The role of cAMP-dependent protein kinase A in the formation of long-term memory in Bactrocera dorsalis

The cAMP-dependent protein kinase A(PKA)signaling pathway has long been considered critical for long-term memory(LTM)formation.Previous studies have mostly focused on the role of PKA signaling in LTM induction by multiple spaced conditioning with less attention to LTM induction by a single conditioning.Here,we conducted behavioral-pharmacology,enzyme immunoassay and RNA interference experiments to study the role of the PKA signaling pathway in LTM formation in the agricultural pest Bactrocera dorsalis,which has a strong memory capacity allowing it to form a two-day memory even from a single conditioning trial.We found that either blocking or activating PKA prior to conditioning pretreatment affected multiple spaced LTM,and conversely,they did not affect LTM formed by single conditioning.This was further confirmed by enzyme-linked immunosorbent assay(ELISA)and silencing of the protein kinase regulatory subunit 2 and catalytic subunit 1.Taken together,these results suggest that activating PKA during memory acquisition helps to induce the LTM formed by multiple spaced conditioning but not by a single conditioning.Our findings challenge the conserved role of PKA signaling in LTM,which provides a basis for the greater diversity of molecular mechanisms underlying LTM formation across species,as well as possible functional and evolutionary implications.

Characterization of Domeless receptors and the role of Bd Domeless3 in anti-symbiont-like virus defense in Bactrocera dorsalis

The Janus kinase/signal transducers and activators of transcription(JAK/STAT)signaling pathway play a pivotal role in innate immunity.Among invertebrates,Domeless receptors serve as the key upstream regulators of this pathway.In our study on Bactrocera dorsalis,we identified three cytokine receptors:BdDomeless1,BdDomeless2,and BdDomeless3.Each receptor encompasses five fibronectin-type-III-like(FN III)extracellular domains and a transmembrane domain.Furthermore,these receptors exhibit the increased responsiveness to diverse pathogenic challenges.Notably,only BdDomeless3 is upregulated during symbiont-like viral infections.Moreover,silencing BdDomeless3 enhanced the infectivity of Bactrocera dorsalis cripavirus(BdCV)and B.dorsalis picorna-like virus(BdPLV),underscoring BdDomeless3’s crucial role in antiviral defense of B.dorsalis.Following the suppression of Domeless3 expression,six antimicrobial peptide genes displayed decreased expression,potentially correlating with the rise in viral infectivity.To our knowledge,this is the first study identifying cytokine receptors associated with the JAK/STAT pathway in tephritid flies,shedding light on the immune mechanisms of B.dorsalis.

The Essential Oil of Ocimum americanum from Senegal and Gambia as a Source of Methyleugenol for the Control of Bactrocera dorsalis, Fruit Fly

The fruit fly, Bactrocera dorsalis (Diptera: Tephritidae) is one of the most important pests in all mango-producing areas, particularly in West Africa. In Senegal, O. americanum leaves have been used for several years to control this fly. However, to our knowledge, no chemical studies have been carried out. Thus, the aim of this study is to determine the chemical composition of the essential oil of O. americanum leaves collected in Senegal and Gambia. The essential oil obtained by hydrodistillation of these leaves is analyzed by GC/FID and GC/MS. Yields of essential oils from O. americanum leaves are 3.84% and 2.13%, respectively. Analysis of these essential oils by GC/FID and GC/MS allowed the identification of 23 compounds representing almost 100% of the total compositions. These essential oils are mainly dominated by methyleugenol (72.0% and 75.8%, respectively). Other components in significant percent are trans-β-caryophyllene (13.9% and 13.0%, respectively), germacrene D (4.1% and 3.7%, respectively), β-elemene (3.3% and 0.9%, respectively). Due to the high methyleugenol content, this study explains the attractive potential of O. americanum towards B. dorsalis. In perspective, we plan to evaluate the attractive effect of the essential oil and leaf powder of O. americanum against B. dorsalis, a real pest of mango orchards in Senegal.

Research Progress on the Innate Immunity of Bactrocera dorsalis (Hendel) and the Regulation Mechanism of Parasitic Wasp Venom Protein

[Objectives]The use of natural enemies of living insects and their derivatives can effectively avoid the problems of pesticide residues,pest resistance,biodiversity decline,control effect weakening and so on.[Methods]Parasites inject various parasitic factors into hosts to inhibit the development of hosts,adjust the immunity of hosts,interfere with the growth and development of hosts,and reduce the nutrition metabolism of hosts,so as to ensure the growth and development of the offspring.Host pests can escape or conquer the parasitism of parasitic wasps through immune defense system in order to reproduce their own offspring.[Results]Under intense and strong selection pressure,in order to effectively ensure the success rate of parasitism,the adaptive diversity of parasitism strategies of parasitic wasps is finally caused.In the process of evolution and under the pressure of directional selection,the innate immunity and acquired immunity gradually evolve.[Conclusions]In-depth research on parasitic factors of parasitic wasps and their interaction with crop pests immunity and development can not only improve theoretical understanding of insect immunity and development biology,pest biological control and other disciplines,but also be expected to enable the application of some components of parasitic factors to agriculture,medicine and pharmacy.Bactrocera dorsalis is a destructive fruit and vegetable pest.This paper summarized the venom protein of B.dorsalis parasitoids and the immune interaction with hosts,in order to provide theoretical basis for biological control of plant pests by using parasitic natural enemies.

广州桔小实蝇(Bactrocera dorsalis (Hendel))发生动态及气象因子

2002-2005年期间,在广东广州利用性引诱剂对桔小实蝇进行了全年种群动态监测,调查可知桔小实蝇可在广州全年发生。该虫数量从5月开始迅速上升,6-9月份是发生盛期;10月份虫口密度逐渐下降,11月到翌年3月份种群数量很低。对桔小实蝇发生数量和气象因子进行主成分分析和相关分析,结果表明温雨因子作用最大,其中月平均降雨量是影响桔小实蝇种群变动的关键因子;日照因子作用次之,但月总日照时数对该虫的发生数量没有显著影响。

Light intensity regulates the sexual behaviors of oriental fruit fly Bactrocera dorsalis under laboratory conditions

The oriental fruit fly,Bactrocera dorsalis(Hendel),is a devastating pest of citrus fruits.After successful mating,adult females insert their eggs into the ripened fruit,resulting in moldy and rotten fruit and causing great economic losses for the citrus industry.In the field,flies initiate copulatory behaviors as twilight approaches,and decreasing light intensity in this period is the normal stimulus for copulation.In this study,ten light intensities ranging from 0–30000 lux were set to identify the typical intensity that strongly regulates the copulation behavior of B.dorsalis.Three light intensities found to regulate the copulation behavior were then selected to verify their effects on adult male wing fanning and female chemotaxis towards 2,3,5-trimethylpyrazine(TMP).At last,strong light and complete darkness were artificially combined in the lab to verify whether they could prevent copulation to inform behavioral manipulation of oriental flies in the future.The results indicated that adult flies generally initiated copulatory behaviors at low light intensity(<1000 lux).Stronger light significantly prevented copulation in proportion to intensity,with nearly no copulation events initiated when light intensity was above 20000 lux.Both male wing fanning and female chemotaxis towards TMP were attenuated as light intensity became stronger.However,at 10000 lux,males still fanned their wings to a certain extent while TMP completely lost its attractiveness to females.In the darkness,adults did not initiate any sexual behaviors,e.g.,copulation,wing fanning,or chemotaxis to TMP.One hour of strong light(10000 lux)combined with continuous darkness completely prevented mating.These results show that light condition is an essential factor for copulatory behaviors in the oriental fruit fly.Researchers could thus manipulate light conditions artificially or disrupt the molecular target in flies’light transduction pathway to develop environmentally-friendly techniques to control this pest.

Co-Existence of <i>Bactrocera dorsalis</i>Hendel (Diptera: Tephritidae) and <i>Ceratitis cosyra</i>Walker (Diptera: Tephritidae) in the Mango Orchards in Western Burkina Faso

Fruit flies (Diptera: Tephritidae) are one of the insect groups that menace the horticultural sector in sub Saharan Africa. The main fruit fly species that caused mango fruits (Mangifera indica L.) damage in Western Burkina Faso include Bactrocera dorsalis Hendel and Ceratitis cosyra Walker. This work was carried out in Western Burkina Faso to study the relationships between these two insect pests on mango fruits in mango orchards. Thirty mango fruits per variety were sampled in six mango orchards every two weeks during two consecutive mango seasons (2017 and 2018). Each mango fruit was incubated individually for the emergence of adult fruit flies. Bactrocera dorsalis accounted for 66.30% of fruit flies reared from mango fruits and C. cosyra was represented by 33.52% of adult flies. Among mango fruits infested by fruit flies, 53.50% were attacked only by B. dorsalis, 22.14% by C. cosyra and 20.35% were infested by both species. In the mango fruits co-infested, 54.03% of adults belonged to B. dorsalis and 45.96% of adults were individuals of the C. cosyra species. The infestation rates of C. cosyra were higher at the beginning of the mango season while those of B. dorsalis were zero, and vice-versa at the end of mango season. This study highlights the relatively stable co-existence between these two major insect pests of mango fruits in mango orchards in Western Burkina Faso.

Relationship between Population Fluctuation of Oriental Fruit Fly Bactrocera dorsalis Hendel and Abiotic Factors in Yezin, Myanmar

Population fluctuation of oriental fruit fly, Bactrocera dorsalis （Hendel） （Diptera： Tephritidae）, was monitored by using methyl eugenol traps during May, 2011 to December, 2011 and May, 2016 to December, 2016 in mango orchard farms of Department of Agricultural Research in Yezin, Myanmar. In 2011, the highest mean number of male oriental fruit flies/trap/day （241.42 ± 11.79） was recorded in June and the lowest （2.21 ± 0.40） in December. The highest mean number of male oriental frui t flies/trap/day （388.95 ± 8.56） was recorded in the month of June and the lowest （2.33 ± 0.20） in December, 2016. Population data were correlated with meteorological data including temperature, duration of sunshine, and rainfall. Population fluctuation of male fruit flies was positively correlated with temperature and rainfall, and negatively correlated with the duration of sunshine.

利用GARP生态位模型预测桔小实蝇(Bactrocera dorsalis)在中国的适生区域

桔小实蝇Bactrocera dorsalis(Hendel)是一种多食性害虫,明确其可能适生的区域对该虫的科学监测及防治意义重大。利用桔小实蝇在我国的已知分布点数据和亚洲地区的14个环境地理变量图层,运用GARP生态位模型结合GIS空间分析模块预测了该虫在亚洲的地理分布。结果表明桔小实蝇可分布在中国、日本、菲律宾、马来西亚、泰国北部、越南、柬埔寨、老挝、缅甸、尼泊尔、巴基斯坦、孟加拉国和斯里兰卡,这与EPPO报道的分布区域一致。将拟合过程中获得的生态位运算法则投影到我国,并考虑模型间的一致性,预测桔小实蝇在我国各省及市县范围的分布:云南大部、四川南部和东部、贵州大部、重庆大部、广西、广东、台湾、香港、澳门、海南、福建、江西、浙江大部、湖南大部、湖北大部、上海、江苏南部、河南局部及安徽部分地区为桔小实蝇的适生区。次适生区沿适生区周围分布,为四川、贵州、重庆、湖北北部、河南南部和江苏南部的一些零星地区。适生区和次适生区大多有较高密度的寄主果树,为桔小实蝇的生存提供了条件。预测结果经独立验证数据的适合性测验表明,选择的最优模型具有显著的统计学意义,显示了很好的预测能力。GARP生态位模型可以解决生态学、生物地理学和环境保护方面的一系列问题,具有广泛的应用前景,为物种已知基础分布点资料的综合分析以及有害生物的适生性分析、监测和防治提供了技术平台。

基于荧光标记的怒江流域桔小实蝇(Bactrocera dorsalis)的迁移扩散

2005年7月在云南怒江流域地区,以荧光粉作为标记物,采用“标记-释放-回收”方法,对怒江流域桔小实蝇迁移扩散规律进行了研究。以释放点潞江坝为中心,东南西北4个方位设立桔小实蝇回收点,经过7d的回捕,从释放点沿潞江以北至六库沿线共回收到的标记桔小实蝇43头,最远在距释放点以北97km的地方回收到标记桔小实蝇5头。沿怒江在释放点以南,仅在小于29km的范围内回收到标记桔小实蝇17头。释放点东面和西面未能回收到标记桔小实蝇。分析释放点以北各回收点标记桔小实蝇与非标记桔小实蝇的相互关系揭示,非标记桔小实蝇与标记桔小实蝇在空间动态中具有相同的行为模式,由此推论非标记桔小实蝇与标记桔小实蝇可能来自同一种群。分析怒江流域区的自然地理发现,潞江坝桔小实蝇可借助怒江两边高大山脉形成的天然河谷通道,在适宜的气候条件下,在北上气流的携带下,实现由南向北的远距离迁移扩散;同时,由于高大山脉的阻隔,使潞江坝桔小实蝇没能向东西两个方向作远距离扩散迁移。研究首次揭示了在特定峡谷地区桔小实蝇扩散迁移现象,为桔小实蝇迁移扩散研究提供了新鲜实例,为在当地制定切实有效的桔小实蝇防治策略提供了基础信息。

云南桔小实蝇(Bactrocera dorsalis)季节性分布区4个地理种群遗传结构

对云南桔小实蝇季节分布区内六库、大理、昆明和曲靖4个典型地区桔小实蝇种群(Bactrocera dorsalis),共52个个体的线粒体DNACOⅠ基因中的部分序列进行了测定分析。在获得的503bp序列中,共发现15个多态位点,定义了14种单倍型,其中种群间的共享单倍型有4个。通过对桔小实蝇4个地理种群的K2P遗传距离、Fst值,种群间和种群内遗传差异平均数的统计检测,以及4个种群之间基因流状况分析表明,研究的各种群间均存在不同程度的遗传分化。六库种群与其余3个种群间的遗传分化最大,遗传差异显著(p<0.05)。大理种群与曲靖种群之间存在一定程度遗传分化(p<0.10),但与昆明种群间的分化程度较低。昆明种群与曲靖种群间的遗传分化程度最低。简言之,在桔小实蝇季节性分布区内,位于西部的种群遗传分化程度最高,由西向东,遗传分化程度渐次下降,位于东部的两个种群遗传结构相近。研究认为,地理隔离是导致六库种群与其余3个种群遗传分化的主要原因,而大理、昆明和曲靖种群之间遗传分化较低,可能是这些种群来自相近或相同的虫源地。研究结果对于在桔小实蝇季节性分布区的不同地点制定桔小实蝇治理方案具有重要的参考价值。

Influence of Host Shift on Genetic Differentiation of the Oriental Fruit Fly,Bactrocera dorsalis

Invasion of the oriental fruit lfy, Bactrocera dorsalis, into new niches containing different food sources （a process referred to as host shift）, may cause population genetic differentiation and sympatric speciation. To attempt to infer that experimentally, test populations were established by transferring a subset of the original populations, which had been grown on banana for many generations, onto navel orange, and then subculturing the navel orange population and banana population for at least 20 generations. Four pairs of SSR primers with high polymorphism on laboratory strains were used to detect population genetic differentiation. All six tested populations （the 5th, 10th and 15th generations of B. dorsalis fed on banana and navel orange, respectively） were found to have low genetic diversity. Furthermore, the genetic diversity of the navel orange populations was found to decline after being crossed for several generations. Populations initially were deviated from Hardy-Weinberg equilibrium, however, equilibrium was achieved with increasing numbers of generations in both of the host populations. Limited gene lfows were found among the six populations. The Nei’s standard genetic distances between the two host populations of the same generation were initially low, but increased with generation number. Genetic distances between banana and navel orange populations of the same generation were lower than genetic distances between different generations grown on the same host plant. Analysis of molecular distance （AMOVA） results based on generation groups and host groups demonstrated that genetic variation among generations was greater than that between the two host populations. The results indicated that population genetic differentiation occurred after the host shift, albeit at low level. Biogeography and taxonomy of the B. dorsalis complex revealed that speciation of B. dorsalis might be tightly associated with host shift or host specialization of B. dorsalis following dispersal.

Trapping Effects of Different Treatments on Bactrocera dorsalis and Bactrocera cucurbitae

Five different trapping treatments, spraying attractant on bottle surface and spraying attractant inside the bottles with 0, 50,100 and 200 mL water, were set to trap Bactrocera dorsalis and B. cucurbitae in guava （Psidium guajava） park. The results showed that when the usage of attractant was 1 g, both Haonian and Wende had trapping effect on B. dorsalis and B. cucurbitae. The trapping effect of Haonian on B. dorsalis was better than that of Wende, while their trapping effects on B. cucurbitae was just the opposite. The trapping effects of different treatments had great difference. The trapping effect of Haonian on two species of fruit flies enhanced with the increasing volume of water, and reached the ma^mum value as the water volume was 200 mL. With the increasing volume of water, the trap- ping effect of Wende on two species of fruit flies first increased, and then decreased, which reached the maximum value as the water volume was 50 mL. Different treatments with attractants spraying inside bottles had better trapping effects on two species of fruit flies than that spraying on bottle surface.

Advances in Detection Methods for Invasive Pest Bactrocera dorsalis

Bactrocera dorsalis Hendel （Diptera： Tephritidae） is an invasive pest around the world. The paper summarizes biological and ecological characteristics of B, dorsalis, and reviews its detection methods from the aspects of morphological identification, acoustic detection and molecular detection, in order to provide a reference for further research and development of new detection methods. The hot issues in the study of B. dorsalis, such as ecological adaptation pattern, diffusion pathways and mechanisms, sustainable control measures, are also put forward in the paper.

Monitoring and Control Technology of Bactrocera dorsalis

After systematic monitoring and field survey in orchard for three years from 2009 to 2011, it was found that Bactrocera dorsalis occurred for more than three generations each year on the north shore of the middle and lower reaches of Yangtze River, with overlapping generations; the activity peak of adults was from mid August to late September; the occurrence in citrus orchard in hilly and mountainous area was severe; the average insect-fruit rate in October reached 0.20% - 15.88% ; B. dorsalis had sporadic occurrence in other orchards. The integrated control measures of plowing in winter to kill pupae, removing insect-fruits, boycott- ing on the ground, trapping by sex attraetants and spraying pesticides could basically control the damage of B. dorsalis.

A Rapid Identification Method of Bactrocera cilifera (Hendel) with Species-Specific Primers(SS-COI)

[Objective]The paper was to establish a rapid identification method of Bactrocera cilifera(Hendel)with species-specific primers(SS-COI).[Method]Using B.cilifera(Hendel)as the positive control,and 19 species of fruit flies such as B.diaphora(Coquillett)and B.dorsalis(Hendel)as the negative controls,a pair of species-specific primers,YF290 and YR511,were designed and screened for accurate identification of B.cilifera,based on mitochondrial DNA COI sequence.[Result]The PCR products were amplified and detected by electrophoresis.Only a clear and single band was observed at about 222 bp in the positive control,while no bands were found in the other negative controls.[Conclusion]The established rapid identification method with species-specific primers(SS-COI)is of great practical significance for rapid identification of fruit flies intercepted from import and export fruits and vegetables at ports,and for rapid clearance and early warning of import fruits and vegetables at ports.

Identification and functional verification of Y-chromosome-specific gene typo-gyf in Bactrocera dorsalis

Genes on the Y chromosome play important roles in male sex determination and development.The identification of Y-chromosome-specific genes not only provides a theoretical basis for the study of male reproductive development,but also offers genetic control targets for agricultural pests.However,Y-chromosome genes are rarely characterized due to their high repeatability and high heterochromatinization,especially in the oriental fruit fly.In this study,1011 Y-chromosome-specific candidate sequences were screened from 2 to 4 h Bactrocera dorsalis embryo datasets with the chromosome quotient method,6 of which were identified as Y-chromosome-specific sequences by polymerase chain reaction,including typo-gyf,a 19126-bp DNA sequence containing a 575-amino acid open reading frame.Testicular deformation and a significant reduction in sperm number were observed after typo-gyf knockdown with RNA interference in embryos.After typo-gyf knockout with clustered regularly interspaced palindromic repeats(CRISPR)/CRISPR-associated protein 9 in the embryonic stage,the sex ratio of the emergent adults was unbalanced,with far more females than males.A genotype analysis of these females with the Y-chromosome gene MoY revealed no sex reversal.Typo-gyf knockout led to the death of XY individuals in the embryonic stage.We conclude that typo-gyf is an essential gene for male survival,and is also involved in testicular development and spermatogenesis.The identification of typo-gyf and its functional verification provide insight into the roles of Y-chromosome genes in male development.

橘小实蝇在中国北方果蔬区的发生与防控概况

橘小实蝇是中国果蔬产区重要害虫之一。近年来,随着区域气候、物流发展和种植技术的改变,北方果蔬区也遭受危害并表现出与南方不同的特点。汇总了北方果蔬区橘小实蝇的发生范围及特点,明晰了越冬问题和应对措施,从化学、物理、农业、生物及新技术与设备5个方面比较了实际防控效果及技术优劣,认为套袋和化学防控仍然为该虫高效控制的首选。“预防为主,外防入侵,内防扩散,综合防控,统防统治”仍然是橘小实蝇防控必须坚持的重要方针和关键策略。

非寄主植物精油对桔小实蝇的驱避效果研究

桔小实蝇Bactrocera dorsalis Hendel幼虫期隐蔽性的取食习性降低了化学防治的效果,而普遍存在的杀虫剂耐药性则加剧了这一问题。利用非寄主植物挥发物驱避害虫是替代化学防治、有效控制虫害的策略之一。为了筛选更有效的植物源产卵驱避剂,本研究选取23种非寄主植物精油作为候选材料,进行4轮试验,首先采用行为趋向反应试验,筛选出8种驱避率较高且选择反应率和驱避反应率差异极显著(P<0.01)的非寄主植物精油:绿花白千层、山鸡椒、广藿香、当归、茶树、茴香、薄荷、艾草;然后通过产卵驱避活性试验,筛选出4种驱避率高且处理组与对照组的产卵量差异极显著(P<0.01)的植物精油:绿花白千层、广藿香、当归、茶树。浓度梯度试验表明,浓度为5000μg/mL时,绿花白千层、广藿香、当归驱避率最高,浓度为3000μg/mL时,茶树精油驱避率最高;在最佳浓度下对桔小实蝇产卵驱避持效性分析,结果表明最佳浓度下4种精油处理过的果实,随着时间延长,桔小实蝇产卵孔和产卵量逐渐增加,驱避率逐渐降低,驱避产卵活性逐渐消失,前3 d降速较快,然后逐渐放缓。本研究通过行为趋向反应试验、产卵驱避活性试验、浓度梯度试验和驱避活性持效试验,从23种非寄主植物精油中,筛选到绿花白千层精油对桔小实蝇有较高的产卵驱避活性,通过剂型改良等措施有望开发成植物源驱避剂。

北细辛精油对桔小实蝇杀虫活性及其机理研究

[目的]对北细辛精油对桔小实蝇的熏蒸和触杀的杀虫活性进行研究,并初步确定北细辛精油对桔小实蝇的杀虫机理,旨在寻找天然有效的植物源杀虫剂。[方法]采用密闭熏蒸法和微量点滴法测定北细辛精油对桔小实蝇的熏蒸及触杀活性,采用微板法测定北细辛精油对桔小实蝇体内乙酰胆碱酯酶(AchE)和羧酸酯酶(CarE)活力的影响。[结果]在杀虫活性试验中,随着北细辛精油浓度的增加,杀虫效果均逐渐增强,且随着时间的延长,毒性也均逐渐增强;在熏蒸试验中,当浓度为1mL/L且处理时间为12h时,校正死亡率达到最大为100%;在触杀试验中,当浓度为156.25μL/L且处理时间为12 h,校正死亡率达到最大为100%;对桔小实蝇进行熏蒸处理、触杀处理12h的LC_(50)分别为0.243 mL/L、30.884μL/L;用固定浓度为156.25μL/L的北细辛精油处理桔小实蝇不同时间后,其体内AchE和CarE整体均表现为抑制作用,用不同浓度的北细辛精油处理桔小实蝇8 h后,虫体内的AchE呈现低浓度诱导高浓度抑制的作用,北细辛精油对桔小实蝇体内CarE的抑制作用随着浓度的增大而不断增强。[结论]北细辛精油对桔小实蝇有较好的触杀和熏蒸活性,且触杀活性较强,北细辛精油对桔小实蝇体内的AchE和CarE均有抑制作用。该研究为天然植物源杀虫剂的研发提供理论依据。