Metamorphic changes in the central projects of hair sensilla inTenebrio molitor L. (Insecta: Coleoptera)

Summary This paper describes the afferent projections of hair sensilla of the pro- and mesothoracic legs and the lateral thoracic sclerites of larval and adultTenebrio molitor and the corresponding set of pupal hair sensilla. The sensory neurons that innervate the hair sensilla of larval or adult insects project somatotopically into the thoracic neuropil. Different types of sensilla on the same region of the body surface project to the same zone of the ipsilateral thoracic ventral neuropil but exhibit different arborization patterns. Although there is a profound reorganization of body surface sensilla, the basic somatotopic layout of the larva is maintained in the adult. The sensory neurons that innervate the pupal hair sensilla possess central projections similar to those of the corresponding adult sensory neurons. The central projections of pupal sensory neurons are somatotopically oriented. Their projection pattern is serially homologous in the thoracic and the abdominal ganglia. The central projection pattern of the described pupal sensory neurons is constant throughout pupation. MAb 22C10 immunoreactivity allows an estimate of the timing of the early differentiation of the imaginal sensory neurons originating during pupation. Ablation experiments indicate that pupal sensory neurons influence the central projection pattern of the differentiating imaginal sensory neurons.     

The structure of the cereal sensory system and ventral nerve cord of Grylloblatta

Summary The structure of cereal sensilla, the cereal nerve and the central projections of the cereal sensory nerve of a notopteran (Grylloblatta sp.) are described and compared with other orthopteroid insects in which the cereal sensory system and central connections are well known. The cereal sensilla are similar to those of gryllids and blattids, but the gross structure of the cerci and distribution of cereal sensilla more closely resemble those of the Thysanura. The elements of the cereal sensory nerves and the central nervous system are similar to those of other orthopteroid insects, but extracellular material is present in greater quantity, and more extensive glial bundling of axons occurs in both the cereal nerve and central connectives. Glial structure, extracellular material and large multicristate mitochondria may be adaptations to life near 0° C. The form of central projections of the cereal nerve and the configuration of the largest abdominal interneurons are unlike those of gryllids and Dictyoptera; they are similar to those of Dermaptera.     

Properties of the trochanteral hair plate and its function in the control of walking in the cockroach.

1. The physiological properties of the group of long hair sensilla of the trochanteral hair plate in the cockroach metathoracic leg were studied. The sensilla were divided into type I and type II according to their responses to imposed displacements. 2. Type I hair sensilla responded to dynamic displacements whereas type II hair sensilla responded to both dynamic and static displacements. The hair sensilla are normally excited by phasic flexion movements of the femur near the end of leg protraction. 3. Activity in the trochanteral hair plate afferents had a short latency excitatory effect on the motoneurone producing slow extension movements of the femur and an inhibitory effect on the femur flexor motoneurones. 4. Removal of the trochanteral hair plate in one leg caused overstepping of that leg in a walking animal due to exaggerated flexion of the femur. This change in leg movement can be explained by the removal of the inhibitory influence from the hair plate afferents to the femur flexor motoneurones. 5. We conclude that one function of the trochanteral hair plate is to limit femur flexion during a step cycle.     

小菜蛾成虫喙管感器的超微结构及其神经元中枢投射

【目的】明确小菜蛾Plutella xylostella成虫喙管感器的形态结构及感器神经元的投射。【方法】利用扫描电子显微镜观察小菜蛾成虫喙管结构和感器,利用神经回填技术和激光共聚焦显微镜观察喙管感器神经元在脑部的投射。【结果】小菜蛾成虫喙管上存在毛形感器(两种亚型)、腔锥形感器、锥形感器、刺形感器和栓锥形感器5种不同类型的感器。毛形感器表面光滑,分布于外颚叶外侧,可分为毛形感器Ⅰ型和Ⅱ型两种亚型,其中Ⅰ型比Ⅱ型长;锥形感器分布于喙管外表面,由一个感觉锥和一个短的圆形基座组成;腔锥形感器仅分布于食管内侧,只有一个粗短感觉锥而无基座;刺形感器由一个细长的感觉毛和一个圆形基座组成,表面无孔,分布于喙管的外表面;栓锥形感器是昆虫喙管上最典型的感受器,集中分布于喙管顶端区域,感器顶部凹腔伸出一个单感觉锥。此外,喙管上的感觉和运动神经元投射到初级味觉中枢咽下神经节。【结论】本研究阐明了小菜蛾成虫喙管感器的类型、分布和形态特征及其感器神经元在脑部的投射形态,为深入了解小菜蛾喙管感器的生理和功能奠定了基础。     

Sensory projections of identified coxal hair sensilla of the scorpionHeterometrus fulvipes (Scorpionidae)

The topography of long hair sensilla on the coxae of walking legs and pedipalps of the scorpionHeterometrus fulvipes is described. Identified long hair sensilla are cobalt filled, and central projections of sensory fibres are reported for the first time in the suboesophageal ganglion of this scorpion. The afferent fibres arising from each long hair sensilla segregate into ventral, dorsomedial and dorsal tracts upon their entry into the suboesophageal ganglion. These transverse tracts bifurcate towards the middle of the leg neuromere and form three ipsilateral, plurisegrnental, longitudinal sensory pathways. Filling a pair of bilaterally distributed long hair sensilla shows bilaterally arranged longitudinal afferent tracts interconnected by distinct transverse commissures. Similar patterns of sensory projections are observed when filling homologous hairs on other legs and pedipalps. Numerous fine collaterals arise from the longitudinal sensory trancts that subdivide and end in small blebs presumed to be presynaptic endings. The dorsal and dorsomedial longitudinal tracts and their respective commissures are in close association with the dendritic arborisations of pedipalpal and leg motor neurons, suggesting direct contact between them. The probable functions of these multisegmental hair afferent pathways are discussed.     

Sensilla on the palps and legs of the adult soft tick argas persicus oken (IXODOIDEA: ARGASIDAE) and their projections to the central nervous system

The sensory structures present on the palps and legs of adult Argas persicus Oken (Ixodoidea: Argasidae) were studied by light, scanning and transmission electron microscopy. The number, distribution, surface morphology and the fine structure of the prominent sensilla present on these appendages were determined. The palps have 2 morphologically prominent types of sensilla: one with a grooved surface of the hair and the other having a non-grooved hair. The TEM distinguishes at least 4 prominent subtypes in grooved sensilla with single or double lumina and dendrites occupying the periphery of the central lumen or distributed all over the central lumen. Amongst the sensilla with non-grooved hair-shaft, a rare type of Olfactory Mechanoreceptive (OM) sensillum was found on the palps and the first legs of A. persicus. At the base of the hair-shaft, the OM sensillum has 2 mechanosensory dendrites. The hair-shaft of the sensillum has a porous cuticle, characteristic of an olfactory sensillum. The lumen of the hair-shaft is invested with branching dendrites from 3–8 neurons, which are surrounded by 4 sheath cells. The sensilla on the legs, including those present in the Hallers organ, are of at least 3 prominent categories. (i) Single wall with un-innervated hair-shaft. (ii) Single wall, multiporous sensillum with dendrites present in the hair shaft. (iii) Double walls with spoke channels and dendrites present in the central lumen. Sensory projections from the crown of sensilla located on the distal end of the palp extend to the palpal and suboesophageal (SOG) ganglia. Projections in the SOG extend further to the contralateral side. Sensilla in the Hallers organ project to the first pedal ganglion and to the anterodorsal region of supraoesophageal ganglion. As expected, the primary sensory projections from the sensilla of the other 3 legs extend to the respective pedal ganglia.     

Encoding of force increases and decreases by tibial campaniform sensilla in the stick insect, <Emphasis Type="Italic">Carausius morosus</Emphasis>

Detection of force increases and decreases is important in motor control. Experiments were performed to characterize the structure and responses of tibial campaniform sensilla, receptors that encode forces through cuticular strains, in the middle leg of the stick insect (Carausius morosus). The sensilla consist of distinct subgroups. Group 6A sensilla are located 0.3 mm distal to the femoro-tibial joint and have oval shaped cuticular caps. Group 6B receptors are 1 mm distal to the joint and have round caps. All sensilla show directional, phasico-tonic responses to forces applied to the tibia in the plane of joint movement. Group 6B sensilla respond to force increases in the direction of joint extension while Group 6A receptors discharge when those forces decrease. Forces applied in the direction of joint flexion produce the reverse pattern of sensory discharge. All receptors accurately encode the rate of change of force increments and decrements. Contractions of tibial muscles also produce selective, directional sensory discharges. The subgroups differ in their reflex effects: Group 6B receptors excite and Group 6A sensilla inhibit tibial extensor and trochanteral depressor motoneurons. The tibial campaniform sensilla can, therefore, encode force increases or decreases and aid in adapting motor outputs to changes in load.     

The organization of the chemosensory system in Drosophila melanogaster: a rewiew

This review surveys the organization of the olfactory and gustatory systems in the imago and in the larva of Drosophila melanogaster, both at the sensory and the central level. Olfactory epithelia of the adult are located primarily on the third antennal segment (funiculus) and on the maxillary palps. About 200 basiconic (BS), 150 trichoid (TS) and 60 coeloconic sensilla (CS) cover the surface of the funiculus, and an additional 60 BS are located on the maxillary palps. Males possess about 30% more TS but 20% fewer BS than females. All these sensilla are multineuronal; they may be purely olfactory or multimodal with an olfactory component. Antennal and maxillary afferents converge onto approximately 35 glomeruli within the antennal lobe. These projections obey precise rules: individual fibers are glomerulus-specific, and different types of sensilla are associated with particular subsets of glomeruli. Possible functions of antennal glomeruli are discussed. In contrast to olfactory sensilla, gustatory sensilla of the imago are located at many sites, including the labellum, the pharynx, the legs, the wing margin and the female genitalia. Each of these sensory sites has its own central target. Taste sensilla are usually composed of one mechano-and three chemosensory neurons. Individual chemosensory neurons within a sensillum respond to distinct subsets of molecules and project into different central target regions. The chemosensory system of the larva is much simpler and consists essentially of three major sensillar complexes on the cephalic lobe, the dorsal, terminal and ventral organs, and a series of pharyngeal sensilla.     

The organization of the chemosensory system in Drosophila melanogaster: a rewiew

This review surveys the organization of the olfactory and gustatory systems in the imago and in the larva of Drosophila melanogaster, both at the sensory and the central level. Olfactory epithelia of the adult are located primarily on the third antennal segment (funiculus) and on the maxillary palps. About 200 basiconic (BS), 150 trichoid (TS) and 60 coeloconic sensilla (CS) cover the surface of the funiculus, and an additional 60 BS are located on the maxillary palps. Males possess about 30% more TS but 20% fewer BS than females. All these sensilla are multineuronal; they may be purely olfactory or multimodal with an olfactory component. Antennal and maxillary afferents converge onto approximately 35 glomeruli within the antennal lobe. These projections obey precise rules: individual fibers are glomerulus-specific, and different types of sensilla are associated with particular subsets of glomeruli. Possible functions of antennal glomeruli are discussed. In contrast to olfactory sensilla, gustatory sensilla of the imago are located at many sites, including the labellum, the pharynx, the legs, the wing margin and the female genitalia. Each of these sensory sites has its own central target. Taste sensilla are usually composed of one mechano-and three chemosensory neurons. Individual chemosensory neurons within a sensillum respond to distinct subsets of molecules and project into different central target regions. The chemosensory system of the larva is much simpler and consists essentially of three major sensillar complexes on the cephalic lobe, the dorsal, terminal and ventral organs, and a series of pharyngeal sensilla.     

Central Projections of Gustatory Receptor Neurons in the Medial and the Lateral Sensilla Styloconica of Helicoverpa armigera Larvae

Food selection behavior of lepidopteran larvae is predominantly governed by the activation of taste neurons present in two sensilla styloconica located on the galea of the maxilla. In this study, we present the ultrastructure of the sensilla styloconica and the central projection pattern of their associated receptor neurons in larvae of the heliothine moth, Helicoverpa armigera. By means of light microscopy and scanning electron microscopy, the previous findings of two morphologically fairly similar sensilla comprising a socketed conic tip inserted into a large peg were confirmed. However, the peg size of the medial sensillum was found to be significantly bigger than that of the lateral sensillum. The sensory neurons derived from each sensillum styloconicum were mapped separately using anterograde staining experiments combined with confocal laser-scanning microscopy. For determining the afferents’ target regions relative to each other, we reconstructed the labeled axons and placed them into a common reference framework. The sensory axons from both sensilla projected via the ipsilateral maxillary nerve to the suboesophageal ganglion and further through the ipsilateral circumoesophageal connective to the brain. In the suboesophageal ganglion, the sensory projections targeted two areas of the ipsilateral maxillary neuropil, one located in the ventrolateral neuromere and the other adjacent to the neuromere midline. In the brain, the axon terminals targeted the dorso-anterior area of the ipsilateral tritocerebrum. As confirmed by the three-dimensional reconstructions, the target regions of the neural projections originating from each of the two sensilla styloconica were identical.     

Ultrastructure of the chemosensitive basiconic single-walled wall-pore sensilla on the antennae in adults and embryonic stages of Locusta migratoria L. (Insecta,Orthoptera)

Summary The structure and embryonic development of the two types (A, B) of basiconic sensilla on the antennae of Locusta migratoria were studied in material that had been cryofixed and freeze-substituted, or chemically fixed and dehydrated. Both types are single-walled wall-pore sensilla. Type-A sensilla comprise 20–30 sensory and 7 enveloping cells. One enveloping cell (thecogen cell secretes the dendrite sheath); four are trichogen cells, projections of which form the trichogen process during the 2nd embryonic molt. The trichogen cells form two concentric pairs proximally. Two tormogen cells secrete the cuticular socket of the sensillum. The dendritic outer segments of the sensory cells are branched. Bifurcate type-A sensilla have also been observed. Type-B sensilla comprise three sensory and four enveloping cells (one thecogen, two trichogen and one tormogen). The trichogen process is formed by the two trichogen cells, each of which gives rise to two projections. The trichogen cells are concentrically arranged. The dendritic outer segments of the sensory cells are unbranched. In the fully developed sensillum, all trichogen and tormogen cells border on the outer receptor lymph cavity. It is suggested that the multicellular organization of the type-A sensilla can be regarded as being advanced rather than primitive.Supported by the Dcutschc Forschungsgemeinschaft (SFB 4/G1)     

Development of the sensory system in larvae and pupae of Chaoborus crystallinus (DeGeer, 1776; Diptera, Chaoboridae): sensory cells, nerves and ganglia of the tail region

Using various microscopical techniques, we have studied changes in the sensory equipment and architecture of the peripheral nervous system (PNS) around the first metamorphic molt from larva to pupa in the phantom midge Chaoborus. The transparent larvae and pupae of this dipteran with ancestral features allow us to investigate sensilla and their central projections from whole-mount preparations of complete groups of segments. Each sensillum on the posterior larval and pupal segments was identified using its external shape and position, and the morphology of the abdominal ganglia and segmental nerves was investigated. In addition, retrograde fills with the carbocyanine dye DiI were used to trace the axonal paths of most of the extero- and proprioreceptors. These findings were combined to produce maps of the sensory elements of larval and pupal abdomens that were analyzed at three levels: seriality (homonomy), ontogenetic changes of individual sensilla, and homology of the PNS between different species. Comparison of different segments shows for both stages that primarily there is a homonomous basic design of the PNS, but segment-specific modifications are evident in segments 8-10. Comparison of corresponding larval and pupal segments shows that many sensilla retain their internal structure and axonal projections. However, their external cuticular parts are changed in relation to the different life habits of larvae and pupae. Furthermore, some sensilla are completely reduced during the pupal molt, especially those of the tenth segment which appears as a distinct larval structure (caenogenesis). Comparison between species indicates that despite the varying types of sensilla their basic segmental arrangement and their axonal trajectories are conserved.     

Thoracic mechanoreceptors in the wing bases of Heliothis zea (Lepidoptera: Noctuidae) and their central projections

The thoracic mechanoreceptors of the wings and their central projections in the noctuid moth Heliothis zea (Lepidoptera: Noctuidae) were investigated using cobalt chloride infiltration methods. The different mechanoreceptors, tegula, campaniform sensilla, and chordotonal organ were identified as being present in the wing bases. The forewing and hindwing bases were innervated by two large nerve trunks (IIN1 and IIIN1, respectively). Terminal projections for both wing bases included massive regions within the fused meso-metathoracic and prothoracic ganglia, as well as direct projections to the suboesophageal ganglia. The terminal fields of IIIN1 were exclusively ipsilateral, whereas those of IIN1 also were contralateral. The relationship of these sensory mechanoreceptors to the neural basis of evasive flight behaviours is discussed.     

Primary sensory projections from the labella to the brain of Drosophila melanogaster Meigen (Diptera : Drosophilidae)

Golgi silver impregnation of sensory neurons arising from labellar taste sensilla of Drosophila melanogaster Meigen (Diptera : Drosophilidae) revealed 7 distinct types I-VII of primary (sensory) fibres projecting to the suboesophageal ganglion (SOG) of the brain. Each fibre was classified on the bases of the neuropil volume occupied by its terminal arborisation, the shape of neuropil region receiving the arborisations and the detailed morphology of the arborisations. The primary sensory fibre projections from the labella are confined to the SOG where they project mainly in the anterior and central neuropils. No labellar sensory fibres project to posterior SOG. Of these 7 types of sensory fibres, three (III, IV and VII) show ipsilateral projections, while others have both ipsi-, and contralateral branches.Four types of interneurons are suggested to be associated with taste perception. Type A interneurons are local interneurons with arborisations confined only to the taste sensory neuropil of the SOG. The types B - D interneurons are interganglionic/output neurons with axons projecting to various brain regions-SOG, calyces of the mushroom bodies, tritocerebrum and thoracic ganglia. These projections suggest that more than one centre (SOG, tritocerebrum, calyces of the mushroom bodies and thoracic ganglia) are involved in processing gustatory information.     

Central projections from contact chemoreceptors of the locust ovipositor and adjacent cuticle

Contact chemoreceptors (basiconic sensilla) located on the ovipositor and genital segments of the locust serve to control the chemical features of the substrate before and during oviposition. They occur dispersed and also crowded in fields between mechanosensory exteroceptors sensitive to touch or wind (trichoid and filiform sensilla). The central nervous projections of the four chemosensory and one mechanosensory neurons from single basiconic sensilla were stained selectively, focusing on receptors on the ovipositor valves, which usually contact the substrate during the pre-oviposition probing movements. All axons and neurites from one contact chemoreceptor usually stay close together in most of their projections. Segregation occurs mainly when single axons terminate in one neuromere while the others proceed to a different neuromere or ganglion. For projections from one chemoreceptor, there is evidence neither for functional segregation of mechanosensory from chemosensory afferent terminals nor for specific segregation between different chemosensory afferents. The projections from sensilla of dorsal cuticle tend to project rather uniformly along the midline of the terminal ganglion. Comparative staining of touch- and wind-sensitive hair receptor neurons shows mostly central projections, similar to those of neighbouring contact chemoreceptors. From the typical intersegmental projections of most primary afferents and from the lack of segregation into glomerular structures, we conclude that integration of chemosensory information from the genital segments is distributed in the terminal and the 7th abdominal ganglion.     

The mechanism of sensory transduction in the sensilla of the trochanteral hair plate of the cockroach,Periplaneta americana

Summary The trochanteral hair plate of the cockroach leg contains approximately 60 hair sensilla that are deflected by a joint membrane during flexion of the leg. Previous work has shown that the organ is a mechanoreceptor which limits leg flexion during walking by reflex connections to flexor and extensor motoneurons. Functional analysis of the largest sensilla has shown that their behaviour may be well approximated by a velocity detector followed by a unidirectional rectifier.We report here the results of an examination of the largest sensilla by scanning and transmission electron microscopy in an attempt to correlate the structure with the known functional elements. Each hair is innervated by a single sensory dendrite which is surrounded by an electron dense dendritic sheath. The dendrite terminates below the hair shaft in a tubular body containing a parallel array of microtubules embedded in an electron dense matrix, while the dendritic sheath extends beyond the tubular body to form the walls of the ecdysial canal. At the proximal end of the tubular body the dendritic sheath and sensory dendrite are anchored to the cuticular socket by a fibrous dome which seems to form a fulcrum around which the tubular body can be deflected by movements of the hair. We suggest that the basis for the detection of velocity may be mechanical differentiation by a fluid space between the dendritic sheath and the tubular body. The structure is also discussed with relation to the mechanism of sensory transduction and the possible causes of the unidirectional sensitivity.Supported by the Canadian Medical Research Council. The authors gratefully acknowledge the expert technical assistance of Sita Prasad     

Neural projection patterns from homeotic tissue of Drosophila studied in bithorax mutants and mosaics.

The central projection patterns of sensory cells from the wing and haltere of Drosophila, as revealed by filling their axons with cobalt, consist of dorsal components arising from small campaniform sensilla and ventral components arising from large campaniform sensilla and from bristles. All of the bristles of the wing are innervated, some singly and some multiply. All three classes of sensilla are strongly represented on the wing, but the haltere carries primarily small campaniform sensilla and has a correspondingly minute ventral projection. In bithorax mutants in which the haltere is transformed into wing, ventral components are added to the projection pattern, while the dorsal components appear as if haltere tissue were still present. Thus, the three classes of receptors not only produce different projection patterns when they develop in their native mesothoracic segment, but also behave differently in the homeotic situation. Consequently, different developmental programs are inferred for each class. When somatic recombination clones of bithorax tissue are generated in phenotypically wild-type flies, they also produce ventral projections. However, these projections of mutant fibers into wild-type ganglia differ in certain details from the projections of mutant fibers into mutant ganglia. Thus, homeotic changes are inferred to occur in the CNS of mutant flies, but these are not required for the execution of those developmental instructions carried in the genome of large campaniform and bristle sensory cells which specify that their axons should grow ventrad in the CNS.     

Projection pattern of sensory neurons in the central nervous system of a homeotic mutation of the moth Manduca sexta

Octopod (Octo) is a mutation of the moth Manduca sexta, which transforms the first abdominal segment (A1) in the anterior direction. Mutant animals are characterized by the appearance of homeotic thoracic-like legs on A1. We exploited this mutation to determine what rules might be used in specifying the fates of sensory neurons located on the body surface of larval Manduca. Mechanical stimulation of homeotic leg sensilla did not cause reflexive movements of the homeotic legs, but elicited responses similar to those observed following stimulation of ventral A1 body wall hairs. Intracellular recordings demonstrated that several of the motoneurons in the A1 ganglion received inputs from the homeotic sensory hairs. The responses of these motoneurons to stimulation of homeotic sensilla resembled their responses to stimulation of ventral body wall sensilla. Cobalt fills revealed that the mutation transformed the segmental projection pattern of only the sensory neurons located on the ventral surface of A1, resulting in a greater number with intersegmental projection patterns typical of sensory neurons found on the thoracic body wall. Many of the sensory neurons on the homeotic legs had intersegmental projection patterns typical of abdominal sensory neurons: an anteriorly directed projection terminating in the third thoracic ganglion (T3). Once this projection reached T3, however, it mimicked the projections of the thoracic leg sensory neurons. These results demonstrate that the same rules are not used in the establishment of the intersegmental and leg-specific projection patterns. Segmental identity influences the intersegmental projection pattern of the sensory neurons of Manduca, whereas the leg-specific projections are consistent with a role for positional information in determining their pattern. © 1995 John Wiley & Sons, Inc.     

小菜蛾成虫下唇须感器的超微结构及其神经元中枢投射

【目的】明确小菜蛾Plutella xylostella成虫下唇须感器的形态结构及感器神经元的投射。【方法】利用光学显微镜观察和扫描电子显微镜观察下唇须结构和感器类型,利用神经回填技术和激光共聚焦显微镜观察下唇须感器神经元在脑部的投射。【结果】小菜蛾成虫下唇须共3节,其上存在Böhm氏鬃毛、钟形感器、鳞形感器、锥形感器、微毛形感器5种不同类型的感器和一个陷窝器结构。Böhm氏鬃毛短小尖细,钟形感器形如顶部凹陷的圆帽,两种感器均分布于下唇须第1节,且大小上均无雌雄二型差异;鳞形感器形同柳叶,锥形感器粗而直,均散生于下唇须的第2和3节,两种感器在大小上均存在雌雄二型差异,其中雌性的鳞形感器显著大于雄性的,根据其雌雄二型差异现象推测雌蛾的鳞形感器可能与感受寄主植物挥发物有关;下唇须第3节中上部具有一个圆形陷窝器结构,雄虫的陷窝器内径为5.68±0.33μm,雌虫的为6.03±0.23μm,雌雄间无显著性差异;凹坑内长有表面光滑的微毛形感器。小菜蛾下唇须感器神经元主要投射于脑部咽下神经节、每个触角叶的下唇须陷窝器神经纤维球和腹神经索3条通路。【结论】阐明了小菜蛾下唇须感器的类型、分布和形态特征及其感器神经元在脑部的投射形态,为深入了解小菜蛾下唇须感器的生理和功能奠定了基础。     

Projection pattern of poreplate sensory neurones in honey bee worker,Apis mellifera L. (Hymenoptera : Apidae)

The projections of olfactory receptor cells of the poreplate sensilla were studied in the worker honey bee, Apis mellifera L. (Hymenoptera : Apidae) by filling single sensilla iontophoretically with cobalt chloride. Successful fillings of individual sensilla lead to staining of one to 22 sensory neurones. All stained receptor cell axons are uniglomerular. Seven fillings of poreplates from the 5th flagellar segment in different animals were compared to analyse the distribution patterns of the receptor cell axons in the antennal lobe. The sensory neurones of individual poreplates project to widely distributed glomeruli in the antennal lobe. The projection patterns of different poreplates are not the same, but may be overlapping.