Sensilla on maxillary and labial palps in a helicophagous ground beetle larva (Coleoptera,Carabidae)

Sensilla on the labial and maxillary palp of Carabus lefebvrei Dejean, 1826 larvae were investigated using scanning and transmission electron microscopy. Two identical sets of sensilla were present on the tips of both palp pairs, and four morphological types of sensilla were identified: sensilla basiconica types 1 and 2, sensilla coeloconica and sensilla digitiformia. Ultrastructure indicates that the sensilla basiconica type 1 and coeloconica have a chemical role as gustatory and olfactory receptors, respectively, while sensilla basiconica type 2 are mechanoreceptors and the sensilla digitiformia are probably thermo‐ and hygroreceptors. Their function is discussed in relation to specialized prey detection and habitat adaptations.     

山茱萸蛀果蛾幼虫触角和口器感器的超微形态

【目的】探索寄主范围不同的蛀果蛾科(Carposinidae)幼虫感器之间是否存在差异。【方法】采用扫描电子显微镜观察了为害山茱萸Cornus officinalis Sieb. et Zucc.的单食性蛀果害虫--山茱萸蛀果蛾Carposina coreana Kim老熟幼虫触角和口器感器的超微形态。【结果】山茱萸蛀果蛾幼虫触角柄节未见感器分布, 梗节上有2个刺形感器和3个锥形感器, 鞭节上有1个栓锥感器和3个锥形感器。口器上共有6种感器： 刺形感器数量多, 分布广; 栓锥感器主要分布在颚叶、 下颚须和下唇须上; 指形感器位于内唇和下颚须端节侧缘; 锥形感器和板形感器仅存在于下颚上; 内唇感器为内唇所特有。【结论】蛀果蛾幼虫触角和口器的感器与寄主范围之间未发现严格的对应关系。     

The maxillary palp of Drosophila : ultrastructure and physiology depends on the lozenge gene

The ultrastructure and physiology of the maxillary palp of Drosophila melanogaster have been studied in wild-type and lozenge mutants. Olfactory physiology in the maxillary palp is shown to depend upon the lozenge(lz) gene. Reduced response amplitudes were recorded for all odorants tested, and the physiological defect was shown to map to the lz locus. The structure of the maxillary palp sensilla is described by scanning electron microscopy (SEM) at high magnification, initially in the wild-type. A linear arrangement of pores, connected by furrows, was found in one class of sensilla, the basiconic sensilla. In the lz ³ mutant, morphological alterations in the basiconic sensilla and duplications of sensilla are documented by SEM. The correlation of structural abnormalities in the lz sensilla and physiological abnormalities in odorant response are consistent with an olfactory role for the basiconic sensilla of the maxillary palp. Accepted: 10 September 1996     

External morphology and abundance of mouthpart sensilla in Australian Gryllacrididae,Stenopelmatidae, and Tettigoniidae

Sensilla diversity and abundance were extremely high on the apex of the maxillary and labial palpi of two species of Gryllacrididae. The terminal segment of the maxillary palpi of these species had 9 and 15 sensilla types, respectively, and up to 2,834 sensilla. The labial palpi had 7 and 12 types, respectively, and up to 5,195 sensilla. Several types of multiporous smooth and ridged olfactory basiconic sensilla, and coeloconic, coelosphaeric, placoid, and multipapilliform sensilla occurred, as well as many trichoid sensilla and the more typical uniporous basiconic contact receptors. Two species of the closely related Stenopelmatidae were compared to the gryllacridids and found to have similar sensillar diversity and abundance, but three species of the more distantly related Tettigoniidae had only 4 or 5 sensilla types and a total number ranging from 320 to 960 on their maxillary palpi.     

Comparative external ultrastructure and diffusion pathways in styloconic sensilla on the maxillary galea of larval Mamestra configurata (Walker) (Lepidoptera: Noctuidae) and five other species

The external ultrastructure of sensilla on the maxillary galea are investigated in Mamestra configurata and five other lepidopterous larvae using scanning electron microscopy. The galea and lacinia, comprising the mesal lobe of the maxilla, are either completely separate, fused, or incompletely fused in these species. The distal surface of the mesal lobe of all species examined bears two styloconic sensilla, three basiconic sensilla, and three trichoid sensilla, whereas the midventral wall of this lobe bears a campaniform sensillum. The latter sensillum is visible in only three of the six species examined. The styloconic and basiconic sensilla occupy a ventro anterior location, whereas the trichoid sensilla are positioned dorsoposteriorly. Interspecific comparisons of galeal size, as well as sensillar size, shape, and position are made for all species. The styloconic sensilla are the only sensillar type permeable to an aqueous solution of cobalt chloride when viewed by brightfield light microscopy in all species examined. Cobalt ions permeate through the terminal pore of each styloconic peg and percolate through the fenestrated fibrillar pore matrix, located directly below the pore. These ions permeate along the dendritic channel and accumulate in the adjacent sensillar sinus surrounding the peg and/or style by way of a presumably permeable dendritic sheath in all species, but to varying extents. The cuticular sidewall pores surrounding the terminal pore also appear to be permeable to cobalt ions in all the species examined. In most species examined, the styloconic sensilla are only minimally permeable to mercury ions. In these species, mercury ions permeate through the terminal pore, but become trapped within the plug of fenestrated fibrils within it. The sidewall pores are not permeable to mercury ions in any of the species examined. The styloconic sensilla are not permeable to lead ions in M. configurata or Malacosoma lutescens, the only species tested. © 1996 Wiley-Liss, Inc.     

七星瓢虫唇须感器分布和统计特征的雌雄差异

应用扫描电镜观察七星瓢虫Coccinella septempunctata的唇须和附节,以便确认在感应农药残留时起主要作用的化学感受器。研究证明分布在下颚须上的感器类型包括两种锥形感器（兼有机械感受器和化学感受器的功能）和一种钟形感器。同时本文首次报道了对这些感器精确的形态测量,明确了其性二型性。对下颚须的测量表明其左右末节的长度差异与七星瓢虫的性别之间有明显的相关性。文中还记述了下唇须上一种新的钟形感器,其在每个下唇须上的数量大约为12～17个。经测量这些机械感受器的平均直径为2.4 μm。早期研究中所记述的锥形感器被证实是下唇须上仅有的化学感应器,并且首次证明这些锥形感器的数量与性别相关,雄性平均为18个,雌性平均为16个。附节上也存在性别差异： 第2跗节跗垫的宽度在雄性中是从后向前逐渐增大,而在雌性中刚好相反。本文还就这些差异的意义以及新发现感器的功能进行了讨论。     

Comparative morphology of sensilla on antenna,maxillary palp and labial palp of larvae of white‐spotted and yellow‐spotted Asian long‐horned beetle,Anoplophora glabripennis Motschulsky (Coleoptera: Cerambycidae)

The Asian long‐horned beetle (ALB) is one of the most important wood‐boring insects worldwide that damages broad‐leaved trees, primarily poplar, willow, elm and maple. Based on the color of the spots on the elytra, the beetles are separated into white‐spotted (ALB‐W) and yellow‐spotted (ALB‐Y) Asian long‐horned beetles. In order to clarify the morphology of sensilla on antenna, maxillary palp and labial palp of ALB‐W and ALB‐Y larvae, we studied the typology, morphology, number and distribution of the sensilla by scanning electron microscopy. The results showed that: (i) the antennae of two biotypes had five types of sensilla, including three types of sensilla basiconica (b.) and two types of sensilla twig basiconica (s.tb); numbers of b.1, b.2, b.3 and s.tb1 on antenna were not significantly different (P > 0.05) between two biotypes, and the numbers of s.tb2 were significantly different (P < 0.05); (ii) the maxillary palp of two biotypes had four types of sensilla, including sensilla styloconica (st.), two types of s.tb and digitiform sensilla (ds.); the numbers of st. and ds. on the maxillary palp were not significantly different (P > 0.05) between two biotypes, and the numbers of s.tb1 and s.tb2 were significantly different (P < 0.05); (iii) the labial palp of two biotypes had four types of sensilla, including b., st. and two types of s.tb, and the numbers of b.3, st., s.tb1 and s.tb2 on the labial palp were not significantly different (P > 0.05) between two biotypes. We discuss the relationships between sensilla and damage caused by the larvae inside the host trees.     

Functional anatomy of sensory structures on the antennae of Psylliodes chrysocephala L. (Coleoptera: Chrysomelidae)

The ultrastructure and distribution of sensilla on the antennae of the cabbage stem flea beetle, Psylliodes chrysocephala, were investigated using scanning and transmission electron microscopy techniques. Eight different sensillar types were distinguished. These were; hair plate sensilla, sensilla chaetica, three types of sensilla trichodea, sensilla basiconica, grooved peg sensilla and styloconic sensilla. The sensilla chaetica are known to be gustatory receptors. Ultrastructure indicates that the hair plate sensilla and sensilla trichodea type one are probably mechanoreceptors, whilst the sensilla styloconica are probably thermo-hygro receptors. These thermo-hygroreceptors are unusual in that they are innervated by two sensory cells (one hygroreceptor and one thermoreceptor) rather than the more usual triad. The remaining four sensillar types all have a porous hair shaft, indicating an olfactory role. One of these (the grooved peg sensillum) may also have a thermoreceptive function. No sexual dimorphism was found in the structure, number or distribution of the antennal sensilla.     

The fine structure of the antennal sensilla of the pine saw flyNeodiprion sertifer (Insecta: Hymenoptera)

Summary There is a considerable sexual dimorphism as regards the development of the antenna inNeodiprion sertifer. In the male this is manifested in a larger antennal surface area and the possession of a great number of long single-walled sensilla (SW 1), which are located on the antennal branches. In the female the antennal branches are vestigial, and the single-walled sensilla, of a second type (SW 2), are shorter and present in lower numbers. Both sexes have in addition four types of sensilla in common:viz. a third type of single-walled sensilla (SW 3), terminal pore sensilla, double-walled sensilla, and poreless sensilla. These four sensillar types are characterized not only by their external appearance but also by their internal morphology. Especially the cells enveloping the sensory cells vary in number and appearance.Supported by joint grants from the Swedish Council for Planning and Coordination of Research, the Swedish Natural Science Research Council, and the Swedish Council for Forestry and Agricultural Research.     

Fine structure of maxillary sensilla of larval Toxorhynchites brevipalpis (Diptera: Culicidae) with comments on the role of sensilla in behavior

Each maxilla of fourth instar Toxorhynchites brevipalpis bears nine sensilla: Four are located at the tip of the maxillary palp and five on the maxillary body. At the palp tip are three tapered pegs on bulbous bases (MS₁, MS₂, MS₆) that are innervated by four, two, and two neurons, respectively, and probably function in chemoreception. Also at the palp tip is a sturdy, cuticular rod with a lumen (MS₅) that opens distally to the exterior. The proximal end of the rod is closed by a cuticular base to which a single unbranched dendrite containing only a few microtubules is attached. The function of MS₅ is enigmatic; possibilities include mechanoreception and detection of infrared radiation. On the maxillary body are two tapered pegs on a common bulbous base (GS₁, GS₂) that are each innervated by three neurons, and probably are chemosensory. Three setae also occur on the maxillary body. They arise from prominent sockets and are each innervated by a neuron terminating at the hair base as a tubular body, a characteristic of cuticular mechanosensilla. The maxillary sensilla are innervated by a total of 18 neurons: 14 are probably chemosensory, three mechanosensory, and one is of unknown function. These results, combined with those from a previous study on antennal sensilla (Jez and McIver, '80), indicate that the mechanosensitive neurons of the antennae and maxillae are a relatively small percentage of the total mechanosensilla on the entire larva. In contrast the chemosensitive neurons of the antennae and maxillae provide most of the information about the chemical environment of the larva. T. brevipalpis has three less than the maximum of seven maxillary palpal sensilla found in larval mosquitoes so far studied. This difference may reflect a lesser need for sensory information about the acceptability of potential food in predators compared to browsers and filter-feeders.     

Fine structure and functional morphology of the mouthparts of Bittacus planus and Terrobittacus implicatus (Insecta: Mecoptera: Bittacidae)

The Bittacidae are unique in Mecoptera for their adults being predaceous. However, their mouthparts have not been well documented for functional morphology to date. Here, we investigated the mouthpart morphology of the hangingflies Bittacus planus Cheng and Terrobittacus implicatus (Huang & Hua) using scanning electron microscopy. The mouthparts are of the mandibulate type and situated at the tip of an elongated rostrum. The labrum is greatly elongated, roughly twice as long as the subquadrate clypeus. The epipharynx is furnished with a row of basiconic sensilla arranged evenly as a median band extending from the apex to the base. The mandibles are slender and elongated, bearing a sharp lateral and a small mesal tooth. The maxillae are well developed, each consisting of a partially sclerotized cardo and a stipes, a hirsute galea and a lacinia, and a five-segmented maxillary palp. The sensillar pattern on the distal segment of the maxillary palp differs slightly between the two bittacid species. The labium is composed of a postmentum, a prementum, and a pair of two-segmented labial palps. The feeding mechanism of bittacids is briefly discussed in combination with the mouthpart morphology and their feeding habits.     

Antennal sensilla on cave species of Australian Paratemnopteryx cockroaches (Blattaria : Blattellidae)

The external morphology and distribution of antennal sensilla of cave-dwelling Australian cockroaches, Paratemnopteryx stonei (Races B and C), P. howarthi and P. sp. nov. (Blattaria : Blattellidae), are described using scanning electron microscopy. Eight major types of sensilla were found. Long and medium-length sensilla chaetica are deeply grooved mechano and contact chemo-receptors with a terminal pore; the long type forms 5–11% and the medium-length 7–22% of all sensilla. Sensilla trichodea type 1 are very slender, non-porous, and form 43–60% of all sensilla. Sensilla trichodea type 2 are stouter, shorter and have wall pores; they form 5–14% of the sensilla. Sensilla basiconica type B are very short, non-porous, inflexible-socket receptors that are known to be hygro- and thermo-receptors; they comprise less than 0.6% of the sensilla. Sensilla basiconica type Gl are short, grooved and have a terminal pore; they form 5–11% of all sensilla. Type G2 are longer with indications of a terminal pore and form 7–10% of the sensilla. Sensilla basiconica type P are short with wall pores, and they form 3–9% of the sensilla. Total sensillar numbers ranged from 5700–8900 for P. stonei, depending on the race and sex, 6950–9950 for P. sp. nov. and 11,700-15,100 for the smaller and possibly more epigean-related P. howarthi. Females had 700–3150 fewer sensilla than males. Comparisons are made between Paratemnopteryx and common epigean cockroaches in relation to sensillar types and numbers.     

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.     

Sexual dimorphism of adult labial palps of the peach fruit moth Carposina sasakii Matsumura (Lepidoptera: Carposinidae) with notes on their sensilla

The labial palps and their sensilla of the peach fruit moth Carposina sasakii Matsumura, a serious pest of pome fruits in eastern Asia, were investigated using light microscopy and scanning and transmission electron microscopy. The labial palps are three‐segmented and exhibit distinct sexual dimorphism in length: much longer in the female than in the male. Four types of sensilla were found on the labial palps: campaniform, squamiform, chaetic and flattened sensilla. The campaniform sensilla are present on the first segment alone. The squamiform sensilla are located on all the three segments. The chaetic sensilla are mainly present on the third segment. The flattened sensilla are grooved with wall pores and situated in a labial palp‐pit organ, which is located at the apex of the distal segment of the labial palp. The sexual dimorphism of the labial palp and the labial palp‐pit organ was briefly discussed.     

黑胸大蠊下颚须和下唇须上感器扫描电镜观察

利用扫描电子显微镜观察了黑胸大蠊Periplanetafuliginosa(Serville)成虫下颚须和下唇须上的感器形态。结果发现,在黑胸大蠊下颚须和下庸须末节顶端何感器密集区,尤其是下颚须第5节内侧顶端,有一狭长沟壑,内有大量的带槽锥形感器。通过重点观察感器密集区,发现主要有5~6种类型感器,分别为带槽锥形、毛形、刺形、钟形、齿状、针形感器,其中有些感器又可分为几种亚类型。比较研究发现下颚须和下唇须上感器类型除了带槽锥形感器以外基本相似,只是数量上有区别。     

桑天牛头部附器感器的扫描电镜观察

利用扫描电镜观测桑天牛Apriona germari(Hope)成虫的触角、下颚须和下唇须上感器的分布及超微结构。结果表明,雌、雄桑天牛触角上共存在6种感器,即毛形感器、锥形感器、刺形感器、芽形感器、鳞形感器和棒形感器,其中锥形感器分5种亚型,刺形感器分2种亚型,且部分感器在雌雄成虫触角上的分布模式及数量存在差异,如棒形感器及角锥形感器丛模式仅在雄虫触角上发现,而雌虫触角上的细锥形感器和耳锥形感器多于雄虫,芽形感器少于雄虫;下颚须和下唇须存在5种感器,即毛形感器、刺形感器、末梢锥形感器、钟形感器和隙缝感器,各种感器在雌、雄天牛下颚须和下唇须上的分布和数量无明显的区别。     

Sensory structures involved in prey detection on the labial palp of the ant‐hunting beetle Siagona europaea Dejean 1826 (Coleoptera,Carabidae)

Giglio, A., Ferrero E.A., Perrotta, E., Talarico, F.F. and Zetto Brandmayr, T. 2010. Sensory structures involved in prey detection on the labial palp of the ant‐hunting beetle Siagona europaea Dejean 1826 (Coleoptera, Carabidae). —Acta Zoologica (Stockholm) 91 : 328–334 The ultrastructure and distribution of sensilla on the labial palps of a myrmecophagous carabid beetle, Siagona europaea, were investigated using scanning and transmission electron microscopy techniques. Five types of sensilla were identified: three types of sensilla basiconica on the apical sensory area and two types, one sensillum trichodeum and one coeloconicum, on the external palp surface. On morphological grounds, the s. basiconica type 1 were considered as olfactory, the type 2 as gustatory, the type 3 and the s. trichodeum as mechanoreceptive, and the s. coeloconicum as a thermo/hygroreceptor. Their function is discussed in relation to prey detection and habitat adaptations.     

Fine structure and distribution of antennal sensilla of the desert locust, Schistocerca gregaria (Orthoptera: Acrididae)

The fine structure and distribution of various types of antennal sensilla in three nymphal stages and in adults of both solitary-reared (solitary) and crowd-reared (gregarious) phases of the desert locust, Schistocerca gregaria, were investigated by scanning and transmission electron microscopy. Four types of sensilla were identified: sensilla basiconica, s. trichodea, s. coeloconica and s. chaetica. S. basiconica contain up to 50 sensory neurons, each of which displays massive dendritic branching. The sensillar wall is penetrated by a large number of pores. In contrast, s. trichodea contain one to three sensory neurons that branch to give five or six dendrites in the sensillar lumen; the sensillum wall is penetrated by relatively few pores. The s. coeloconica are situated in spherical cuticular pits on the antennal surface. The s. coeloconica are of two types: one type contains one to three sensory neurons with double sensillar walls penetrated by slit-like pores, whereas the second type contains four sensory neurons with non-porous double sensillar walls. The s. chaetica have a flexible socket and a thick non-porous sensillum wall and contain four sensory neurons that send unbranched dendrites to a terminal pore. A fifth sensory neuron of the s. chaetica terminates in a tubular body at the base of the hair. S. basiconica and coeloconica are normally distributed over the entire antennal flagellum, with a concentration in the middle segments; s. trichodea have three areas of concentration on the 5th, 10th and 14th flagellar segments. Sensilla chaetica are most abundant on the terminal segment. Locusts raised in solitary conditions have more olfactory sensilla (s. basiconica and s. coeloconica) than crowd-reared locusts. The difference in sensillar numbers is more evident in adults than in nymphs. These results suggest that differences in the odour-mediated behaviour of nymphs and adults, and between the phases of S. gregaria, may be attributable to differences at the sensory input level.     

灰茶尺蠖成虫触角及幼虫头部感器超微结构

【目的】明确灰茶尺蠖Ectropis grisescens成虫触角及幼虫头部感器的种类、形态、数量和分布,以探讨灰茶尺蠖的行为机制。【方法】利用扫描电镜技术观察灰茶尺蠖雌、雄成虫触角和5龄幼虫头部感器的超微结构。【结果】灰茶尺蠖成虫触角上分布有8种感器,分别是栓锥形感器、耳形感器、毛形感器(Ⅰ-Ⅳ)、B?hm氏鬃毛、腔锥形感器(Ⅰ和Ⅱ)、鳞形感器、锥形感器(Ⅰ和Ⅱ)和刺形感器。其中,栓锥形感器仅分布在雌蛾触角上,耳形感器、毛形感器(STⅠ-Ⅲ)仅分布在雄虫触角上。5龄幼虫触角上着生1个栓锥形感器、1个锥形感器和2个刺形感器;上唇着生有6对刺形感器,内唇着生有3对刺形感器和1对指形感器;上颚基部外侧着生有2个刺形感器;下颚及下颚须着生有5个刺形感器、9个锥形感器和2个栓锥形感器;下唇须着生有1个锥形感器和1个刺形感器;吐丝器前端着生有1对刺形感器。【结论】灰茶尺蠖雌、雄成虫触角感器存在性二型性,且雄虫上感器种类和数量较多,据此推测雄虫感受寄主植物或性信息素的能力较强;幼虫头部感器具有嗅觉和味觉功能,在其判断食物的种类和适应性等生态行为中发挥重要作用。     

Sensory organs inIps typographus (Insecta: Coleoptera) — Fine structure of antennal sensilla

Summary The antennal sensilla inI. typographus are almost exclusively confined to the flattened terminal flagellar segment. The sensillar types have distinct distribution patterns in the three areas where they are found. Judging from the ultrastructural characteristics the following functions can be assigned to the sensillar types: chemoreception, single-walled and double-walled sensilla; chemoreception/mechanoreception, terminal-pore sensillum. Moreover there are two types of mechanoreceptors, one of which is connected to a bristle, whereas the other terminates within the cuticle of the flagellar segment.This study was made within the Swedish project Odour Signals for Control of Pest Insects.