Structural and functional classification of antennal sensilla of the cockroach,Leucophaea maderae

Summary Antennal sensilla of Leucophaea maderae were investigated electrophysiologically, labeled and then examined with the scanning or transmission electron microscope. The sensilla can be classified into morphological types according to their external shape and the structure of their hair wall. Sensilla showing similar reaction spectra of their cells can be cathegorized into physiological groups. The morphological classification corresponds to the physiological grouping: one morphological type of sensillum comprises one or several groups of physiologically similar sensilla. In many of these groups constant combinations of physiologically different cells occur. The possible functional significance of the relationships found between the structural features of the sensilla and the physiological properties of their sensory cells is discussed.Supported by the Deutsche Forschungsgemeinschaft (Scha 292/1)     

昆虫的触角感器

在自然界里 ,昆虫家庭日趋庞大 ,已占到动物物种的 2 / 3以上。昆虫在亿万年的进化过程中具备了自己独特的适应环境的能力。择食、取食、觅偶、交配、繁殖、栖息、防御、迁移等等 ,这些适应性行为比其他动物更依赖于环境化学、物理因子的调节 ,昆虫触角是接受外来化学信号的主要器官。随着分子生物学的崛起 ,利用昆虫自身的生理生化微观特性探索其宏观行为的奥妙 ,已作为害虫防治中的新方向 ,其中触角感器的研究倍受重视 ,而且已取得显著进展。1　历史回顾与发展1 880年 Hauser首先开始评论昆虫嗅觉这个主题 ,他详细描述了直翅目、脉翅目、…     

Ultrastructure of the antennal sensilla of aphids

Summary An electron microscopical study of aphid antennal sensilla has revealed two types of trichoid sensilla. Type I, innervated by a single neuron is mechanoreceptive; type II, innervated by three to five neurons is both mechanoreceptive and chemoreceptive with possibly a third function. Johnston's organ in the pedicel comprises a peripheral ring of scolopidia inserted into the joint with the flagellum; two non-peripheral groups of scolopidia lie in the lumen with attachment points in the wall of the third segment. The fine structure of a campaniform sensillum on the pedicel is described together with two homologous and previously unknown sense organs at the joint between the fifth and sixth antennal segments. An unusually placed scolopidium in the lumen of the sixth segment has also been found. The function of this scolopidium is unknown but Johnston's organ, the campaniform sensillum and joint receptors are suggested to act as antennal proprioceptors.The authors thank the Long Ashton Research Station, Bristol for use of the SEM facilities. A.K. Bromley gratefully acknowledges the tenure of a S.R.C. CASE Studentship and thanks Professor L.H. Finlayson for research facilities     

Ultrastructure of the antennal sensilla of aphids

Summary An electron microscopical study was made of the coeloconic and placoid sensilla on the antennae of the aphids Aphis pomi, Macrosiphum euphorbiae, Nasonovia ribis-nigri, and Pemphigus bursarius. Scanning electron microscopy revealed some variation in morphology which may be functionally important but is more likely to reflect the evolution of these species.The placoid sensilla were shown by transmission electron microscopy to have the same basic structural pattern. Each group of two or three neurons is surrounded by two ensheathing cells. The ciliary regions of the dendrites pass through a vacuole into a cavity between an outer and an inner cuticle where they may be connected to the dendritic branches although such connections were not seen. Small pores (8 nm diameter) partially penetrate the cuticle implying that these sensilla have an olfactory function. They are suggested to be important in host selection by alate aphids.The coeloconic sensilla are poreless pegs with nonsensory cuticular projections at their tips. The distal portions of their dendrites contain densely packed microtubules and the cellular arrangement of the sensilla is similar to that of the placoid sensilla. It is suggested that they may function as thermoreceptors.The authors thank the Long Ashton Research Station, Bristol for use of the SEM facilities. A.K. Bromley gratefully acknowledges the tenure of a S.R.C. CASE Studentship and thanks Professor L.H. Finlayson for research facilities     

食木性隐尾蠊属的触角感器特征及分类意义探究（蜚蠊目：隐尾蠊科）

利用扫描电镜观察了3种食木性蜚蠊:滇南隐尾蠊、哈巴隐尾蠊和长白隐尾蠊的触角感器。在本文中对上述3种隐尾蠊的触角形态进行了详细的描述,3种隐尾蠊触角无明显差异。观察并测量了6种主要的感器类型:刺形感器、毛形感器、锥形感器、腔锥形感器、钟形感器和小头感器。结果发现,在3种隐尾蠊触角上毛形感器是最丰富的感器。统计表明感器在3种隐尾蠊种间和两性间存在一些差异。与其他蜚蠊和白蚁进行了比较,并讨论了它们在生活习性上的差异。综上所述,感器的形态描述和统计分析不足以对3种隐尾蠊进行分类鉴别,不宜作为种级单元分类特征。     

Mechanosensory control of antennal movement by the scapal hair plate in the American cockroach

The voluntary movement of antennae of blinded cockroaches was examined in the tethered-walking condition. An object of metal plate was presented to a tip of a single antenna in order to induce tactile orientation behavior. Horizontal movements of the antenna before and during the object presentation were analyzed both before and after ablation of a mechanosensory organ, the scapal hair plate (S-HP), at the base of antenna. The resting antennal position shifted outwardly by about 20 degrees after the S-HP ablation. Spontaneous antennal movements in ablated animals became stiff and wider ranged. The tactile object was set at two different horizontal positions, 45 degrees and 90 degrees clockwise to the head, for the right side antenna. The number of contacts in a constant test period was significantly decreased in the tests at 45 degrees after ablation. Trajectories of antennal movements before and after contacts were categorized into four patterns. In the case that an antenna made contact with the object during its abduction (outward) movement, it then passed the object outwardly or withdrew inwardly. These were termed "outward-pass (O-P)" and "outward-withdrawal (O-W)" patterns, respectively. Similarly, contacts during the adduction (inward) movement were divided into "inward-pass (I-P)" or "inward-withdrawal (I-W)" pattern. Significant effects of the S-HP ablation appeared in the tests at 90 degrees : the I-P pattern mostly disappeared and was replaced by the I-W pattern. The results strongly suggest that the S-HP has crucial roles for controlling both spontaneous and stimulated movements of the cockroach antenna.     

松褐天牛触角感器电镜扫描和触角电位反应

应用扫描电镜对松褐天牛的触角感器进行扫描观察,并测定了触角对松树主要挥发物的电生理反应.松褐天牛触角上共有7种感器,即毛形感器、锥形感器、指形感器、棒形感器、瓶形感器、芽形感器以及刺形感器,以毛形和锥形感器的数量最丰富.其中毛形感器和锥形感器各有3个型,指形感器有2个型.毛Ⅱ、毛Ⅲ型和锥Ⅰ、锥Ⅱ型感器表皮结构具有深的纵刻纹,具有嗅觉感器的典型特征.同时对各种感器的数量、长度及分布特点等作了描述.电生理研究结果表明,几种供试化合物及其混合物均能引起松褐天牛雌、雄成虫较强的电生理反应;松褐天牛触角不同部位的EAG反应存在显著差异;剂量试验表明,松褐天牛成虫触角对不同浓度的α-Pinene的EAG反应存在一定的规律性.     

Electrophysiological responses to salts from antennal chaetoid taste sensilla of the ground beetle Pterostichus aethiops

Antennal gustatory sensilla of the ground beetle Pterostichus aethiops (Pz., 1797) (Coleoptera, Carabidae) respond to salts, the three sensory cells, A-, B- and C-cells, producing action potentials that are distinguished by differences in their shape, amplitude, duration and polarity of spikes. The B-cell (salt cell) was highly sensitive to both ionic composition and concentration of the tested nine salt solutions showing phasic-tonic type of reaction with a pronounced phasic component. The stimulating effect was dominated by the cations involved, and in most cases, monovalent cations were more effective stimuli than divalent cations. Salt concentration/response relations were tested with NaCl at 1, 10, 100 and 1000 mmol l⁻¹: mean firing rates increased from 0.8 to 44 spikes per first second of the response, respectively. The pH value of the stimulating solutions also influenced the B-cell rate of firing. By contrast, the pH level of stimulus solutions influenced the A-cells’ phasic-tonic response more than the ionic composition or concentration of these solutions. Compared to a standard 100 mmol l⁻¹ salt (NaCl) solution (pH 6.3), alkaline solutions of the salts NaCH₃COO, Na₂HPO₄ and Na₂B₄O₇ (pH 7.9, 8.5 and 9.3, respectively, all 100 mmol l⁻¹) induced remarkably stronger responses in the A-cell. On the other hand, the reaction to an acid solution of NaH₂PO₄ (pH 4.5, 100 mmol l⁻¹) was minimal. A-cell responses to neutral salts like NaCl, KCl, CaCl₂, MgCl₂ and C₅H₁₄NOCl (pH 6.1-6.5) varied largely in strength. Very low or no responses were observed with chlorides of divalent cations, CaCl₂ and MgCl₂, and choline chloride (C₅H₁₄NOCl), indicating that the ionic composition of the solutions also affected A-cell responses. Neural activity of the C-cell was not influenced by the salt solutions tested.     

The role of pore structures in the selective permeability of antennal sensilla of the desert burrowing cockroach, Arenivaga sp

To obtain information about the chemical composition of pore structures in antennal sensilla, the antennae were exposed to lipid solvents, or they were prepared to show negative-contrast images in electron micrographs. A heavy-metal tracer, lanthanum nitrate, was also used to indicate the permeability of the receptors to water. The grooves of the large grooved peg open into tubular cavities containing electronopaque material, through which stimulatory molecules must pass to reach the sensory dendrites at the center of the sensillum. The material in these cavities was removed by chloroform or acetone, suggesting a lipid composition. Lanthanum penetrated this receptor only after it had been exposed to acetone or chloroform. Strands at pores of the thin-walled pegs were also removed by the lipid solvents, and the water-soluble tracer failed to penetrate these receptors unless they had been previously exposed to chloroform or acetone. The pore structures appear to be hydrophobic, allowing entry of lipid-soluble substances, while preventing passage of water. The differential action of the solvents on the various types of sensilla suggests that receptor discrimination among different classes of chemical stimuli may be partially determined by the chemical properties of structures at the sensillar pores.     

二化螟盘绒茧蜂触角感器的超微结构

采用扫描电子显微镜对二化螟盘绒茧蜂Cotesia chilonisMunakata触角感器进行了观察和研究。结果表明,二化螟盘绒茧蜂触角上共存在6种感器,分别为板形感器、毛形感器、刚毛型感器、柱形感器、钟形感器、锥形感器。对各种触角感器的形态、分布特点进行了描述,并对两性间的差异及其功能进行了探讨。     

Embryogenesis of the connective chordotonal organ in the pedicel of the American cockroach: Cell lineage and morphological differentiation

Summary The ontogenesis of single scolopidia of the chordotonal organ of the American cockroach, Periplaneta americana, takes about 4 days. At 23% embryogenesis (100% = 30 d) the first anlagen of scolopidia were identified within the epithelium by staining with anti-horseradish peroxidase. Reconstruction of the cell lineage of the scolopidial cells was facilitated by two facts: (i) the arrangement of the cells throughout ontogenesis follows a strict pattern, and (ii) daughter cells are recognizable for several hours after mitosis by the cytoplasmic bridge and midbody joining them. When they separate, the midbody undergoes lysosomal degeneration in one of these cells. The earliest recognizable stage is a pair of cells, one of which (cell 1) encloses the other (cell 2) apically. The enclosing cell becomes the accessory cell. Cell 2 divides, yielding the mother cell (cell 3) of two sensory cells which degenerate later, and cell 2. Cell 2 gives rise to the attachment cell and to cell 2, which in turn produces the scolopale cell and the mother cell (cell 2 2) of a second pair of sensory cells; the latter are the definitive sensory cells. The end result is the total of 5 cells characteristic of the adult scolopidium. Secretion of the scolopale and cap together with the migration of the sensory cell perikarya into the antennal lumen complete development.     

Pheromone-stimulated locomotory and orientation responses in the American cockroach

Males of Periplaneta americana respond to the sex pheromone secreted by females with increased locomotion and positive chemo-orientation. Both sexes orient toward aggregation pheromone without an increase in locomotion. Immediately following removal of one antenna males exhibit ‘circus’ movements, but after 2 days orient toward pheromones; a bi-modal mechanism of chemo-orientation is proposed. Cockroaches turn away from air currents, but orient toward air currents carrying sex or aggregation pheromone, suggesting the possibility of up-wind orientation. Antennae deflect upward and outward when pheromone is first perceived; the head then moves toward the pheromone source. Following removal of one antenna, the pattern of head and antennal movement changes in a manner which enhances the sweeping of the intact antenna.     

稻小秆蝇触角感受器的超微结构研究

采用扫描电子显微镜对稻小秆蝇触角感受器进行了观察和研究,结果表明,稻小秆蝇触角上共存在5种感受器,分别为毛形感受器、刚毛型感受器、柱形感受器、锥形感受器蒲姆氏鬃。对各种触角感受器的形态、分布特点进行了描述,并对其功能进行了一定的探讨。     

椰子织蛾触角感器的超微结构观察

本文利用光学显微镜和和扫描电子显微镜,观察和测定椰子织蛾成虫的触角外部形态、感器的形态特征和分布,对椰子织蛾感器进行鉴定分类.结果表明,椰子织蛾雌雄成虫触角形状为线形,由38～42节组成,其中柄节1节、梗节1节和鞭节36～40节.椰子织蛾雌、雄成虫触角上有7种类型感器,9种亚型,分别是毛形感器(2种亚型)、刺形感器(2...     

Serotonin-immunoreactive neurons in the antennal lobes of the American cockroach Periplaneta americana: light- and electron-microscopic observations

Summary A large deutocerebral serotonin-immunoreactive neuron arborizes profusely in the glomeruli of the antennal lobes, and also sends neurites into the lateral lobe and the calyces of the mushroom bodies in the ipsilateral protocerebrum. Electron micrographs of the glomerular neuropil show that the main synapses of the serotonin-immunoreactive arborizations are output contacts with unidentified neuron profiles. Only a few synaptic input contacts with serotonin-labeled fibers were observed.     

Serotonin-immunoreactive neurons in the antennal lobes of the American cockroach Periplaneta americana: light- and electron-microscopic observations

A large deutocerebral serotonin-immunoreactive neuron arborizes profusely in the glomeruli of the antennal lobes, and also sends neurites into the lateral lobe and the calyces of the mushroom bodies in the ipsilateral protocerebrum. Electron micrographs of the glomerular neuropil show that the main synapses of the serotonin-immunoreactive arborizations are output contacts with unidentified neuron profiles. Only a few synaptic input contacts with serotonin-labeled fibers were observed.     

The tarso-pretarsal chordotonal organ as an element in cockroach walking

Many types of sense organs have been demonstrated to show repetitive discharges during walking that could provide informational cues about leg movements and other parameters of locomotion. We have recorded activities of receptors of the distal (tarsal) segments of the cockroach hindleg in restrained and freely moving animals while they were videotaped. These recordings show peaks of activities at the onset and termination of the stance phase. We have morphologically and physiologically identified a joint angle receptor, the tarso-pretarsal chordotonal organ, that contributes to the discharges seen late in stance, prior to the onset of leg flexion in swing. This sense organ encodes the angle and rate of change of the most distal leg joint and specifically discharges when the claws are disengaged from the substrate. Applied displacements of the claws in restrained preparations elicit reflex activation of the tibial flexor muscle and a crossed extensor reflex in the opposite hindleg. These reflexes could function to insure that leg flexion in swing does not occur until the claws are disengaged and to enhance support by the opposite hindleg. Thus, the regular discharges of the chordotonal organ could assure efficient and coordinated muscle contractions and movements during normal, unperturbed walking. Accepted: 2 January 1997     

Olfactory responses of the antennal trichoid sensilla to chemical repellents in the mosquito, Culex quinquefasciatus

Insect repellents are widely used to protect against insect bites and thus prevent allergic reaction and the spread of disease. To gain insight into the mosquito’s response to chemicals repellents, we investigated the interaction between the olfactory system of the mosquito Culex quinquefasciatus Say and chemical repellents using single sensillum recording. The interactions of 50 repellent chemicals with olfactory receptor neurons were measured in six different types of mosquito sensilla: long sharp trichoid (LST), short sharp trichoid (SST), short blunt trichoid I (SBT-I), short blunt trichoid II (SBT-II), short blunt trichoid-curved (SBT-C), and grooved peg (GP). A single olfactory neuron reacted to the chemical repellents in each of the sensilla except for SBT-I and SBT-II, where two neurons were involved. Other than LST and GP, which showed no or very weak responses to the repellents tested, all the sensilla showed significant excitatory responses to certain types of repellents. Terpene-derived chemicals such as eucalyptol, α-pinene, and camphor, stimulated olfactory receptor neurons in a dose-dependent manner and mosquitoes responded more strongly to terpene-derived chemical repellents than to non-terpene-derived chemicals such as dimethyl phthalate. Mosquitoes also exhibited a similar response to stereoisomers of chemicals such as (−)-β-pinene versus (+)-β-pinene, and (−)-menthone versus (+)-menthone. This study not only demonstrates the effects of chemical repellents on the mosquito olfactory system but also provides important information that will assist those screening new mosquito repellents and designing new mosquito control agents.