Multiporous Sensilla Trichodea Research Articles

Morphological characterization of antennal sensilla of Earias vittella (Fabricius) (Lepidoptera: Nolidae)

The shoot and fruit borer, Earias vittella Fab. (Lepidoptera: Nolidae) is an important and most devastating insect pest on okra and cotton. The pest mainly responsible for causing significant direct damage to tender shoots and fruits of okra, flowers and green bolls of cotton causing net yield loss in both crops. Many non-chemical control strategies have been developed under the insect pest management program, A complete knowledge on the antennal morphology of E. vitella is essential for future electrophysiological and behavioural studies. In the present study, the antennal morphology and types of sensilla on the antennae of both sexes of E. vitella were examined using light and scanning electron microscopy. Nine distinct types of sensilla were identified on the antennae of both sexes: sensilla trichodea, sensilla basiconica, sensilla coeloconica, sensilla auricillica (multiporous), sensilla chaetica, uniporous peg sensilla (uniporous), sensilla styloconica, sensilla squamiformia and bohm bristles (aporous). Among all sensilla, the most widespread are multiporous sensilla trichodea with 42.90 ± 1.77/flagellomere in male and 37.38 ± 1.38/flagellomere in female. Sensilla basiconica were the second most common sensillum type in male antennae with 15.67 ± 1.92/flagellomere. Other multiporous sensilla such as auricillica (11.90 ± 0.99) and coeloconica (4.57 ± 0.25) were significantly more abundant in female than in male antennae. Results of the study provide morphological evidence that E. vitella antennae possess microscopic cuticular structures that can play a role in perception of pheromones, plant odours and other chemical stimulants. This will open up opportunities to assess the possibility of using pheromones and plant-derived compounds for the monitoring or management of E. vittella moths in the agricultural landscapes.

Sensilla localization and sex pheromone recognition of odorant binding protein OBP4 in the mirid plant bug Adelphocoris lineolatus (Goeze)

Pheromone binding proteins (PBPs) are well studied in lepidopteran moths and are considered to be crucial in detection of sex pheromones as well as some green leaf volatiles. In contrast, evidence that PBPs interact with sex pheromones of hemipteran species is not available. The mirid plant bug, Adelphocoris lineolatus (Goeze), is a notorious hemipteran pest that uses two butyrate esters, trans-2-hexenyl butyrate (E2HB) and hexyl butyrate (HB), and one hexenoic aldehyde trans-4-oxo-2-hexenal (E4O2H), as sex pheromones. In the present study, we report on an odorant binding protein, AlinOBP4, with particular focus on its potential physiological roles in the detection of A. lineolatus sex pheromone components. Phylogenetic analyses indicated that AlinOBP4 and two mirid orthologs clustered in a general phylogenetic clade with the lepidopteran ABX OBPs, the fly LUSH and the OBP83a/b subfamily. Cellular localization by fluorescence in situ hybridization and immunolabeling further demonstrated that AlinOBP4 was strongly expressed in the multiporous sensilla trichodea (str) and middle long sensilla basiconica (mlsba) of male A. lineolatus adults, suggesting a key role associated with sex pheromone and odorant detection. A ligand binding assay revealed that recombinant AlinOBP4 protein highly bound not only to the sex pheromone components E4O2H but also to some host plant volatiles. These findings together with the evidence of insect PBPs available in the literature support the view that AlinOBP4 is involved in sex pheromone detection in male A. lineolatus and provide foundational information for further elucidating the molecular mechanisms of chemosensory based mating behavior in hemipteran mirid bugs.

Antennal sensilla of Didesmococcus koreanus Borchsenius (Hemiptera: Coccoidea: Coccidae) in different instars

To better understand the morphology, structure and function of antennae and antennal sensilla of Didesmococcus koreanus Borchsenius, family Coccidae (Hemiptera: Coccoidea), in the first-instar nymph, adult female and adult male stages, we investigated these stages using light microscopy and scanning and transmission electron microscopy. The results show that the antennae of first-instar nymphs and adult females are similar in morphology and sensilla distribution. The antennae of first-instar nymphs comprise six segments, and each antenna has 24 sensilla of six types: one campaniform sensillum (Ca), eleven smooth aporous trichoid sensilla (St), two basiconic sensilla (Ba), five multiporous pegs (Mp), two smooth multiporous pegs (sMp) and three chaetica sensilla (Ch). The antennae of adult females have six or seven segments, and each antenna has 25 sensilla of the same six types as the first nymphs, but with twelve sensillum St. The antennae of adult males are more developed, and each antenna contains 155–213 sensilla of eight types: 16–34 St, 1 Ca, 2–5 Ba, 1 Johnston’s organ (Jo), 3 knob sensilla (Ks), 5 Mp, 2 sMp and 120–181 multiporous sensilla trichodea (Mt). Based on our analysis, we discuss the possible functions of the antennae and antennal sensilla of D. koreanus in different instars.

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.

Scanning Electron Microscopy Study of the Antennal Sensilla of Monema flavescens 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.

Scanning electron microscopy studies of antennal sensilla of Isoceras sibirica Alpheraky (Lepidoptera, Cossidae)

SummaryThe carpenterworm, Isoceras sibirica Alpheraky (Lepidoptera, Cossidae), is a destructive pest affecting Asparagus officinalis L. To provide background information for chemical ecology studies, we examined the external morphology of the antennal sensilla of this pest with scanning electron microscopy. Antennae of male and female I. sibirica are bipectinate in shape, and nine morphological sensilla types were recorded in both sexes. The uniporous sensilla chaetica are gustative sensilla. The multiporous sensilla trichodea, multiporous sensilla basiconica and multiporous sensillum coeloconica are presumably olfactive sensilla. The aporous sensilla styloconica are thermo-hygroreceptors while Böhm’s bristles monitor the position of the antennae.

The antenna‐specific odorant‐binding protein AlinOBP13 of the alfalfa plant bug Adelphocoris lineolatus is expressed specifically in basiconic sensilla and has high binding affinity to terpenoids

Odorant-binding proteins (OBPs) are crucial in the olfactory pathway of insects. In the present study, the antenna-enriched OBP AlinOBP13 was investigated because of its potential contribution to the peripheral olfactory perception in the alfalfa plant bug Adelphocoris lineolatus. The results of quantitative reverse transcriptase-PCR showed that the transcript level of AlinOBP13 was higher in the adult stage than in the nymph stages. The transcript levels of AlinOBP13 in the male and female antennae significantly increased after 4 and 8 h of starvation, respectively. Fine ultrastructures of different types of chemosensilla in both female and male antennae were investigated using transmission electron microscopy and immunocytochemical labelling. The results revealed that the anti-AlinOBP13 antiserum strongly and specifically labelled short basiconic sensilla; this antiserum was restricted to the inner lumen and the cavities below the sensillum base of the sensilla. By contrast, multiporous sensilla trichodea, medium long sensilla basiconica, and aporous sensilla chaetica were not labelled. The present study is the first to report an OBP showing specific expression in the short basiconic sensilla of a member of the Hemipteran species. The results of a fluorescence displacement binding assay indicated that recombinant AlinOBP13 showed a more specific binding preference to terpenoids than to sex pheromones and other classes of chemicals. This binding ability was dramatically affected by pH; higher binding affinities were displayed at pH 10.0 than at pH 7.4 and 5.0. In addition, the results of dose-dependent electroantennogram recordings from the antennae showed that both female and male adult bugs responded to the terpenoids tested, suggesting an apparent physiological relevance of AlinOBP13 in A. lineolatus chemoreception. The results of this study suggest that AlinOBP13 functions as a specific carrier of terpenoids and provide insights into the mechanism of A. lineolatus in response to green volatiles.

Perception of potential sex pheromones and host-associated volatiles in the cotton plant bug, Adelphocoris fasciaticollis (Hemiptera: Miridae): morphology and electrophysiology

Highly developed chemoreception allows insects to detect foods, find mates, and escape natural enemies. We described the structures and distributions of antennal chemosensilla in Adelphocoris fasciaticollis Reuter by scanning electron microscopy and transmission electron microscopy. Seven major types of antennal sensilla were identified in adults of both sexes. Types 1 and 2 are sensilla chaetica and have thick cuticular walls with conspicuous grooves at their surfaces. Types 3 and 4 are multiporous sensilla trichodea with 1–3 dendrites located at the sensillum lymph, indicating a putative olfactory function. Types 5 and 6 are typical sensilla basiconica but share different characteristics in both external morphology and internal ultrastructure, and may be involved in the perception of host-associated odorants. The last sensilla were Bohm bristles. In addition to the morphological characterization, electrophysiological responses of antennal chemosensilla to 51 semiochemicals were investigated based on electroantennogram (EAG) recordings. Results revealed that different chemical stimuli elicited significantly different dose-dependent EAG responses, in which potential sex pheromone components and green leaf volatiles showed relatively higher EAG responses, but neither monoterpenes nor sesquiterpenes can elicit favorable EAG values. The results provided direct morphological and electrophysiological evidence that the adult antennae of A. fasciaticollis could function in searching for mates and host plants.

Antennal sensory receptors of Pteromalus puparum female (Hymenoptera: Pteromalidae), a gregarious pupal endoparasitoid of Pieris rapae

The external morphology of the antennal sensilla of Pteromalus puparum females (Hymenoptera: Pteromalidae) is described using scanning electron microscopy. The antennae of P. puparum females are geniculate in shape, formed from a large, cylindrical scape with a basal radicel fitting into the antennal socket, a shorter, barrel-shaped pedicel and a flagellum composed of 12 subsegments. Eight morphologically distinct types of sensilla were found on the female antennae. These are: nonporous sensilla trichodea types 1 and 2, which are putative mechanosensilla, nonporous sensilla chaetica, which may function as proprioceptors, uniporous sensilla trichodea types 3 and 4, which are presumably contact chemosensilla, basiconic capitate peg sensilla, which probably function in thermo-hygro reception, multiporous sensilla trichodea, and multiporous sensilla placodea which are all presumed to be olfactory sensilla.

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.

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 in female Heterobathmia pseuderiocrania (Insecta, Lepidoptera, Heterobathmiina)

The female antennae of Heterobathmia pseuderiocrania bear 9 types or subtypes of sensilla: multiporous sensilla trichodea of subtypes I and II, multiporous sensilla basiconica, multiporous sensilla auricillica of subtypes I and II, multiporous sensilla coeloconica, uniporous sensilla basiconica, uniporous sensilla chaetica, aporous Bohm’s bristles. Aporous sensilla styloconica are not observed. During evolution of Lepidoptera, it is in the suborder Heterobathmiina that typical sensilla auricillica appear for the first time. Moreover, it is the first description in Lepidoptera, on the one hand of two very different subtypes of sensilla auricillica in the same species and, on the other hand, of a sexual dimorphism related to one subtype of these sensilla. The sensory structures are compared with those of the three other suborders of Lepidoptera. The Heterobathmiina do not possess the specialized sensillar types which occur in the basal suborders Zeugloptera and Aglossata. They have three possible autapomorphies which concern the sensilla auricillica. Their sensilla are close to those of the suborder Glossata which group together all the higher lepidopterans.