大豆蚜嗅觉在选择寄主植物中的作用

大豆蚜 Aphis hlycines 有翅和无翅孤雌生殖蚜为其寄主植物大豆叶和鼠李叶气味所引诱,而非寄主植物棉花叶和黄瓜叶气味处于中性,丝瓜叶和南瓜叶气味具有明显的排斥作用。非寄主植物气味可以遮蔽寄主植物气味的引诱作用。大豆蚜触角感受器对植物气味具有嗅觉生理反应,对一些化合物的最小感觉阈值达10-5至10-6体积比浓度,表明大豆蚜触角上存在识别植物气味的嗅觉受体细胞。由此证明,嗅觉在大豆蚜选择寄主植物过程中起重要作用。     

大豆蚜触角嗅觉感器结构及其功能

采用扫描电镜观察大豆蚜Aphis giycines各型触角上嗅觉感器的细微结构,结合触角电位记录,发现大豆蚜有翅孤雌生殖蚜对萜烯衍生物的感受部位在第6节原生感器上,而萜烯烃类则在第5节原生感器上,两原生感器都对绿叶气味和芳香类起嗅觉反应。末端2节上还有其它化学感器对植物气味起反应。因此,各型对植物气味的感觉部位在末端2节上。各型对报警信息素的作用部位主要在第6节原生感器上,无翅型第5节原生感器和有翅型第3节次生感器也有一定的感觉能力。     

昆虫对宿主植物的嗅觉定向

在混虫辨别宿主植物所利用的各种信息中,植物的气味是一个很重要的因素昆虫利用触角上的嗅觉感受器来感觉植物气味。触角电位是昆虫的触角感受到植物气味后所产生的神经反应,而嗅觉编码则是嗅觉感受器将植物的气味信息传至神经中枢的脉冲系列。本文从行为生理学的角度介绍了昆虫利用植物气味寻找宿主植物的过程。     

植食性昆虫寄主植物嗅觉搜寻述介

植食性昆虫与寄主植物关系的本质是化学。植食性昆虫搜寻寄主的嗅觉媒介是植物气味即化学信息物质。在介绍植物气味构成及其扩散模型基础上,阐述了植物气味在地上植食性昆虫成虫、幼虫和地下植食性昆虫搜寻寄主过程中的嗅觉导向作用,并指出了今后相关研究需要注意的问题。从植物与环境因子的关系来看,植物气味包括构成性气味和诱发性气味两类,这两类气味的概念既相联系而又不同。构成性气味组分及构成因植物分类地位等而不同。诱发性气味组分因植食性昆虫取食、植物病原微生物、机械致伤等因子的胁迫而变化,这种变化性状随植物属和/或种、植株生长发育阶段、胁迫因子性质及其作用方式而不同。无论是哪种植物气味,其释放均具有节律性。气味扩散过程比较复杂,扩散状态可用数学模型表征。对于地上植食性昆虫成虫,植物气味对其寄主搜寻行为具有导向特异性,重点分析了这种特异性形成的两个假说;鳞翅目昆虫幼虫,能够利用植物化学信息物质趋向寄主植物或回避非寄主植物;地下植食性昆虫搜寻寄主,既与寄主植物地下组织释放或分泌的次级代谢物有关,又与一些初级代谢物有关。初级代谢物中的CO₂,起着“搜寻触发器”作用。有助于增强人们对昆虫与植...     

美洲大蠊对多种化合物的触角嗅觉电位反应

用多种化合物的气味制激美洲大蠊(Periplaneza americana)触角,诱导、记录触角电位(EAG)反应.试验了各类化合物154种,其中53%能诱发出明显的EAG反应.绝大多数EAG反应是负相慢波,波幅多数为0.5—2mV,时程1.5—3秒.苯等少数化合物能诱发正相EAG反应.剂量-反应曲线大致呈“S”形,还可见适应现象.萜类化合物和挥发性植物油类诱发EAG反应的作用最强,其次是酮、醇、酯、胺类化合物.化合物的含氧功能基团和空间构型与EAG反应的诱发有一定的关系.可能是同一种化合物对不同种的感受器都可能诱发EAG反应.一般性化合物诱发雌、雄、成、幼虫EAG反应的差异不大,但雌虫类提取物仅对雄性成虫触角诱发较强的EAG反应.一些已知的驱、诱、杀虫剂也能诱发EAG反应,但仅表现为对一般化合物的反应特征.     

美凤蝶觅食过程中的视觉和嗅觉利用

[目的]植物的花色和花香是访花蝴蝶识别花蜜的重要信息来源,本研究旨在利用花香挥发物、蜂蜜水加花色的诱集试验探讨美凤蝶Papilio memnon视觉、嗅觉在觅食行为中的作用.[方法]测试美凤蝶对不同颜色的假花和喷施蜂蜜的假花的行为反应,采用触角电位仪(EAG)测定美凤蝶对花香挥发物的触角电位反应,并通过行为学进行验证.[结果]在无气味的7种颜色的假花诱集时,美凤蝶对蓝色(440-475 nm)、紫色(380-420 nm)和红色(615-630 nm)显示出明显的颜色趋性;在假花上喷洒蜂蜜水后,雌雄蝶总体访花次数增加1.85倍;在单一蜂蜜水、苯甲醇和苯甲醛气味诱集时,美凤蝶访问次数较少,而在气味基础上加蓝色假花诱集时,蜂蜜水诱集时美凤蝶访问次数增加了27.40倍,苯甲醇和苯甲醛诱集时美凤蝶访问次数增加了52.59倍和75.80倍.而在颜色与颜色加气味比较时,蜂蜜水诱集时美凤蝶访问次数只增加了1.41倍,苯甲醇和苯甲醛诱集时美凤蝶访问次数增加了2.67倍和2.16倍.雌雄蝶对花颜色和挥发物的敏感性均有区别,美凤蝶雌蝶对颜色和挥发物(蜂蜜水、苯甲醇和苯甲醛)的敏感性高于雄蝶(P＜0.05).[结论]颜色是美凤蝶觅食的主要因子,单一气味对美凤蝶的引诱作用有限.美凤蝶在觅食过程中,以视觉为主嗅觉为辅,雌蝶对颜色和气味的识别能力和敏感性高于雄蝶,推断可能与雌蝶在繁殖中扮演的角色相关.     

大豆蚜在寄主与非寄主植物上的口针刺吸行为

用EPG记录法记录了大豆蚜Aphis glycines Matsunra在寄主和非寄主植物上的口针刺吸行为。结果表明,大豆蚜在寄主大豆植物的韧皮部取食时间长,而在非寄主棉花、黄瓜和丝瓜植物韧皮部取食时间甚短或根本未取食;非寄主植物内部对大豆蚜的侵害存在抗性,影响取食的因素和其所在部位因非寄主植物种类的不同而不同。     

嗅觉受体在非嗅觉组织和细胞中的作用及其机制

嗅觉受体(olfactory receptor)不仅表达在鼻腔中,还广泛表达在全身其他部位,起着重要的生理作用.本文综述了非嗅觉组织和细胞中表达的嗅觉受体及其功能,这些嗅觉受体通过调控细胞周围的内源性化学物质,维持正常的生理功能,并且能在选定的外源性配体刺激下,表现出特定的功能.在医药领域,大约有40%上市药物的作用靶点都来自于G蛋白偶联受体(GPCR)家族,而嗅觉受体是GPCR中最大的基因家族,鉴于其表现出的重要作用,我们推测这些嗅觉受体可能成为未来重要的药物靶标.本文对非嗅觉组织和细胞中嗅觉受体功能的综述,一方面有利于将其作为潜在药物靶点,开发新的药物,另一方面也为中药中挥发性单体的药理作用提供了新的研究思路.     

昆虫神经生物学研究技术:触角电位图记录

触角电位图记录是昆虫神经生物学中用于昆虫嗅觉、信息素生物测定研究的重要技术之一。该技术具有敏感性、选择性高及操作简单易行等优点。该文以荷兰Syntech公司的产品为例详细介绍了此技术原理、装置、操作及应用     

寄生蜂嗅觉蛋白研究进展

寄生蜂对外界环境中气味的识别过程尤为复杂,需要很多组织器官参与,嗅觉系统在寄生蜂选择寄主、识别定位寄主和寄生过程中发挥着重要的作用。常见的嗅觉相关蛋白有气味结合蛋白、化学感受蛋白、气味受体等,本文从嗅觉蛋白的鉴定、结构特征与分类、表达定位、系统发育、功能研究等方面综述了寄生蜂嗅觉蛋白的国内外研究进展,为更多寄生蜂嗅觉相关蛋白的鉴定及其功能研究提供参考。     

寄主植物对棉蚜羧酸酯酶活性的影响

不同棉花品种对棉蚜Aphis gossypii Glov.羧酸酯酶活性具有明显的影响,在试验的7个棉花品种中,取食中棉12叶片的棉蚜α-乙酸萘酯(α-NA)羧酸酯酶活性最高(2.47微摩尔/毫克蛋白质分钟),是取食泾阳鸡脚棉种群的5.74倍.β-乙酸萘酯(β-NA)羧酸酯酶的活性以取食方渑双无的棉蚜最高(3.41微摩尔/毫克蛋白质分钟),是取食BR-S-10棉蚜的4.49倍.在取食方渑双无叶片的棉蚜中,羧酸酯酶活性大于2.5(微摩尔/毫克蛋白质分钟)的个体占28.3%(α-NA)和67.1%(β-NA),而在取食BR-S-10的种群中仅占2.6%(α-NA)和1.3%(β-NA).取食中棉12的棉蚜对β-NA与α-NA活性的比值为0.79,而取食其它棉花品种的种群β-NA与α-NA活性比值均大于1.用中棉12饲养的棉蚜对α-NA和β-NA活性均低于种群平均值的个体(CE1型)占26%;均高于平均值的个体(CE2型)占19%;对α-NA活性高于平均值,对β-NA活性低于平均值的个体(CE3型)占31%;对α-NA活性低于平均值,对β-NA活性高于平均值的个体(CE4型)占24%.取食其它6个棉花品种的棉蚜中,CE1和CE2型的比例分别为49.4—64.0%和23.4—47.2%,明显高于取食中棉12的种群,而CE3和CE4型个体仅占0—7.6%和3.4—10.4%,明显低于取食中棉12的种群.说明寄主植物对棉蚜羧酸酯酶的量和质均有影响.     

A TRADE-OFF FOR HOST PLANT UTILIZATION IN THE BLACK BEAN APHID,APHIS FABAE

Many studies on insect herbivores have sought to find trade-offs between utilization of alternate host plants, both to understand the prevalence of specialization and to appreciate the likelihood of sympatric speciation due to disruptive selection. To date, few studies have found trade-offs. Seventy-seven clones of the black bean aphid, Aphis fabae, were collected from field sites in East Anglia, U.K., over an area of about 10,000 km². These clones exhibit a trade-off in fitness between two alternative hosts, broad bean and nasturtium. This pattern is maintained in the F2 generation. The predominance of broad bean in the area, the fact that clones were only sampled from one of these two hosts, and the absence of “master-of-all-trades” genotypes after recombination all point to the importance of antagonistic pleiotropy rather than linkage disequilibrium in maintaining this trade-off. It is concluded that this population presents strong evidence for a fundamental trade-off for host utilization.     

HOST ALTERNATION IN APHIS FABAE SCOP.

Experiments on the feeding preferences and relative fecundity of Aphis fabae among leaves of different ages and kinds were extended to the comparison of different forms of the aphid: apterous and alate virginoparae and gynoparae.
All three forms showed a preference for the primary host, Euonymus , over a secondary host, sugar beet, but this preference was strongest in the gynoparae, weaker in the alate virginoparae and weakest in the apterae. The relative fecundity of the aphids on the two kinds of leaf paralleled their feeding preferences most closely in the gynoparae, less so in the alate virginoparae and least in the apterae.
All three forms also showed some preference for growing over mature leaves of the same kind, but this preference was strongest in the apterous virginoparae, weaker in the alate virginoparae and weakest in the gynoparae. The relative fecundity of the aphids on the two ages of leaf paralleled their feeding preferences most closely in the apterae, less so in the alate virginoparae and least in the gynoparae.
The physiological, ecological and evolutionary significance of the results is discussed in the light of the dual discrimination theory of aphid host selection.     

LARGE-SCALE CANDIDATE GENE SCAN REVEALS THE ROLE OF CHEMORECEPTOR GENES IN HOST PLANT SPECIALIZATION AND SPECIATION IN THE PEA APHID

Understanding the drivers of speciation is critical to interpreting patterns of biodiversity. The identification of the genetic changes underlying adaptation and reproductive isolation is necessary to link barriers to gene flow to the causal origins of divergence. Here, we present a novel approach to the genetics of speciation, which should complement the commonly used approaches of quantitative trait locus mapping and genome-wide scans for selection. We present a large-scale candidate gene approach by means of sequence capture, applied to identifying the genetic changes underlying reproductive isolation in the pea aphid, a model system for the study of ecological speciation. Targeted resequencing enabled us to scale up the candidate gene approach, specifically testing for the role of chemosensory gene families in host plant specialization. Screening for the signature of divergence under selection at 172 candidate and noncandidate loci, we revealed a handful of loci that show high levels of differentiation among host races, which almost all correspond to odorant and gustatory receptor genes. This study offers the first indication that some chemoreceptor genes, often tightly linked together in the genome, could play a key role in local adaptation and reproductive isolation in the pea aphid and potentially other phytophagous insects. Our approach opens a new route toward the functional genomics of ecological speciation.     

DIFFERENCE IN PROBING BEHAVIOUR OF TEA APHID ON VEGETATIVE PARTS OF TEA PLANT AND NON‐HOST PLANTS*

Abstract Electrical penetration graph (EPG) investigation showed that the secreting (El) and sucking (E2) times of tea aphid stylet in tea phloem were much longer than that on non‐host plants such as soybean and wheat. However, non‐feeding wave (np) was shorter than that on soybean and wheat. Duration of both El and E2 of stylet in tea phloem of 1st leaf, bud, 4th leaf and tender stem occupied 30.2%, 22.3%, 9.2% and 8.2% of the total experimental time, respectively. E2 wave was accompanied by honeydew secretion, with a time lag. Tea aphid preferred the tender parts, in which amino acids and other nutritional components were very rich. While the stylet of hungry tea aphid was forced to pierce phlom of non‐host plant (soybean or wheat), El and E2 waves were also produced, but the action of stylet could be disrupted by tea shoot volatile (10–6 V/V linalool, etc.) emitted near to the antennae. It was considered that before and under probing tea aphid made use of olfactory clues.     

豆蚜有翅蚜产生的原因

本文研究拥挤、寄土质量、温度和蚜型等因子对大豆蚜(Ahis glyeines)有翅蚜产生的影响。结果表明：1.大豆蚜无翅胎生成好个体间的拥挤是有翅蚜产生的主要原因。在低密度下拥挤反应随密度增大而增强,但过度拥挤会导致反应的降低。无翅若好间的拥挤不能导致其本身发育为有翅胎生蚜。 2.寄主质量能改变无翅胎生成蚜对拥挤的反应。每笼2头经成熟叶片处理的无翅胎生成蚜后代中有姻蚜的比例高于幼嫩叶片和对照(无叶片)处理,且饥饿不能促进有翅蚜的产生。3.温度能影响有翅蚜的产生。较高的温度(30℃和25℃)较21℃对有翅胎生蚌的产生有较强的抑制作用。4.不同母蚜型产生有翊蚜的能力不同。有翅胎生蚜间的拥挤也能使其在后代中产生少量的有翊蚜,但对拥挤的敏感程度低于无翅胎生蚜。