Ultrastructure of the antennal sensilla of the cockroach-egg parasitoid,Tetrastichus hagenowii (Hymenoptera: Eulophidae)

Eggs of a number of cockroach species are parasitized by Tetrastichus hagenowii. The ultrastructure of the sensilla on the antennae of females and males was examined by scanning and transmission electron microscopy. The females have two types of multiporous plate sensilla while the males have only one. Type 1 is found in females and males and has a relatively thin cuticular wall and many pores, while type 2 is found only in females and has a relatively thick cuticular wall and few pores. Both sexes have nonporous, thick-walled, socketed hairs; multiporous, nonsocketed hairs; multiporous, thick-walled pegs; and terminal hairs. In addition, males have multiporous, nonsocketed, long hairs. The sensilla are similar, in many respects, to the sensilla of other chalcid parasitoids. The antennal sensilla of female T. hagenowii are probably involved in ovipositional behavior. The multiporous, long hairs of the male possibly receive stimuli during mating behavior A chemoreceptive function is proposed for the multiporous plate sensilla.     

Antennal sensilla of male Lophocorona pediasia Common 1973 and their phylogenetic implications (Lepidoptera: Lophocoronidae)

The male antennae of Lophocorona pediasia reveal seven types of sensilla: multiporous sensilla trichodea, multiporous sensilla basiconica of subtypes 1 and 2, multiporous sensilla auricillica, aporous sensilla styloconica, multiporous sensilla coeloconica and aporous Böhm’s sensilla. All these sensillum types are present in the higher Lepidoptera. The existence of sensilla auricillica, hitherto denied by several authors, is demonstrated in this study. Typically, they are located on the distal edge of the flagellomeres as in most Lepidoptera. Therefore, their so-called absence must no longer be regarded as an autapomorphy of the Lophocoronidae. Their presence is a common characteristic of all «Dacnonypha», which include, apart from the Lophocoronidae, the Eriocraniidae and the Acanthopteroctetidae. Their number in L. pediasia is smaller than in these two families and more in accordance with the condition found in higher Lepidoptera, suggesting a more advanced position of the Lophocoronidae. The presence of very numerous sensilla basiconica is a possible autapomorphy of the family.     

Sensory Organs on the Antennae of Micropterix calthella L. (Lepidoptera, Micropterigidae)

Antennal sensilla of Micropterix calthella were studied with the scanning electron microscope to determine their morphological types, relative abundance, distribution, location and possible functions. Of the 12 types occurring in both male and female moths, seven are found in most higher Lepidoptera: sensilla trichodea, multiporous s. basiconica, s. coeloconica, s. styloconica, s. chaetica, s. campaniformia and Böhm's bristles. Two types (uniporous s. basiconica and cupuliform organs) are found only in a few families. Three structures are peculiar to Micropterix : ascoïd sensilla, multiporous s. placodea and circular organs. All types of sensilla have characteristic distribution and location pattern similar in both sexes.     

Antennal sensilla in five Psychodini moth flies (Diptera: Psychodidae: Psychodinae) pollinators of Arum spp. (Araceae)

The pollination of the genus Arum (Araceae) is mainly achieved by deception, the floral odour mimicking the pollinator ovipositing site. In order to discover the sensory organs involved in this attraction, we have studied the antennae of five species of psychodine moth-flies (former Psychoda sensu lato=Psychodini), pollinators of Arum spp. The antennae of the five Psychodini reveal seven types of sensilla: multiporous tribranched sensilla basiconica (sensilla ascoidea), multiporous sensilla basiconica, multiporous sensilla coeloconica, multiporous sensilla auricillica, uniporous sensilla basiconica, aporous sensilla chaetica, aporous Böhm’s sensilla. Each species possesses three, five or six of these sensillum types. All the multiporous sensilla are probably olfactory receptors while the uniporous sensilla basiconica must possess a contact chemoreceptive function. The multiporous tribranched sensilla basiconica (s. ascoidea), present in all the species, are the best candidates for the reception of the odours given off by the ovipositing sites and the inflorescences of Arum. The multiporous sensilla basiconica and the multiporous sensilla coeloconica may be involved respectively as CO₂ receptors or thermoreceptors. Psychoda phalaenoides, which is the main pollinator of A. maculatum, is the species which possesses the largest number of antennal sensilla. The sexual dimorphism, studied only in Psycha grisescens, as concerns the number of sensilla and the absence of a sensillum type which differ according to sex, is difficult to interpret.     

椰心叶甲啮小蜂触角感觉器的扫描电镜观察

应用扫描电镜(SEM)对椰心叶甲啮小蜂Tetrastichus brontispae Ferrière成虫触角感器的超微结构进行观察。结果表明,在触角上共有8种感器,分别为毛形感器、多孔板状感器、刺形感器、锥形感器、耳形感器、乳状感器、腔形感器和Bhm氏鬃毛;其中毛形感器和板形感器是主要感器,数量较多分布较广;雌雄蜂触角有明显的性二型现象,表现为雌雄触角大小不同,触角感器类型、大小、数量、分布不同。     

The antennae of neopseustid moths: Morphology and phylogenetic implications, with special reference to the sensilla (Insecta, Lepidoptera, Neopseustidae)

The antennae of Lepidoptera Neopseustidae were examined with the scanning electron microscope. The studied species, Nematocentropus cfr. omeiensis, Neopseustis meyricki, Synempora andesae, Apoplania valdiviana and Apoplania penai possess nine types of antennal flagellum sensilla: multiporous large sensilla basiconica, multiporous thin sensilla basiconica, multiporous small sensilla basiconica, multiporous sensilla trichodea, multiporous sensilla coeloconica; uniporous sensilla chaetica; aporous sensilla chaetica, aporous stylus-shaped sensilla chaetica, aporous sensilla styloconica.The multiporous sensillum type here termed “multiporous large sensillum basiconicum” is unknown from other Lepidoptera and probably constitutes an autapomorphy of the family Neopseustidae. This sensillum type is remarkable by having a single base in female Apoplania and Synempora while in male Apoplania it has a bifid or trifid base, and in male Synempora it is composed of two or three incompletely separated hairs. This may be the first recorded example of a sexually dimorphic lepidopteran sensillum type. The stylus-shaped sensillum chaeticum is a primitive type which occurs only in some lower Lepidoptera.     

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.     

Ultrastructure of the funicular sensilla of the cabbage root fly,Delia radicum L. (Diptera : Anthomyiidae)

A transmission electron microscope study of the funicular sensilla of the cabbage root fly, Delia radicum, (Diptera : Anthomyiidae), showed 4 types of surface sensilla and 5 types of pit sensilla. The ultrastructure of the surface sensilla indicated all had a primary olfactory function. These include thick-walled multiporous trichoid sensilla, thin-walled multiporous basiconic sensilla (with 2 subtypes), thin-walled multiporous clavate sensilla, and grooved sensilla with channels at the base of each of the grooves. Clavate sensilla had 2 types of dendrites, one tubular, the other “scrolled”. This 2nd type may indicate an additional thermosensitive function. The dorsal pits contained thin-walled multiporous basiconic sensilla with a tapered tip. The ventral pits contain 3 types of sensilla, which have no wall pores and an inflexible socket. These may contain thermo- and/or hygroreceptors and include smooth-walled conical-, smooth-walled tapered- and striated pit sensilla. The 4th type is a grooved pit sensillum similar to the surface type.     

Structure and function of antennal pore plate sensilla of oryctes rhinoceros (L.) (Coleoptera : Dynastidae)

The antennae of the rhinoceros beetle, Oryctes rhinoceros (Coleoptera : Dynastidae), comprise 4 parts : the scape, the pedicel, a funicle, and a club of 3 lamellate segments. The inner surfaces of the lamellate club segments carry one type of trichoid sensilla, 2 types of sensilla coeloconica, and 3 types of multiporous pore plate sensilla. The total surface occupied by the sensilla on the antenna is 5.2±0.4 mm² in males (mean±SD) and 5.4±0.5 mm² in females. With a measured density of 8665±1254 sensilla per mm² in males and 8952±1642 sensilla per mm² in females, the total number of pore plate sensilla was estimated to be between 45,000 and 50,000. The structure of the 3 types of pore plate sensilla is described. SP1 are the most abundant type of placoid sensilla. They show a convex and rugged plate whose infoldings form a circle of irregular cavities. SP2 sensilla are characterised by a smooth and convex plate, surrounded by a furrow with a ridge. SP2 are localised on a wide band situated along the straight side of the lamella. The plate of SP3 is nearly flat and there is no furrow. SP3 are confined within a narrow margin along the convex edge of lamellae. The 3 types of pore plate sensilla house 2 neurones whose dendrites branch repeatedly under a plate of thin (0.2 μm) cuticle, which is pitted with numerous pores, 40 nm in diameter. Single sensillum recordings with tungsten microelectrodes revealed the firing activity of 2 neurones. These receptor neurones responded specifically to olfactory stimulus. Olfactory receptor neurones tuned to the male pheromone compound, ethyl 4-methyl octanoate, were found in male and female antennae. Other receptor neurones responded to plant volatiles. Morphological and electrophysiological data suggest the absence of a sexual dimorphism in the olfactory organs. The functional organisation of the olfactory organs is discussed in terms of their adaptation to the ecology of O. rhinoceros.     

Olfactory sensilla on the antenna and maxillary palp of the sheep head fly,Hydrotaea irritans (Fallen) (Diptera : Muscidae)

Antennae and maxillary palps of both sexes of the Sheep Head fly Hydrotaea irritans (Diptera : Muscidae) were investigated using scanning electron microscopy to describe the types, morphology, and distribution of olfactory sensory structures. Only socketed bristles and microtrichia were found on the scape of the antennae. These structures were also observed on the pedicel together with a group of 7–8 as yet undescribed sensilla, whose function is unknown. Olfactory sensilla were not found on these 2 segments or on the arista. Large numbers of olfactory sensilla and microtrichia were present on the funiculus. The former included sensilla trichodea (thick-walled, multiporous sensilla), sensilla styloconica and 6 types of sensilla basiconica (thin-walled, multiporous sensilla), 4 of which occurred individually and 2 of which were found in groups. An olfactory pit containing groups of thin-walled multiporous sensilla was located on the dorsomedian side of the funiculus. All sensilla basiconica were classified on morphological characteristics. The maxillary palps were covered with microtrichia and socketed bristles, but only 1 type of olfactory sensillum was found. This was a type of sensillum basiconicum that differed from any of those found on the antennae. No differences were found in sensilla diversity and distribution between males and females.     

Sensilla on the larval antennae and mouthparts of the european sunflower moth,Homoeosoma nebulella Den. and Schiff. (Lepidoptera : Pyralidae)

Sensilla on the larval antennae and mouthparts of Homoeosoma nebulella (Lepidoptera : Pyralidae) were examined with a scanning electron microscope. The antenna possesses 2 aporous sensilla chaetica, one aporous sensillum styloconicum, 3 large multiporous sensilla basiconica, and 3 small multiporous s. basiconica. The labrum bears 12 aporous s. chaetica and the epipharynx has 6 aporous flattened s. chaetica and 4 epipharyngeal sensilla. It is the first time that more than 2 epipharyngeal sensilla have been reported in caterpillars. The mandible possesses 4 aporous s. chaetica. Each galea bears 2 uniporous s. styloconica, 2 small aporous s. basiconica, one s. campaniformium and 3 aporous s. chaetica. Each maxillary palp bears a distal group of 8 uniporous s. basiconica, one large s. digitiformium and one pore plate. Minute grooves exist on the s. digitiformium. Each labial palp possesses one aporous s. chaeticum and one aporous s. styloconicum. An attempt has been made to identify the function of sensilla by comparing them with those of other larvae.     

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.     

伪鞘榕小蜂雌雄成虫触角感器的超微形态、分布及适生意义

伪鞘榕小蜂Sycoscapter trifemmensis是一种寄生于鸡嗉子榕间花期榕果的专性寄生蜂,雌雄两性繁殖策略分化明显,为更好理解和诠释雌蜂寄主定位和雄蜂配偶识别机制,有必要对两性的触角感器进行观察。运用环境扫描电镜观察,对比和探讨了伪鞘榕小蜂雌雄成虫的触角和触角感器类型、分布、数量及其生态适应性。结果表明:雌蜂触角鞭节由11鞭小节组成,总长817.82±33.23μm,分布有毛形感器、刺形感器(类型1)、锥形感器(类型1)、多孔板形感器(类型1)、栓锥形乳突状感器5类5种;雄蜂触角鞭节仅由6鞭小节组成,全长为雌蜂的1/3,且各节有明显的缩短和增粗特征,着生感器包括毛形感器、刺形感器(类型2和类型3)、锥形感器(类型1和类型2)、多孔板形感器(类型2)、腔锥形感器5类7种。雌蜂触角感器的数量与分布显著高于雄蜂,且同类型感器在雌蜂上具有明显的延伸、增粗、分支的特征,以板形感器和锥形感器最为突出。伪鞘榕小蜂雌雄成虫的触角及其感器有明显的性二型,特别是与化学信息识别相关的感器,反映了雌雄蜂在不同生态环境和繁殖压力下的形态分化、行为策略和生态适应。     

Ultrastructure and distribution of sensilla on the antennae of female fig wasp Eupristina sp. (Hymenoptera: Agaonidae)

In the species‐specific and obligate mutualism between the fig (Moraceae: Ficus spp.) and its pollinator (Hymenoptera: Agaonidae), the continuity of lifecycle of both partners completely depends on the female pollinator's ability to detect receptive figs. To better understand the chemical location mechanism, we examined the antennae and their sensilla of the female fig pollinator Eupristina sp. using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The antennae of female Eupristina sp. are geniculated, and in total, there were seven types of sensilla found on the antennae: two types of multiporous placoid sensilla (type 1 is sausage‐like and type 2 is rounded), sensilla trichodea (ST), basiconic sensilla (BS), chaetica sensilla (ChS), coeloconic sensilla (CoS), and one specialized sensillum classified as sensillum obscurum (SO). We described external morphology, abundance, distribution, ultrastructure and discussed putative functions. We inferred from their ultrastructures as chemoreceptors that two types of multiporous placoid sensilla, BS and CoS, were innervated by sensory neurons. The aporous type ST, ChS, and SO were not innervated by dendrites which may function as mechanoreceptor/proprioceptor. These results were also discussed in relation to the interaction between Eupristina sp. and its host fig.     

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.     

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.     

苹果榕传粉小蜂雌性触角感器及其生态学意义

利用扫描电子显微镜对苹果榕传粉小蜂Ceratosolen sp.雌性触角感器进行观察。结果显示:苹果榕传粉小蜂雌性触角呈膝形,分布着7类13种类型的感器,包括毛型感器、多孔的板型感器、锥型感器(2种类型)、栓锥型乳突状感器、刺型感器(4种类型)、腔锥型感器(3种类型)和一种专一性的角锥型感器。对各感器的形态、数量、分布进行描述,并结合感器的选择性染色(Ag+染色)、传粉小蜂行为及其榕/蜂互惠共生系统,对不同类型感器的功能和生态学意义进行探讨。     

Mapping and ultrastructure of antennal chemosensilla of the wheat bug Eurygaster maura

Antennae of the wheat stink bug Eurygaster maura L. (Hemiptera: Scutelleridae) were investigated to elucidate structure and distribution of antennal chemosensilla in females. Five type of sensilla were identified and characterized using a scanning electron microscope (SEM) and a transmission electron microscope (TEM). Type 1 sensilla are mechanical and contact chemoreceptors with a single apical pore. Types 2 and 3 sensilla are multiporous chemoreceptors both with typical features of olfactory sensilla. Type 4 are multiporous peg-like sensilla, short and with a grooved surface. Type 5 are sensilla coeloconica with a smooth and aporous peg completely inserted in a sub-cuticular chamber. All types are distributed on the two flagellar segments, but we considered only the apical flagellomere in which the largest number of sensilla are located. The most abundant sensilla are type 3, while the less numerous are type 5. All types, except type 2, decreased in number from the tip to the base of the segment. The lower density of sensilla was recorded on the dorsal-internal part of the apical antennomere, while the higher density was recorded on the opposite side (external-ventral).     

The chemosensory system of the monophagus grasshopper,Bootettix argentatus bruner (Orthoptera : Acrididae)

Bootettix argentatus (Orthoptera : Acrididae) is a monophagous grasshopper in the subfamily Gomphocerinae. The numbers of chemoreceptors in most groups on the mouthparts increase with each molt and are generally similar in the 2 sexes. There are fewer sensilla in the A3 groups than in other gomphocerine grasshoppers, and the possibility that this is related to host-plant specificity is discussed. Only very small numbers of sensilla are present on the pulvillar pads of the tarsi and on the arolia. The number of sensilla on the antennae is proportional to the length of the flagellum and coeloconic sensilla comprise 30–35%. Most of the remainder are multiporous basiconic sensilla. Adult males have more antennal sensilla than adult females.     

Scanning Electron Microscopy Study of the Antennal Sensilla of <Emphasis Type="Italic">Monema flavescens</Emphasis> Walker (Lepidoptera: Limacodidae)

Monema flavescens Walker (Lepidoptera: Limacodidae) is a serious polyphagous defoliator. Using scanning electron microscopy, the external morphology of the antennal sensilla of this pest was examined for a better understanding of the mechanisms of insect-insect and insect-plant chemical communications. The antennae of M. flavescens were filiform in shape, and 11 morphological types of sensilla were found in both sexes. Six types of likely chemosensory sensilla were identified: uniporous sensilla chaetica, multiporous sensilla trichodea, and four types of multiporous sensilla basiconica. The sensilla identified as likely mechanoreceptors included two subtypes of aporous sensilla chaetica, aporous sensilla coeloconica, aporous sensilla styloconica, and Böhm’s bristles, whereas the position of the antennae was monitored by Böhm’s bristles.