Male Antennae Research Articles

Antennal ultrastructure of three species of Cyclocephala Dejean, 1821 (Coleoptera: Scarabaeidae)

This study describes the antennal ultrastructure in Cyclocephala forsteri Endrodi, 1963, Cyclocephala melanocephala (Fabricius, 1775) and Cyclocephala tucumana Brethes, 1904 (Coleoptera: Scarabaeidae). Adult of Cyclocephala Dejean, 1821 specimens were collected using a light trap placed near a pasture area, segregated by gender, based on male-specific dilated pre-tarsomeres and preserved in 70% alcohol. Scanning electron microscopy (SEM) images of the antenna lamellae were obtained from ten specimens at Universidade Estadual Paulista (UNESP) in Ilha Solteira, SP, Brazil. We identified trichoid, chaetic, placoid, coeloconic, basiconic sensilla, and pores in antenna of all the species. Placoid sensilla were prevalent in the antennal lamellae. The antennae of C. forsteri females had 5,457 sensilla, of which 5,327 (97.62%) were placoid, 123 (2.25%) coeloconic, and seven (0.13%) basiconic, while the antennae of males showed 5,351 sensilla, with 5,238 (97.89%) being placoid, 100 (1.87%) coeloconic, and 13 (0.24%) basiconic. The antennae of C. melanocephala females presented 6,814 sensilla, with 6,581 (96.58%) being placoid, 231 (3.39%) coeloconic, and two (0.03%) basiconic; while those of males had 6,333 sensilla, with 6,023 (95.11%) being placoid and 310 (4.89%) coeloconic. Finally, the antennae of C. tucumana females had 1,981 sensilla, with 1,845 (93.13%) being placoid, 127 (6.42%) coeloconic, and nine (0.45%) basiconic; while the antennae of males had 3,756 sensilla, with 3,656 (97.34%) being placoid, 99 (2.64%) coeloconic, and one (0.02%) basiconic. Overall, adults of C. melanocephala and C. tucumana presented dimorphism in the antennal sensilla.

Functional types of long trichoid sensilla responding to sex pheromone components in Plutella xylostella.

Sex pheromones, which consist of multiple components in specific ratios promote intraspecific sexual communications of insects. Plutella xylostella (L.) is a worldwide pest of cruciferous vegetables, the mating behavior of which is highly dependent on its olfactory system. Long trichoid sensilla on male antennae are the main olfactory sensilla that can sense sex pheromones. However, the underlying mechanisms remain unclear. In this study, 3 sex pheromone components from sex pheromone gland secretions of P. xylostella female adults were identified as Z11-16:Ald, Z11-16:Ac, and Z11-16:OH in a ratio of 9.4 : 100 : 17 using gas chromatography - mass spectrometry and gas chromatography with electroantennographic detection. Electrophysiological responses of 581 and 385 long trichoid sensilla of male adults and female adults, respectively, to the 3 components were measured by single sensillum recording. Hierarchical clustering analysis showed that the long trichoid sensilla were of 6 different types. In the male antennae, 52.32%, 5.51%, and 1.89% of the sensilla responded to Z11-16:Ald, Z11-16:Ac, and Z11-16:OH, which are named as A type, B type, and C type sensilla, respectively; 2.93% named as D type sensilla responded to both Z11-16:Ald and Z11-16:Ac, and 0.34% named as E type sensilla were sensitive to both Z11-16:Ald and Z11-16:OH. In the female antennae, only 7.53% of long trichoid sensilla responded to the sex pheromone components, A type sensilla were 3.64%, B type and C type sensilla were both 0.52%, D type sensilla were 1.30%, and 1.56% of the sensilla responded to all 3 components, which were named as F type sensilla. The responding long trichoid sensilla were located from the base to the terminal of the male antennae and from the base to the middle of the female antennae. The pheromone mixture (Z11-16:Ald : Z11-16:Ac : Z11-16:OH=9.4 : 100 : 17) had a weakly repellent effect on female adults of P. xylostella. Our results lay the foundation for further studies on sex pheromone communications in P. xylostella.

Two sex pheromone receptors for sexual communication in the American cockroach.

Volatile sex pheromones are vital for sexual communication between males and females. Females of the American cockroach, Periplaneta americana, produce and emit two sex pheromone components, periplanone-A (PA) and periplanone-B (PB). Although PB is the major sex attractant and can attract males, how it interacts with PA in regulating sexual behaviors is still unknown. In this study, we found that in male cockroaches, PA counteracted PB attraction. We identified two odorant receptors (ORs), OR53 and OR100, as PB/PA and PA receptors, respectively. OR53 and OR100 were predominantly expressed in the antennae of sexually mature males, and their expression levels were regulated by the sex differentiation pathway and nutrition-responsive signals. Cellular localization of OR53 and OR100 in male antennae further revealed that two types of sensilla coordinate a complex two-pheromone-two-receptor pathway in regulating cockroach sexual behaviors. These findings indicate distinct functions of the two sex pheromone components, identify their receptors and possible regulatory mechanisms underlying the male-specific and age-dependent sexual behaviors, and can guide novel strategies for pest management.

Binding Properties of Odorant Binding Protein 37 in Plagiodera versicolora to Host Volatile, o-Cymene.

The chemosensory system plays an important role in the host plants location. Plagiodera versicolora (Coleoptera: Chrysomelidae) is a worldwide leaf-eating forest pest that feeds exclusively on salicaceous trees. There is no function study of odorant binding proteins (OBPs) in P. versicolora. In the current study, we found that PverOBP37 has a high expression in male and female antennae, heads, and legs by quantitative real-time PCR. The binding properties of PverOBP37 to 18 host plant volatiles were determined by fluorescence competition binding assays. The results showed that PverOBP37 could bind to the host plant volatile, o-cymene. Furthermore, four candidate key amino acid residues (F8, Y50, F103, and R107) of PverOBP37 to o-cymene were identified by molecular docking. The functional assay to confirm Y50, F103, and R107 mutations were key amino acid residues of PverOBP37 involved in the binding to o-cymene. Knockdown of PverOBP37 and Y-tube behavioral bioassays of mated females led to a significantly reduced attraction to o-cymene. This study not only revealed the molecular mechanism of PverOBP37 but also suggested that PverOBP37 is essential to detect host plant volatiles as cues to search for egg-laying sites in P. versicolora.

Antennal Sensitivity of Spotted Lanternflies, Lycorma delicatula: Differential Electrophysiological Responses of Males and Females to Compounds Derived from Host Plants and Conspecifics.

In herbivorous insects, antennae play a crucial role in chemical communication and orientation when locating host plants and mates. To evaluate antennal sensitivity in response to odor stimuli, electroantennography (EAG) has been a practical technique. In the current study of the invasive spotted lanternfly (SLF), Lycorma delicatula (Hemiptera: Fulgoridae), we evaluated and compared their antennal sensitivity to a series of volatile chemicals collected from their bodies, honeydew, and host plants. To do this, we exposed the antennae of SLF fourth-instar and adult males and females to individual chemicals at a fixed dose of 50 ng. Further, a series of dose-response tests were carried out within a range of 0.5 to 100 ng. Although the amplitude of antennal responses varied among stages and sexes, adult males generated the strongest antennal responses in both experiments. In dose-response experiments, increased doses of chemicals up to 50 ng revealed the saturation points except in adult females which required a higher dose (100 ng) to reveal the saturation point. Although EAG does not provide any information on behavioral responses, our results are consistent with the olfactory bioassays in previous publications in which adult males, not females, were attracted to natural volatiles of their conspecifics. EAG indicated a higher sensitivity of adult male antennae to odor stimuli, particularly conspecific volatiles, than female antennae and highlighted sexual differences in the perception of chemical cues in SLF.

Identification of candidate chemosensory genes in Bactrocera cucurbitae based on antennal transcriptome analysis.

The melon fly, Bactrocera cucurbitae (Coquillett) (Tephritidae: Diptera), is an invasive pest that poses a significant threat to agriculture in Africa and other regions. Flies are known to use their olfactory systems to recognise environmental chemical cues. However, the molecular components of the chemosensory system of B. cucurbitae are poorly characterised. To address this knowledge gap, we have used next-generation sequencing to analyse the antenna transcriptomes of sexually immature B. cucurbitae adults. The results have identified 160 potential chemosensory genes, including 35 odourant-binding proteins (OBPs), one chemosensory protein (CSP), three sensory neuron membrane proteins (SNMPs), 70 odourant receptors (ORs), 30 ionotropic receptors (IRs), and 21 gustatory receptors (GRs). Quantitative real-time polymerase chain reaction quantitative polymerase chain reaction was used to validate the results by assessing the expression profiles of 25 ORs and 15 OBPs. Notably, high expression levels for BcucOBP5/9/10/18/21/23/26 were observed in both the female and male antennae. Furthermore, BcucOROrco/6/7/9/13/15/25/27/28/42/62 exhibited biased expression in the male antennae, whereas BcucOR55 showed biased expression in the female antennae. This comprehensive investigation provides valuable insights into insect olfaction at the molecular level and will, thus, help to facilitate the development of enhanced pest management strategies in the future.

Identification of candidate genes associated with host-seeking behavior in the parasitoid wasp Diachasmimorpha longicaudata

BackgroundDiachasmimorpha longicaudata is a hymenopteran fruit fly endoparasitoid. Females of this species find their hosts for oviposition by using complex sensorial mechanisms in response to physical and chemical stimuli associated with the host and host habitat. Ecological and behavioral aspects related to host-seeking behavior for oviposition have been extensively studied in D. longicaudata, including the identification of volatile organic compounds acting as attractants to females. In this sense, molecular mechanisms of chemoreception have been explored in this species, including a preliminary characterization of odorant-binding proteins (OBPs), chemosensory proteins (CSPs) and odorant receptors (ORs), among other proteins. Functional assays on OBP and CSP have been conducted as a first approach to identify molecular mechanisms associated with the female host-seeking behavior for oviposition. The aims of the present study were to identify the D. longicaudata sensory gene repertoire expressed in the antenna of sexually mature and mated individuals of both sexes, and subsequently, characterize transcripts differentially expressed in the antennae of females to identify candidate genes associated with the female host-seeking behavior for oviposition.ResultsA total of 33,745 predicted protein-coding sequences were obtained from a de novo antennal transcriptome assembly. Ten sensory-related gene families were annotated as follows: 222 ORs, 44 ionotropic receptors (IRs), 25 gustatory receptors (GRs), 9 CSPs, 13 OBPs, 2 ammonium transporters (AMTs), 8 pickpocket (PPKs) receptors, 16 transient receptor potential (TRP) channels, 12 CD36/SNMPs and 3 Niemann-Pick type C2 like proteins (NPC2-like). The differential expression analysis revealed 237 and 151 transcripts up- and downregulated, respectively, between the female and male antennae. Ninety-seven differentially expressed transcripts corresponded to sensory-related genes including 88 transcripts being upregulated (87 ORs and one TRP) and nine downregulated (six ORs, two CSPs and one OBP) in females compared to males.ConclusionsThe sensory gene repertoire of D. longicaudata was similar to that of other taxonomically related parasitoid wasps. We identified a high number of ORs upregulated in the female antenna. These results may indicate that this gene family has a central role in the chemoreception of sexually mature females during the search for hosts and host habitats for reproductive purposes.

The Sequence Characteristics and Binding Properties of the Odorant-Binding Protein SvelOBP1 from Sympiezomias velatus (Coleoptera: Curculionidae) to Jujube Volatiles.

Sympiezomias velatus (Chevrolat) (Coleoptera: Curculionidae) has caused serious damage on jujube trees (Ziziphus jujuba Mill) in northern China. Semiochemicals emerging from the host are essential in the process of insects identifying and localizing the host. The highly expressed odorant-binding protein 1 of S. velatus (SvelOBP1) was assumed to play a possible role in the recognition of host volatiles. In this study, SvelOBP1 was cloned based on the antennal transcriptome of S. velatus. The recombinant SvelOBP1 protein was expressed in Escherichia coli and purified by Ni-NTA resin. The predicted protein SvelOBP1 belonged to a classic OBP subfamily. The expression patterns revealed that SvelOBP1 was mainly expressed in the antennae of both males and females, whereas the expression of SvelOBP1 in other body parts could be neglected. The fluorescence binding assay indicated that SvelOBP1 displayed very strong binding affinities to dibutyl benzene-1,2-dicarboxylate and (Z)-hex-3-en-1-ol (Ki = 6.66 ± 0.03 and 7.98 ± 0.06 μM). The molecular docking results showed that residues Trp114, Phe115 and Asp110 may be involved in binding to both dibutyl benzene-1,2-dicarboxylate and (Z)-hex-3-en-1-ol and may have a great impact on odorant recognition of S. velatus. Our results provide evidence that SvelOBP1 might participate in the olfactory molecular perception of S. velatus and would promote the development of pest attractants for S. velatus control.

(−)‐myrtenol and (−)‐α‐pinene: Aggregation pheromone components of the cypress bark beetle Phloeosinus aubei

AbstractThe cypress bark beetle, Phloeosinus aubei, is of increasing concern in the European market of scale‐leafed conifers. Neither the reproductive behaviour nor the chemical ecology have been studied in detail so far, and no specific attractant traps are available to monitor the flight of adults. We established that stridulation by males is crucial for acceptance by calling females. To unravel the chemical communication, hindgut extracts from unmated females were analysed by GC‐EAD, using male antennae. Gut extracts and Thuja occidentalis leaf extracts were analysed by GC/MS. Two antennally active compounds from gut extracts were identified as (−)‐myrtenol and (−)‐α‐pinene by enantioselective GC/MS. (−)‐Myrtenol was shown to be female‐specific, while (−)‐α‐pinene was found as a 2:1 mixture with the (+)‐enantiomer also among the volatiles of the host tree, T. occidentalis. To prove that the production of the above compounds in the beetles is related to reproduction, we treated females with JHIII. The gut extracts from these sexually mature females showed elevated levels of (−)‐α‐pinene compared to untreated control groups. Synthetic enantiomers of myrtenol and α‐pinene were tested separately by electroantennography, and all were found to be electrophysiologically active. The attractiveness of different mixtures of these compounds was compared using 4‐arm olfactometer tests: 4:1 mixtures of racemic α‐pinene with either (−)‐ or (+)‐myrtenol were significantly attractive to males and females, respectively. In field tests, multifunnel traps baited with a 5:1 mixture of (−)‐α‐pinene and (−)‐myrtenol caught significantly more males and females than unbaited control traps. We concluded that (−)‐α‐pinene and (−)‐myrtenol are components of a female‐produced aggregation pheromone. EAD activity and behaviour assays indicated that α‐pinene from Thuja is used by the beetles as part of a host plant kairomone. The complex communication system of P. aubei is discussed in a chemoecological context.

A new endemic clove tree pest of Cryptophasa Lewin, from Sangihe Island, Indonesia (Lepidoptera: Xyloryctidae).

A novel endemic pest of clove tree, Cryptophasa warouwi sp. nov., has been discovered on Sangihe Island. This new species can be distinguished from its closest relative species, C. watungi Sutrisno & Suwito, 2015 which is found in North Sulawesi, by its dark brown straw-coloured wings in both males and females. The most distinctive diagnostic characters of this new species are observed in its genitalia structure: a bent-downward uncus with a strongly sclerotized finger-shaped apex, a bent phallus gradually widened towards coecum, and a double, membranous corpus bursae branching off at mid-ductus corpus bursae of female genitalia. Additionally, DNA barcodes revealed this new species to be embedded among Australian Cryptophasa species despite having fasciculated male antennae that have been considered diagnostic of the genus Paralecta. This suggests that the male antennae may not be a reliable character for separating Cryptophasa from Paralecta. A more comprehensive study including all Cryptophasa and Paralecta will be required to elucidate the definition of each genus. Images depicting both adults and genitalia are provided for this newly recognized species.

The structure and morphogenic changes of antennae of Spilococcus alhagi (Hall) (Hemiptera: Coccoidea: Pseudococcidae) in different instars

To better understand the antennal morphology and sensilla distribution of Spilococcus alhagi (Hall) in different instars, the antennae are examined using light microscopy and scanning electron microscopy. The results show that the antennae of S. alhagi could be differentiated in different instars based on their stucture, number of flagellomere, and sensillar distribution. Functional antennae of S. alhagi appear in first instar nymphs, adult females, and adult males as many scale insects. The antennae of first-instar nymphs comprise six segments, and each antenna has 62–71 sensilla of eight types, including sensilla basiconica (SB), one type of sensilla trichoidea (ST1), two types of sensilla companiform (SCa, sSCa), two types of sensilla coeloconica (SCo1, SCo2) and two types of sensilla chaetica (SCh1, SCh2). The antennae of adult females have eight segments, but each antenna has 164–188 sensilla of the same eight types as the first instar nymphs. The antennae of adult males are more developed, and each antenna contains ten segments and 670–725 sensilla of eleven types, including knobbed seta sensilla (Ks), intersegmental sensilla (Ins), two types of sensilla trichoidea (ST1, ST2), two types of sensilla companiform (SCa, sSCa), two types of sensilla coeloconica (SCo1, SCo2) and three types of sensilla chaetica (SCh1, SCh2, bSCh). Of these, four types of sensilla, viz., Ks, ST2, Ins, bSCh are only observed on the antennae of adult males. The prepupa-like and pupa-like male nymphs both possess simplified antennae, and exhibit four types of sensilla (ST1, SCa, SCh1, SCh2). Based on these results, the morphogenic changes and potential functions of antennae of S. alhagi in different instars are discussed.

Evidence for a role of SNMP2 and antennal support cells in sensillum lymph clearance processes of moth pheromone-responsive sensilla

In insect antenna, following the activation of olfactory sensory neurons, odorant molecules are inactivated by enzymes in the sensillum lymph. How the inactivation products are cleared from the sensillum lymph is presently unknown. Here we studied the role of support cells (SCs) and the so-called sensory neuron membrane protein 2 (SNMP2), a member of the CD36 family of lipid transporters abundantly expressed in SCs, in sensillum lymph clearance processes in the moths Heliothis virescens and Bombyx mori. In these species, the sex pheromone components are inactivated to long-chain fatty acids. To approach a role of SNMP2 in the removal of such inactivation products, we analyzed the uptake of a fluorescent long-chain fatty acid analog into a newly generated HvirSNMP2-expressing cell line. We found an increased uptake of the analog into SNMP2-cells compared to control cells, which could be blocked by the CD36 protein inhibitor, SSO. Furthermore, analyses of sensilla from antenna treated with the fatty acid analog indicated that SNMP2-expressing SCs are able to take up fatty acids from the sensillum lymph. In addition, sensilla from SSO-pretreated antenna of B. mori showed reduced removal of the fluorescent analog from the sensillum lymph. Finally, we revealed that SSO pretreatment of male silkmoth antenna significantly prolonged the duration of the female pheromone-induced wing-fluttering behavior, possibly as a result of impaired lymph clearance processes. Together our findings in H. virescens and B. mori support a pivotal role of olfactory SCs in sensillum lymph maintenance processes and suggest an integral role of SNMP2 in the removal of lipophilic “waste products” such as fatty acids resulting from sex pheromone inactivation.

Comparative Transcriptomic Assessment of Chemosensory Genes in Adult and Larval Olfactory Organs of Cnaphalocrocis medinalis.

The rice leaf folder, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae), is a notorious pest of rice in Asia. The larvae and adults of C. medinalis utilize specialized chemosensory systems to adapt to different environmental odors and physiological behaviors. However, the differences in chemosensory genes between the olfactory organs of these two different developmental stages remain unclear. Here, we conducted a transcriptome analysis of larvae heads, male antennae, and female antennae in C. medinalis and identified 131 putative chemosensory genes, including 32 OBPs (8 novel OBPs), 23 CSPs (2 novel CSPs), 55 ORs (17 novel ORs), 19 IRs (5 novel IRs) and 2 SNMPs. Comparisons between larvae and adults of C. medinalis by transcriptome and RT-qPCR analysis revealed that the number and expression of chemosensory genes in larval heads were less than that of adult antennae. Only 17 chemosensory genes (7 OBPs and 10 CSPs) were specifically or preferentially expressed in the larval heads, while a total of 101 chemosensory genes (21 OBPs, 9 CSPs, 51 ORs, 18 IRs, and 2 SNMPs) were specifically or preferentially expressed in adult antennae. Our study found differences in chemosensory gene expression between larvae and adults, suggesting their specialized functions at different developmental stages of C. medinalis. These results provide a theoretical basis for screening chemosensory genes as potential molecular targets and developing novel management strategies to control C. medinalis.

The temporal-spatial expression and functional analysis of three gustatory receptor genes in Solenopsis invicta using sweet and bitter compounds.

The insect gustatory system participates in identifying potential food sources and avoiding toxic compounds. During this process, gustatory receptors (GRs) recognize feeding stimulant and deterrent compounds. However, the GRs involved in recognizing stimulant and deterrent compounds in the red imported fire ant, Solenopsis invicta, remain unknown. Therefore, we conducted a study on the genes SinvGR1, SinvGR32b, and SinvGR28a to investigate the roles of GRs in detecting feeding stimulant and deterrent compounds. In this current study, we found that sucrose and fructose are feeding stimulants and the bitter compound quinine is a feeding deterrent. The fire ant workers showed significant behavior changes to avoid the bitter taste in feeding stimulant compounds. Reverse transcription quantitative real-time polymerase chain reaction results from developmental stages showed that the SinvGR1, SinvGR32b, and SinvGR28a genes were highly expressed in fire ant workers. Tissue-specific expression profiles indicated that SinvGR1, SinvGR32b, and SinvGR28a were specifically expressed in the antennae and foreleg tarsi of workers, whereas SinvGR32b gene transcripts were also highly accumulated in the male antennae. Furthermore, the silencing of SinvGR1 or SinvGR32b alone and the co-silencing of both genes disrupted worker stimulation and feeding on sucrose and fructose. The results also showed that SinvGR28a is required for avoiding quinine, as workers with knockdown of the SinvGR28a gene failed to avoid and fed on quinine. This study first identified stimulant and deterrent compounds of fire ant workers and then the GRs involved in the taste recognition of these compounds. This study could provide potential target gustatory genes for the control of the fire ant.

N-octyl acrylate is a candidate sex pheromone component involved in courtship in parasitoid wasp Microplitis mediator.

Sex pheromones are considered to play critical roles in partner communication of most parasitic Hymenoptera. However, the identification of sex pheromone components remains limited to a few families of parasitoid wasps. In this study, we functionally characterized a candidate sex pheromone component in Microplitis mediator (Hymenoptera: Braconidae), a solitary parasitoid of Noctuidae insects. We found that the body surface extract from female wasps could significantly stimulate courtship behavior of males. Gas chromatography-electroantennographic detection (GC-EAD) analysis revealed that a candidate semiochemical from extract triggered significant electrophysiological response of antennae of males. By performing gas chromatography-mass spectrometer (GC-MS) measurement, GC-EAD active compound was identified as n-octyl acrylate, a candidate sex pheromone component in female M. mediator. In electroantennogram (EAG) tests, antennae of male wasps showed significantly higher electrophysiological responses to n-octyl acrylate than those of females. Y-tube olfactometer assays indicated that male wasps significantly chose n-octyl acrylate compared with the control. Furthermore, male wasps showed a remarkable preference for n-octyl acrylate in a simulated field condition behavioral trial; simultaneously, n-octyl acrylate standard could also trigger significant courtship behavior in males. We propose that n-octyl acrylate, as a candidate vital sex pheromone component, could be utilized to design behavioral regulators of M. mediator to implement the protection and utilization of natural enemies.

Contribution to the knowledge of genus Nalassus Mulsant, 1856 (Coleoptera: Tenebrionidae) from the Eastern Caucasus, Russia.

A new species of darkling beetle of the tribe Helopini is described from the Eastern Caucasus (Russia): Nalassus magomedrasuli Nabozhenko sp. n. It was originally described as the Dagestan population of N. kalashiani Nabozhenko, 2001 based on the similar structure of the male aedeagus. The new species is similar to N. kalashiani in that it differs in the structure of the eyes, male antennae, the shape of the pronotum, the scutellar shield, the male abdomen and habitats. Nalassus magomedrasuli occurs in xerophytic limestone mountain phryganoid steppes in Dagestan, whereas N. kalashiani is distributed in wet alpine meadows in the Chechen Republic and Ingushetia (Russia). The female of N. kalashiani collected in the State Natural reserve Erzi (Ingushetia) is described for the first time.

Molecular Characterization of Three Chemosensory Proteins from Carposina sasakii

The peach fruit moth, Carposina sasakii, is part of the Carposinidae, and is harmful to the families Rosaceae and Rhamnaceae. C. sasakii lays eggs on the hairy surface of the fruit’s stalk cavity and calyx end. After hatching, the moth can bore into the fruits and feed on the flesh inside. Chemosensory proteins (CSPs) are a class of low-molecular-weight soluble carrier proteins that are highly evolutionarily conserved. To enhance our understanding of the recognition of host plant volatiles by CSPs of C. sasakii, the expression patterns and binding characteristics of CsasCSP7, CsasCSP9 and CsasCSP11 in C. sasakii were investigated. In our study, the results of real-time quantitative polymerase chain reaction (qPCR) assays demonstrate that CsasCSP7 and CsasCSP9 transcripts were abundantly expressed in the antennae of males, and CsasCSP11 was highly expressed in the wings of females. Fluorescence competitive binding assays with 38 candidate ligands showed that CsasCSP7 could bind to benzaldehyde and dodecanal, whereas CsasCSP9 bound to butyl octanoate, decanal and (-)-beta-pinene. CsasCSP11 could also bind to1-hexanol, beta-ocimene and 6-methyl-5-hepten-2-one. Our results suggest that CsasCSP7, CsasCSP9 and CsasCSP11 may play a crucial role in locating the host plant of C. sasakii.

Two new species of Deuterophlebia Edwards, 1922 from Southwestern China (Diptera, Deuterophlebiidae)

The family Deuterophlebiidae is considered the most plesiomorphic Diptera family, with striking morphology and life history. In this study, we provide detailed descriptions and figures of two new species from Southwestern China: Deuterophlebia pseudopodasp. nov. and Deuterophlebia pachychaetasp. nov., along with genetic distances of COI sequences between the seven known Chinese species of Deuterophlebia Edwards, 1922. The two new species can be identified by the adults’ male terminalia, head structures, male and female antennae and mesothoracic spines or abdominal projections of the pupae. As a result, China is currently the country with the highest Deuterophlebia species diversity.

Identification of sex pheromone in Macdunnoughia crassisigna Warren (Lepidoptera: Noctuidae) and field optimization of the sex attractant.

Sex pheromones have proven to be a viable tool for monitoring and controlling pests and is an important part of integrated pest management (IPM). The noctuid moth Macdunnoughia crassisigna Warren poses a significant threat as a defoliator pest, impacting soybean and cruciferous vegetable production and quality in East Asia. However, a lack of comprehensive knowledge about its sexual chemical signaling hampers the development of semiochemical-based IPM approaches for M. crassisigna. We first determined the mating rhythms of M. crassisigna. We then collected pheromones from the sex glands of virgin females at the mating peak and analyzed their components using gas chromatography-electroantennogram detection analysis. The results showed that three components elicited significant electrophysiological responses in male antennae. Gas chromatography-mass spectrometry analysis characterized these components as (Z)-7-dodecene acetate (Z7-12:OAc), (Z)-9-tetradecene acetate (Z9-14:OAc), and (Z)-11-hexadecen-1-ol (Z11-16:OH). Further field experiments indicated that the mixture of Z7-12:OAc and Z9-14:OAc at a ratio of 3:1 displayed significant attractivity to males, confirming its role as a putative sex pheromone of M. crassisigna. Long-term monitoring tests showed that traps baited with these pheromone lures effectively mirrored the population dynamics of M. crassisigna. This study successfully identified and validated the sex pheromone released by female M. crassisigna and formulated potent sex lures for field-based pest monitoring. These findings enriched our understanding of chemical communication in Noctuidae and laid a foundation for developing practical monitoring and control methods against M. crassisigna. © 2023 Society of Chemical Industry.

Morphological Characterization of the Antennal Sensilla of the Legume Pod Borer, Maruca vitrata (Fabricius) (Lepidoptera: Crambidae).

Maruca vitrata (Fabricius) is an important lepidopteran pest of legumes in the tropics and subtropics. Here, we studied the ultrastructural organization of its antennal sense organs using scanning electron microscopy. The antennae of both sexes of M. vitrata were filiform with the number of flagellar segments varying from 72 to 84. Nine major morphological types of sensilla were observed on male and female antennae: sensilla trichodea (ST), sensilla basiconica (SB), sensilla auricillica (SA), sensilla chaetica (SCh), sensilla coeloconica (SCoe), sensilla cylindrica (SCy), sensilla squamiformia (SSq), sensilla styloconica (SSt), and Böhm sensilla (BS). Three of these sensilla types (SB, SSq, and BS) are newly reported for M. vitrata. Morphological observations revealed that four types are multiporous (ST, SB, SA, and SCoe), two types are uniporous (SCh and SCy), and three types are aporous (SSq, SSt, and BS). The average length of male ST was longer than that of the female. Sensilla cylindrica were observed only on male antennae, indicating sexual dimorphism. This study aims to provide some basic evidence for further studies on the mechanism of insect-plant chemical communication and future semiochemical-based management strategies of the major legume pest M. vitrata.