Host preferences of introduced and native parasites (Hymenoptera: Braconidae) of phytophagous plant bugs (Hemiptera: Miridae) in alfalfa-grass fields in the northeastern USA

During an eight-year field study at two widely-separated locations (NJ & DE, USA), seven species of phytophagous mirid plant bugs were found in alfalfa and alfalfa-grass fields grown for animal forage. Five species of parasites were reared from these mirids. Two parasite species introduced from Europe killed significantly higher proportions of nymphs of the two important mirid pests of alfalfa than did native parasites. The introduced Peristenus digoneutis Loan parasitized an average of 31% of first and second generation tarnished plant bugs, Lygus lineolaris, a native insect; and the introduced Peristenus conradi parasitized 22% of first generation alfalfa plant bugs, Adelphocoris lineolatus, an introduced species. In addition, Peristenus pallipes significantly parasitized nymphs of Trigonotylus caelestialium (43%) and Leptopterna dolabrata (37%); both mirids are immigrant species. Because the parasite P. pallipes significantly attacked only these two non-native mirids, and is present in Europe, it also may be an accidental introduction to North America. A native wasp, Leiophron uniformis, heavily parasitized (49%) the native garden fleahopper, Halticus bractatus. A third native species, P. pseudopallipes, occasionally parasitized a few Lygus lineolaris in alfalfa at one location. Two other mirids, Stenotus binotatus and Megaloceroea recticornis, both accidently-introduced grass-feeding species, were not parasitized by native or introduced species. It is noteworthy that the effective host ranges of all the parasites in alfalfa-grass fields were limited: four of the five parasite species significantly parasitized only one of the seven mirid species, and the other parasite significantly parasitized only two mirids. Activity of the four common parasites was correlated with the mirids' host plant: three species principally parasitized alfalfa-feeding mirids, and one species principally parasitized grass-feeding mirids.     

授粉用明亮熊蜂的人工饲养技术

为提高授粉用熊蜂人工繁育效率,降低生产成本,对明亮熊蜂Bombus lucorumL.人工饲养中诱导蜂王产卵和人工控制下的交配2个技术环节进行了研究。结果表明,采用诱导器和伴饲2~3只蜜蜂工蜂的诱导方法,蜂王产卵率和蜂群成群率最高,成群时间最短;使用塑料诱导器和木制诱导器的效果没有显著差异。将8~9日龄的蜂王和11~12日龄的雄蜂放入交配笼时,其交配成功率最高。交配笼内的蜂王数量应控制在30只/m3左右。在晴天,交配笼放置在室外(758 000 lux),其交配成功率最高;在阴天,交配笼应放在交配室内,并开启荧光灯照明(35 000 lux),其交配成功率最高。     

Stage-dependent feeding behavior by western tarnished plant bugs influences flower bud abscission in cotton

Unexplained variability in the relationship between the number of herbivores in a field and the amount of crop damage can arise if there is a large amount of variation among herbivore individuals in the amount of feeding damage each generates. In California, populations of the western tarnished plant bug, Lygus hesperus Knight (Heteroptera: Miridae), produce highly variable levels of damage to cotton plants (Gossypium hirsutum L.) (Malvaceae), even when found at low densities. Because L. hesperus populations are also highly variable in their overall stage structure, we hypothesize that differences in crop damage might result from varying impact by each L. hesperus stage on cotton flower buds (termed squares). Laboratory measurements of L. hesperus mouth‐parts and distance to anther sacs, a preferred feeding site, revealed that 1st?3rd instar L. hesperus nymphs will not be able to feed on anther sacs of larger squares (over 8 mm in length) but will be able to feed on squares that are most sensitive to L. hesperus damage (<7 mm). Because even the 1st instars can feed on the most sensitive ‘pinhead’ squares, size constraints do not rule out damaging effects from the youngest L. hesperus. Laboratory observations revealed that later developmental stages, and adults, spend more time feeding on cotton squares relative to 2nd and 3rd instars. In addition, a field experiment revealed no effect of 2nd instars on square retention (relative to control cages) but did reveal a significant decrease in square retention generated by adult L. hesperus (4th instar L. hesperus resulted in an intermediate level of square retention). In a final study we sampled L. hesperus stage structure and density across 38 cotton fields. Multiple regression revealed that the densities of 1st?3rd instars of L. hesperus are not correlated with anther sac damage or square retention. However, in 2 years 4th and 5th instars were positively correlated with anther sac damage and negatively correlated with square retention. In the a third year, adult L. hesperus showed correlations in the same direction, across fields and across sites within fields. Overall, these results suggest that the adults and the largest nymphs of L. hesperus (4th and 5th instars) are particularly damaging to cotton squares, with the 1st?3rd instars of L. hesperus causing little damage to plants.     

Optimal concentration of Beauveria bassiana vectored by bumble bees in relation to pest and bee mortality in greenhouse tomato and sweet pepper

Greenhouse cage trials were conducted to determine the optimal concentration of Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreales) (BotaniGard 22WP^® formulation) as vectored by the bumble bee, Bombus impatiens (Cresson) (Hymenoptera: Apidae) pollinator for control of greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) on greenhouse tomato, tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae) and green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae) on greenhouse sweet pepper. Three inoculum concentrations of B. bassiana: low, 9 × 10⁹; middle, 6.24 × 10¹⁰; and high, 2 × 10¹¹ conidia g^?1 of inoculum and two controls (one with bees and heat-inactivated inoculum, and the other which contained only the host plants and pest species) were tested in a completely randomized block design. Beauveria bassiana killed 18, 54 and 56% of the adult T. vaporariorum and 33, 70 and 67% of the adult L. lineolaris, respectively, at the low, middle and high concentrations; but no infection from B. bassiana occurred in each of the control treatments. Internal infection rates after surface sterilization of the pest insects were 11, 34 and 35% for adult T. vaporariorum, 29, 54 and 58% for adult L. lineolaris, 22, 34 and 30% for nymphal M. persicae and 17, 29 and 32% for nymphal T. vaporariorum, respectively, at the low, middle and high concentrations. Significantly more bumble bees died at the high concentration of B. bassiana (42–45%) than at the other concentrations (9–15%) and the controls (5–7%). Spores of B. bassiana were collected throughout the plant canopy with the greatest numbers sampled from the top third of the canopy [ca. 1,200 colony forming units (CFU) per cm^?2]. The middle concentration was selected as the optimal concentration because it provided the best pest control with the least impact on the bees.     

绿盲蝽气味结合蛋白AlucOBP7的表达及气味结合特性

气味结合蛋白(odorant binding proteins, OBPs) 在昆虫嗅觉识别中起着重要的作用, 尤其是在运输外界脂溶性气味分子通过嗅觉感器淋巴液到达嗅觉受体(olfactory receptors, ORs)的过程中发挥关键作用。明确OBPs在昆虫同外界进行信息交流过程中的作用有利于阐明昆虫嗅觉识别的机制, 同时可为利用干扰昆虫嗅觉识别来进行害虫防治奠定理论基础。本研究克隆了一个绿盲蝽Apolygus lucorum (Meyer-Dür)气味结合蛋白AlucOBP7基因（GenBank登录号: JQ675724）, 并进行了原核表达, 以1-NPN为荧光探针采用荧光竞争结合实验研究了AlucOBP7蛋白和10种棉花挥发物及 6种性信息素类似物的结合能力。结果表明： 在10种棉花挥发物中, AlucOBP7能够和2 己酮及水杨酸甲酯有效结合, 结合常数分别为55.13 μmol/L和28.26 μmol/L。在6种盲蝽性信息素类似物中, 4-氧代-反-2-己烯醛和AlucOBP7 具有较强的结合能力, 结合常数为23.14 μmol/L。丁酸乙酯、 丁酸丁酯及己酸己酯也能够和AlucOBP7 有效结合, 但结合能力中等, 结合常数分别为30.58, 39.26和35.81 μmol/L。初步推测, AlucOBP7 可能是绿盲蝽性信息素结合蛋白(pheromone binding proteins, PBPs), 并在感受性信息素和植物挥发物的过程中发挥双重功能。     

温度和光周期对绿盲蝽滞育诱导的影响

为了阐明环境因子对绿盲蝽Apolygus lucorum Meyer-Dür卵滞育诱导作用,测定了3个温度和6个光周期组合处理对绿肓蝽的滞育诱导和绿盲蝽光周期感应的敏感虫态,系统调查了绿肓蝽在不同温度和不同光照组合下所产卵的孵化率.结果表明:绿盲蝽的敏感虫态为1龄若虫;在17℃,20℃和23℃3个不同温度下,光照时间小...     

The mitochondrial genome of the plant bug Apolygus lucorum （Hemiptera： Miridae）＂ Presently known as the smallest in Heteroptera

The complete mitochondrial （mt） genome of the plant bug, Apolygus lucorum, an important cotton pest, has been sequenced and annotated in this study. The entire circular genome is 14 768 bp in size and represents the smallest in presently known heteropteran mt genomes. The mt genome is encoding for two ribosomal RNA （rRNA） genes, 22 transfer RNA （tRNA） genes, 13 protein coding genes and a control region, and the order, content, codon usage and base organization show similarity to a great extent to the hypothetical ancestral model. All protein coding genes use standard initiation codons ATN. Conventional stop codons TAA and TAG have been assigned to the most protein coding genes; however, COIII, ND4 and ND5 genes show incomplete terminator signal （T）. All tRNA genes possess the typical clover leaf structure, but the dihydrouridine arm of tRNAser（A6N） only forms a simple loop. Secondary structure models of rRNA genes are generally in accordance with the former models, although some differences exist in certain parts. Three intergenic spacers have never been found in sequenced mt genomes of Heteroptera. The phylogenetic study based on protein coding genes is largely congruent with previous phylogenetic work. Both Bayesian inference and maximum likelihood analyses highly support the sister relationship ofA. lucorum and Lygus lineolaris, and Miridae presents a sister position to Anthocoridae.     

Parasitism ofLygus lineolaris eggs onCoronilla varia,solanum tuberosum,and three host weeds in southeastern Québec

Parasitism ofLygus lineolaris (Palisot de Beauvois) eggs by three species ofMymaridae, Anaphes iole Girault,Erythmelus miridiphagus Dozier andPolynema pratensiphagum Walley and one species ofScelionidae, Telenomus sp., was investigated at Ste-Anne-de-Bellevue, Québec. The maximum level of field parasitism ofL. lineolaris eggs by individual species was 15.4, 53.8, 70.0 and 16,7%, respectively. Parasitoids were retrieved from eggs ofL. lineolaris inserted in stems and branches ofAmaranthus retroflexus L.,Chenopodium album L.,Coronilla varia L.,Rumex obtusifolius L. andSolanum tuberosum L. Amaranthus retroflexus andS. tuberosum sustained a large population ofL. lineolaris and egg parasitism was high enough to consider it as a potential control factor.      

绿盲蝽气味受体基因AlucOR40的克隆及功能研究

【目的】从绿盲蝽Apolygus lucorum触角中克隆气味受体基因Aluc OR40,研究该气味受体基因在绿盲蝽不同组织中的表达水平,然后对该基因的功能进行研究,为理解绿盲蝽的嗅觉识别机制提供理论基础。【方法】在绿盲蝽成虫触角转录组测序与分析的基础上,通过PCR技术克隆得到气味受体基因Aluc OR40的全长序列。用半定量RT-PCR研究该基因在雌雄虫不同组织中的表达水平。然后通过爪蟾卵母细胞体外表达该基因,并结合双电极电压钳检测了该气味受体对60种气味分子包括绿盲蝽性信息素组分和植物挥发物的反应。然后,利用触角电位技术测定羽化后3 d的绿盲蝽成虫对Aluc OR40的气味配体的触角电位反应。【结果】克隆了Aluc OR40(Gen Bank登录号:KU886190)。Aluc OR40编码398个氨基酸,蛋白具有7个跨膜结构域,N末端位于胞内,C端位于细胞外,符合昆虫气味受体的典型特征。半定量RT-PCR的结果显示,Aluc OR40在触角中特异表达,且在雄虫触角中的表达水平高于雌虫。双电极电压钳记录结果显示,Aluc OR40只对反-2-己烯醇一种气味分子具有特异反应。EAG实验结果表明,羽化后3 d的绿盲蝽雌雄虫都对反-2-己烯醇有反应,且雄虫触角的EAG反应显著高于雌虫。【结论】结果提示Aluc OR40参与了绿盲蝽对反-2-己烯醇的识别过程,推测其在绿盲蝽交配过程中雄虫对雌虫的识别中发挥作用。     

绿盲蝽中枢神经系统的解剖结构

【目的】阐述绿盲蝽Apolygus lucorum中枢神经系统的组成,辨识各组成部分的神经节解剖结构及其形态,计算中枢神经系统各神经节结构体积大小、解析其空间分布关系以及连接模式。【方法】采用免疫组织化学方法,使用突触蛋白抗体对绿盲蝽中枢神经系统神经髓进行染色标记,利用共聚焦激光扫描显微镜获取中枢神经系统各结构数码图像,使用三维图像分析软件对绿盲蝽中枢神经系统进行分析,并构建三维模型。【结果】绿盲蝽中枢神经系统从前往后分别由脑神经节、咽下神经节、前胸神经节和后部神经节组成。脑、咽下神经节和前胸神经节3个神经节融合在一块,形成脑-咽下神经节-前胸神经节复合体,并通过长的神经连索与后部神经节相连,从外观上看似由2个大的神经节构成,这种神经节愈合形式尚未在昆虫中发现过。前胸神经节与后部神经节分离,二者由长的神经连索连接起来。除前胸神经节由单独的神经原节构成外,其他3个神经节又由多个神经原节融合而成。脑包括前脑、中脑和后脑3部分。咽下神经节包括上颚神经节、下颚神经节和下唇神经节。后部神经节包括中胸、后胸和腹部神经节3部分。【结论】明确了绿盲蝽中枢神经系统的神经节构成,发现了绿盲蝽中枢神经系统各神经节的高度融合特性。该项研究结果为研究绿盲蝽中枢神经系统的发育、重塑和系统演化奠定了形态学基础,为研究中枢神经元形态、分布以及其对昆虫生理和行为的功能调控机制提供了结构框架。