) orchards in central Canada. Resistant strains had significantly longer larval developmental times and lower pupal masses compared with the susceptible strain. Although the forewings of resistant moths were smaller in resistant than control strain, no difference in wing FA was detected. Longer developmental times could increase exposure time to natural enemies, and reduced adult size could affect longevity and total reproductive output.     

Biological activity of ethyl (e,z)-2,4-decadienoate on different tortricid species: electrophysiological responses and field tests

Ethyl (E,Z)-2,4-decadienoate (pear ester) is known to be a kairomonal attractant for both male and female codling moths, Cydia pomonella (L.) (Lepidoptera: Tortricidae). Electroantennographic (EAG) studies were conducted to investigate the sensitivities of codling moth, the chestnut torticid species Cydia fagiglandana (Zeller), Cydia splendana (Hübner), and Pammene fasciana L., and the green budmoth Hedya nubiferana Haworth to pear ester. The attractiveness of this compound to the different species was tested in several field-trapping experiments conducted in Italy. The EAG responses of the different tortricids species were dose-dependent. The field-trapping experiments confirmed the attractiveness of the compound to codling moth; similar activity was also shown on the chestnut tortricids in their respective host plant environment.     

甘肃、新疆、内蒙苹果蠹蛾成虫消长规律

苹果蠹蛾Cydia pomonella(L.)是我国重要的果树害虫和检疫对象。2005年至2010年,本研究在甘肃、新疆及内蒙古的不同区县选取了16个果园,使用性信息素诱捕器对其中的苹果蠹蛾成虫发生规律进行长期监测。结果表明,苹果蠹蛾在西北地区每年发生2.5个世代;在正常气候条件下,3个成虫发生高峰分别出现在5月上旬、7月中下旬和8月中下旬,但不同地区及同一地区不同果园之间存在较大差异;化学防治、迷向防治等防治措施对苹果蠹蛾成虫捕获量的影响较大,因此生活史研究为主的监测并不适合在上述果园中开展。综合上述研究结果,未对苹果蠹蛾的季节动态进行准确的预测,需要对苹果蠹蛾除成虫外的其他虫态的季节性变化进行详细研究,并建议选择3个以上的果园进行监测,综合各个果园的监测结果并得出结论。     

分子模拟技术及其在苹果蠹蛾代谢杀虫剂分子机制研究中的应用进展

苹果蠹蛾是世界性重要的果树害虫,也是我国一类进境检疫性有害生物,严重威胁着我国黄土高原和环渤海湾优势苹果产区的果业生产。化学防治是当前苹果蠹蛾防治最经济有效的措施,然而频繁使用化学杀虫剂引发的抗药性问题也在世界范围内相继报道。代谢抗性是苹果蠹蛾抗性中重要的机制,苹果蠹蛾解毒酶代谢杀虫剂的分子机制是当前代谢抗性研究的重点方向。基于分子模拟的方法在相关研究中扮演着越来越重要的角色,本文综述了分子模拟涉及的主要方法及其在苹果蠹蛾代谢杀虫剂分子机制研究中的应用,并展望未来可能的研究方向。     

Comparing the genetic structure of codling moth Cydia pomonella (L.) from Greece and France: long distance gene-flow in a sedentary pest species

Codling moth Cydia pomonella L. (Lepidoptera: Tortricidae) is the most important insect pest of apple production in Europe. Despite the economic importance of this pest, there is not information about the genetic structure of its population in Greece and the patterns of gene-flow which might affect the success of control programs. In this study, we analysed nine samples from apple, pear and walnut from various regions of mainland Greece using 11 microsatellite loci. Six samples from the aforementioned hosts from southern France were also examined for comparison. Bayesian clustering and genetic distance analyses separated the codling moth samples in two genetic clusters. The first cluster consisted mainly of the individuals from Greece, and the second of those from France, although admixture and miss-classified individuals were also observed. The low genetic differentiation among samples within each country was also revealed by F(ST) statistics (0.009 among Greek samples and 0.0150 among French samples compared to 0.050 global value among all samples and 0.032 the mean of the pair-wise values between the two countries). These F(ST) values suggest little structuring at large geographical scales in agreement with previous published studies. The host species and local factors (climatic conditions, topography, pest control programs) did not affect the genetic structure of codling moth populations within each country. The results are discussed in relation to human-made activities that promote gene-flow even at large geographic distances. Possible factors for the genetic differentiation between the two genetic clusters are also discussed.     

甘肃酒泉苹果蠹蛾的发生规律

苹果蠹蛾Cydia pomonella(L.)是我国重要的果树害虫和检疫对象。本文通过田间调查和性诱芯诱捕器诱捕的方法,研究了2008年苹果蠹蛾在甘肃酒泉的年发生规律和空间分布特性。结果表明,苹果蠹蛾在我国甘肃酒泉1年发生2代;越冬代和第1代成虫发生高峰期分别为5月上旬至中旬和7月上旬至中旬,成虫在树冠的中层、向阳的方向(东部和南部)、果实和叶背面产卵较多;幼虫发生的两次高峰分别发生在6月17日和7月26日,刚孵化幼虫很快蛀果隐蔽为害,给防治带来很大困难;幼虫化蛹前,主要从树的上部向下爬行,并常以老熟幼虫潜入树干或分枝的树皮下结茧化蛹或越冬,次年4月中下旬开始羽化。     

Trade-off between mobility and fitness in Cydia pomonella L. (Lepidoptera: Tortricidae)

Abstract.  1. The codling moth Cydia pomonella , one of the most important pest insects of apple fruit orchards worldwide, is regarded as a 'sedentary' insect, but the natural populations consist of both mobile and sedentary genotypes that display different dispersal capacity in the field. The current study investigated whether there is a fitness consequence of being mobile in this species by comparing two strains with contrasting levels of mobility obtained through bi-directional selection.
2. Female moths of the sedentary strain were significantly larger, laid more eggs during their lifespan, and both male and female moths of this strain lived longer, when compared with the mobile strain.
3. The age-specific fecundity of female moths from the sedentary strain was significantly greater, in particular between 3 and 5 days after emergence when the peaks of both oviposition and flight capacity occur, relative to the mobile moths, thereby leading to a greater reproductive function.
4. These differences resulted in different demographic parameters between the two strains. The sedentary strain had a significantly greater net reproductive rate ( R _o ) and a higher intrinsic rate of natural increase ( r _m ), although the generation time ( T ) was similar, hence requiring a shorter time to double the population size, in comparison to the mobile strain.
5. This study provides empirical evidence for the cost of being mobile in C. pomonella . Trade-offs between mobility and fitness might have contributed to the existence of genetic variance for dispersal behaviour in the natural populations and the maintenance of relative sedentariness in the species.     

入侵生物苹果蠹蛾监测与防控技术研究——公益性行业(农业)科研专项(200903042)进展

苹果蠹蛾Cydia pomonella(L.)是世界著名的严重危害苹果的重要入侵害虫,常造成20%～30%的产量损失,现已传入新疆、甘肃、内蒙古、宁夏、黑龙江和吉林等省区,对我国全国苹果安全生产构成严重威胁。2009年农业部科教司批准设立公益性行业(农业)专项"入侵生物苹果蠹蛾监测与防控技术研究",由中国科学院动物研究所主持,全国农业技术推广服务中心、西北农林科技大学、中国农科院植保所和郑州果树所、中国农业大学、河北农业大学以及相关省区植保部门等16单位参加。本文对该项目执行3年中在苹果蠹蛾关键生物学特性、实用监测和防治技术方面取得的主要进展进行了总结,详细情况可通过苹果蠹蛾信息网(www.codlingmoth.net)获得。     

Genetic architecture in codling moth populations: comparison between microsatellite and insecticide resistance markers

The codling moth, Cydia pomonella, is renowned for developing resistance to insecticides and causing significant economic damage to pome fruits worldwide. In spite of its economic importance, little is known about the patterns of movement of this pest and the effects of insecticide treatment on the population genetic structure. Here, we investigated the genetic structure of the pest in 27 orchards from France, Italy, Armenia and Chile at seven microsatellite loci and two resistance markers [biochemical activity of cytochrome P450 oxidases and proportion of knockdown resistance (kdr) alleles in the sodium channel gene]. According to the microsatellite loci, we detected isolation by distance at the supranational scale but found no evidence of geographical structure among the 24 French orchards, which were mainly structured by the intensity of the insecticide treatments. Similarly, the highest levels of metabolic resistance associated with activity of the cytochrome P450 oxidases were detected in the most treated orchards. The kdr alleles were observed in southern France and Armenia where the pyrethroid insecticides were or have been intensively sprayed. The intensity of the insecticide treatments marginally affected the allelic richness in each orchard, but not the level of inbreeding. These results suggest important and high-distance gene flow among the codling moth populations, which were mainly structured according to the history of insecticide applications. Differences in mutation-migration-drift equilibrium among treated and untreated orchards also suggest that insecticide applications are the main force regulating the local dynamics of codling moth populations.     

苹果蠹蛾抗药性研究进展

苹果蠹蛾是世界各国高度关注的严重危害苹果生产的外来有害生物。该虫于20世纪50年代在我国首次报道,目前是我国一类进境检疫性有害生物,正严重威胁我国苹果主产区的水果生产安全。苹果蠹蛾以幼虫钻蛀到果实内部为害,防治难度高,对其主要采用化学农药、交配干扰和苹果蠹蛾颗粒体病毒进行防治。由于农药的长期大量使用,苹果蠹蛾已对有机磷、氨基甲酸酯、拟除虫菊酯、昆虫生长调节剂、阿维菌素和苹果蠹蛾颗粒体病毒等不同类型的杀虫剂产生了抗药性。本文总结了国内外有关苹果蠹蛾抗药性现状和抗药性机理方面的研究,并分析了其对几种农药产生抗性的主要原因,同时结合国外苹果蠹蛾防治和抗药性相关研究,以及其在我国发生与防治的现状,提出该虫抗药性治理策略,即及时对我国疫区苹果蠹蛾的抗药性现状进行监测,在此基础上,注意科学地使用化学农药,并结合农业防治和生物防治等措施对该虫进行综合治理。     

生物源农药在苹果蠹蛾防治中的应用

苹果蠹蛾是世界性检疫害虫,对我国苹果优势产区构成了巨大威胁。长期依赖化学防治使该虫抗性问题变得十分严峻。为了保障食品安全,以环境友好的生物源农药替代化学农药已成为当前苹果蠹蛾防治的热点。本文对国内外现有的生物源农药,如寄生蜂、不育昆虫、颗粒体病毒、病原线虫、Bt、病原真菌、微孢子虫、性信息素、斑蝥素、多杀菌素等,在苹果蠹蛾防治中的最新应用及其存在的问题进行论述,讨论了生物源农药凭借其种类多、来源广且在用药时期上选择性强等特点,在该虫综合治理中的重要地位及面临的挑战。     

甘肃苹果蠹蛾的发生现状与研究进展

苹果蠹蛾是果园最重要的害虫之一,1987年入侵甘肃敦煌,2005年苹果蠹蛾在河西地区严重发生。各地先后开展了一系列的防控与监测工作,并对苹果蠹蛾的发生规律及防治技术进行了大量的研究。本文就甘肃苹果蠹蛾的发生历史、为害与防控现状及其生物学、生态学及防治技术方面的研究进展进行概述,以期为全国苹果蠹蛾的防控提供参考。     

Genetic analysis of Cydia pomonella (Lepidoptera: Tortricidae) populations with different levels of sensitivity towards the Cydia pomonella granulovirus (CpGV)

Microsatellite (simple sequence repeats, SSR) and mitochondrial DNA markers were used to assess the structure of European codling moth populations showing different levels of susceptibility towards one of the most important biocontrol agents used in apple production, the Cydia pomonella granulovirus CpGV-M. In 638 C. pomonella individuals from 33 different populations a total of 92 different alleles were scored using six SSR loci. The global estimate of genetic differentiation for all 33 populations was not significantly different from zero, thus indicating a lack of genetic differentiation. AMOVA analysis revealed a very weak but significant variance among C. pomonella populations from different geographic regions, however, no significant variation was evident between CpGV-M resistant or susceptible C. pomonella populations. Sequence analysis of a fragment of the cytochrome oxidase subunit 1 in eight C. pomonella populations resulted in 27 haplotypes, which were grouped in two distinct clusters. Again, no genetic differentiation between CpGV-M resistant and susceptible codling moth populations was detectable. In addition, Structure analysis using microsatellites and association tests with mtDNA haplotypes found neither population-level nor individual correlations associated with CpGV-M resistance. Accordingly, this lack of population structure does not allow discriminating between one or several, separate origins of CpGV-M resistance.     

苹果蠹蛾的综合防控和遗传控制研究进展

苹果蠹蛾是仁果类水果的重要检疫害虫,在世界各地造成了巨大的经济损失。目前对其化学防治、化学生态调控、病毒等防治方法研究较多,但仍不能满足防控该害虫的需要,对新型防控技术的需求日益增强。不育昆虫释放技术(SIT)是一种可控制甚至根除靶标害虫的环境友好型防控技术,但传统SIT技术存在一定的局限性,如较难区分性别与筛选雌雄虫、辐射不育昆虫的交配竞争力和适合度降低等问题,这些缺陷随着昆虫遗传修饰技术的发展将得以解决,并将在害虫防控进程中起到积极作用。本文综述了苹果蠹蛾主要防控技术研究现状,介绍了通过遗传修饰技术改善SIT的技术策略,并综合分析了我国开展苹果蠹蛾遗传修饰研究情况和将其应用在苹果蠹蛾防控体系中的可行性及优势。     

苹果蠹蛾成虫产卵特性

苹果蠹蛾Cydia pomonella(L.)是全球温带地区果园主要害虫之一,是中国的重要检疫性有害生物,对我国苹果、梨等水果的安全生产造成极大危害及威胁。为详细了解苹果蠹蛾的产卵特性,从而为进行有效的监测与防控提供基础信息,作者于2006年在甘肃省山丹县梨果园中对树冠不同高度与朝向的蛀果率进行了调查,并于2010在内蒙古阿拉善左旗对梨树果枝上不同部位的产卵量进行了详细调查。主要研究结果如下:1)树冠2.5m以上的蛀果率显著高于2.5m以下的蛀果率,树冠东面的蛀果率最高,南面的蛀果率最低;2)在整个果园中,靠近北侧的果树上果实受害程度要高于南侧果树上的果实受害程度,整个果园中蛀果率由北向南逐渐降低;3)叶片上的卵数最多,占总卵数的73.1%,果实上的卵数次之,占总卵数的14.6%,枝条上的卵数最少,占总卵数的12.2%;4)在产卵的叶片上,卵主要产在叶背面,叶片背面卵量是叶正面的6.65倍。鉴于以上研究结果,在开展化学防治或颗粒体病毒防治时,应注意充分喷施果树上层树冠,且在对果实进行处理的同时,叶片和枝条也需要充分喷药。