Specialized receptor neurons for pheromones and host plant odors in the boll weevil, Anthonomus grandis Boh. (Coleoptera: Curculionidae)

Antennal olfactory receptor neurons in the boll weevil, Anthonomusgrandis, were investigated through single neuron recordings.Receptor neurons for both pheromone components and host plantodors were associated with type I sensilla within the sensoryband regions. Nine types of receptor neurons were identified,based on their responsiveness to the four aggregation pheromonecomponents and selected host plant odors. Three receptor neurontypes responded to either compound I, II or IV of the aggregationpheromone. Dose—response curves were similar for eachof these receptor neuron types, which differed only in theirkey compound. In each instance, I neurons responded primarilyto (+)-I, the optical isomer produced by the boll weevil whichwas found to be active in field tests. Receptor neurons forII also responded to a lesser degree to III, its aldehydic analog,at the same stimulus load. Six additional receptor neuron typesresponded to selected host plant odors: ß-caryophyllene,trans-2-hexen-l-o1 and other six carbon alcohols and aldehydes,trans-ß-ocimene, benzaldehyde, linalool, and B-bisabolol.These neurons were as responsive as, or in some cases more responsiveat the same stimulus load as receptor neurons for pheromonecomponents. Receptor neurons responsive to six-carbon alcoholsand aldehydes were generally most responsive to trans-2-hexen-l-ol.Receptor neurons for other plant odors responded principallyto only one compound among the odorants tested. However, responsesof these neurons were not uniform, suggesting possible specializationfor other unidentified key odorants. Comparisons were also madebetween single neuron and electroantennogram responses. Theresults indicate that the boll weevil, a narrowly oligaphagousinsect, detects its host plant at some distance, and utilizesinformation about a wide range of chemical structures in itsolfactory-mediated behavior.     

湖北高海拔地区性信息素对小菜蛾的诱捕和防治效果

2002年应用性诱剂对海拔1 200 m山区甘蓝田小菜蛾的发生及防治进行了研究。在第一茬蔬菜生长期有2个诱蛾高峰,诱蛾量(头/盆)分别为11.7±2.4和9.2±1.0;第二茬蔬菜生长期有3个诱蛾高峰,诱蛾量(头/盆)分别为70.9±8.0、16.1±2.5和11.1±1.9。应用性诱剂诱捕山区甘蓝田小菜蛾时,第一茬田间蛾密度与单盆诱捕量相关性不显著,而第二茬菜生长期田间蛾密度与单盆诱蛾量相关性显著(y=0.0116x+0.1614, r=0.9213, P=0.0011)。性诱剂在光期与暗期都可诱到小菜蛾雄虫, 没有明显的诱蛾高峰。应用性诱剂可以使菜田的农药使用减少3～5次,降低田间子代幼虫密度。     

Discrimination of female sex pheromone by male Trichoplusia ni (Hubner)

The olfactory discrimination process of male cabbage loopermoths, Trichoplusa ni (Hübner), was assessed by measuringtheir response to one of two emission sources within a windtunnel. The males discriminated between (1) Z7–12:Ac concentrations;(2) Z7–12:Ac alone and the volatile emission from excisedfemale sex pheromone glands; and (3) Z7–12:Ac and theemission from a mixture of six synthetic pheromone componentsthat mimics the volatile emissions of a female gland. Althoughmales could discriminate between a freshly excised female sexpheromone gland and 7.4x 10^–11 M Z7–12:Ac, theycould not discriminate between a gland and 78.5x10^–11M Z7–12:Ac. Males also could not discriminate betweenthe mixture of six volatile compounds and 28.7x10^–11 Mof Z7–12:Ac. The data show that male cabbage looper mothshave difficulty discriminating between Z7–12:Ac aloneand in mixtures with other female-emitted volatile compounds.     

Behavioral olfactory discrimination of mixtures in the spiny lobster (Panulirus argus) based on a habituation paradigm

A habituation paradigm was used to examine behavioral aspectsof discrimination of stimulus quality in olfaction in the spinylobster (Panulirus argus). Magnitude of search response to twoconcentrations of artificial mixtures of crab, oyster, mulletand shrimp and to artificial seawater was measured in five lobstersbefore and immediately after habituation to crab mixture. Habituationto crab mixture was accomplished through 2-min presentationsof 5 ml of alternating concentrations (0.05 and 0.5 mM) of crabmixture stimulus, repeated every 5 min for a total durationof at least 3 h. This procedure resulted in at least a 42% decreasein response to any mixture, but the decrease was greatest forcrab mixture, the habituating stimulus. A habituation index,measured as post-habituation response relative to pre-habituationresponse, was used to evaluate discrimination between crab andeach of the other three mixtures. The habituation index wassignificantly greater for crab (90%) than for oyster (49%) andfor mullet (47%) mixtures. The habituation index for shrimpmixture (65%) was intermediate to these three mixtures. Thus,shrimp mixture is perceived by lobsters as being more similarto crab mixture than is either oyster or mullet mixture. Thesepatterns of discrimination parallel those reported for associativelyconditioned lobsters (Fine-Levy et al., 1987, 1988) and fora population of olfactory receptor cells (Girardot and Derby,1988).     

Neurophysiological responses of pheromone-sensitive receptor neurons on the antenna of Trichoplusia ni (Hubner) to pulsed and continuous stimulation regimens

Both the frequency and the temporal pattern of action potentialproduction in an insect olfactory receptor neuron are stronglyaffected by odorant composition and the time course over whichstimulus concentration varies. To investigate the temporal characteristicsof the neurophysiological responses of these neurons, we deviseda stimulus delivery system that allows us to repeatedly presentwell-mixed, constant concentration odor pulses with relativelysharp onsets and offsets. Here we compare neurophysiologicalresponses to several different stimulation regimens, includingpulses of different durations and repetition rates. During stimulationwith high concentrations of pheromone, the temporal patternof neural activity from olfactory receptor neurons on the antennaof Trichoplusia ni (Hübner) is characterized by an initialphasic period (100–200 ms), followed by a tonic periodwhich is typically maintained for the remaining duration ofthe stimulus. Different olfactory receptor neurons appear tovary among themselves in the relative distribution between thephasic and tonic portions of the overall discharge. During stimulationregimens involving rapid repeated pulses of odorants, a portionof the phasic response levels is preserved during each pulse.Consequently, T. ni males probably detect much of the fluctuationin concentration of pheromone that may normally occur downwindfrom the site of pheromone release.     

LOCALIZATION AND REACTIONS OF A PHEROMONE DEGRADATIVE ENZYME ISOLATED FROM AN INSECT ANTENNA

A fluid isolated from chemosensory sensilla on the antennaeof males and females of the cabbage looper, Trichoplusia ni(Hübner), was fractionated by gel filtration. Enzymaticdegradation of the pheromone was associated with 2 distinctgroups of fractions. The first group contained membrane fragments,vesicles, and membrane-bound enzyme or insoluble enzyme aggregates.The second group of fractions contained solublilized enzyme.Because of the method of isolating the ‘sensillum liquor’by breaking the tips of the hairs, membranes from chemoreceptorcell dendrites should greatly predominate. In general, 3 isomersand the saturated analog of the pheromone were hydrolyzed morerapidly than the pheromone. ^*Mention of a proprietary product in this paper does not constitutean endorsement of this product by the U. S. Department of Agriculture.     

旋花蛾性信息素成分的鉴定

提取和鉴定了杂草田旋花Convolvulus arvensis的天敌旋花蛾Tyta luctuosa的性信息素主要成分,并应用风洞实验对雄蛾进行了测试。结果表明,腺体提取物和雌蛾求偶时所释放的主要性信息素成分均为2种化合物：顺-9-十四碳烯醛（Z9-14∶Ald）和顺-11-十六碳烯醛（Z11-16∶Ald）。腺体提取物中2种化合物的总量在个体间差异很大（22～167 ng）,但二者的比率相对稳定（Z9-14∶Ald/Z11-16∶Ald=0.3±0.15）。雌蛾所释放的性信息素量及比率在个体间也存在差异。每只雌蛾求偶时平均每小时释放94 ng Z9-14∶Ald和45 ng Z11-16∶Ald,平均比率为2.2。风洞实验结果显示,48%的雄蛾可被合成的性信息素混合物（0.4 μg Z9-14∶Ald, 2 μg Z11-16∶Ald）引诱完成逆风飞行并最终触及刺激源,而2种对照组（以求偶期雌蛾或性信息素腺体提取物为刺激源）的引诱率则分别为62%和44%。     

Taste Responses to Binary Mixtures of Amino Acids in the sea catfish, Arius felis

In vivo electrophysiological recordings in the sea catfish,Arius felis, showed that the magnitude of the integrated facialtaste responses to binary mixtures of amino acids was predictablewith knowledge obtained from previous cross-adaptation studiesof the relative independence of the respective binding sitesof the component stimuli. Each component from which equal aliquotswere drawn to form the mixtures was adjusted in concentrationto provide for approximately equal reponse magnitudes. The magnitudeof the taste responses to binary mixtures whose component aminoacids showed minimal cross-adaptation was significantly greaterthan that to binary mixtures whose components exhibited considerablecross-reactivity. There was no evidence for mixture suppression.The relative magnitude of the taste responses in the sea catfishto stimulus mixtures is similar to that previously reportedfor olfactory receptor responses in the freshwater channel catfishand chorda tympani taste responses in the hamster. Chem. Senses21: 45–53, 1996.     

Changes in Sugar Content during Cold Acclimation and Deacclimation of Cabbage Seedlings

The relationship between freezing tolerance and sugar contentin cabbage seedlings was investigated. Seedlings exposed tonon-freezing low temperature (5 °C) acquired freezing tolerancedown to -6 °C. The degree of freezing tolerance increasedwith duration of exposure to low temperature (up to 10 d). Sucrose,glucose, fructose and myo -inositol were detected as solublesugars in cabbage leaves, and all soluble sugars, except formyo -inositol, and starch increased gradually during cold acclimationsuch that their levels were positively correlated with the degreeof freezing tolerance. The induced freezing tolerance was attributednot to ontogenetic changes but to cold acclimation. However,the induced freezing tolerance was lost after only 1 d of deacclimationat control temperatures, and this change was associated witha large reduction in sugar content. These results reveal that the sugar content of cabbage leavesis positively correlated with freezing tolerance. Brassica oleracea L.; cabbage; cold acclimation; deacclimation; freezing tolerance; sugars     

利用人工合成性信息素诱捕器诱捕印度谷螟的影响因素分析

采用自行设计式及仿制圆筒式诱捕器,以人工合成性信息素(Z,E)-9,12-tetradecadienyl acetate (简称TDA) 为引诱源在实验室条件下对影响诱捕器诱捕印度谷螟Plodia interpunctella效果的几个因素进行分析测定。多元线性回归分析结果表明：日平均温度在18.5～26.2℃,人工合成性信息素TDA散发日数9～37天,温度(X₁)、TDA散发日数(X₂)、当日释放蛾(雄)量(X₃)、累计2日释放蛾量(X₄)、累计3日释放蛾量(X₅)等5个因素与每日诱捕蛾量间存在着相关关系。对5个因素进行逐步回归分析和筛选,得出线性回归方程：Y=-27.31+1.37X₁+0.28X₃,回归系数R（0.90）>R_0.01(n-2,0.63)。统计分析结果表明：日平均温度(X₁)、当日释放蛾量(X₃)与诱蛾量(Y)之间呈显著线性相关关系。卡方测验表明预测值与实测值之间差异不显著。     

B型烟粉虱对三种寄主植物及其挥发物的行为反应

利用Y型嗅觉仪,测定了B型烟粉虱Bemisia tabaci（Gennadius）雌虫对3种寄主植物、挥发物提取液、挥发物标样以及寄主植物挥发物模拟样的行为反应,并比较鉴定寄主植物挥发物的组分和含量,以期明确植物挥发物在B型烟粉虱寄主定向行为中的作用。结果表明：1）番茄植株和甘蓝植株及其相应的挥发物提取物对烟粉虱雌成虫均具有显著的引诱作用,而辣椒植株和挥发物提取物的引诱作用不明显;3种寄主植物和挥发物提取物分别两两之间比较时,烟粉虱的选择行为均极显著地表现为番茄 > 甘蓝 > 辣椒。2）番茄、甘蓝和辣椒具有不同的挥发物化学图谱,且挥发物组分的相对百分含量差异很大;番茄挥发物总量远远大于甘蓝和辣椒;从组分来看,番茄挥发物中主要为萜烯类（89.8%）,甘蓝挥发物中主要为烷烃类（53.0%）。3）8种寄主植物挥发物标样（10-¹～10^-6 μL/μL）中,除1,8-桉树脑始终对烟粉虱具有引诱作用外,丁子香酚、苎烯、里那醇和月桂烯则是分别在10^-4～10^-6,10^-1～10^-4,10^-1～10^-4和10^-1～10^-4μL/μL时,才具有引诱作用;α-蒎烯、顺-3-已烯-1醇则在高浓度下（10^-1和10^-2 μL/μL）对烟粉虱具有排斥作用,低浓度下对烟粉虱没有任何影响;正十二烷在任何浓度下对烟粉虱均没有任何作用。4）在辣椒上分别喷施番茄挥发物模拟样和甘蓝挥发物模拟样,均显著增加对烟粉虱的引诱作用,而在番茄上喷施辣椒挥发物模拟样则无明显增效作用。综合分析认为,挥发性物质在B型烟粉虱对不同寄主植物的选择偏好时具有重要的行为导向作用。     

黄斑卷蛾雄蛾对性信息素的行为反应

分别在风洞中和田间观察了黄斑卷蛾Acleris fimbriana Thunberg et Becklin雄蛾对合成性信息素三种成分（E11,13-14∶Ald, E11,13-14∶Ac和E11-14∶Ac）及其不同组合的行为反应。在风洞中,主要活性成分E11,13-14∶Ald能引起雄蛾完成从兴奋到搜索释放源的行为反应,但雄蛾对单个组分E11,13-14∶Ac 或 E11-14∶Ac不呈现任何行为反应。当释放源为双组分 E11,13-14∶Ald＋E11,13-14∶Ac （6∶4）或三组分E11,13-14∶Ald＋E11,13-14∶Ac＋E11-14∶Ac（6∶4∶1）时,可以明显增加雄蛾定向飞行和到达释放源的数量。三组分 E11,13-14∶Ald＋E11,13-14∶Ac＋E11-14∶Ac的比例为6∶4∶1时,500 μg剂量效果最好。田间试验结果表明,E11,13-14∶Ald单独使用表现出良好的诱蛾活性,其诱蛾量为活雌蛾的1.9倍,而E11,13-14∶Ac和E11-14∶Ac则不具有诱蛾活性。E11,13-14∶Ac对E11,13-14∶Ald有明显的增效作用,三组分E11,13-14∶Ald＋E11,13-14∶Ac＋E11-14∶Ac（6∶4∶1）诱芯的诱蛾效果最好。     

合成黑翅土白蚁踪迹信息素类似物的生物活性

合成了黑翅土白蚁踪迹信息素类似物(Z,Z)-3,6-十二碳二烯醇-1（DDE-OH）,该类似物对黑翅土白蚁工蚁具有和信息素提取物类似的行为反应。活性反应阈值为10^-3～10 ng/cm,大于10 ng/cm时产生较强的驱避作用。最佳活性浓度DDE-OH与信息素提取物的活性反应之间没有显著差别。     

Use of bilateral information to determine the walking direction during orientation to a pheromone source in the silkmoth Bombyx mori

Odor source localization is an important animal behavior. Male moths locate mates by tracking sex pheromone emitted by conspecific females. During this type of behavior, males exhibit a combination of upwind surge and zigzagging flight. Similarly, the male walking moth Bombyx mori responds to transient pheromone exposure with a surge in movement, followed by sustained zigzagging walking. The initial surge direction is known to be influenced by the pheromone input pattern. Here, we identified the sensory input patterns that determine the initial walking direction of males. We first quantified the stimulus by measuring electroantennogram values, which were used as a reference for subsequent tests. We used a brief stimulus pulse to examine the relationship between sensory stimulus patterns and the turning direction of initial surge. We found that the difference in input timing and intensity between left and right antennae affected the walking direction, indicating that B. mori integrate bilateral pheromone information during orientation behavior. When we tested pheromone stimulation for longer periods, turning behavior was suppressed, which was induced by stimulus cessation. This study contributes toward understanding efficient strategies for odor-source localization that is utilized by walking insects.     

Pulsed pheromone stimuli affect the temporal response of antennal receptor neurones of the adult cabbage looper moth

Abstract. Male cabbage looper moths, Trichoplusia ni (Hiibner) (Lepidoptera: Noctuidae), fly upwind in response to pheromone blends produced and released by calling conspecific females. Specialized sensilla on the male antenna contain sensitive, highly specific olfactory receptor neurones which respond to constant olfactory signals, with a phasic-tonic pattern of action potential discharge. Olfactory stimuli in nature are not uniform. They are thought to consist of pulses of odours whose distribution is shaped by wind and local environmental features. We begin to evaluate this natural situation by stimulating pheromone-sensitive sensilla with short (200 ms) paired pulses of the major component of the female's pheromone blend, (Z)-7-dodecen-l-ol acetate (Z-7,12:AC). Different stimulus protocols in which the pulses were separated from each other by varying intervals were evaluated. The interval between pulses had a large effect on the phasic component of the response. Intervals between pulses as short as 30 ms reduced the response to a second pulse by > 50%. When the intervals between pulses were longer than 3 s, significant differences were not seen between the responses to the first and second pulse. Implications for male orientation in natural, female-produced, pheromone plumes are discussed.     

A comparative study of pheromone perception in two species of Noctuid moths

The electrical activity of single olfactory receptor neurons in male soybean looper (SBL) Pseudoplusia includens(Walker) and cabbage looper (CL) Trihoplusia ni(Hübner) moths was evaluated in response to stimulation with fixed amounts of the individual components of their respective pheromone blends. In common with earlier observations in the CL, there are at least two classes of morphologically distinct pheromone sensitive sensilla on the antenna of male SBL, each of which contains two olfactory receptor neurons. In both species, one class of sensilla contains an olfactory receptor neuron sensitive to (Z)-7-dodecen-1-ol acetate (Z-7, 12:AC), the major component in each insect's blend, and a companion receptor neuron which is sensitive to (Z)-7-dodecen-1-ol (Z7,12: OH). In both species the second class of sensilla contains an olfactory receptor neuron which is sensitive to one of the minor components of the pheromone blend. (Z)-5-dodecen-1-ol acetate (Z-5,12:AC) is an effective stimulus in SBL, whereas (Z)-7-tetradecen-1-ol acetate (Z-7,14:AC) is an effective stimulus in CL. However, these two stimulatory compounds have been identified only in the female CL gland; neither has been found in the SBL gland. Thus, in contrast to the CL, which has receptor neurons which are responsive exclusively to conspecific pheromone components, the SBL has a class of receptor neurons which is responsive to a minor component of another species' pheromone blend. Field-trapping assays in which Z-5,12:AC is added to the SBL blend suggest that this single CL component is a powerful inhibitor of male SBL behavioral responses to conspecific pheromone blends. The difference observed in the specificity of the receptor neurons in this second class of sensilla are thus believed to play an integral role in the isolation processes that are maintained between these two species and may well account for the observed behavioral differences in their responses to heterospecific pheromone blends.     

Behavioral discrimination of binary mixtures and their components: effects of mixture interactions on coding of stimulus intensity and quality

There is mounting evidence that mixture interactions resultin a physiological response that is different from that predictedfrom observed responses to individual mixture components. Mixtureinteractions that act to alter the neural coding of mixtureintensity (intensity mixture interactions) or quality (patternmixture interactions) may ultimately lead to dramatic differencesbetween the perceived intensities and qualities of a mixtureand its components. These perceptions could be expressed andobserved at the behavioral level. Toward examining this question,we have tested the ability of the Florida spiny lobster (Panulirusargus) to behaviorally discriminate between three odorant compounds[adenosine 5'-monophosphate (AMP), L-glutamate (Glu), and taurine(Tau)] and their binary mixtures through the use of a differentialaversive associative conditioning paradigm. Six groups of lobsterswere used, each being conditioned to avoid one of the singlecompounds or binary mixtures. Behavioral expression of intensitymixture interactions was evident. Preconditioning response magnitudesto binary mixtures were either less than those to their components(e.g. AMP + Glu) or less than predicted from responses to theircomponents (e.g. AMP + Tau). Behavioral expression of patternmixture interactions was also observed. Relationships betweenthe quality of each binary mixture and the qualities of themixture's components were determined from the results of analysisof variance and multidimensional scaling analysis. Analysesincorporated observed responses to all stimuli and ‘predicted’responses to the binary mixtures. Lobsters easily discriminatedbetween the qualities of AMP, Glu and Tau. The quality of themixture of AMP + Glu was different from either component aswell as from the predicted value for this mixture. The mixtureof AMP + Tau was intermediate between both components and wassimilar to the predicted value. The mixture of Glu + Tau, whilemore similar to Glu than to Tau, was different from the predictedvalue, and there was some indication that the Glu was actingto suppress the response to Tau. Behavioral results for AMP+ Tau, which suggest no pattern mixture interactions betweenthese compounds, are in accordance with results of recentlyconducted binding assays which indicate independent receptorsfor these compounds (Olson et al., 1992). Results, especiallyfor AMP + Glu and Glu + Tau, are consistent with results ofour electrophysiological analysis of the effects of patternmixture interactions on coding of stimulus quality and intensityby olfactory receptor cells (Derby et al., 1991a,b). This providesfurther evidence for the effects of peripherally initiated mixtureinteractions on the coding and perception of the quality ofodorant mixtures. ¹Present address: Departments of Psychology and Biology, GeorgiaState University, University Plaza, Atlanta, Georgia 30303,USA     

Behavioral chemoattractants for the shrimp, Palaemonetes pugio: identification of active components in food extracts and evidence of synergistic mixture interactions

We are studying chemoattractants for the shrimp, Palaemonetespugio, to identify the active components of stimulatory foodextracts, and to determine whether the mixtures of substancesoccurring in extracts express themselves in an additive or aninteractive manner. The results of quantitative analyses ofthe specific amino acids, quaternary ammonium compounds, organicacids, nucleotides and related substances in extracts of fourorganisms (crab, shrimp, oyster, mullet) were used to formulateartificial mixtures based on the composition of each organism.Quantitative behavioral bioassays with P. pugio showed thatthe artificial mixtures based on the composition of the craband shrimp extracts were virtually as effective as the respectivenatural extracts, whereas artificial mixtures based on the compositionof the oyster and mullet extracts were far less effective. Sincethe same types of substances were included in all of the mixtures,it is apparent that the substances serving as chemoattractantsin different extracts are not constant but can vary dependingupon the source of the extract. To examine for interactionsamong the components of the four artificial mixtures, responsesto the mixtures and to their individual components were analyzedusing the additive methods of stimulus summation and responsesummation. Synergistic interactions were evident since eachmixture was markedly more effective than predicted on the basisof these additive models. The degree of synergism varied withthe composition of the mixture.     

枫杨枝把在田间对棉铃虫的引诱作用

观察了枫杨枝把和性诱剂在田间对棉铃虫Helicoverpa armigera (Hübner) 的引诱作用。结果表明,枫杨枝把在田间对棉铃虫成虫有较强的引诱作用,所诱雌蛾略多于雄蛾。枫杨枝把上所诱雄蛾量与上把的雌蛾量呈正相关。棉铃虫性诱剂对枫杨枝把的诱蛾作用没有显著的影响。讨论了枫杨枝把在田间引诱棉铃虫的作用。     

Patterns of Endopolyploidy During Seedling Development in Cabbage (Brassica oleracea L.)

Flow cytometric analysis of nuclear DNA contents of somatictissues of cabbage (Brassica oleracea L.) has revealed extensiveendopolyploidization, resulting in tissues that comprise mixturesof cells with different DNA contents, ranging from 2C to 16C.Patterns of endopolyploidy are specific to each developmentalstage. Multiple polyploidy was not present in the embryos ofdry seeds. Rapid endoreduplication occurred in the radicle andthe hypocotyl of the embryos during seed germination. Furtherendoreduplication cycles were detected in all tissues exceptthose of the shoot tips. In five cabbage cultivars tested, seedlingscontained cells of four ploidy levels, corresponding to 2C,4C, 8C and 16C. Multiploidy may be an integral part of differentiationprograms in cabbage plants. The biological significance of endoreduplicationin cabbage plants is discussed. Copyright 2001 Annals of BotanyCompany Cabbage (Brassica oleracea L.), endopolyploidy, endoreduplication, flow cytometry