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.     

Ultrastructural Analysis of the Sensilla of Austroperipatus aequabilis Reid, 1996 (Onychophora,Peripatopsidae)

The head of Austroperipatus aequabilis bears five types of sensilla. which were examined by electron microscopy. They differ from each other in position, shape of outer sensory elements and cuticular socket structures. Thus, we distinguish sensilla with sensory hairs, sensilla with sensory bulbs, cone-shaped sensilla. sensilla with sensory bristles, and sensilla of the lips. They are composed of up to 15 cells, which can he separated into four cell types. The most frequent cell type is the bipolar receptor cell that occurs in all sensilla. The apical surface of this primary receptor cell is characterized by one or two partly branched cilia with a basal 9 × 2 + 0 pattern of microtubules. A modified bipolar receptor cell was found in all sensilla bearing a sensory peg except for the sensilla equipped with sensory bristles. The apical dendrite extends to a long pale process which exclusively contains mitochondria and single microtubules. In all sensilla examined in this study at least one supporting cell occurs which is characterized by parallel microvilli. An additional function of this cell type as a part of the stimulus-conducting system is possible. In the sensillum with a sensory bulb two kinds of supporting cells occur. A unique cell type with an upside down position has regularly been found in all sensilla bearing a sensory peg. Apart from the sensilla they also occur within the labial epidermis. Since most sensilla contain several different receptor cells, they can be considered as complex sense organs. © 1998 The Royal Swedish Academy of Sciences. Published by Elsevier Science Ltd. All rights reserved     

Adaptation of sensory systems of gamasid mites (Parasitiformes, Gamasina) to dwelling in different environment

The main complication sensory organs (the palpal organ and the tarsal sensory complex) of several species of gamasid mites were studied in scanning electron microscope. The species examined included permanent ectoparasites (Laelaps agilis, Laelaptidae), parasites of the nasal cavity and respiratory tract of birds (Sternostoma tracheocolum and Ptilonyssus reguli, Rhinonyssidae), dwellers of the sea littoral zone (Parasitus kempersi, Parasitus immanis, Parasitidae), and mites found on soil and on plants (Amblyseius barkeri, Parasitidae). Similar sensillar types, including olfactory SW-WP sensilla, contact chemo-mechanosensory (SW-UP and DW-UP) sensilla, termo-chemo-mechanosensitive (DW-WP) sensilla of two types, and tactile (NP) sensilla were found in all these species, excluding endoparasites, where some sensillar types (in particular, DW-WP sensilla with slit-like pores) are absent. It was shown that the topography of olfactory SW-WP sensilla of the tarsal complex reflects taxonomic position and phylogenetic history of mite genera, whereas the number of certain sensillar types and the degree of their development reflect ecological specialization of species. The palpal organ is characterized by rather uniform structure in mites of different families, dwellers of different environments, except for the endoparasites of the family Rhinonyssidae, where this organ is strongly reduced.     

疟疾媒介中华按蚊触角感器的扫描电镜观察

【目的】明确中华按蚊Anopheles sinensis雌成虫与幼虫触角感器的类型、形态和分布。【方法】利用光学显微镜观察中华按蚊成虫与幼虫触角的形态结构,利用扫描电镜观察触角上的感器类型、形态和分布。【结果】中华按蚊雌成虫触角由柄节、梗节和鞭节组成,鞭节有13个亚节。触角上共发现4种类型的感器,分别为毛形感器(锐型和钝型)、刺形感器(大型和小型)、锥形感器(Ⅰ型和Ⅱ型)和腔锥形感器(大型和小型)。雌成虫触角各类感器总计约1 135.67±86.75个,其中毛形感器数量最多(662.00±6.22个),随后是刺形感器(294.67±33.35个)和锥形感器(146.00±42.39个),腔锥形感器数量最少(36.50±5.90个)。毛形感器、刺形感器和锥形感器在鞭节的每个亚节均有分布,而大型腔锥形感器在第9-11亚节没有分布,小型腔锥形感器仅分布于第13节的顶端。幼虫触角的鞭节不分亚节,呈管状,触角末端有一个感觉锥,鞭节上分布有与成虫锥形感器相似的锥形凸起,初步定名为类锥形感器,其数量和大小随幼虫龄期的增长而显著增加,锥体表面的凹槽越来越明显,其功能还需要通过超微结构和电生理等研究进一步确定。【结论】本研究对中华按蚊幼虫和雌成虫触角感器的形态特征、类型、数量及其分布进行了观察和分析,结果为进一步研究中华按蚊感器的生理功能奠定了基础。     

红火蚁触角及其上感受器的扫描电镜观察

应用扫描电镜对采自我国广东吴川和广西南宁的红火蚁Solenopsis invicta Buren工蚁、有翅雌蚁和雄蚁触角的形态和感受器类型进行了研究。结果表明,工蚁、雌蚁和雄蚁的触角存在着较大的差异。工蚁和雌蚁的触角为膝状,末端2或3节膨大为棒状,雌蚁的触角11节,比工蚁(10节)的多1节。雄蚁的触角为线状,12节,末端没有棒状结构。工蚁和雌蚁的触角上共有7种感受器,分别为毛形、曲毛形、锥形、腔锥形、坛形、刺形感受器和Böhm氏鬃毛,前6种感受器大多集中在触角末端的棒节,棒节以外的各鞭节上主要是毛形感受器,Böhm氏鬃毛则分布于柄节和梗节的基部,鞭节上无此感受器。雄蚁触角上也有7种感受器,但其分布与工蚁的有较大差异,Böhm氏鬃毛的分布与工蚁和雌蚁的相同,锥形感受器分布在末端2节,坛形感受器分布在末端3节,其余的4种感受器较为均匀地分布在各鞭节,而不是聚集在端节。另外,新发现雄蚁中存在一种与已知的毛型感受器不同的超短毛状感受器,定名为超短毛感受器。最后,对红火蚁的触角及感受器在蚁群社会性行为中的作用进行了讨论。     

Relationship between structure and function of antennal chemo-, hygro-, and thermoreceptive sensilla in Periplaneta americana

Summary On the antennae of Periplaneta americana, 25 chemo-, hygro- or thermosensitive sensilla were investigated electrophysiologically and, after marking, by transmission and scanning electron microscopy. A clear-cut relationship of functional types to structural types was observed. Two different stimulus conducting structures were observed: a) pore tubules which are found only in smooth, single-walled sensory pegs and b) secretion-filled canals which occur only in grooved double-walled sensilla. Temperature and humidity-sensitive receptors occur only in double-walled sensilla with secretion material as the stimulus conducting system. Olfactory sensory cells were found in both types, however, those with a specific sensitivity for short-chain n-alcohols are restricted to single-walled pegs with pore tubules, while those which are most sensitive to short-chain n-acids and amines are found in double-walled sensilla, sometimes together with thermosensitive units. The stimulus conducting systems may control the access of odorous substances to the dendritic membranes and thus contribute to the discriminatory properties of the sensilla.Supported by the Deutsehe Forschungsgemeinschaft (Al 56/6)     

Cuticular sensory receptors on the antenna and maxillary palp of a fly larva, Nephrotoma suturalis (Diptera: Tipulidae)

Abstract. The apex of the larval antenna of the crane fly Nephrotoma suturalis has 6 cuticular sensilla that stained intensely black with silver nitrate, which indicates their porosity. The large sensory cone is innervated by 14 neurons and the 3 small, smooth surfaced, conical pegs have 4 neurons each. The small and large cylindrical sensilla with their smooth walls and pleated apices are innervated by 4 and 6 nerve cells, respectively. The 15 sensilla on the apex of the maxillary palp are all stained by silver nitrate. These sensilla are of five types: 7 type A sensilla with a smooth surface, a distinct apical pore, and 3 or 4 neurons; 2 type B sensilla with a smooth surface, many pores, and 5 neurons; 1 type C sensillum with a grooved surface, a large apical pore, smaller pores in the grooves, and 6 neurons; 3 type D sensilla with a smooth surface, a grooved apex that is elongated into a projection, and 4 neurons; 2 type E sensilla with many pores covering the surface, leaf-like appearance, and 4 neurons. The number and types of sensilla are similar to those in other nematocerous larvae, but in the many different forms of sensilla and the structure of the sensory cone, these tipulid larvae differ greatly from other larvae of lower Diptera.     

Antennal sensillar equipment in closely related predatory wasp species (Hymenoptera: Philanthinae) hunting for different prey types

Despite its potential value in phylogenetic and ecological studies, the morphology of antennal sensilla has rarely been compared quantitatively within the Apoidea. Here, through a scanning electron microscopy analysis, we provide an inventory of different types of antennal sensilla and compare their morphology across 10 species of predatory wasps (Crabronidae: Philanthinae) including species that hunt exclusively either on beetles or on bees to feed their larvae. A sensilla-free area was found on the apical flagellomer of all but two species, and its shape and size appear to be useful for separating Philanthini from Cercerini within the subfamily. A total of eight types of sensilla (sensilla placoidea, sensilla basiconica, two types of pit organs, sensilla coelocapitula and three types of sensilla trichoidea) were found in all species, and an additional rarer type (grooved peg sensilla) was found only in three bee-hunting species and for first time in the genus Cerceris. Certain morphological features confirmed the separation of the apoid wasps from the rest of the Apoidea (i.e., bees). A cluster analysis based on the sizes of the different types of sensilla suggested that, overall, sensilla morphology is not a useful taxonomic tool, and thus, other factors likely determine interspecific variability. One candidate factor is the prey type, given some differences in the presence, density, size and distribution of certain types of olfactory sensilla between beetle-hunters and bee-hunters. This hypothesis needs to be further tested quantitatively using a larger species set, more individuals per species, additional sensilla features, and a correction for phylogeny.     

Sensilla on antenna,ovipositor and leg of Eriborus applicitus (Hymenoptera: Ichneumonidae), a parasitoid wasp of Holcocerus insularis staudinger (Lepidoptera: Cossidae)

Eriborus applititus Sheng & Sun (Hymenoptera: Ichneumonidae) is a specialist parasitoid of the small carpenter moth Holcocerus insularis Staudinger (Lepidoptera: Cossidae). Each year damages to trees caused by H. insularis lead to extensive economic and ecological losses. E. applititus is thus a promising candidate for use as a biocontrol agent against H. insularis. To investigate the means by which E. applititus locates and parasitizes H. insularis, we used scanning electron microscopy to determine the morphology and distribution of sensilla on antenna, ovipositor and leg of male and female E. applititus. Eight different sensilla types were found: sensilla chaetica, sensilla trichodea, sensilla placodea, sensilla basiconica, sensilla coeloconica, sensilla pit basiconica, sensilla campaniformia and Böhm's bristles. The sensilla types were differently distributed in the three organs. In addition, differences between sexes were found in the distribution of sensilla trichodea type 2, sensilla placodea and sensilla chaetica type 4. Putative functions of the sensilla are discussed based on the morphological and location data and on previous research. Chemosensitive sensilla are putatively involved in host detection, pheromone detection and host discrimination processes. Mechanoreceptive sensilla likely function as vibrational sensors and are thought to be critical for accurate ovipositor positioning.     

Ultrastructure and Comparative Morphology of Mouth-part Sensilla in Ground Beetle Larvae (Insecta, Coleoptera, Carabidae)

Labial and maxillary palps in 22 species of ground beetle larvae revealed the presence of four different types of sensilla: sensilla digitiformia, sensilla campaniformia, sensilla basiconica and sensilla chaetica. Using transmission electron microscopy techniques, the role of most of them was defined: sensilla campaniformia and sensilla chaetica are mechanoreceptors; while sensilla basiconica are chemoreceptors. Sensilla digitiformia can be both mechanoreceptors and chemoreceptors, though hygroreception may also be postulated on the basis of their abundance on the mouthparts of some hygrophilous species that depend on damp or wet patchy biotopes/seasons. The number and location of the sensory structures has been found to vary among the investigated taxa. The differences are related to the larval behavioural types, and are an adaptive response to different lifestyles, feeding habits and use of space.     

Sensilla on the antennal funiculus of the horse stomach bot fly, Gasterophilus nigricornis

Gasterophilus nigricornis (Loew) (Diptera: Oestridae) is one of the most damaging obligate parasites of equids in Kalamaili, Xinjiang, China. The main olfactory organs of this stomach bot fly are paired antennae that bear microscopic sensillar structures. The external morphology of the antennal funiculus and sensilla of male G. nigricornis were studied using stereopic microscopy and scanning electron microscopy. A cross-sectional view of the funiculus shows it to be triangular, with an anterodorsal surface, a dorsolateral margin and a posteroventral surface. Almost the entire surface of the funiculus is densely covered with microtrichiae. Small patches lacking these microtrichiae appear as depressions or pits in the surface of the funiculus. Six distinct types of sensilla are recorded, including one trichoid, three basiconic, one auriculate and one clavate sensilla. Trichoid sensilla are the most abundant, followed by the basiconic, auriculate and clavate types in descending order. Only auriculate sensilla are found in pits on the funiculus. Distributions of different sensilla types located on the antennal funiculus are provided. These results are compared with equivalent findings in several other fly species. In addition, the possible functions of the various sensilla types are discussed.     

Antennal sensilla of male and female of the nut weevil,Curculio nucum Linnaeus, 1758 (Coleoptera: Curculionidae)

The nut weevil, Curculio nucum (Linnaeus, 1758), is the main pest in hazelnut orchards (Corylus avellana L.). Semiochemicals are interesting bio control tools that could be used to manipulate the pest behaviour and to control pest populations. The study of the sensorial equipment of the insect antennae provides information on the importance of olfaction in the adult life for host plants and mate findings as well as on the putative other senses. Before electrophysiological investigation, the knowledge of antennae equipment is also necessary. The aim of this study is to determine the types, number and location of sensilla on the antennae of male and female adult C. nucum in order to determine their implication in seeking a sexual partner and a host plant. The 12-segmented antenna comprises a scape, a 7-segmented funicle and a 4-segmented club. Out of the nine sensillum types listed, three are present on the scape and the funicle and seven types on the club which gathers 71–73% of the total of sensilla. Tactile aporous sensilla chaetica C1, gustatory uniporous sensilla chaetica C2, olfactory multiporous sensilla basiconica B1 and B2 are found on both the dorsal and ventral surfaces of the club in both sexes. Thermo-hygroreceptive dome-shaped sensilla D, olfactory multiporous sensilla basiconica B3 and olfactory multiporous fluted sensilla basiconica F are found exclusively on the ventral surface of the club, suggesting that these sensilla are utilized in host plant acceptance during antennal tapping. The sexual dimorphism concerns only the numbers of sensilla chaetica C1 and sensilla basiconica B2.     

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.     

Sensillary morphology on the rostral apex and their possible role in prey location behaviour of the carnivorous stinkbug,Eocanthecona furcellata (Wolff) (Heteroptera: Pentatomidae)

Eocanthecona furcellata (Wolff), the carnivorous heteropteran, demonstrates interesting feeding mechanisms that suggest the involvement of the antennal and labial tip sensilla. This study was conducted to identify the morphology of various sensilla present on the labial tip of this insect using scanning electron microscopy. Four morphologically different types of trichoid sensilla comprise the largest and most numerous sensilla and occur throughout the surface of the labial tip. Three new and unique types of sensilla were discovered. Long hairs with profusely branched shafts are present at the entrance of the rostral groove. An oval‐shaped peg surrounded by sensory hairs with branched shafts and a short, stout peg encircled by a group of long hair‐like sensilla was found among the sensilla population of two lobes. The morphology of the new sensilla is given and possible functions of individual receptors are suggested on morphological grounds.     

豆柄瘤蚜茧蜂触角感受器的扫描电镜观察(英文)

利用扫描电镜对豆柄瘤蚜茧蜂Lysiphlebus fabarum的触角感受器进行了观察, 发现有7 种感受器, 分别为毛形感受器、刺形感受器Ⅰ型、刺形感受器Ⅱ型、锥形感受器、腔锥形感受器Ⅰ型、腔锥形感受器Ⅱ型和板形感受器。毛形感受器是数量最多的感器; 除了腔锥形感受器Ⅱ型只在雌虫触角发现外, 雌、雄触角感受器的类型和结构没有较大的差别, 并且腔锥形感受器Ⅱ是数量最少的感器。     

The source of chilopod sensory information: External structure and distribution of antennal sensilla in Scutigera coleoptrata (chilopoda,Scutigeromorpha)

The investigation of the antennae of Scutigera coleoptrata (Linnaeus, 1758) by scanning electron microscopy (SEM) revealed the presence of five types of sensilla: sensilla trichodea, beak‐like sensilla, cone‐shaped sensilla brachyconica on the terminal article, sensory cones at the antennal nodes, and the shaft organ. Alongside the presence and absence of antennal sensillar types, three unique characters were found in the Scutigeromorpha: the presence of long antennae with nodes bearing sensory cones, the presence of a bipartite shaft including the shaft organ, and the presence of beak‐like sensilla. Neuroanatomical data showed that the animals' brains are equipped with well‐developed primary olfactory and mechanosensory centers, suggesting that the antennae must be equipped with specialized sensilla to perceive chemosensory and mechanosensory cues. With the evidence provided in this article for the Scutigeromorpha, SEM data are available at last on the antennal sensilla for all five chilopod taxa, allowing a comparative discussion of antennal morphology in Chilopoda. J. Morphol., 2011. © 2011Wiley‐Liss, Inc.     

Ultrastructure of antennal sensilla of four skipper butterflies in Parnara sp. and Pelopidas sp. (Lepidoptera,Hesperiidae)

Most species of Parnara and Pelopidas (Hesperiidae) are important pests of rice. In this study, the antennal morphology, types of sensilla, and their distribution of four skipper butterflies, including Parnara guttata (Bremer & Grey), Pa. bada (Moore), Pelopidas mathias (Fabricius) and Pe. agna (Moore), were observed using a scanning electron microscope. Six distinct morphological types of sensilla were found on the antennae of all of these species: sensilla squamiformia, sensilla trichodea, sensilla chaetica, sensilla auricillica, sensilla coeloconica, and Böhm sensilla. The sensilla trichodea are the most abundant sensilla among the four skipper butterflies, and the sensilla auricillica are confirmed on the antennae of butterflies for the second time. In addition, the possible functions of these sensilla are discussed in the light of previously reported lepidopteran insects, which may provide useful information for further study of the function of these antennal sensilla and for related pests control by applying sex pheromones.     

Antennal sensilla of the ground beetle Bembidion lampros Hbst (Coleoptera, Carabidae)

Antennal sensilla typology, number and distribution pattern were studied in the ground beetle Bembidion lampros Hbst (Coleoptera, Carabidae) using scanning electron microscopy. The 1.6–1.8 mm long filiform antennae of both sexes consist of the scape, pedicel and of the flagellum composed of nine flagellomeres. In both sexes, three types of sensilla chaetica, two types of sensilla trichodea, five types of sensilla basiconica, one type of sensilla coeloconica, one type of sensilla campaniformia and Böhm sensilla were distinguished. The possible function of the sensilla was discussed and three types of sensilla were considered as olfactory, sensilla trichodea type 2 and sensilla basiconica types 1 and 2. Olfactory sensilla occupy dorsal and/or ventral areas of the flagellomeres and occur sparsely (sensilla basiconica type 1) or not at all (sensilla basiconica type 2 and sensilla trichodea type 2) outside these areas. No remarkable sexual differences in the types, numbers and distribution of antennal sensilla were found.     

Sensilla on the antennal flagellum of the sawyer beetles Monochamus notatus (Drury) and Monochamus scutellatus (Say) (Coleoptera: Cerambycidae)

The antennae of the sawyer beetles Monochamus notatus and M. scutellatus were examined with the light and scanning electron microscopes to determine the types, number, distribution and innervation of the sense organs. Nine types of sensilla are described. Both short, thin-walled pegs (sensilla basiconica) and reversely curved thick-walled hairs (sensilla trichodea) are chemoreceptors. There are three types of long, thick-walled hairs (sensilla chaetica) which may be mechanoreceptors. One of these is modified in males to form unique snail-shaped pegs. A few dome-shaped organs, probably campaniform sensilla, were found. In addition to sense organs, many glands occur in association with the sensilla, and the antennae are well supplied with dermal glands connected by canals to small pores on the surface.     

Obstacle perception by insect antennae during terrestrial locomotion

Abstract. Insect antennae bear several types of sensilla including chemo-receptors, hygroreceptors, thermoreceptors and mechanoreceptors. A large proportion of sensilla is chemoreceptors, providing olfactory function. Pro-prioreceptors located on the antennae provide information on the position of these organs and are used in flight control. This type of sensillum is present in most insects and might serve other functions. We tested the hypothesis that antennae are used to perceive obstacles in the path of walking beetles. When adult Colorado potato beetles, Leptinotarsa decemlineata (Say), touch an obstacle with their antennae during terrestrial locomotion, they modify the angle of their body to allow the tarsi of one prothoracic leg to reach the top of the obstacle. Our results demonstrate that antennae, by their movements and their position ahead of the beetle, provide information on the presence of the obstacle necessary to initiate step-up behaviour. Furthermore, the change in the body angle needed to increase the reach of the prothoracic leg and step on the obstacle, is proportional to the height of the obstacle. Since the eyes are not involved in the process, normal behaviour can be performed in the dark.