Electroantennogram responses of the carrot fly, Psila rosae, to volatile plant components

ABSTRACT. Electroantennogram (EAG) responses of male and female carrot flies, Psila rosae F. (Diptera: Psilidae), were recorded to thirty-six volatile plant constituents. The most distinct EAG responses were obtained to: (1) the general green leaf volatiles 1-hexanol, trans-2-hexen-1-ol and cis-3-hexen-1-ol, their isomers cis-2-hexen-1-ol and trans-3-hexen-1-ol, the alcohol 1-heptanol, the ester cis-3-hexenyl acetate and the leaf aldehydes hexanal and trans-2-hexenal, and (2) from four compounds associated with the umbelliferous host plants of this insect, namely trans-methyl-iso-eugenol, β-caryophyllene, linalool and trans-2-nonenal. Higher responses were elicited by the leaf aldehydes than by the corresponding alcohols. Although the absolute amplitude of the female response was over twice that of the male, there were no differences between the relative responses to the compounds tested in both sexes, with the exception of a much higher response to the leaf aldehydes in the male. The shape of the EAG evoked by the various compounds was consistently different, with the slowest recovery being recorded for trans-methyl-iso-eugenol. While the antennal olfactory receptors of the carrot fly are sensitive to the closely related general green leaf volatiles, they are most specifically tuned to the aldehyde component of this green odour complex. In addition, the ability of this insect to discriminate between different plants may be augmented by the perception of a group of more host specific volatiles. The conformity of the responses of males and females to the compounds tested may indicate that host plant volatiles plays an additional role as an aggregation cue for both sexes.     

豆野螟成虫触角对植物挥发性和性信息素化合物的触角电位反应

以顺3-己烯乙酸酯为标准化合物,研究了豆野螟雌、雄成虫触角对不同浓度的植物挥发性和性信息素化合物组分的触角电位（EAG）反应.结果表明：豆野螟雌、雄成虫触角对植物挥发性气味具有强烈的EAG反应,但在大部分浓度下,雌、雄虫的反应没有显著差异.在测试的9种植物挥发性化合物中,雌、雄虫对高浓度反-2-己烯醛刺激的相对EAG反应的最大值分别达到250%和260%,且雌、雄虫触角对这种化合物的EAG反应的形状也有很大差异;但对豇豆花气味中的柏木烯和柏木脑没有明显的EAG反应.雌、雄蛾对性信息素都有明显反应,且雌、雄虫的反应存在显著差异,雄虫触角对性信息素化合物主要组分（反10,反12）-十六碳二烯醛的EAG反应的最大值达到250%,远超过雌虫反应的最大值(53%).雌、雄成虫这种神经感觉反应的差异反映了它们在感器结构、功能和行为上的差异.     

苹褐带卷蛾成虫对主要寄主植物挥发物的触角电位反应和行为反应

【目的】苹褐带卷蛾Adoxophyes orana是危害苹果、桃、梨、枣等果树的一种重要昆虫。近年来在陕西苹果和红枣产区发生面积逐年扩大,危害日趋严重。本研究旨在明确寄主植物挥发物在苹褐带卷蛾成虫嗅觉通讯中的作用,为开发植物源引诱剂提供基础数据。【方法】利用触角电位(electroantennogram, EAG)仪测定苹褐带卷蛾2日龄未交配雌、雄成虫对51种寄主植物挥发性化合物的EAG反应;利用本实验室开发的小型蛾类昆虫嗅觉行为测试装置测定苹褐带卷蛾成虫对15种具有显著EAG反应的挥发性化合物的行为反应。【结果】EAG测试结果表明,苹褐带卷蛾成虫对不同挥发性化合物的EAG反应相对值有显著差异,雌、雄成虫对顺-3-己烯-1-醇、反-2-己烯-1-醇、1-己醇、1-庚醇、己醛、反-2-己烯醛、庚醛、辛醛、壬醛、乙酸丁酯、乙酸异戊酯和乙酸-顺-3-己烯酯的EAG反应较强。此外,雄成虫对3-甲基-1-丁醇、1-戊烯-3-醇、苯甲醛、丁酸丁酯、乙酸乙酯、三甲基巴豆酸乙酯、己酸乙酯、丙酸丁酯、异戊酸-顺-3-己烯酯、苯甲腈和柠檬腈的反应较强。在待测的51种挥发性化合物中,苹褐带卷蛾成虫对29种化...     

Role of plant volatiles in host plant location of the leafminer, Liriomyza sativae (Diptera: Agromyzidae)

Abstract The role of plant volatiles in host plant location of the leafminer Liriomyza sativae Blanchard was studied. Four types of antennal sensilla were identified on the funiculus by scanning electron microscopy: trichoid, basiconic, clavate and grooved sensilla. An olfactory pit, containing groups of sensilla, was present on the ventral side of the funiculus. No sexual difference was detected in sensilla diversity and distribution. In behavioural assays, both males and females were attracted by the odour of the bean Phaseolus vulgaris L. They had distinct EAG responses to the bean odour. No significant sexual difference was found in behaviour or EAG responses.
Electroantennograms were recorded from female L. sativae to 14 plant volatile compounds. The most distinct EAG responses were obtained for: (1) the general green leaf volatiles 1-hexanol (E)-2-hexen-1-ol, (E)-3-hexen-1-ol and its isomers, (Z)-3-hexen-1-ol, the acetate (E)-3-hexenylacetate and the aldehyde hexanal; and (2) limonene, a compound associated with tomato, which is a key host plant of this insect. Other volatile compounds associated with host plants, such as α-pinene, myrcene, β-caryophyllene, and eugenol did not elicit responses. The ability of this insect to locate a host plant appears to be augmented by the perception of a combination of host-specific and general green leaf volatiles. A modification of the EAG recording method of Dipteran species was provided.     

Increased EAG responses of tortricid moths after prolonged exposure to plant volatiles: evidence for octopamine-mediated sensitization

As measured by electroantennograms (EAG), both male and female obliquebanded leafrollers, Choristoneura rosaceana (Harris), and redbanded leafrollers, Argyrotaeniavelutinana (Walker), were similarly sensitive to host-related plant volatiles: trans-2-hexenal, benzaldehyde, 1-hexenol, cis-3-hexen-1-ol, geraniol, linalool, (+)-limonene, hexenal and trans-2-hexenol. Females of both species were similarly sensitive to the shared major component of their sex-attractant pheromone ((Z)11-14:Ac). Continuous 60 min pre-exposure of male and female C. rosaceana and A. velutinana to successively higher concentrations of a mixture of the nine plant volatiles in Teflon chambers with continuous air exchange caused a dosage-dependent increase in subsequent responsiveness (sensitization) to green leaf volatiles, as measured by EAGs. In addition, 60 min of pre-exposure of male C. rosaceana to certain individual volatiles ((+)-limonene, geraniol, benzaldehyde) increased EAGs nearly as much as did the mixture of nine volatiles. Pre-exposures to the nine plant-volatile mixture at concentrations achieved by 100 microg and 1 mg loading dosages in 100 microl of mineral oil significantly increased EAG depolarization to pheromone (cross-sensitization) in males but not females of both moth species. Antennae of male C. rosaceana pre-injected with 100 microg of octopamine (OA) without volatile pre-exposure exhibited sensitization nearly identical to that induced by pre-exposing moths to sensitizing concentrations of the plant-volatile mixture. Moreover, injection of the OA antagonist chlorpromazine (CP) blocked sensitization by the plant-volatile pre-exposure. Collectively, these findings suggest that exposures of tortricid moths to certain host-plant related volatiles may modulate subsequent olfactory sensitivity to behaviorally relevant chemical cues and that plant-volatile induced sensitization may be octopamine mediated.     

云斑天牛对10种植物挥发物的EAG和行为反应

【目的】为了探明对云斑天牛Batocera lineolata Chevrolat成虫具有行为导向的寄主植物挥发物对成虫行为反应的影响。【方法】采用触角电位(EAG)和"Y"型嗅觉仪技术,测定云斑天牛成虫(未交配雌虫、未交配雄虫、已交配雌虫)对10种寄主植物挥发物的电生理和行为反应。【结果】所选化合物在特定浓度下,均能引起云斑天牛成虫较为明显的EAG反应,浓度为100μg/μL时,云斑天牛成虫对所测试的植物挥发物的EAG反应最强,其中未交配雌、雄及已交配雌虫对(Z)-3-己烯-1-醇的EAG反应相对值均为最大,分别达2.35、2.31和2.22。行为反应生测中,(Z)-3-己烯-1-醇对未交配雌、雄虫可产生明显的引诱作用,芳樟醇则对两者具有明显的趋避作用,而已交配雌虫对所有化合物均无明显趋性。【结论】试验结果可为开发对其有效的林间引诱剂提供一定的理论依据。     

松毛虫狭颊寄蝇对被害马尾松针叶挥发物的触角电位反应

松毛虫狭颊寄蝇Carcelia matsukarehaeShima是我国松毛虫Dendrolimus punctatus(Walke)的重要天敌。通过对被害马尾松(Pinus massonianaLamb.)针叶挥发性物质的提取、鉴定以及对松毛虫狭颊寄蝇的电生理测定,结果表明,大多数的挥发性物质,包括绿叶性挥发物以及松针特有的单萜、氧化单萜和倍半萜,对雌蝇均有明显的电生理活性,其中以顺-3-己烯-1-醇最高,长叶烯最低。雌蝇对4大类挥发性物质的平均相对触角电位反应值,以绿叶性挥发物为最高,其余依次为单萜、氧化单萜和倍半萜。     

小菜蛾对合成植物挥发物的活性反应

在室内检验了小菜蛾已交配和未交配雌、雄成虫对3种合成植物挥发物乙酸顺-3-己烯酯（Z-3-hexenyl acetate,ACTE）、异硫氰酸丙烯酯（allyl isothiocyanate,NCS）和顺-3-己烯醇（Z-3-hexen-1-ol,OH）的触角电位(EAG)反应。不同浓度（0.008 μg/μL、0.08 μg/μL、0.2 μg/μL、0.8 μg/μL、8 μg/μL、20 μg/μL和40 μg/μL）实验表明,随着刺激化合物浓度的提高,小菜蛾反应活性增强。但小菜蛾的性别及其交配状态可能影响其对3种化合物的反应强度：不同性别及交配状态的小菜蛾对ACTE的反应差异不大;未交配雌、雄虫对OH的反应强于已交配雌、雄虫;未交配雌虫对低浓度的NCS反应较强,NCS超过一定浓度时已交配雌虫的反应强于未交配雌虫,雄虫对NCS反应较小且与交配状态无关。以小菜蛾性信息素作为对照,在湖北长阳和越南河内试验了这3种植物挥发物诱芯（6 μL/诱芯）对小菜蛾的引诱作用。结果表明,在湖北,第1天时 ACTE、NCS对雄虫具有很强的引诱作用,引诱量显著大于性诱剂的引诱量,但随着诱芯放置时间延长,NCS引诱作用迅速下降,第2天时引诱作用已经很小;ACTE的引诱作用下降缓慢,第4天的诱蛾量才显著小于性信息素的诱蛾量,OH的引诱力较弱。在河内,ACTE、NCS、OH第1天对小菜蛾引诱作用很强,引诱量大于性信息素,但差异不显著;随着诱芯放置时间延长,3种挥发物对小菜蛾的引诱量均下降很快,第4天的引诱力就很弱。3种植物挥发物的混合物(体积比1∶1∶1)对小菜蛾的引诱作用与性信息素相似,且诱蛾活性持效期相对较长。无论在越南或湖北,植物挥发物或其混合物均很少引诱到雌虫。     

稻纵卷叶螟对43种禾本科植物挥发物的触角电位(EAG)反应

【目的】为了筛选对稻纵卷叶螟Cnaphalocrocis medinalis成虫有生物活性的植物挥发物,为开发植物引诱剂诱集稻纵卷叶螟提供依据。【方法】采用触角电位技术(Electroantennogram,EAG)测定了稻纵卷叶螟雌雄蛾对来自禾本科植物的43种挥发物的触角电位反应。【结果】稻纵卷叶螟雌、雄蛾对50 000μL/L反-2-己烯醛的EAG反应分别较对照高16.6倍、10.9倍。稻纵卷叶螟雄蛾对50 000μL/L正戊醛的EAG反应值为(7.347±1.582)m V,是对照的2.6倍;对5 000μL/L和50 000μL/L苯甲醛的EAG反应分别较对照高2.0倍、2.4倍;对50μL/L、500μL/L水杨酸甲酯的EAG反应较对照分别提高了65.2%、72.1%。【结论】反-2-己烯醛、正戊醛、苯甲醛、水杨酸甲酯对稻纵卷叶螟具有EAG活性,可能为稻纵卷叶螟植物源引诱剂的主要成分。     

Differential electroantennogram response of females and males of two parasitoid species to host-related green leaf volatiles and inducible compounds

Parasitoids employ different types of host-related volatile signals for foraging and host-location. Host-related volatile signals can be plant-based, originate from the herbivore host or produced from an interaction between herbivores and their plant host. In order to investigate potential sex- and species-related differences in the antennal response of parasitoids to different host-related volatiles, we compared the electroantennogram (EAG) responses of both sexes of the specialist parasitoid, Microplitis croceipes (Cresson), and the generalist, Cotesia marginiventris (Cresson), to varying doses of selected plant-based host-related volatiles: two green leaf volatiles (cis-3-hexenol and hexanal) and three inducible compounds (cis-3-hexenyl acetate, linalool, and (E,E)-alpha-farnesene). Mating had no significant effect on EAG response. Females of both species showed significantly greater EAG responses than conspecific males to green leaf volatiles, which are released immediately after initiation of herbivore feeding damage. In contrast, males showed greater responses than conspecific females to inducible compounds released much later after initial damage. Cotesia marginiventris females and males showed greater EAG responses than counterpart M. croceipes to the tested compounds at various doses, suggesting that the generalist parasitoid shows greater antennal sensitivity than the specialist to the tested host-plant volatiles. These results are discussed in relation to the possible roles of green leaf volatiles and inducible compounds in the ecology of female and male parasitoids.     

Host plant volatiles induce oriented flight behaviour in male European grapevine moths, Lobesia botrana

The European grapevine moth Lobesia botrana relies on a female produced sex pheromone for long-distance mate finding. Grapevine moth males compete heavily during limited time windows for females. The aim of this study was to investigate the perception of host plant volatiles by grapevine moth males and whether such compounds elicit upwind oriented flights. We compared five host plant headspace extracts by means of gas chromatography linked electroantennogram (EAG) recording. We identified 12 common host plant volatiles (aliphatic esters, aldehydes, and alcohols, aromatic compounds and terpenes) that elicit EAG responses from grapevine moth males and that occur in at least three of the host plant volatile headspace extracts tested. Subsequently the behavioural response of grapevine moth males to four these compounds presented singly and in mixtures (1-hexanol, 1-octen-3-ol, (Z)-3-hexenyl acetate and (E)-β-caryophyllene) was recorded in a wind tunnel. Grapevine moth males engaged in upwind flights to all of four compounds when released singly at 10,000 pg/min and to all, except 1-octen-3-ol, when released at 100 pg/min. A blend of the four host plant volatiles released at 10,000 pg/min and mixed at a ratio based on the analysis of Vitis vinifera cv. Solaris volatile emissions attracted significantly more males than any single compound. Grapevine moth males perceive and respond to host plant volatiles at biologically relevant levels indicating that host plant volatiles figure as olfactory cues and that L. botrana males can discern places where the likelihood of encountering females is higher.     

Electroantennogram responses of the three migratory forms of the damson-hop aphid, Phorodon humuli, to aphid pheromones and plant volatiles

Electroantennogram (EAG) responses were recorded from alate fundatrigeniae (spring migrants), gynoparae (the winged female form that produces sexual females) and males, the three migratory forms of the damson-hop aphid, Phorodon humuli (Schrank). EAG responses of gynoparae and males showed typical dose response characteristics to (E)-2-hexenal, (-)-R-carvone, hexanenitrile and (1RS,4aR,7S,7aS)-nepetalactol, the sex pheromone of this species. The 34 plant volatiles elicited broadly similar EAG response profiles in the three migratory forms. Green leaf volatiles produced large responses in all forms; however, the relative order of responsiveness varied. EAG responses to isomers of the monoterpene carvone differed between forms, with males being most, and spring migrants least, responsive. The hop-plant volatile and aphid alarm pheromone, (E)-beta-farnesene, evoked similar EAG responses in all forms. By contrast, males were most responsive to the three sex pheromone components, (-)-(4aS,7S,7aR)-nepetalactol, (+)-(4aS,7S,7aR)-nepetalactone and (1RS,4aR,7S,7aS)-nepetalactol. Males were no more responsive to their own sex pheromone, (1RS,4aR,7S,7aS)-nepetalactol, than to the other aphid sex pheromone components tested. Spring migrants and gynoparae also responded to the three sex pheromone components. This study indicates that migratory forms of P. humuli detect a wide range of volatile compounds, and that they are equally well-adapted for the detection of volatiles associated with host and non-host plants and with other species of aphid.     

绿盲蝽对性信息素类似物和植物挥发物的触角电位反应

为了更好地利用性信息素类似物与植物挥发物对绿盲蝽Lygus lucorum进行监测和生物防治, 本研究采用电生理学方法测试了绿盲蝽成虫对9种性信息素类似物和12种植物挥发性物质的触角电位(electroantennogram, EAG)反应。结果表明: 在测试的这21种化合物中, 绿盲蝽对丁酸酯类化合物和绿叶气味物质的EAG反应较强; 雄虫对性信息素类似物比雌虫更敏感, 而雌虫对植物挥发物更敏感。其中性信息素类似物中, 绿盲蝽对反-2-丁酸己烯酯的EAG反应最强; 植物挥发物中, 绿盲蝽对反-2-己烯醛的EAG反应最强, 雌虫对反-2-己烯醇、反-2-己烯醛、顺-3-己烯醇等绿叶气味物质的EAG反应相对高于萜类化合物的反应。剂量反应曲线表明, 在测定的浓度范围内, 雄虫对反-2-丁酸己烯酯的反应比雌虫显著高, 而对β 蒎烯的反应则比雌虫显著低。绿盲蝽成虫对性信息素类似物和植物挥发物的EAG反应存在的两性差异具有生态适应意义: 雄虫对性信息素类似物更敏感将更有利于其寻找交配对象, 而雌虫对绿叶气味物质更敏感将更有利于其寻找产卵寄主。     

苹毛丽金龟对植物挥发物成分的触角电位及行为反应

为筛选适宜的苹毛丽金龟Proagopertha lucidula (Faldermann)引诱剂化学物质, 对已报道的金龟子科两性引诱剂单一组分进行了触角电位（EAG）和Y型嗅觉仪中的嗅觉反应测定。结果表明: 在10 μg刺激剂量下测试的11 种植物挥发物中, 只有顺-3-己烯-1-醇、香叶醇、茴香脑和丁香酚有明确的EAG反应值, 其他7种化合物具有弱反应值。剂量反应曲线表明, 具有明确的EAG活性的4种化合物激发的反应强度与化合物的剂量呈正相关。在Y型嗅觉仪中, 顺-3-己烯-1-醇、香叶醇、茴香脑和丁香酚4种化合物在1, 10, 100 μg剂量下的行为反应百分率都显著高于对照溶剂正己烷, 且雌雄之间无显著差异。该研究结果可为开发苹毛丽金龟田间引诱剂奠定基础。     

Electroantennographic bioassay as a screening tool for host plant volatiles

Plant volatiles play an important role in plant-insect interactions. Herbivorous insects use plant volatiles, known as kairomones, to locate their host plant. When a host plant is an important agronomic commodity feeding damage by insect pests can inflict serious economic losses to growers. Accordingly, kairomones can be used as attractants to lure or confuse these insects and, thus, offer an environmentally friendly alternative to pesticides for insect control. Unfortunately, plants can emit a vast number volatiles with varying compositions and ratios of emissions dependent upon the phenology of the commodity or the time of day. This makes identification of biologically active components or blends of volatile components an arduous process. To help identify the bioactive components of host plant volatile emissions we employ the laboratory-based screening bioassay electroantennography (EAG). EAG is an effective tool to evaluate and record electrophysiologically the olfactory responses of an insect via their antennal receptors. The EAG screening process can help reduce the number of volatiles tested to identify promising bioactive components. However, EAG bioassays only provide information about activation of receptors. It does not provide information about the type of insect behavior the compound elicits; which could be as an attractant, repellent or other type of behavioral response. Volatiles eliciting a significant response by EAG, relative to an appropriate positive control, are typically taken on to further testing of behavioral responses of the insect pest. The experimental design presented will detail the methodology employed to screen almond-based host plant volatiles by measurement of the electrophysiological antennal responses of an adult insect pest navel orangeworm (Amyelois transitella) to single components and simple blends of components via EAG bioassay. The method utilizes two excised antennae placed across a "fork" electrode holder. The protocol demonstrated here presents a rapid, high-throughput standardized method for screening volatiles. Each volatile is at a set, constant amount as to standardize the stimulus level and thus allow antennal responses to be indicative of the relative chemoreceptivity. The negative control helps eliminate the electrophysiological response to both residual solvent and mechanical force of the puff. The positive control (in this instance acetophenone) is a single compound that has elicited a consistent response from male and female navel orangeworm (NOW) moth. An additional semiochemical standard that provides consistent response and is used for bioassay studies with the male NOW moth is (Z,Z)-11,13-hexdecadienal, an aldehyde component from the female-produced sex pheromone.     

Perception of volatiles associated with sex and food by different adult forms of the black bean aphid, Aphis fabae

Abstract. Electroantennograms (EAGs) were recorded from adult male and asexual forms (winged and wingless virginoparae and gynoparae) of the black bean aphid, Aphis fabae , during stimulation with two sex pheromone components, (+)-(4a S ,7 S ,7a R )-nepetalactone and (-)-(1 R ,4a S ,7 S ,7a R )-nepetalactol, as well as six plant volatiles, i.e. ( E )-2-hexenal, ( E )-2-hexenol-1, ( Z )-3-hexenol-1, ( Z )-3-hexenyl acetate, hexanal and allyl isothiocyanate. The male antennae are 1000-10,000 times more sensitive to nepetalactol and nepetalactone than to the plant compound ( E )-2-hexenal. Besides this marked difference of EAG peak responses in males, the EAG rise and decay are slower for the sex pheromone components. Males are also much more sensitive to the sex pheromone components than asexual females. This high sensitivity correlates with a predominance of antennal secondary rhinaria, the major sites of pheromone perception in the male. However, it is the primary rhinaria on the antennae of the wingless asexual females that are responsible for pheromone perception. Male antennae are as responsive as the asexual female antennae to the plant volatiles. The specialization of the male for mate location is discussed.     

芒果不同部位挥发物及横线尾夜蛾对其触角电位反应

【背景】芒果横线尾夜蛾是严重危害芒果花序和嫩梢的重要害虫,其发生面积不断扩大,给我国南方芒果造成了巨大损失。【方法】通过气质联用仪（GC-MS）对芒果花、梢和成熟果实的挥发性物质及其相对含量进行分析;采用触角电生理方法,测定不同性别和交配状态的芒果横线尾夜蛾对12种芒果挥发物的触角电位反应。【结果】芒果3个部位的挥发性物质多为萜烯类化合物,主要物质（相对含量在O．06％以上）的数量分别为芒果花中22种、梢11种和成熟芒果13种。芒果花中含量较高的为d．水芹烯（43．64％）和异松油烯（29．33％）;芒果梢中α-古芸烯（23．63％）含量最高;成熟芒果中8-石竹烯含量最高,为29．47％。仅异松油烯和β-荜澄茄油烯在芒果3个部位中均被检测到,但其含量差异较大;异松油烯在花、梢、果实中的含量分别为29．33％、19．99％、0．59％,而β-荜澄茄油烯分别为3．51％、2．18％、6．05％。芒果横线尾夜蛾未交配雌、雄蛾和已交配雌、雄蛾对同一种化合物的触角电位相对值之间均无显著差异。4种成蛾对反-2-已烯醛的触角电位反应值与其他化合物相比均有显著差异。交配后雌、雄蛾的触角电位反应值均有所降低,但与交配前相比无显著差异。【结论与意义】筛选出的反-2-己烯醛可作为横线尾夜蛾信息素的增效物质,对性引诱剂的研制具有重要意义。本研究可为从化学信号角度阐明横线尾夜蛾寄主定向和雌、雄交配机理,以及其致害机理提供依据。     

金龟甲对蓖麻叶挥发物的触角电位和行为反应

为了探明金龟甲偏爱选择有害非寄主植物蓖麻的原因,应用触角电位（EAG）仪和“Y”型嗅觉仪,分别测定了华北大黑鳃金龟、暗黑鳃金龟和铜绿丽金龟雌、雄虫对5种蓖麻叶挥发物的触角电位和选择行为反应。EAG测定结果表明,3种金龟甲雄虫对各处理挥发物的EAG反应值均比参照挥发物顺-3-己烯-1-醇强。华北大黑鳃金龟对邻苯二甲酸二丁酯和肉桂醛的EAG反应值相对较高,暗黑鳃金龟对苯甲醇的EAG反应值相对较高,铜绿丽金龟对邻苯二甲酸二丁酯和苯甲醇的EAG反应值相对较高。选择行为反应测定结果表明,当顺-3-己烯-1-醇与其他挥发物配对测试时,华北大黑鳃金龟对邻苯二甲酸二丁酯和肉桂醛2种蓖麻叶挥发物表现出明显的选择偏好,暗黑鳃金龟对蓖麻叶挥发物苯甲醇表现出明显的选择偏好,铜绿丽金龟则更偏好选择蓖麻的绿叶气味物质顺-3-己烯-1-醇。总之,蓖麻叶的挥发性物质与引诱金龟甲偏爱选择密切相关,且偏爱的挥发物因金龟甲的种类而异。     

Electroantennogram responses of Douglas-fir seed chalcids to plant volatiles

Douglas fir seed chalcids females oviposit specifically into Douglas cones which they locate using olfactory and visual cues. We have tested whether this specialization was correlated with a specialized sensitivity towards cone volatiles. Field collected adults were presented a series of pure volatile chemicals. Electroantennogram responses (EAG) were recorded to generally occurring terpenoids and straight chain alcohols and aldehydes found in flowers and plant leaves. Monoterpenes identified in Douglas cone headspaces (alpha-pinene, beta-pinene, 3-thujene, alpha- and beta-phellandrene, gamma-terpinene and myrcene) elicited lower EAG responses than fatty acid derivatives corresponding to green odours. The EAG response profile of females differed significantly from that of males. Females were very sensitive to hexanol-1, heptanal, (Z)-3 hexenol-1, terpineol and terpinen-4-ol. Male responses were significantly higher to humid air, nerolidol, thujan-4-ol, hexanal, carvacrol, piperitone and farnesol. Several compounds (Z- verbenol, carvone, jasminol, geraniol, nerol and eugenol) elicited long lasting electrophysiological responses (over 5 s) in both sexes.