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.     

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.     

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.     

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.     

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.     

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.     

Distribution of chemo- and mechanoreceptors on the antennae and maxillae of Busseola fusca larvae

The stem borer Busseola fusca (Fuller) (Lepidoptera: Noctuidae) is a major pest of maize, Zea mays L., and sorghum, Sorghum bicolor (L.) Moench (both Poaceae), in sub-Saharan Africa. Like in many other lepidopteran insects, the success of B. fusca in recognizing and colonizing a limited variety of plants is based on the interaction between its sensory systems and the physicochemical characteristics of its immediate environment. The sensilla on the maxillary galeae of B. fusca larvae are typical of Lepidoptera and comprise two uniporous styloconic sensilla, which are contact chemoreceptors, three basiconic sensilla, and two aporous sensilla chaetica. The maxillary palp is two-segmented and has eight small basiconic sensilla at the tip, which were also found to be gustatory. The antennae of B. fusca larvae are short and simple. The sensilla of the antenna are composed of two aporous sensilla chaetica, three multiporous cone-shaped basiconic sensilla, three small basiconic sensilla, and one aporous styloconic sensillum. The basiconic sensillum located on the third antennal segment displayed a contact chemoreception response. The other basiconic sensilla did not show any action potential activity in tip-recording tests. The significant and positive dose–response curve obtained for the antennal basiconic sensillum with sucrose indicated for the first time the presence of gustatory chemoreceptors on the antennae of a lepidopteran larva.     

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.     

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.     

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.     

Sensillum types on the proboscis of the Lepidoptera: a review

The external surface of lepidopteran proboscides may bear six morphological types of sensilla: chaeticum, basiconicum, styloconicum, coeloconicum, filiformium, and campaniformium, with the first three types being the most common. There are four types of pore-system: aporous, uniporous, multiporous, and uniporous-multiporous. Sensilla chaetica and campaniformia are aporous sensilla with a tactile or a proprioceptive function, respectively. Aporous sensilla filiformia are probably vibroreceptors. Uniporous sensilla with a gustative function exist in sensilla basiconica, styloconica and coeloconica. Multiporous sensilla were found in long sensilla basiconica and seem rare. Uniporous-multiporous sensilla are relatively common and are to be found both in sensilla styloconica (Arctiidae, Noctuidae) and in sensilla basiconica (Adelidae, Pyralidae, Arctiidae, Noctuidae). It is difficult to establish their function (gustative or olfactive). More extensive research would make it possible to discover them in other families. Only gustative uniporous sensilla basiconica exist in the food canal. The morphology of the proboscis and the distribution of sensilla are adapted to food habits.     

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.     

Structure and sensilla of the antennae and mouthparts of Loxocephala perpunctata Jacobi (Hemiptera: Fulgomorpha: Eurybrachidae)

The ultramorphology of the antennae and mouthparts of the adult Loxocephala perpunctata Jacobi was studied through a scanning electron microscope. Seven types of sensilla were found on antennomeres, including a Böhm bristle on the scape, sensillum trichoideum and plaque organ on the pedicel, two subtypes of sensilla chaetica and two subtypes of sensilla campaniformia on these two antennomeres; and Bourgoin's organ with sensory pegs and sensilla basiconicum on the basal bulb of the flagellum. The mouthparts of L. perpunctata are of the typical piercing-sucking type, similar to mouthparts found in other hemipteran insects. In general, six types of sensilla (i.e., four subtypes of sensilla chaetica, sensillum basiconicum, subapical labial sensillum, uniporous peg-like sensillum, multiporous peg-like sensillum and two subtypes of bristle-like sensilla) were detected on different locations of the labium, with the last three, and numerous cuticular processes, present on the labial tip. The potential functions of these sensilla are discussed.     

Antennal sensilla in adult Agathiphaga vitiensis dumbl. and A. queenslandensis dumbl. (Lepidoptera : Agathiphagidae)

The antennae of both sexes of Agathiphaga vitiensis and the antenna of the female of A. queenslandensis (Lepidoptera : Agathiphagidae) were studied with a scanning electron microscope. In both sexes, 10 types of sensilla were observed on the antennae of A. vitiensis: Böhm's bristles, chaetica (types I and II), squamiformia, trichodea, biforked basiconica, short basiconica and coeloconica (types I, II and III). The female of A. queenslandensis possesses the same types of sensilla, except that the biforked basiconica are flattened. Biforked sensillum basiconicum is being reported in Lepidoptera for the first time. Their presence supports Kristensen's hypothesis on the phylogeny of Lepidoptera (1984). The female of A. vitiensis possesses more sensilla than that of A. queenslandensis. The male of A. vitiensis has a greater number of s. trichodea than the female, but the biforked sensilla basiconica are more numerous on the female antenna than on the male one.     

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。     

Reproductive strategies and parasitization behavior of Ageniaspis citricola, a parasitoid of the citrus leafminer Phyllocnistis citrella

We describe the number, distribution, and function of sensilla located on different organs of Lobesia botrana (Lepidoptera: Tortricidae) females using scanning electron microscopy, selective staining, and contact electrophysiology. The tarsi of the prothoracic legs bear contact chemo‐mechanoreceptor sensilla chaetica (5–13 per tarsomere), arranged in rings mainly concentrated on ventral surfaces, and different mechanosensory structures (sensilla chaetica, sensilla squamiformia, sensilla campaniformia, and spines). A single contact chemo‐mechanoreceptor sensillum chaeticum is present between the claws on the pretarsus. The ventral surface of the ovipositor lobes is covered with numerous mechanosensory sensilla chaetica of different types, out of which 10 have a contact chemosensory function. Putative contact chemo‐mechanoreceptor sensilla were also observed on the proboscis and antenna. Longitudinal rows of alternated sensilla styloconica and basiconica are present on the distal part of the proboscis, and rings of sensilla chaetica are present at the antennal tip. The sensilla on these body parts may play different roles in the selection of an oviposition site.     

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。     

Scanning Electron Microscopy Studies of the Antennal Sensilla of Metaphycus parasaissetiae Zhang & Huang (Hymenoptera: Encyrtidae)

Metaphycus parasaissetiae Zhang & Huang (Hymenoptera: Encyrtidae) is an important adult parasitoid of Parasaissetia nigra Nietner (Hemiptera: Coccoidea). The external morphology of the antennal sensilla of male and female M. parasaissetiae was examined using scanning electron microscopy. The geniculate antennae of male and female M. parasaissetiae were composed of a scape with a basal radicula, a barrel-shaped pedicel, and a long flagellum. Twelve morphologically distinct types of sensilla were identified, including multiporous placoid sensilla, campaniform sensilla, finger-like sensilla, multiporous basiconic sensilla (BS-1), three aporous types of basiconic sensilla (BS-2, BS-3, and BS-4), two types of aporous trichoid sensilla (TS-1 and TS-3), a type of multiporous trichoid sensilla (TS-2), and two types of sensilla chaetica (CH-1 and CH-2). Sex dimorphism in the sensilla composition of M. parasaissetiae is also observed. Major differences between the sexes were found in the number, distribution, shape, structure, and size of the identified sensilla. We also discuss on the functional aspects of these sensilla to elucidate the mechanisms involved in host searching and courtship behavior of M. parasaissetiae.     

梨小食心虫幼虫感受器扫描电镜观察

梨小食心虫Grapholita molesta(Busck)是一种世界性蛀果害虫,主要以幼虫钻蛀蔷薇科果树的嫩梢和果实进行为害.本文利用扫描电子显微镜观察了梨小食心虫幼虫的超微形态和感受器.结果表明,幼虫触角上有3种类型的感受器:2个刺形感受器、6个锥形感受器和1个栓锥形感受器.上唇有6对刺形感受器.上颚的前端有切齿叶.在下颚的轴节和茎节各有1个刺形感受器.每个外颚叶有3个短而尖的锥形感受器、2个大的栓锥形感受器和3个刺形感受器.体节末梢的下颚须有7个锥形感受器、1个栓锥形感受器.下颚须的末端有1个指形感受器和2个板形感受器.每个下唇须末端具有1个尖锥状刺形感受器和1个长的栓锥形感受器.胸足与腹足上也分布有不规则的毛型感受器和刺型感受器.该研究将为进一步阐明梨小食心虫与其寄主的关系提供形态学的理论基础.