白纹伊蚊幼虫期经香茅液处理后成蚊刺叮选择行为的变化

植物性驱蚊剂的开发研究受到了极大的关注,但昆虫的习惯化行为反应是制约有效植物性驱蚊剂发展的障碍之一.为了了解登革热重要媒介昆虫白纹伊蚊Aedes albopictus对植物性驱避剂的行为机制,本研究在分析了香茅油溶液对幼虫存活影响和对成蚊驱避作用的基础上,将白纹伊蚊幼虫于经稀释的香茅Cymbopogon nardus油溶液中饲养,然后通过局部涂肤的方法,测定白纹伊蚊雌蚊的刺叮选择行为变化.结果显示,香茅油对成蚊具有显著的驱避效果,但是幼虫经香茅油溶液饲养后,尽管仍具有显著的驱避作用,但是44.5 mg/L和178 mg/L的低浓度香茅油对白纹伊蚊的驱避作用发生了明显的减弱.说明幼虫期对精油溶液的经历,可诱导白纹伊蚊刺叮选择行为的习惯化反应,从而降低植物性驱避剂的驱避效果.     

小蓬草精油对两种蚊虫的毒杀活性和成分分析

【目的】明确小蓬草Conyza canadensis ( L.) Cronq.精油的杀虫潜力及其活性成分。【方法】通过浸虫法和密闭熏蒸法测试了小蓬草精油对白纹伊蚊Aedes albopictus和致倦库蚊Culex pipiens quinquefasciatus幼虫及成蚊的毒杀活性, 并利用气相色谱 质谱联用仪（GC-MS）对精油的挥发性成分进行了定性分析。【结果】 小蓬草精油对白纹伊蚊1-4龄期幼虫及蛹的24 h LC50值分别为25.01, 45.88, 56.94, 64.60和346.23 μg/mL; 对致倦库蚊幼虫1-4龄期幼虫及蛹的24 h LC₅₀值分别为9.16, 8.65, 32.12, 43.68和197.83 μg/mL。在剂量分别为48, 64, 80, 96, 112和128 μg/cm3时, 小蓬草精油对白纹伊蚊成蚊的KT₅₀值分别为28.81, 22.31, 20.38, 17.05, 13.92和9.74 min; 对致倦库蚊的KT50值分别为34.90, 32.97, 23.97, 19.60, 15.20和10.34 min。 24 h熏蒸对白纹伊蚊和致倦库蚊成蚊的LC50值分别是75.46和99.19 μg/cm³。小蓬草精油的GC MS定性分析共分离鉴定出31种化合物, 其中单萜类物质6种, 倍半萜烯类物质17种, 含氧萜烯类6种。【结论】结果表明小蓬草精油对这两种蚊虫的毒杀活性较高, 具有深开发潜力。     

羟基香茅醛缩醛类化合物的合成及对蚊虫的驱避活性

为了寻找新的萜类驱避剂, 以羟基香茅醛为原料, 合成羟基香茅醛二甲缩醛、 羟基香茅醛乙二醇缩醛、 羟基香茅醛1, 3-丙二醇缩醛和羟基香茅醛1, 2-丙二醇缩醛, 用红外光谱IR、 质谱MS分析其结构, 对羟基香茅醛1, 2-丙二醇缩醛还进行了¹H NMR及¹³C NMR分析。按国标GB/T 13917.9-2009测定了它们对白纹伊蚊Aedes albopictus、 中华按蚊Anopheles sinensis及淡色库蚊Culex pipiens的驱避活性。结果表明: 10%（质量分数）羟基香茅醛二甲缩醛和羟基香茅醛1, 2-丙二醇缩醛对中华按蚊的驱避时间均达到国标B级; 羟基香茅醛1, 2-丙二醇缩醛还对其他的蚊虫具有驱避作用, 20%（质量分数）羟基香茅醛1, 2-丙二醇缩醛对白纹伊蚊的驱避时间超过国标B级; 10%（质量分数）羟基香茅醛1, 2-丙二醇缩醛对淡色库蚊的驱避时间超过国标A级。这些结果说明它们对不同蚊种驱避活性的差别, 为不同场合的驱蚊需要提供了理论基础。     

四种植物精油对德国小蠊的驱避效果

室内测定4种蚊虫驱避效果较好的植物精油(香叶醇、芳樟醇、柠檬醛和茴香醛)对德国小蠊雄性成虫的驱避性,并与传统上常用的驱避剂DEET作对比研究,以期从中筛选出对德国小蠊驱避效果较好的驱避剂。每种植物精油设置4个剂量,即1,10,100和1000μg/cm2。结果表明,每种植物精油的驱避性均随剂量的增加而升高,4种精油的驱避性均高于DEET,驱避性最好的是芳樟醇;当剂量为100和1000μg/cm2时,每种植物精油的驱避性与对照组相比均有显著差异(P<0·05);除芳樟醇外,其余植物精油在剂量为1000μg/cm2时的驱避性与100μg/cm2的驱避性相比差异显著(P<0·05)。提示芳樟醇可能是一种很有发展前景的德国小蠊驱避剂。     

三色迷彩油添加避蚊胺对白纹伊蚊驱避效果的实验室评价

参照中华人民共和国国家标准GB/T 17322.10-1998和《军队特需药品研发勤务技术指导原则(试行)》规定的测试方法,测试了避蚊胺和水溶性二氧化钛处理迷彩油(CFP)对白纹伊蚊Aedes albopictus的驱避效果,为研发我军专用的防蚊虫迷彩油提供依据。结果表明:在3种颜色迷彩油中加入DEET后,不影响DEET的驱蚊效果;添加不同浓度DEET对蚊虫的驱避效果差异显著,20%DEET和25%DEET+迷彩油对白纹伊蚊的平均防护时间均达到或超过10 h,达到《军队特需药品研发勤务技术指导原则(试行)》规定的标准,15%DEET+迷彩油平均防护时间不足10 h,未达《军队特需药品研发勤务技术指导原则(试行)》规定的标准。研究表明:将适量DEET与迷彩油混合涂抹于皮肤可能作为演习或战时的伪装和防蚊的一种有效的综合保护措施。     

The laboratory evaluation of repellent effect of camouflage face paint mixed with DEET to Aedes albopictus

参照中华人民共和国国家标准GB/T 17322.10-1998和《军队特需药品研发勤务技术指导原则(试行)》规定的测试方法,测试了避蚊胺和水溶性二氧化钛处理迷彩油(CFP)对白纹伊蚊Aedes albopictus的驱避效果,为研发我军专用的防蚊虫迷彩油提供依据.结果表明:在3种颜色迷彩油中加入DEET后,不影响DEET的驱蚊效果;添加不同浓度DEET对蚊虫的驱避效果差异显著,20％dEET和25％dEET+迷彩油对白纹伊蚊的平均防护时间均达到或超过10h,达到《军队特需药品研发勤务技术指导原则(试行)》规定的标准,15％dEET+迷彩油平均防护时间不足10h,未达《军队特需药品研发勤务技术指导原则(试行)》规定的标准.研究表明:将适量DEET与迷彩油混合涂抹于皮肤可能作为演习或战时的伪装和防蚊的一种有效的综合保护措施.     

烟蓟马成虫对不同植物挥发物的行为选择

【目的】评价不同植物挥发物对烟蓟马Thrips tabaci雌性成虫的行为调控作用,解析烟蓟马成虫嗅觉识别行为,为研发成虫引诱剂或驱避剂提供科学依据。【方法】利用嗅觉行为测定装置测试烟蓟马雌性成虫对不同种类、不同浓度植物挥发物的室内选择行为,筛选出具有高引诱或驱避活性的挥发物。【结果】与溶剂正己烷相比,烟蓟马雌性成虫对浓度为1μg/μL的γ-癸酸内酯、(+)α-蒎烯、芳樟醇、2-乙酸苯乙酯、(-)α-蒎烯没有显著的行为选择（P>0.05）,而壬醛、马鞭草烯酮、香茅醛、橙花醇和桉树脑对烟蓟马表现出显著的吸引作用（P<0.05）,4-乙酰吡啶、邻茴香醛、δ-癸酸内酯、顺-3-己烯醇、香叶醇和1-辛烯-3-醇的吸引作用极显著（P<0.001）;但水杨醛、香芹酚、顺茉莉醛、丁香酚和对烯丙基苯甲醚对烟蓟马表现出显著的驱避作用（P<0.05）,水杨酸甲酯、茉莉酸甲酯、百里酚和异戊醛4种挥发物具有极显著的驱避作用（P<0.001）。同时,随着测试浓度的增加,大部分挥发物对烟蓟马雌性成虫的吸引或驱避作用明显增强。【结论】δ-癸酸内酯、香叶醇、1-辛烯-3-醇、邻茴香醛和4-乙酰吡啶对烟蓟马雌性成虫具有强烈吸引作用,水杨酸甲酯、茉莉酸甲酯和百里酚则具有明显驱避效应,为开发烟蓟马行为调控剂奠定了重要基础。     

迷迭香植物精油对白纹伊蚊的驱避作用及其化学成分

应用水蒸气蒸溜法和超临界二氧化碳萃取法提取生长于云南的迷迭香茎叶植物精油,测试2种精油对白纹伊蚊Aedes albopictus Skuse的驱避作用,并利用GC/MS联用仪分析2种精油的化学成分。结果表明:超临界二氧化碳提取的迷迭香精油对白纹伊蚊的驱避时间是(5.82±1.13)h,达到国标驱避剂评价的B级标准。2种精油化学成分中都含有驱纹活性物质:柠檬烯、樟脑、Eucalyptol、(+)-4-Carene、1-methyl-4-(1-methyle thylidene)-cyclohexene、Beta-pinene等,且驱蚊活性成分在挥发油中占有较高比例,显示该植物精油在驱蚊方面有一定开发价值。     

蚊虫搜寻吸血寄主和产卵行为的调节因子及相关嗅觉机理

嗅觉在蚊虫的吸血寄主搜寻、产卵和糖源搜寻行为中起决定作用,而在交配行为中的作用并不清楚。本文系统全面地综述了近20年来蚊虫化学生态学和嗅觉识别的分子机理的研究。蚊虫的触角、下颚须和口喙上的嗅觉感器感觉环境中释放的各种挥发性化合物。气味分子与嗅觉气味结合蛋白和气味受体的结合所启动的一系列生化反应产生神经动作电位。蚊虫嗅觉神经元编码气味中化合物的组成、浓度及其暂时瞬间的浓度变化和空间分布。吸血前后神经元的活性在数量和质量上有变化,反映了蚊虫在搜寻吸血寄主和产卵行为上的调节。在吸血寄主搜寻中,人体和动物释放的二氧化碳、乳酸以及其他气味协同引诱蚊虫向目标气味源定向飞行,最后找到吸血寄主。而成熟产卵雌蚊是利用产卵场所释放的腐烂气味寻找适宜的产卵场所,一些蚊虫卵、幼虫或蛹分泌的产卵信息素引诱和刺激雌蚊产卵,并与产卵生境气味起协同作用。植物气味尤其是花香味引诱蚊虫找到蜜源。驱避剂也是直接或间接通过嗅觉起作用,一些驱蚊剂由于阻断嗅觉反应而抑制蚊虫的定向飞行。从植物、动物或人体以及产卵场所释放的气味中有望找到有效的引诱和驱避化合物。对蚊虫嗅觉识别机理的认识将使我们开发出有效的蚊虫诱捕技术,进而应用于种群监测和控制。     

水菖蒲超临界CO_2萃取物对德国小蠊的触杀和驱避活性

水菖蒲(Acorus calamus L.)超临界CO2萃取物对德国小蠊Blattella germanica L.同时具有很好的触杀和驱避活性。采用药膜接触法和滤纸药膜选择法,分别研究水菖蒲超临界CO2萃取物对德国小蠊3龄若虫的触杀和驱避活性。结果表明:水菖蒲超临界CO2萃取物对德国小蠊的生物活性存在着明显的浓度-时间-效应。触杀作用中处理试虫12h后,最高浓度124.00μg/cm2的校正死亡率就达到98.33%,24h后达到100%。试虫在处理12h后的LC50为36.45μg/cm2。驱避活性中,最高浓度815.28μg/cm2的驱避率为67.73%,驱避等级达到了Ⅳ级。     

Efficacy of the botanical repellents geraniol,linalool, and citronella against mosquitoes

We determined the degree of personal protection provided by citronella, linalool, and geraniol in the form of commercially available candles or diffusers, both indoors and outdoors. Under the uniform conditions of the experiments, all substances repelled significantly more mosquitoes than the unprotected control. Furthermore, the repellents tested were more active when in the form of a continuous release diffuser than in candle form. All candles were 88g containing 5% of the active ingredient and all diffusers contained 20g of 100% active ingredient. Indoors, the repellency rate of citronella candles was only 14% while the repellency rate of citronella diffusers was 68%. The repellency of geraniol candles was 50% while the diffusers provided a repellency rate of 97%. No linalool candles were available for study but linalool diffusers repelled mosquitoes by 93%. Outdoors, citronella diffusers placed 6 m from mosquito traps repelled female mosquitoes by 22%, linalool repelled females by 58%, and geraniol repelled females by 75%. Trap catches were significantly reduced again when diffusers were placed 3 m from the traps. We concluded that geraniol had significantly more repellent activity than citronella or linalool in both indoor and outdoor settings.     

Relationship between the olfactory sensilla of Papilio demoleus L. larvae and their orientation responses to different odours

Papilio demoleus larvae showed maximum attraction to odours of citral, cirtonellal and citronellol, slightly less to geraniol and 1-limonene, and low attraction to hydroxy-citronellal and geranyl acetate. These chemicals (except the last) are the main odorous constituents of the insect's host plant (Citrus) leaves. Phellandrene was almost inert, whereas farnesol and d-limonene elicited a low, and linalool, eugenol and clove oil a high repulsion. Larvae deprived of one antenna and both maxillary palps were similar to normal larvae in their orientational responses. Normal larval responses changed with the inactivation of one or more of the three specific antennal sensilla. A full complement of the three sensilla was not essential for the normal larval response to certain chemicals. Any of the sensilla singly or in combination with any other sensillum could mediate the normal larval response (attraction) to citral and geraniol. For a few other chemicals, certain specific sensilla, singly or in a combination of two, mediated the normal response. Only for d-limonene were all three sensilla essential for the normal response.     

Forty‐two compounds in eleven essential oils elicit antennal responses from Aedes aegypti

Essential oils of various plants can be effective at repelling mosquitoes. The repellent properties are often ascribed to their dominant constituents. Our objective was to analyse several essential oils by coupled gas chromatographic‐electroantennographic detection (GC‐EAD) on the premise that those compounds that are detected by the antennae of the yellow fever mosquito, Aedes aegypti L. (Diptera: Culicidae), are candidate repellents even though they may be minor constituents and thus be overlooked in GC‐mass spectrometric analyses of essential oils. In the essential oils of catnip, cinnamon, citronella, cumin, eucalyptus, geranium, ginger, melissa, peppermint, rosemary, and thyme, 42 components induced antennal responses, most commonly β‐caryophyllene, linalool, 1,8‐cineole, geraniol, and geranial. Some of these 42 components are known insect repellents, indicating that GC‐EAD screening of essential oils is a viable analytical technique to detect quantitatively minor constituents, which could be potent repellents when tested at an appropriate dose.     

Variability in essential oil composition of Turkish basils (Ocimum basilicum L.)

Sweet basil (Ocimum basilicum L.), one of the most popular aromatic plants, shows great variation in both morphology and essential oil components. In this study, the composition of 18 Turkish basil essential oils was investigated by GC and GC–MS. Variation of essential oils in the landraces was subjected to cluster analysis, and seven different chemotypes were identified. They were (1) linalool, (2) methyl cinnamate, (3) methyl cinnamate/linalool, (4) methyl eugenol, (5) citral, (6) methyl chavicol (estragol), and (7) methyl chavicol/citral. Methyl chavicol with high citral contents (methyl chavicol/citral) can be considered as a “new chemotype” in the Turkish basils. Because methyl eugenol and methyl chavicol have structural resemblance to carcinogenic phenylpropanoids, chemotypes having high linalool, methyl cinnamate or citral contents and a mixture of these is suitable to cultivate for use in industry.     

Spatial repellency and other effects of transfluthrin and linalool on Aedes aegypti and Aedes albopictus

In the present study, the effects of two spatial repellents (SR) were determined for Aedes aegypti and Ae albopictus, the main vectors of dengue, Chikungunya, and Zika fever. The modular high‐throughput screening system (HITSS ) was used to evaluate the response of both species to transfluthrin and linalool SR at different concentrations. The highest spatial repellency results for Ae. aegypti were obtained by transfluthrin to 0.001% with 37.50 ± 4.33%, and for linalool to 10% with 77.50 ± 3.90%. For Ae. albopictus, the highest spatial repellency percentages for transfluthrin 0.01% were 45.00 ± 3.78%, and linalool at 1% and 10% were 56.25 ± 7.06% and 56.25 ± 6.46%, respectively. Transfluthrin caused high levels of mortality with 71.25 ± 6.66%, 79.75 ± 8.65%, and 100% to Ae. aegypti and 70.00 ± 5.98% and 98.75 ± 0.82% to Aedes albopcitus. With the results of this study, we concluded that both the transfluthrin and linalool could be used as protection measures against the bite of Ae. aegypti and Ae. albopictus in the integral strategies for the control of vectors in Mexico.     

Biotransformation of geraniol, nerol and citral by sporulated surface cultures of Aspergillus niger and Penicillium sp

The biotransformation of geraniol, nerol and citral by Aspergillus niger was studied. A comparison was made between submerged liquid, sporulated surface cultures and spore suspensions. This bioconversion was also carried out with surface cultures of Penicillium sp. The main bioconversion products obtained from geraniol and nerol by liquid cultures of A. niger were linalool and alpha-terpineol. Linalool, alpha-terpineol and limonene were the main products obtained from nerol and citral by sporulated surface cultures, whereas geraniol was converted predominantly to linalool, also resulting in higher yields. Bioconversion of nerol with Penicillium chrysogenum yielded mainly alpha-terpineol and some unidentified compounds. With P. rugulosum the major bioconversion product from nerol and citral was linalool. The bioconversion of nerol to alpha-terpineol and linalool by spore suspensions of A. niger was also investigated. Finally the biotransformation with sporulated surface cultures was also monitored by solid phase microextraction (SPME). It was found that SPME is a very fast and efficient screening technique for biotransformation experiments.     

Laboratory and field evaluation of insect repellents as larvicides against the mosquitoes Aedes albopictus and Anopheles albimanus

Acute toxicity and persistence of three insect repellents, deet and two piperidines (AI3-35765 and AI3-37220), were evaluated against mosquito larvae of Aedes albopictus (Skuse) and Anopheles albimanus Wiedemann (Diptera: Culicidae) in the laboratory, and against natural populations of Ae. albopictus in the field. In laboratory studies, the LC50 values of the repellents for first instars ranged between 0.005 and 0.021% (Ae. albopictus) and between 0.01 and 0.014% (An. albimanus) and, for fourth instars, between 0.019 and 0.034% (Ae. albopictus) and between 0.015 and 0.024% (An. albimanus). A 0.1% concentration of deet caused 90-100% mortality in first-instar Ae. albopictus for 4 weeks, whereas AI3-35765 and AI3-37220 at the same concentration killed 95-100% of larvae for 12 weeks and 98-100% of larvae for 33 weeks post-treatment, respectively. Deet and AI3-35765 at 0.1 % concentration resulted in complete mortality of first-instar An. albimanus for 3 weeks post-treatment, whereas AI3-37220 resulted in 91-99% larval mortalities for 35 weeks post-treatment. A 0.1% concentration of A13-37220 provided 77-98% larval mortality for 20 weeks and 63-97% larval mortality for 12 weeks post-treatment, respectively, against fourth-instar Ae. albopictus and An. albimanus.In the field, in artificial containers, the reduction of Ae. albopictus larvae caused by deet, AI3-35765 and AI3-37220 was 88-95% for 3-4 weeks, 98-100% for 7 weeks, and 82-100% for 13 weeks post-treatment, respectively. In used tyres, the same concentration of the repellents resulted in 100% reduction of Ae. albopictus larvae for 2 weeks (deet), 4 weeks (AI3-35765) and 5 weeks (AI3-37220) post-treatment. In cemetery flower vases, Aedes spp. larvae were eliminated for 4 weeks (deet) and 6 weeks post-treatment by both A13-35765 and AI3-37220. These topical repellents (particularly AI3-37220) have good potential for development and use in the management of container-inhabiting mosquitoes because they deter oviposition and kill larvae.     

Sodium channel gene expression in mosquitoes, Aeries albopictus （S.）

A mosquito strain of Aedes albopictus, HAmAal^G0, from Huntsville, Alabama, USA, showed a normal susceptibility and low tolerance to permethrin and resmethrin （pyrethroid insecticides） compared to a susceptible Ikaken strain, even though these pyrethroid insecticides have been used in the field for a long period of time in Alabama. Recently, we treated HAmAal^G0 in the laboratory with permethrin for five generations and detected no significant change in the level of resistance to permethrin in the selected mosquitoes, HAmAal^G0, compared with the parental strain HAmAal^G0. We then examined the allelic expression at the L-to-F kdr site of the sodium channel gene in the Aedes mosquitoes to address our hypothesis that the L-to-F kdr mutation was not present in HAmAal^G0 and HAmAal^G5 mosquitoes. We found that every tested individual in Ikaken, HAmAal^G5, and HAmAal^G5 populations expressed a codon of CTA at the L-to-F kdr site encoding Leu, strongly corresponding to their susceptibility to insecticides.     

Wolbachia strain wAlbB enhances infection by the rodent malaria parasite Plasmodium berghei in Anopheles gambiae mosquitoes

Wolbachia, a common bacterial endosymbiont of insects, has been shown to protect its hosts against a wide range of pathogens. However, not all strains exert a protective effect on their host. Here we assess the effects of two divergent Wolbachia strains, wAlbB from Aedes albopictus and wMelPop from Drosophila melanogaster, on the vector competence of Anopheles gambiae challenged with Plasmodium berghei. We show that the wAlbB strain significantly increases P. berghei oocyst levels in the mosquito midgut while wMelPop modestly suppresses oocyst levels. The wAlbB strain is avirulent to mosquitoes while wMelPop is moderately virulent to mosquitoes pre-blood meal and highly virulent after mosquitoes have fed on mice. These various effects on P. berghei levels suggest that Wolbachia strains differ in their interactions with the host and/or pathogen, and these differences could be used to dissect the molecular mechanisms that cause interference of pathogen development in mosquitoes.