Fine structure of antennal sensilla of male Aedes aegypti (L.)

The terminal two antennal segments of male Aedes aegypti bear the same variety of sensillar types as the female's antenna, namely, sensilla chaetica, sensilla coeloconica, sensilla ampullacea, grooved pegs, and four types of sensilla trichodea: long and short, pointed-tipped trichodea and blunt-tipped types I and II. Each type of sensillum has a similar fine structure in both sexes. Of the 514 neurones which innervate these sensilla in the male, 91% are olfactory receptors, 7% mechanoreceptors, and 2% thermoreceptors. The total number of neurones in the male is about four times fewer than in the female, but the ratio of those responding to the various stimuli is similar.The sensilla studied herein probably mediate stimuli involved in location of suitable resting sites and nectar meals. In addition they are apparently involved in location of vertebrates as recent studies indicate that certain male mosquitoes are attracted to hosts to bring them into the proximity of the females for mating. This host finding behaviour of males would explain why they have the same sprectrum of sensillar types as do females.     

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.     

Morphology of antennal sensilla of the brown spruce longhorn beetle,Tetropium fuscum (Fabr.) (Coleoptera: Cerambycidae)

The antennal sensilla of the brown spruce longhorn beetle, Tetropium fuscum (Fabr.) (Coleoptera: Cerambycidae) were examined with particular focus on the sensilla present on the apical flagellomere. T. fuscum antennae are composed of 11 segments, namely the scape, pedicel, and nine flagellomeres. Nine types of sensilla were observed: three types of sensilla chaetica, sensilla trichodea, two types of sensilla basiconica, grooved peg sensilla, thick-walled sensilla, and Böhm bristles. Seven of these types were present on the apical flagellomere, the exceptions were sensilla chaetica type 3 and Böhm bristles. There were no significant differences in the distribution or density of sensilla present on the ninth flagellomere of males and females, except that males had significantly more sensilla chaetica type 1, which are put forward as the putative contact chemoreceptors for T. fuscum.     

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.     

Morphology and distribution of antennal sense organs and diversity of mouthpart structures in Odontopus nigricornis (Stall) and Nezara viridula L. (Hemiptera)

Sensilla on the antennae and labial tip of the adult hemipteran bugs, Odontopus nigricornis Stall (Pyrrhocoridae) and Nezara viridula L. (Pentatomidae) (Hemiptera) were examined with an electron microscope in order to study their morphology, distribution, and possible chemo- and mechanoreceptive functions for food detection. The antenna contains 2 types of sensilla trichodea and 3 types of sensilla basiconica on the flagellar segments. S. trichodea are most abundant in both insects. Long slender hairs with elevated bases, and slightly shorter hairs with flexible sockets at the bases are common in both species. However, on each antennal segment of O.nigricornis, 1 or 2 rows of very long trichodeal hairs with longitudinal grooves and blunt tips are visible. At the periphery, S. basiconica with bulbous bases were also observed in addition to sensilla chaetica. The tripartite apex of the labium in both species consists of 2 lateral lobes and an apical plate. Each lateral lobe possesses a field of 11 thick-walled uniporous peg sensilla and long non-porous hair sensilla. Mandibular stylets of O.nigricornis have barbs, which may help in penetrating the hard seed coat. These insects made circular holes while feeding on the seed. A possible mechanism of feeding is discussed.     

Structure and distribution of antennal sensilla in Oranmorpha guerinii (Gervais, 1837) (Diplopoda,Polydesmida)

Detailed information on sensory organs of Diplopoda especially on antennal sensilla are still sparse and fragmentary. The present study on the antennae of Oranmorpha guerinii (Polydesmida, Paradoxosomatidae) utilizing scanning electron microscopy revealed the presence of six sensillar types: (1) apical cones, (2) sensilla trichodea, (3) sensilla microtrichodea, (4) sensilla chaetica, (5) sensilla basiconica bacilliformia, and (6) sensilla basiconica spiniformia. External structure and distribution of cuticular antennal sensilla are compared with data from other diplopod species. We moreover discuss possible functions of antennal sensilla in millipedes.     

玉龙蝠蛾触角感觉器的扫描电镜观察

本文报道玉龙蝠蛾 Hepialus yulongensis Liang 触角感觉器种类、形态和分布的扫描电镜观察结果。蝠蛾触角呈丝状,由柄节、梗节和21—27个鞭节组成,总长2.3—2.7毫米,柄节比以后各节长,触角表面缺少隆起的网纹。触角感觉器计有七种,其名称为毛形感器、刺形感器、腔锥感器、锥形感器、鳞形感器、Bohm氏鬃毛及仅出现于雄蛾的钟形感器。根据中心栓的长度,腔下陷的深度和直径,腔锥感器基本上可分为长栓和短栓两种形态类型,腔的周围都无向内倾斜的缘栓;毛形感器可进一步分为A型和B型;Bohm氏鬃毛数量多,主要分布于柄节、梗节,但在端节也能见到。     

Types of Antennal Sensilla of the Asian Corn Borer,Ostrinia furnacalis (Guenéee)

This study was carried out to investigate the types of sensilla and their distribution on the antennae of the Asian corn borer, Ostrinia furnacalis (Guenéee). O. furnacalis had six types of antennal sensilla: sensilla trichodea, sensilla chaetica, sensilla coeloconica, sensilla auricillica, sensilla styloconica and Böohms bristle. S. auricillica, single-walled multiporous sensilla, were presumed to be involved in chemical reception. S. coeloconica were double-walled, multiporous sensilla and could detect chemicals also. S. chaetica appeared to be mechano-receptors. S. styloconica were poreless and were thought to have thermo- and hygro-receptors. S. trichodea were single-walled chemosensilla and two subtypes were identified by transmission electron microscopy. The scape and the pedicel had Böohms bristles, which seem to function as mechanical stimulus receptors.     

Olfactory responses and sensilla morphology of the blackcurrant leaf midge Dasineura tetensi

Olfactory responses of Dasineura tetensi (Rubs) (Diptera; Cecidomyiidae) to leaf volatiles of blackcurrant (Ribes nigrum) were tested in a 4-way olfactometer. Newly emerged virgin females showed no response to the leaf volatiles emitted from a blackcurrant shoot. Newly emerged males (which are known to respond to a pheromone released by the female) also showed no response to the leaf volatiles. Two hours after mating females responded positively, indicating that leaf volatiles may play a role in host plant finding. Scanning (SEM) and transmission (TEM) electron microscopy of the antennae of D. tetensi showed that males and females share five sensillum types; sensilla chaetica (mechanoreceptors), sensilla trichodea, sensilla basiconica, uniporous peg sensilla and circumfila (chemoreceptors). The sensilla chaetica and sensilla trichodea resemble those found on other insects. Sensilla basiconica were found on all antennal subsegments except the tip. These are multiporous receptors with five unbranched dendrites filling the lumen. Small peg sensilla located on the tips of both male and female antennae may function as contact-chemoreceptors. The circumfila, which are a unique type of sensilla found only on cecidomyiid antennae, form loops around each of the antennal subsegments, being attached to the surface by a series of stalks. TEM revealed that each stalk consisted of one sensillum containing a single highly branched dendrite. The distal regions of the walls of each sensillum are fused together to form the circumfila. Circumfila have multiporous walls and a lumen filled with multiple branches of dendrites. Their structure suggests that they are important olfactory receptors in both the male and female.     

二纹蕈甲成虫触角的感器类型与分布特点

利用扫描电子显微镜（SEM）对二纹蕈甲Dacnepicta Crotch的触角感器进行了观察。发现该虫的触角感器有6种类型,分别为毛形感器、刺形感器、锥形感器、栓锥形感器、钟形感器和B曲m氏鬃毛。其中,锥形感器有4种形态,刺形感器具有3种形态,毛形感器、栓锥形感器和钟形感器各有1种形态。感器的数量和分布在触角的每一节上差异较大。     

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。     

Antennal sensilla of male and female Telenomus reynoldsi gordh and coker (Hymenoptera : Scelionidae)

Sensilla on the antennae of both sexes of Telenomus reynoldsi (Hymenoptera : Scelionidae) were studied with the scanning electron microscope to determine their structure and possible function in mating and host recognition. Two types of setiform sensilla occur: curved, grooved sensilla trichodea and erect, stout sensilla chaetica. Horn-like sensilla trichodea curvata are abundant on the male antennae, but are less abundant and only present dorsally on the female. Sensilla basiconica are unique to the ventral surface of the apical 4 segments of the female antennae. Sensilla styloconica are located on A4 and A10 of the female and A7 and A9 of the male. Multiporous grooved sensilla are present on A4, A6, and A11 of the female and A4 and A6-A11 of the male. A possible sex gland is located on the venter of A5 of the male. The functions of sensilla trichodea curvata and sensilla basiconica in courtship and host recognition, respectively, are hypothesized by correlation with behavioral observations.     

Antennal sensilla of female Trichogramma nubilale (Ertle and Davis) (Hymenoptera : Trichogrammatidae) and comparisons with other parasitic Hymenoptera

We describe the external morphology and relative positions of antennal sensilla of female Trichgramma nubilale (Hymenoptera : Trichogrammatidae) by scanning electron microscopy (SEM), and compared the results with 11 similar studies representing 15 species and 8 families within the parasitic Hymenoptera. There are 6 morphologically and structurally distinct structures on female T. nubilale antennae, which are probably sensilla, and one seta and one campaniform-like structure that may have a sensory function. Sensilla pore numbers and positions suggests that the multiporous grooved basiconica (MPG) C, multiporous pitted (MPP) trichodea A and the MPP placodea A have an olfactory function, whereas the MPP trichodea C have a gustatory function. The lack of pores and the presence of a basal socket suggests a mechanoreceptor function for aporous (AP) trichodea B, and the uniporous pitted (UPP) trichodea D, although, the latter also have a minute pore or dimple at the sensillar apex. Positions and numbers of these sensilla, setae and campaniform-like structures were consistent in all the specimens examined. These analyses suggest that antennal sensilla types and relative positions are highly conserved within the genus Trichogramma, and there are broad similarities within the parasitic Hymenoptera.     

红彩真猎蝽成虫触角、喙和前足跗节感受器的扫描电镜观察

利用扫描电镜对红彩真猎蝽成虫的触角、喙、前足跗节感受器进行观察。结果表明：红彩真猎蝽触角上分布4种类型的感受器,分别为毛形感受器、刺形感受器、锥形感受器和腔锥形感受器。其中,毛形感受器、刺形感受器各有3种形态,锥形感受器和腔锥形感受器各有2种形态,雌、雄性成虫个体间触角感受器类型、数量及分布未发现明显差异。喙的末端分布3种类型感受器,分别为毛形感受器、刺形感受器和锥形感受器,其中毛形感受器1种形态,刺形感受器2种形态,锥形感受器有3种形态。前足跗节末节存在刺形感受器和锥形感受器,其中刺形感受器有3种形态,锥形感受器有4种形态。     

Morphology and distribution of sensilia on the cephalic appendages,tarsi and ovipositor of the European sunflower moth,Homoeosoma nebulella Den. & Schiff. (Lepidoptera : Pyralidae)

Sensilla on male and female antennae, mouthparts, tarsi and on the ovipositor of the European sunflower moth, Homoeosoma nebulella (Lepidoptera : Pyralidae) have been investigated by means of scanning electron microscope. The antennal flagellum bears multiporous sensilla (trichodea, basiconica, auricillica, coeloconica) and uniporous sensilla (chaetica, styloconica). A sexual dimorphism is found in the numbers of sensilla trichodea (8300 in males and 6000 in females) and sensilla basiconica (1150 in females and 650 in males). The proboscis has uniporous s. styloconica, multiporous s. basiconica (described for the first time in Lepidoptera), aporous s. chaetica, and some rare uniporous s. basiconica in the food channel. The labial palp-pit organ houses multiporous s. coeloconica, while the maxillary palps have aporous sensilla. Tarsi of both sexes possess one type of aporous s. chaetica and 2 types of uniporous s. chaetica. There is no significant difference in the distribution of tarsal sensilla between males and females. The surface of each lobe of the ovipositor is covered by 3 types of aporous s. trichodea of different lengths and about 60 multiporous s. basiconica, sensilla unusual on the ovipositor of Lepidoptera. The role of sensilla in the oviposition site selection is discussed.     

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。     

External morphology of antennal sensilla of four species of adult flea beetles (Coleoptera : chrysomelidae : alticinae)

External morphology of antennal sensilla of both sexes of Phyllotetra cruciferae (Goeze) and Psylloides punctulata Melsh, both of which feed on the mustard family Cruciferae, and Epitrix cucumeris (Harris) and Psylloides affinis (Paykell), both of which feed on the nightshade family Solanaceae, was studied using scanning electron microscopy. All belong to Alticinae (Coleoptera : Chrysomelidae). The number and distribution of antennal sensilla were also determined. Eight types of sensilla could be distinguished on the flagella of the species examined: sensilla chaetica; sensilla trichodea I and II; long sensilla basiconica I and II; and short sensilla basiconica I, II and III. The sensilla chaetica are probable tactile mechanosensilla, whereas both types of sensilla trichodea and long sensilla basiconica likely function in olfaction. Suggested functions for the short sensilla basiconica I, II and III include hygro-/thermoreception and chemoreception.The lack of sexual dimorphism in antennal structure and in types as well as number of sensilla, indicates that the sensilla probably have similar functions in both sexes. Probably most of the antennal olfactory sensilla are involved in host location and recognition. Any correlation between number of a particular type of sensillum or total number of all types and general host preference is not apparent.     

Morphology and distribution of antennal sensilla in the pine wood nematode insect vectors Monochamus alternatus Hope and Monochamus saltuarius Gebler (Coleoptera: Cerambycidae)

As insect vectors of pine wood nematodes, Monochamus alternatus Hope and Monochamus saltuarius Gebler have different levels of attractiveness to semiochemicals. Although active use of chemical communication in both species is well known, there was no report on the differences in morphology and distribution of antennal sensilla between the two Monochamus species. The present study was carried out to explore the morphology, distribution, and ultrastructure of antennal sensilla of the two species using scanning and transmission electron microscopy. The overall shapes of the antennae were not different between M. alternatus and M. saltuarius. However, both M. alternatus and M. saltuarius exhibited sexual dimorphism overall. The antennae of each species were composed of the scape, pedicel, and nine flagellomeres, with four morphological types of sensilla: trichodea, basiconica, chaetica, and coeloconica. The four types occurred in varying numbers and distributions. The sensilla chaetica type was the most abundant in both species. Three types of sensilla (trichodea, basiconica, and chaetica) could be subdivided according to the two Monochamus species; sensilla trichodea could be divided into two subtypes, and sensilla basiconica and sensilla chaetica into three. All sensilla basiconica subtypes were multiporous, indicating that their primary function was olfactory. Sensilla trichodea subtype 2 was uniporous, indicating that the function of these sensilla might be gustatory. The morphological information obtained in our study provides a basis for future investigation of the sensory physiological function of each type of sensilla in the two species.     

Mate recognition and antennal morphology of Octodonta nipae (Coleoptera: Chrysomelidae) adults

The nipa palm hispid beetle, Octodonta nipae (Maulik) has been killing palm trees since its introduction into Hainan province, China, from Malaysia in 2001. It continues to spread within Hainan province, northeast to Fujian province, and northwest to Yunnan province within China. Knowledge on signals involved in mate location and recognition could help develop effective integrated pest management programs. In the present study, we first experimentally proved that antennae were essential in success of O. nipae mating. We then excised various segments/flagellomeres of adult male and female antennae and observed their mating behavior. Results revealed that the 5th to 9th flagellomeres, especially those of males, were important for the mating success. Finally, in an attempt to elucidate the types of antennal sensilla accountable for the mating success, morphology of O. nipae antennae was studied in detail with scanning electron microscopy. Six types of sensilla were distinguished: aporous sensilla trichodea (T1), multiporous sensilla trichodea (T2), aporous sensilla chaetica (Ch1), uniporous sensilla chaetica (Ch2), multiporous sensilla basiconica (B), and Böhm sensilla (Bm). Aporous sensilla trichodea is the most abundant; multiporous sensilla trichodea and sensilla basiconica are considered as olfactory receptors, and uniporous sensilla chaetica as gustatory receptor. Importance of flagellomeres 5–9 in mating success seemed to correspond to the abundance of sensilla on these segments.