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Sex pheromones emitted by female moths play important roles in mate attraction. The molecular mechanism underlying pheromone biosynthesis activating neuropeptide (PBAN)‐regulated sex pheromone biosynthesis has been well elucidated in many moth species, although this mechanism is species‐dependent. Spodoptera litura, an important pest, has caused serious economic losses to agricultural production, yet the mechanism for its sex pheromone biosynthesis has not been fully identified. The present study investigates in detail mechanism underlying PBAN‐regulated sex pheromone biosynthesis in S. litura. The transcriptome sequencing of S. litura pheromone glands (PGs) was analysed to identify a serial of candidate genes potentially involved in sex pheromone biosynthesis. Further investigation revealed a bimodal pattern in both sex pheromone release and mating frequency. PBAN was found to regulate sex pheromone biosynthesis via its receptor by using Ca2+ as a secondary messenger, as demonstrated by RNA interference and the application of pharmacological inhibitors. Furthermore, PBAN/Ca2+ signalling activated calcineurin (CaN) and acetyl‐CoA carboxylase (ACC), which mediated sex pheromone biosynthesis in response to PBAN stimulation. Mostly importantly, hexokinase 2 (HK2) was confirmed to be activated by PBAN/PBANR /Ca2+/PKC signalling via phosphorylation at two specific sites (ser423 and ser434 sites of HK2). Overall, our findings shed light on the intricate processes involved in sex pheromone production in S. litura, in which PBAN regulates sex pheromone biosynthesis through PBAN/PBANR/Ca2+/CaN/ACC and PBAN/PBANR/Ca2+/PKC/HK2 signalling pathways. These insights significantly contribute to our comprehension of the specific mechanisms underlying sex pheromone biosynthesis in this moth species. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is a quarantine pest for certain export markets due to its phytosanitary status in affected crops in sub‐Saharan Africa, including citrus. Consequently, there is a zero‐tolerance policy for T. leucotreta in export markets. In South Africa, an integrated pest management strategy, incorporating a systems approach is used to achieve complete control of T. leucotreta. Preharvest management is multi‐faceted, including reliance on sex pheromone tools such as monitoring, attract‐and‐kill, mating disruptions, and sterile insect technique (SIT). Geographically isolated populations of T. leucotreta occur in South Africa, and there is speculation concerning the possible loss of sexual communication between these isolated populations, thereby compromising the efficiency of sex pheromone tools. To investigate this possibility, we collected samples from five geographically isolated populations of T. leucotreta and a population used for SIT in South Africa. These were subjected to sexual attraction trials under choice and no‐choice scenarios in a semi‐natural environment. Results of the choice tests revealed that males of each population preferred their corresponding population females, except irradiated males. However, when we deprived males of their preferred females, these preferences dissipated, and they were equally attracted to females from all populations. These results indicate that local adaptation and other selection forces in contrasting environments are important in sexual communication and selection in T. leucotreta but do not necessarily prevent recognition of sexual signals and attraction between geographically isolated populations. These findings are crucial for area‐wide IPM and precision control of T. leucotreta. [ABSTRACT FROM AUTHOR]

Juvenile diet can profoundly affect subsequent adult development, morphology and reproductive investment. Yet, little is known about how juvenile diet affects adult investment into chemical‐based sexual signalling, perhaps due to the historical assumption that pheromone production is not costly. We explored how juvenile diet influenced the reproductive investment of adults in the gumleaf skeletonizer moth, Uraba lugens. Juveniles were reared on different host plant species (Eucalyptus camaldulensis and Eucalyptus moorei) and on E. moorei host plants with different fertilizer treatments (fertilized and non‐fertilized). These juvenile diets differ in foliage carbon and nitrogen content. Several adult life history traits were influenced by juvenile diet, including body size in females, and longevity in males. However, we found no evidence from Y‐maze olfactometer assays that diet affected the attractiveness of female pheromones to males. Finally, host plant species affected male pre‐copulatory investment: males reared on E. moorei had longer antennae, but less dense sensilla. Combined, our experiments suggest that the effects of juvenile diet on investment in reproductive traits, including those associated with signalling, differ between males and females. Females allocate nutrients to adult body size, which determines fecundity. In contrast, males allocate nutrients to adult longevity and antennae size, both of which improve mate search and mating success. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Given the limited availability of resources in nature, sexual attractiveness may trade off with immunocompetence, as the immunocompetence handicap hypothesis (ICHH) posits. In invertebrates, a direct link between trade‐offs through hormonal/molecular effectors in sexual signals and immunity has not been found so far. Here, we assessed how variation in sexual signals affected parasite infection in two sex pheromone selected lines of the moth Chloridea virescens: an attractive line with a low ratio of 16:Ald/Z11‐16:Ald and an unattractive line with a high ratio. When infecting these lines with an apicomplexan parasite, we found that the attractive Low line was significantly more susceptible to the parasite infection than the unattractive High line. Since the ratio difference between these two lines is determined by a delta‐11‐desturase, we hypothesized that this desaturase may have a dual role, i.e., in the quality of the sexual signal as well as an involvement in immune response, comparable to testosterone in vertebrates. However, when we used CRISPR/cas9 to knockout delta‐11‐desturase in the attractive Low line, we found that the pheromonal phenotype did change to that of the High line, but the infection susceptibility did not. Notably, when checking the genomic location of delta‐11‐desaturase in the C. virescens, we found that mucin is adjacent to delta‐11‐desaturase. When comparing the mucin sequences in both lines, we found four nonsynonymous SNPs in the coding sequence, as well as intronic variation between the two lines. These differences suggest that genetic hitchhiking may explain the variation in susceptibility to parasitic infection. [ABSTRACT FROM AUTHOR]

In moths, pheromone receptors (PRs) are crucial for intraspecific sexual communication between males and females. Moth PRs are considered as an ideal model for studying the evolution of insect PRs, and a large number of PRs have been identified and functionally characterized in different moth species. Moth PRs were initially thought to fall into a single monophyletic clade in the odorant receptor (OR) family, but recent studies have shown that ORs in another lineage also bind type‐I sex pheromones, which indicates that type‐I PRs have multiple independent origins in the Lepidoptera. In this study, we investigated whether ORs of the pest moth Spodoptera frugiperda belonging to clades closely related to this novel PR lineage may also have the capacity to bind type‐I pheromones and serve as male PRs. Among the 7 ORs tested, only 1 (SfruOR23) exhibited a male‐biased expression pattern. Importantly, in vitro functional characterization showed that SfruOR23 could bind several type‐I sex pheromone compounds with Z‐9‐tetradecenal (Z9‐14:Ald), a minor component found in female sex pheromone glands, as the optimal ligand. In addition, SfruOR23 also showed weak responses to plant volatile organic compounds. Altogether, we characterized an S. frugiperda PR positioned in a lineage closely related to the novel PR clade, indicating that the type‐I PR lineage can be extended in moths. [ABSTRACT FROM AUTHOR]

BACKGROUND: Bactrocera minax is a devastating pest of citrus fruits. However, there have been no effective control measures before. Few reports on the sex pheromones of B. minax are available. RESULTS: In this study, nine of the volatile compounds in adult females were identified using headspace solid‐phase microextraction (HS‐SPME) in combination with gas chromatography–mass spectrometry (GC–MS). Among them, d‐limonene, caprolactam, 2‐Nitro‐1H‐imidazole, and creatinine could evoke antennal responses in males. Field bioassays showed that only d‐limonene could lure male flies, with a relative lure rate of 78.18% in all tested samples, which was significantly higher than that of paraffin oil control, while all volatile compounds did not have any lure effective to female flies. Moreover, d‐limonene was diluted with paraffin oil into differential concentrations, the lure effect on males was better at 100, 500, and 800 μL d‐limonene mL−1 than pure d‐limonene (1000 μL mL−1). The relative male lure rate of d‐limonene at 100 μL mL−1 was 85.88%, which was significantly higher than that of food−baits (14.12%) on day 3. However, d‐limonene was unattractive to female and male Bactrocera dorsalis and Zeugodacus tau. Further kinetic analysis showed that female adults released d‐limonene around 15‐day post eclosion. Electroantennography 1 results showed that 500 μL mL−1 d‐limonene evoked the strongest responses to antennae of 10‐ to 25‐day‐old male flies. CONCLUSION: Our results indicated that d‐limonene could be a sex pheromone from female flies of B. minax, and it could be used as a male‐specific sex attractant for B. minax. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Diabrotica balteata LeConte is one of the most important polyphagous agricultural pests. The sex pheromone of this pest was synthesized using Evans asymmetric alkylation, ring‐opening reaction of (R)‐2‐methyloxirane, SN2 alkylation of secondary tosylate, and coupling of chiral tosylate with Grignard reagent as central strategies. The sex pheromone prepared herein would be useful to control D. balteata. [ABSTRACT FROM AUTHOR]

As differences in sex pheromones usually act as a barrier against interspecific mating, the fact that the closely related moths Xylena fumosa (Butler) and X. formosa (Butler) (Lepidoptera: Noctuidae: Xyleninae) are commonly attracted to the sex pheromone lure for Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae: Heliothinae) seems unlikely, suggesting that some mechanisms exist between them to mitigate a potential reproductive interference in pheromone communications. Thus, we examined the overlaps in ecological niches of the two species, and their attractiveness to commercial pheromone lures for other moths, through pheromone trap surveys and published reports. Long‐term field surveys using traps baited with five to six types of artificial sex pheromone lures including those designed for H. armigera, and information in published works revealed that there was a nonnegligible overlap between the two species in terms of seasonal timing of captures, geographic habitats and host plants. These factors, therefore, did not appear to provide conclusive evidence mitigating reproductive interference. However, there was a slight but significant difference between them in the trends of attraction to different artificial pheromone lures; X. formosa was attracted albeit in a small number to the lures for Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae), whereas X. fumosa was only attracted to those for H. armigera. This suggests that differences in pheromone composition, rather than differences in temporal and spatial distributions, between the two species could play a more significant role in premating reproductive isolations. [ABSTRACT FROM AUTHOR]

Pheromone receptors (PRs) are key proteins in the molecular mechanism of pheromone recognition, and exploring the functional differentiation of PRs between closely related species helps to understand the evolution of moth mating systems. Pheromone components of the agricultural pest Mythimna loreyi have turned into (Z)‐9‐tetradecen‐1‐yl acetate (Z9‐14:OAc), (Z)‐7‐dodecen‐1‐yl acetate (Z7‐12:OAc), and (Z)‐11‐hexadecen‐1‐yl acetate, while the composition differs from that of M. separata in the genus Mythimna. To understand the molecular mechanism of pheromone recognition, we sequenced and analyzed antennal transcriptomes to identify 62 odorant receptor (OR) genes. The expression levels of all putative ORs were analyzed using differentially expressed gene analysis. Six candidate PRs were quantified and functionally characterized in the Xenopus oocytes system. MlorPR6 and MlorPR3 were determined to be the receptors of major and minor components Z9‐14:OAc and Z7‐12:OAc. MlorPR1 and female antennae (FA)‐biased MlorPR5 both possessed the ability to detect pheromones of sympatric species, including (Z,E)‐9,12‐tetradecadien‐1‐ol, (Z)‐9‐tetradecen‐1‐ol, and (Z)‐9‐tetradecenal. Based on the comparison of PR functions between M. loreyi and M. separata, we analyzed the differentiation of pheromone recognition mechanisms during the evolution of the mating systems of 2 Mythimna species. [ABSTRACT FROM AUTHOR]

BACKGROUND: Mythimna loreyi is an important agricultural pest with a sensitive sex pheromone communication system. To clarify the pheromone binding proteins (PBPs) and pheromone receptors (PRs) involved in sex pheromone perception is important for both understanding the molecular olfactory mechanism and developing a new pest control strategy in M. loreyi. RESULTS: First, the electroantennogram (EAG) assay showed that male M. loreyi displayed the highest response to the major sex pheromone component Z9‐14:Ac, and higher responses to two minor components, Z7‐12:Ac and Z11‐16:Ac. Second, the fluorescence competition binding assay showed that PBP1 bound all three pheromones and other tested compounds with high or moderate affinity, while PBP2 and PBP3 each bound only one pheromone component and few other compounds. Third, functional study using the Xenopus oocyte system demonstrated that, of the six candidate PRs, PR2 was weakly sensitive to the major pheromone Z9‐14:Ac, but was strongly sensitive to pheromone analog Z9‐14:OH; PR3 was strongly and specifically sensitive to a minor component Z7‐12:Ac; PR4 and OR33 were both weakly sensitive to another minor component, Z11‐16:Ac. Finally, phylogenetic relationship and ligand profiles of PRs were compared among six species from two closely related genera Mythimna and Spodoptera, suggesting functional shifts of M. loreyi PRs toward Spodoptera PRs. CONCLUSION: Functional differentiations were revealed among three PBPs and six PRs in sex pheromone perception, laying an important basis for understanding the molecular mechanism of sex pheromone perception and for developing new control strategies in M. loreyi. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: 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. RESULTS: 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. CONCLUSION: 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. [ABSTRACT FROM AUTHOR]

BACKGROUND: General odor‐binding proteins (GOBPs) play critical roles in insect olfactory recognition of sex pheromones and plant volatiles. Therefore, the identification of GOBPs in Hyphantria cunea (Drury) based on their characterization to pheromone components and plant volatiles is remain unknown. RESULTS: In this study, two H. cunea (HcunGOBPs) genes were cloned, and their expression profiles and odorant binding characteristics were systematically analyzed. Firstly, the tissue expression study showed that both HcunGOBP1 and HcunGOBP2 were highly expressed in the antennae of both sexes, indicating their potential involvement in the perception of sex pheromones. Secondly, these two HcunGOBPs genes were expressed in Escherichia coli and ligand binding assays were used to assess the binding affinities to its sex pheromone components including two aldehydes and two epoxides, and some plant volatiles. HcunGOBP2 showed high binding affinities to two aldehyde components (Z9, Z12, Z15‐18Ald and Z9, Z12‐18Ald), and showed low binding affinities to two epoxide components (1, Z3, Z6‐9S, 10R‐epoxy‐21Hy and Z3, Z6‐9S, 10R‐epoxy‐21Hy), whereas HcunGOBP1 showed weak but significant binding to all four sex pheromone components. Furthermore, both HcunGOBPs demonstrated variable binding affinities to the plant volatiles tested. Thirdly, in silico studies of HcunGOBPs utilized homology, structure modeling, and molecular docking revealed critical hydrophobic residues might be involved in the binding of HcunGOBPs to their sex pheromone components and plant volatiles. CONCLUSION: Our study suggests that these two HcunGOBPs may serve as potential targets for future studies of HcunGOBPs ligand binding, providing insight in the mechanism of olfaction in H. cunea. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The wheat wireworm, Agriotes mancus (Coleoptera: Elateridae), is a predominant elaterid pest species in the Nearctic region, with a life history and morphology similar to those of Agriotes obscurus, Agriotes lineatus and Agriotes sputator, three Palearctic pest elaterids invasive in North America. Here, we report the identification and field testing of the sex pheromone of A. mancus.We collected headspace volatiles from female beetles on Porapak Q, and analysed aliquots of Porapak extract by gas chromatography with electroantennographic detection (GC‐EAD) and by GC‐mass spectrometry. In GC‐EAD recordings, two esters—geranyl butanoate and geranyl hexanoate—elicited antennal responses from A. mancus males. In field experiments, trap lures containing both geranyl butanoate and geranyl hexanoate afforded large captures of A. mancus males, which were—on average—approximately 30‐fold higher than captures in traps baited with a single ester.Traps baited with geranyl butanoate as a single‐component lure captured a significant number of Palearctic A. sputator, indicating the establishment of A. sputator in its invaded Nearctic range.With the A. mancus sex pheromone now known, it can be included in the development of pheromone‐based programmes to monitor and manage native and invasive Agriotes pests in North America. [ABSTRACT FROM AUTHOR]

Background: The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), is a global pest that feeds on >350 plant species and severely limits production of cultivated grasses, vegetable crops and cotton. An efficient way to detect new invasions at early stages, and monitor and quantify the status of established infestations of this pest is to deploy traps baited with species‐specific synthetic sex pheromone lures. Results: We re‐examined the compounds in the sex pheromone glands of FAW females by gas chromatography‐electroantennogram detector (GC‐EAD), GC–mass spectrometry (MS), behavioral and field assays. A new bioactive compound from pheromone gland extracts was detected in low amounts (3.0% relative to (Z)‐9‐tetradecenyl acetate (Z9‐14:OAc), the main pheromone component), and identified as nonanal. This aldehyde significantly increased attraction of male moths to a mix of Z9‐14:OAc and (Z)‐7‐dodecenyl acetate in olfactometer assays. Adding nonanal to this two‐component mix also doubled male trap catches relative to the two‐component mix alone in cotton fields, whereas nonanal alone did not attract any moths. The addition of nonanal to each of three commercial pheromone lures also increased male catches by 53–135% in sorghum and cotton fields. Conclusion: The addition of nonanal to pheromone lures should improve surveillance, monitoring and control of FAW populations. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Premating behaviors mediated by pheromones play pivotal roles in animal mating choices. In natural populations of the striped stem borer Chilo suppressalis and the rice leaf roller Cnaphalocrocis medinalis in the rice field habitat, we discovered that Z11‐16:Ald, a major component of the C. suppressalis pheromone, modulated the premating behavior of C. medinalis. Z11‐16:Ald evoked a strong olfactory response in male antennae and strongly inhibited the sex pheromone trapping of male C. medinalis in the field. The functions of three C. medinalis sex pheromone receptor genes (CmedPR1–3) were verified through heterologous expression in Xenopus oocytes. CmedPR1 responded to Z11‐18:OH and Z11‐18:Ald, as well as the interspecific pheromone compound Z11‐16:Ac of sympatric species; CmedPR2 responded to Z13‐18:OH and Z13‐18:Ald, as well as the sex pheromone compounds Z11‐16:Ald and Z9‐16:Ald of sympatric species; and CmedPR3 responded to Z11‐18:OH and Z13‐18:OH, as well as the interspecific pheromones Z11‐16:OH, Z9‐16:Ald, Z11‐16:Ac, and Z11‐16:Ald of sympatric species. Thus, CmedPR2 and CmedPR3 share the ligand Z11‐16:Ald, which is not a component of the C. medinalis sex pheromone. Therefore, the sex pheromones of interspecific species affected the input of neural signals by stimulating the sex pheromone receptors on the antennae of male C. medinalis moths, thereby inhibiting the olfactory responses of the male moths to the sex pheromones. Our results demonstrate chemical communication among sympatric species in the rice field habitat, the recognition of intra‐ and interspecific sex pheromones by olfactory receptors, and how insect premating behaviors are modulated to possibly affect resource partitioning. [ABSTRACT FROM AUTHOR]

Lyonetia prunifoliella is a significant pest in orchards and damages apple. The sex pheromones of this pest were prepared via a new and concise method. The central to our method were Evans' chiral auxiliaries, the addition of chiral Grignard reagent to aldehyde and Wittig coupling. [ABSTRACT FROM AUTHOR]

BACKGROUND: Sudden outbreaks of the orange wheat blossom midge, Sitodiplosis mosellana (Géhin) cause huge wheat yield losses. Use of sex pheromones is more efficient than laborious egg counting to monitor these hidden‐concealed insects. Quick synthesis of the sex pheromones is therefore required to meet the sudden outbreak needs. RESULTS: A synthetic approach of stereospecific and racemic S. mosellana pheromones was presented. This method afforded the stereospecific and racemic S. mosellana pheromones in three steps and high enantioselectivity (> 98% ee for (2S,7S)‐2,7‐nonanediyl dibutyrate) in less than 1 day with 74% and 73% overall yields, respectively, whereas most conventional methods require longer synthesis time with less than 40% yield. The synthesis routes could quickly and economically afford the pheromones, starting from synthon (S)‐but‐3‐yn‐2‐ol (1a) or but‐3‐yn‐2‐ol (1b), through the same three‐step processes of coupling, reduction, and esterification. The Y‐tube olfactometer results showed significant attractiveness of the synthetic stereospecific and racemic sex pheromones to S. mosellana males relative to the blank control (P < 0.001). Field trials also demonstrated significant attractiveness of the synthetic stereospecific and racemic sex pheromones relative to the blank control (P < 0.001). CONCLUSION: This modular approach is conducive to the deployment of field traps and timely responses to S. mosellana outbreaks and can be a time‐saving and cost‐effective tool to manage S. mosellana. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Linoleic acid is the material for biosynthesis of sex attracting and blocking (postmating) pheromones in Nasonia vitripennis, it is synthesized from oleic acid by a male‐biased fatty acid desaturase (SCD5a). In this study, we developed a specific antibody and further characterized the expression patterns of SCD5a in males at different mating stages by western blot. SCD5a was mainly expressed in male heads rather than in abdomens. Along with the aging process (from Day 1 to Day 3), SCD5a increased significantly. Compared with virgin males, mated males showed higher levels of SCD5a. Likewise, abdomen dipping frequency, during which males release attracting pheromone, increased with age and mating. Moreover, real‐time quantitative PCR revealed that genes responsible for the first three steps of attracting pheromone biosynthesis were more highly expressed in head than in abdomen, but the final gene for transformation of attracting pheromone was more highly expressed in abdomen than in head. These results suggest that linoleic acid for biosynthesis of attracting pheromones may also originate from the head rather than only synthesized at the rectal vesicles. Research Highlights: SCD5a was expressed more in the head than in the abdomen.Linoleic acid for attracting pheromone synthesis may also originate from male's head.Aged or mated males released more attracting pheromone and possess a higher possibility of successful mating. [ABSTRACT FROM AUTHOR]

The biosynthesis and termination of insect sex pheromones should be accurately regulated. In most moths, the biosynthesis and release of sex pheromones are regulated by a class of neuropeptides known as pheromone biosynthesis activating neuropeptides (PBANs). However, endogenous mechanisms underlying the termination of sex pheromone biosynthesis in moths remain elusive. In the present study, Helicoverpa armigera was employed as a model to investigate the role of octopamine (OA) in the inhibition of sex pheromone biosynthesis. Results demonstrated that the release of sex pheromones decreased with an increase in OA titres in older female moths. Moreover, OA treatment led to a significant decrease in sex pheromone production, female capability to attract male counterparts and subsequent female acceptance, indicating its inhibitory role in sex pheromone release. Subsequent qPCR and RNAi analyses revealed that OctβR was a key receptor of OA that regulated sex pheromone biosynthesis. In addition, the OA/OctβR signal suppressed intracellular Ca2+ levels and attenuated PBAN‐mediated increase in the enzyme activities of calcineurin and acetyl‐CoA carboxylase as demonstrated by OA treatment and OctβR‐RNAi. Altogether, these results revealed a mechanism underlying the inhibition of sex pheromone production by OA via suppression of PBAN signalling in moths. [ABSTRACT FROM AUTHOR]

BACKGROUND The potato tuber moth, Phthorimaea operculella is a key pest of potato and tobacco in China. We compared the sex pheromone titers released by P. operculella female, and the electroantennogram (EAG) responses of male antennae to pheromone compounds under laboratory conditions. Then, the optimal sex pheromone ratio was screened in the field. RESULTS: The P. operculella sex pheromone feeding on potato or tobacco was extracted by solvent‐extraction method. Main sex pheromone compounds including E4, Z7‐13: AC (PTM1) and E4, Z7, Z10‐13: AC (PTM2) were found in gland. The titer and relative ratio of P. operculella sex pheromone compounds secreted by female adult moths differ between host populations, while the relative EAG responses trend of P. operculella males to the pheromone components were the same when directly stimulated. In field trials, PTM1:PTM2 = 8:1–4:1 and PTM1:PTM2 = 1:4–1:7 was the most attractive ratio to P. operculella males in tobacco and potato fields, respectively. During 2019–2020, after 8 weeks of mass trapping for each year, the sex pheromone could reduce the population of P. operculella in the potato and tobacco fields. CONCLUSIONS: In this study, fixed property and quantity analyzing methods were adopted to compare sex pheromones from feeding on potato versus tobacco. EAG tests then were carried out on P. operculella males. Finally, we optimized the ratio of two sex pheromone compounds in potato and examined how this influenced field trapping. By further improving the parameters of sex pheromone application in the field, we demonstrate that deployment of sex pheromones can provide effective control of P. operculella. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In moths, various enzymes, such as fatty acid synthases, fatty acyl desaturases, and fatty acyl reductases (FARs), are involved in pheromone biosynthesis. In particular, pheromone gland‐specific FAR (pgFAR) plays an important role in converting the functional group from carboxylic to alcohol during pheromone biosynthesis. A novel pgFAR of Maruca vitrata, Mvi‐pgFAR, was identified through transcriptome sequencing of its pheromone gland. To investigate the involvement of Mvi‐pgFAR in pheromone biosynthesis, Mvi‐pgFAR was cloned from the pheromone gland and suppressed by RNA interference (RNAi). Mvi‐pgFAR harbored several conserved motifs related to NAD(P)H‐binding, N‐glycosylation, and adenosine / guanosine triphosphate binding. Phylogenetic analysis revealed that Mvi‐pgFAR with other lepidopteran pgFARs formed an independent clade. Mvi‐pgFAR was specifically expressed only in the pheromone gland. Quantitative real‐time polymerase chain reaction showed that the diurnal expression levels of Mvi‐pgFAR in the pheromone gland were the highest at 2 h before the scotophase. After primarily confirming Mvi‐pgFAR suppression by RNAi, (E,E)‐10,12‐hexadecadienal (E10E12‐16:Ald), a major sex pheromone component, was quantified by gas chromatography. When Mvi‐pgFAR was successfully suppressed, E10E12‐16:Ald production was reduced by up to half of that of the control, and the mating rate was subsequently decreased. Our results demonstrate that Mvi‐pgFAR downregulation can suppress mating behavior by changing the relative sex pheromone component ratio, suggesting that Mvi‐pgFAR can be used as a novel control target. [ABSTRACT FROM AUTHOR]

Glyphodes pyloalis (Lepidoptera, Crambidae) is an important pest of mulberry trees in China, and current methods for accurate population monitoring and control of this pest are lacking. The sex pheromone of G. pyloalis in China was re‐identified as E10, E12, Z14‐hexadecenyl acetate (E10E12Z14‐16:Ac) and tentatively E10, E12, E14‐hexadecenyl acetate (E10E12E14‐16:Ac). The emergence began 2 h before the dark period, and the peak emergence was 3 h into scotophase. Analysing the female moth's age from 1–9 days revealed that the titre of sex pheromone E10E12Z14‐16:Ac and E10E12E14‐16:Ac did not change statistically, and the ratio remained constant at 7.19 ± 1.12. The titre of pheromone had a significant circadian rhythm, increasing at 2 h after darkness, peaking at 6–8 h before decreasing, but it was still detected after 4 h into photophase. Mating of G. pyloalis occurred mainly at night, with the highest rate during 3 h into scotophase, which was earlier than the temporal pattern of pheromone titres. 18.1% of unfed moths mated immediately after eclosion during the scotophase. This was lower than what is seen in 1–3‐day‐old moths but similar to 4‐day‐old moth. Mating can occur on the same day after emergence, primarily within 1–4 days. Female moths can release pheromone again 48 h after mating, but the ratio of E10E12Z14‐16:Ac and E10E12E14‐16:Ac was reduced to 5.1 ± 0.73. The trapping of male moths in the field showed a significant circadian rhythm, but significant differences in pheromone trapping in Sichuan Gongxian, Zhejiang Chun'an and Haining, and Jiangsu Wujiang were observed. At the same location, the circadian rhythm of moth trapping showed differences between generations. The trapping of the overwintering generation occurred mostly in the early period of scotophase, while other generations were caught slightly later. Our results contribute to effective pheromone trapping for monitoring and mass trapping to better control G. pyloalis populations. [ABSTRACT FROM AUTHOR]

Most known click beetle (Coleoptera: Elateridae) sex pheromones have been identified from economically important European species. We hypothesized that pheromone components might be conserved between New and Old World species, and so tested blends of known pheromones in California and Washington states.Males of the endemic species Idolus californicus and Idolus columbianus (subfamily Elaterinae) were attracted to blends of neryl esters, many of which are known pheromones of related European species. Electroantennogram assays determined that antennae of male beetles responded strongly to two neryl esters, and in field bioassays, males of both species were specifically attracted to neryl hexanoate.Female I. californicus were found to produce both neryl hexanoate and neryl octanoate, and lures that contained neryl hexanoate alone or in blends attracted male beetles. Neryl octanoate was not attractive, and neither synergized nor antagonized attraction to neryl hexanoate.Males of Dalopius spp. also were captured in traps baited with lures containing neryl octanoate.Our results support the hypothesis that the neryl ester pheromone motif is conserved among taxonomically related European and North American elaterids in the tribe Elaterinae, which should aid in the identification of pheromones of pest species within the tribe. [ABSTRACT FROM AUTHOR]

BACKGOUND Sex pheromones of the fall armyworm, Spodoptera frugiperda, show differences in composition and proportions in different geographical populations, but always contain Z9‐14:OAc as the major component. Odorant receptor neurons (ORNs) housed in the long trichoid sensilla (TS) of male antennae are essential to detect female‐released sex pheromones in moths. RESULTS: In this study, we identified seven components from pheromone gland extracts of female S. frugiperda in the Yunnan population from China, including (Z)‐7‐dodecen‐1‐yl acetate (Z7‐12:OAc), (Z)‐9‐tetradecenal (Z9‐14:Ald), (Z)‐9‐dodecen‐1‐yl acetate (Z9‐12:OAc), (Z)‐9‐tetradecen‐1‐yl acetate (Z9‐14:OAc), (E)‐11‐tetradecen‐1‐yl acetate (E11‐14:OAc), (Z)‐11‐tetradecen‐1‐yl acetate (Z11‐14:OAc) and (Z)‐11‐hexadecen‐1‐yl acetate (Z11‐16:OAc) at a ratio of 1.2:4:0.8:79.1:1.6:1.6:11.7 by gas chromatography coupled with mass spectrometry. Gas chromatography‐electroantennographic detection showed that Z9‐14:OAc, Z7‐12:OAc and Z11‐16:OAc are the male antennal active components. Peripheral coding of pheromones in males was investigated by single sensillum recording. Five functional neurons housed in three types of TS were identified based on profiles of neuronal responses, which are responsible for attractive component Z9‐14:OAc, synergistic components Z7‐12:OAc, Z11‐16:OAc, interspecific pheromones (Z)‐9‐tetradecen‐1‐ol (Z9‐14:OH) and (Z,E)‐9,12‐tetradecadien‐1‐yl acetate (Z9,E12‐14:OAc), respectively. Wind tunnel and field tests demonstrated that a ternary combination of Z9‐14:OAc, Z7‐12:OAc and Z11‐16:OAc at a ratio of 88:1:11 shows the strongest attractiveness to males. Conclusion: An optimized pheromone blend of Z9‐14:OAc, Z7‐12:OAc and Z11‐16:OAc in an 88:1:11 ratio was identified for monitoring the invasive pest S. frugiperda in China. Five functional ORNs encoding intra‐ and interspecific pheromones were identified in male antennae, of which three neurons encode attractive component Z9‐14:OAc, synergistic components Z7‐12:OAc and Z11‐16:OAc, respectively, and the other two neurons encode interspecific pheromones Z9‐14:OH and Z9,E12‐14:OAc, separately. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The fall armyworm Spodoptera frugiperda is a worldwide serious agricultural pest, and recently invaded South China. Sex pheromone can be employed to monitor its population dynamics accurately in the field. However, the pheromone components previously reported by testing different geographic populations and strains are not consistent. On the basis of confirming that the S. frugiperda population from Yunnan Province belonged to the corn strain, we analyzed the potential sex pheromone components in the pheromone gland extracts of females using gas chromatography coupled with electroantennographic detection (GC‐EAD), gas chromatography coupled with mass spectrometry (GC‐MS) and electroantennography (EAG). The results show that (Z)‐9‐tetradecenal acetate (Z9‐14:Ac), (Z)‐11‐hexadecenyl acetate (Z11‐16:Ac), (Z)‐7‐dodecenyl acetate (Z7‐12:Ac) or (E)‐7‐dodecenyl acetate (E7‐12:Ac) with a ratio of 100 : 15.8 : 3.9 induced EAD responses to varying degrees: Z9‐14:Ac elicited a strong EAD response, Z7‐12:Ac or E7‐12:Ac elicited a small but clear EAD response, while Z11‐16:Ac elicited a weak EAD response. Further single sensillum recording (SSR) showed that Z9‐14:Ac and Z7‐12:Ac induced dose‐dependent activities in two types (A and B) of sensilla in male antennae, respectively, while the sensilla in response to E7‐12:Ac and Z11‐16:Ac was not recorded. Finally, wind tunnel tests reveal that Z9‐14:Ac and Z7‐12:Ac are two principal sex pheromone components of the tested population. [ABSTRACT FROM AUTHOR]

Trehalase (Treh) hydrolyzes trehalose to generate glucose and it plays important role in many physiological processes. Acetyl‐CoA, the precursor of sex pheromone biosynthesis in the pheromone gland (PG) of Helicoverpa armigera, originates from glucose during glycolysis. However, the function of Treh in sex pheromone biosynthesis remains elusive. In the present study, H. armigera was used as a model to investigate the function of two Trehs (Treh1 and Treh2) in sex pheromone biosynthesis. Results demonstrated that knockdown of HaTreh1 or HaTreh2 in female PGs led to significant decreases in Z11‐16:Ald production, female ability to attract males, and successful mating proportions. Pheromone biosynthesis activating neuropeptide (PBAN) treatment triggered HaTreh1 and HaTreh2 activities in the isolated PGs and Sf9 cells. However, the activities of HaTreh1 and HaTreh2 triggered by PBAN were offset by H‐89, the specific inhibitor of protein kinase A (PKA). Furthermore, the H‐89 treatment significantly decreased the phosphorylation level of Trhe2, which was induced by PBAN. In addition, sugar feeding (5% sugar) increased the enzyme activities of Treh1 and Treh2. In summary, our findings confirmed that PBAN activates Treh1/2 activities by recruiting cAMP/PKA signalling, promotes glycolysis to ensure the supply of acetyl‐CoA, and ultimately facilitates sex pheromone biosynthesis and mating behaviour. [ABSTRACT FROM AUTHOR]

Insects control their flight toward a distant odour source by integrating multimodal sensory information, such as olfactory and visual information. Control of flight speed in orientation flight toward an odour source using visual patterning below has been observed in many species of moths. However, there are few reports about moth flight behaviour over solid‐coloured floors. To examine, which visual stimuli affect flight behaviour of moths, male smaller tea tortrix (Adoxophyes honmai) were released in a pheromone plume over two striped floors (longitudinal and transverse stripes) and two unpatterned floors (solid white and solid black). Flight behaviours were videotaped, and upwind flight speed, height (altitude) and the number of backward movements moths made as they approached the pheromone source were determined. Male moths significantly increased mean and maximum upwind flight speed over longitudinal stripes relative to their speed over transverse stripes. Their speed over a solid black floor was the fastest of all floor patterns tested. As males approached the pheromone source, their mean upwind speed decreased significantly over all floor patterns, except for the black floor. Fewer moths made backward movements over the black floor compared with the other three floors. In addition, male moths flew significantly higher over the white floor than over the other three floors, while 60–40 cm from the pheromone source. This is the first time that differences in moth flight behaviour over two patternless floors have been reported. These results suggest that orientation flight behaviour of male moths is affected not only by visual patterns, but also by the reflectance or reflected wavelength spectrum of the floor. [ABSTRACT FROM AUTHOR]

Dalopius marginatus (L.) (Coleoptera: Elateridae) is a very common click beetle species developing in forest soils in an area from southwest Europe to eastern Siberia. Here, we studied the composition of the female‐released sex pheromone of D. marginatus using coupled gas chromatography‐mass spectrometry (GC‐MS). Neryl octanoate, neryl decanoate, and neryl dodecanoate, in a ratio of approximately 1:100:3, were the only volatile compounds present in the extracts of the pheromone glands. The main compound neryl decanoate proved to be highly attractive to swarming D. marginatus males in the field, whereas adding the two trace compounds in the natural ratio did not influence its attractiveness. Although closely related to the genus Agriotes, D. marginatus is distinct in the use of neryl compounds with comparatively long acid moieties, as opposed to the use of geranyl‐ and/or (E,E)‐farnesyl esters of shorter‐chain fatty acids as sex pheromones in Agriotes species. [ABSTRACT FROM AUTHOR]

BACKGROUND Athetis lepigone, a noctuid moth feeding on more than 30 different crops worldwide, has evolved a sophisticated, sensitive, and specific chemosensory system to detect and discriminate exogenous chemicals. Odorant‐binding proteins (OBPs) are the most important agent in insect chemosensory systems to be explored as an alternative target for environmentally friendly approaches to pest management. RESULTS: To investigate the olfactory function of A. lepigone OBPs (AlepOBPs), AlepOBP6 was identified and expressed in Escherichia coli. The binding affinity of the recombinant OBP to 20 different ligands was then examined using a competitive binding approach. The results revealed that AlepOBP6 can bind to two sex pheromones and ten maize volatiles, and its conformation stability is pH dependent. We also carried out a structure–function study using different molecular approaches, including structure modeling, molecular docking, and a mutation functional assay to identify amino acid residues (M39, V68, W106, Q107, and Y114) involved in the binding of AlepOBP6 to both sex pheromones and maize volatiles in A. lepigone. CONCLUSION: These results suggest that AlepOBP6 is likely involved in mediating the responses of A. lepigone to sex pheromones and maize volatiles, which may play a pivotal function in mating, feeding, and oviposition behaviors. This study not only provides new insight into the binding mechanism of OBPs to sex pheromones and host volatiles in moths, but also contributes to the discovery of novel target candidates for developing efficient behavior disruptors to control A. lepigone in the future. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Odorant‐binding proteins (OBPs) are translators of the external chemical signals, which are critical for maintaining insect life. However, few OBPs were reported in the yellow peach moth (YPM), Conogethes punctiferalis (Guenée). In the current study, five OBPs (CpunOBP1, CpunOBP2, CpunOBP7, CpunPBP2 and CpunPBP4) were expressed and purified from the antennae of the YPM. The results showed that the proteins encoded by five CpunOBPs had six conserved cysteine residues, which were typical structural features of classic OBPs. Moreover, the fluorescence competitive binding assays indicated that the binding affinity of five CpunOBPs to the selected YPM female sex pheromones, host plant volatiles and Penicillium‐inoculated apple volatiles was obviously different. The binding affinities of CpunOBP1 and CpunOBP2 with β‐ionone were the strongest. CpunOBP7 could bind with 12 host plant volatiles but was unable to interact with any one of the three tested female sex pheromones. CpunPBP2 and CpunPBP4 exhibited the highest binding affinity to female sex pheromone trans‐10‐hexadecenal among 30 tested compounds. In conclusion, these results suggest the functional differentiation of the CpunOBPs in recognizing sex pheromones, host plant volatiles and fungus‐infected host plant volatiles, which will provide new insights into selecting target proteins for YPM biocontrol. [ABSTRACT FROM AUTHOR]

An efficient and gram‐scale enantioselective synthesis of (R)‐ and (S)‐13‐methylheptacosane, the sex pheromone of pear psylla, has been developed. The key steps of the approach included Evans' chiral auxiliaries and Wittig coupling of chiral phosphonium salt with aldehyde. [ABSTRACT FROM AUTHOR]

BACKGROUND: Carboxyl/cholinesterases (CCEs) are thought to play a pivotal role in the degradation of sex pheromones and plant‐derived odorants in insects, but their exact biochemistry and physiological functions remain unclear. RESULTS: In this study, two paralogous antennae‐enriched CCEs from Plutella xylostella (PxylCCE16a and 16c) were identified and functionally characterized. High‐purity protein preparations of active recombinant PxylCCE16a and 16c have been obtained from Sf9 insect cells by Ni2+ affinity purification. Our results revealed that the purified recombinant PxylCCE016c is able to degrade two sex pheromone components Z9‐14:Ac and Z11‐16:Ac at 27.64 ± 0.79% and 24.40 ± 3.07%, respectively, while PxylCCE016a presented relatively lower activity. Additionally, a similar difference in activity was measured in plant‐derived odorants. Furthermore, both CCEs displayed obvious preferences for the two sex pheromone components, especially on Z11‐16:Ac (Km values are in the range 7.82–45.06 μmol L–1) which much lower than plant odorants (Km values are in the range 1290–4030 μmol L–1). Furthermore, the activity of the two newly identified CCEs is pH‐dependent. The activity at pH 6.5 is obviously higher than that at pH 5.0. Interestingly, only PxylCCE016c can be inhibited by a common esterase inhibitor triphenyl phosphate (TPP) with LC50 of 1570 ± 520 μmol L–1. CONCLUSION: PxylCCE16c plays a more essential role in odorant degradation than PxylCCE16a. Moreover, the current study provides novel potential pesticide targets for the notorious moth Plutella xylostella. © 2021 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Biosynthesis of (1R,4aS,7S,7aR)‐nepetalactol (1) and (4aS,7S,7aR)‐nepetalactone (2) in plants involves iridoid synthase (ISY), an atypical reductive cyclase that catalyses the reduction of 8‐oxogeranial into the reactive enol of (S)‐8‐oxocitronellal, and cyclization of this enol intermediate, either non‐enzymatically or by a nepetalactol‐related short chain dehydrogenase enzyme (NEPS) that yields the nepetalactols. In this study, we investigated the biosynthesis in vivo of 1 and 2 in the pea aphid, Acyrthosiphon pisum, using a library of isotopically‐labelled monoterpenoids as molecular probes. Topical application of deuterium‐labelled probes synthesized from geraniol and nerol resulted in production of 2H4−lactol 1 and 2H4−lactone 2. However, deuterium incorporation was not evident using labelled probes synthesized from (S)‐citronellol. These results suggest that iridoid biosynthesis in animals, specifically aphids, may follow a broadly similar route to that characterised for plants. [ABSTRACT FROM AUTHOR]

Heliothine species (Lepidoptera: Noctuidae, Heliothinae) include some of the world's most devastating pest species, such as Heliothis virescens (Fabricius) in the Americas and Helicoverpa armigera (Hübner) in the Old World. Sex pheromone communication of these agricultural pest species has been investigated from pheromone receptors (PRs) to brains and behavior in detail. In recent years, great progress has been made in the mechanistic dissection of pheromone reception, demonstrating that PRs play a key role in determining the response characteristics of pheromone‐sensitive olfactory receptor neurons. In this review, we focus on the functional characterization of PRs in heliothine species, and summarize recent progress in the identification of receptors tuned to principal sex pheromone components including Z11‐16:Ald, Z9‐16:Ald, Z9‐14:Ald, and other related alcohols and acetates. Evolution of PRs in ligand selectivity is also discussed. The efficiency and faithfulness of three frequently used heterologous expression systems – Xenopus laevis Daudin oocytes, modified HEK 293 cells, and Drosophila 'empty neuron' mutants – are compared, and the research strategies, skills, and perspectives in the studies are envisioned. Finally, we propose future research topics on PRs in heliothine species. [ABSTRACT FROM AUTHOR]

BACKGROUND Micromelalopha siversi (Staudinger) (Lepidoptera: Notodontidae) is a defoliator of poplar trees, Populus spp. (Salicaceae). In our previous study, 13,15‐octadecadienal has been conformed as a female‐produced candidate sex pheromone component of M. siversi, but the Z/E stereochemistry of the 1,3‐diene system has not been identified so far. RESULTS: Four unsaturated aliphatic aldehydes, Z13,E15‐18:Ald, Z13,Z15‐18:Ald, E13,E15‐18:Ald, and E13,Z15‐18:Ald, were synthesized from the commercially available 12‐bromo‐1‐decanol mainly by alkylation of lithium alkyne, normal Wittig or Wittig–Schlosser olefination, and hydroboration‐protonolysis. According to gas chromatography (GC) analysis of pheromone gland extracts, Z13,E15‐18:Ald was the main component, and a small amount of Z13,Z15‐18:Ald was also detected, with a ratio of approximately 7:3. However, the results of GC‐electroantennographic detection (GC‐EAD) showed that Z13,E15‐18:Ald was the only compound with electrophysiological activity, whereas Z13,Z15‐18:Ald elicited no activity. In the field, traps baited with only Z13,E15‐18:Ald resulted in much superior results to those with Z13,Z15‐18:Ald as well as the Z13,E15‐18:Ald and Z13,Z15‐18:Ald binary mixture. CONCLUSIONS: Based on geometrically selective synthesis and bioactivity tests, the active sex pheromone component of M. siversi has been identified as Z13,E15‐18:Ald, the pheromone component that has not been identified in Lepidoptera before. The synthetic component was attractive to male moths in preliminary field traps, which provides novel technologies to monitor and control this pest. [ABSTRACT FROM AUTHOR]

The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is one of the most important insect pests of corn, sorghum, rice, and grasses. The sex pheromone produced by S. frugiperda is composed of a mixture of esters. In this study, I determined the antennal responses of FAW males from 22 populations in Mexico to the components of the sex pheromone of this species: (Z)‐7‐dodecenyl acetate (Z7‐12:OAc), (Z)‐9‐tetradecenyl acetate (Z9‐14:OAc), and (Z)‐11‐hexadecenyl acetate (Z11‐16:OAc) at four doses (0.01, 0.1, 1, and 10 μg). In addition, I evaluated the behavioural activity of single compounds in the field. The largest antennal responses of FAW males from all the sampled regions were elicited by Z9‐14:OAc (all doses evaluated) and Z7‐12:OAc (0.01, 0.1, and 1 μg). The male antennal responses evoked by Z11‐16:OAc were smaller but similar to responses to Z7‐12:OAc at lower doses (0.01 and 0.1 μg). In the field test, Z9‐14:OAc produced significantly higher captures of S. frugiperda males compared to Z7‐12:AOc and Z11‐16:OAc. Antennal responses were related to captures obtained in the field, supported by the positive correlation of these variables [electroantennography (EAG) response and behaviour], with the exception of Z7‐12:OAc, which elicited relatively large EAG responses but did not produce high captures of S. frugiperda. These results are of importance to agriculture, enabling the implementation of better methods of monitoring and controlling this pest, and support the suggestion that a mixture of Z9‐14:OAc and Z7‐12:OAc could represent an effective attractant for all evaluated populations of S. frugiperda in Mexico. [ABSTRACT FROM AUTHOR]

Most gall midges (Diptera: Cecidomyiidae) are cryptic agricultural pests. These tiny insects are prone to lurk in cargoes and spread over long distances. Their larvae feed in plant tissues, so their infestations are imperceptible until crop damage and economic loss appear. The application of sex pheromones is an efficient method with which to monitor and manage gall midges. The present review focuses on recent advances in the accurate identification of gall midge sex pheromones based on rapidly evolving analytical techniques and their use in field trials in integrated pest management. To date, sex pheromones from 19 species of gall midges have been identified and reported, and sex pheromone‐based monitoring systems have been developed and commercialized for at least ten gall midge species. All monitoring systems were tested in various experiments with a modicum of success. In addition to further studies of sex pheromones, identification of plant‐derived volatiles may offer potentials for the manipulation of behavioral response of gall midges, which can be used in dispensers for surveillance and control purposes. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND Geographic variation in male response to sex pheromone lures has been studied in the field in a number of moth species. However, only a few studies have investigated geographic variation in female calling and sex pheromone under field conditions. For an effective field implementation of sex pheromone lures, it is essential to know the local sex pheromone blend and local timing of sexual communication. We investigated the level and extent of geographic variation in the sexual communication of the important agricultural pest Helicoverpa armigera (Lepidoptera, Noctuidae) in three continents. RESULTS: We found there is no genetic variation in the calling behavior of H. armigera. In the female sex pheromone, we found more between‐population variation than within‐population variation. In male response experiments, we found geographic variation as well. Strikingly, when adding the antagonistic compound Z11‐16:OAc to the pheromone blend of H. armigera, significantly fewer males were caught in Australia and China, but not in Spain. This variation is likely not only due to local environmental conditions, such as photoperiod and temperature, but also to the presence of other closely related species with which communication interference may occur. Conclusion: Finding geographic variation in both the female sexual signal and the male response in this pest calls for region‐specific pheromone lures. Our study shows that the analysis of geographic variation in moth female sex pheromones as well as male responses is important for effectively monitoring pest species that occur around the globe. © 2020 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In moths, sex pheromones play a key role in mate finding. These chemicals are transported in the antennae by odorant‐binding proteins (OBPs). Commonly, males encounter conspecific females; therefore, several OBPs are male‐biased. Less is known, however, about how the olfactory system of moths has evolved toward inverse sexual communication, ie where females seek males. Therefore, the objective of this study was to identify the profile of OBPs and their expression patterns in the bee hive pest, Galleria mellonella, a moth that uses inverse sexual communication. Here, OBP‐related transcripts were identified by an RNA Sequencing (RNA‐Seq) approach and analysed through both Reverse Transcription Polymerase Chain Reaction (RT‐PCR) in different tissues and quantitative real‐time PCR for two states, virgin and postmating. Our results indicate that G. mellonella has 20 OBPs distributed amongst different tissues. Interestingly, 17 of the 20 OBPs were significantly down‐regulated after mating in females, whereas only OBP7 was up‐regulated. By contrast, 18 OBP transcripts were up‐regulated in males after mating. Additionally, binding assays and structural simulations showed general odorant‐binding protein 2 (GOBP2) was able to bind sex pheromone components and analogues. These findings suggest a possible role of OBPs, especially GOBPs, in the inverse sexual communication of G. mellonella, with gene expression regulated as a response to mating. [ABSTRACT FROM AUTHOR]

BACKGROUND: The plant bug, Apolygus lucorum Meyer‐Dür, has begun a resurgence and has become a key pest in cotton in northern China, with the wide‐scale adoption of transgenic Bt cotton. We attempted to develop a new approach to the control of this plant bug by identifying and utilizing its sex pheromone. RESULTS: Extracts from A. lucorum adults and nymphs were analyzed using gas chromatography–mass spectrometry (GC–MS) and gas chromatography–electroantennogram detection (GC–EAD) to identify the sex pheromone components. (E)‐4‐Oxo‐2‐hexenal and (E)‐2‐hexenyl butyrate were the major sex pheromone components from females and were also electrophysiology‐active towards male antennae. For males, (E)‐4‐oxo‐2‐hexenal and hexyl butyrate were the major sex pheromone components. These three components, however, were not detected in nymphs. Field tests showed that binary blends of (E)‐4‐oxo‐2‐hexenal and (E)‐2‐hexenyl butyrate at a ratio of 3:2 resulted in trapping the greatest numbers of A. lucorum males. A long‐term dispenser was developed by loading the pheromone components dissolved in sunflower oil into polyethylene vials. Further field evaluation showed that the polyethylene dispensers attracted significantly more bugs even when deployed in the field for 5 weeks. CONCLUSION: We identified the sex pheromone of A. lucorum and developed a type of high‐efficiency and long‐term lure. Our results could expand knowledge of the pheromones of plant bugs, and provide novel technologies to monitor and control this pest. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND: The cashew stem borer Anthistarcha binocularis (Meyrick) is a major pest in cashew orchards in Brazil. The damage caused by the larvae results in economic losses, and the available chemical control is not suitable because of the endophytic nature of A. binocularis. The identification of the A. binocularis sex pheromone could provide novel applications for the detection and monitoring of this species. RESULTS: Two compounds from female sex gland extracts elicited electrophysiological responses on male antennae. They were identified as dodec‐6‐en‐1‐ol and dodec‐6‐en‐1‐yl acetate by gas chromatography–mass spectrometry. E/Z stereoisomers of both compounds were synthesized, and the electroantennograms for the synthetic compounds showed the strongest responses for the (E)‐stereoisomers of the alcohol and acetate. In a field trial, the E6‐12:OH/E6‐12:OAc mixture attracted male A. binocularis, whereas the Z6‐12:OH/Z6‐12:OAc mixture attracted no specimens. CONCLUSIONS: The bioactive compounds from the sex pheromone of A. binocularis have been identified as a mixture of two previously unidentified pheromone compounds: E6‐12:OH and E6‐12:OAc. The mixture of both compounds was attractive to males in preliminary field experiments, and this study is the first report of Δ6‐unsaturated monoenyl pheromone compounds in Lepidoptera. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND: Phauda flammans Walker is a notorious defoliating pest of Ficus spp. in Southeast Asian. Sex pheromones have been identified as an effective method of biological control. However, little is known about the sex pheromone communication of P. flammans due to a lack of knowledge regarding the diel rhythms of sexual behavior and a lack of field tests using sex pheromone attractants. RESULTS: Adults of P. flammans eclosed from 6:00 to 16:00 h with a peak at 11:00–12:00 h and mated from 9:00 to 19:00 h with a peak at 14:00–15:00 h. The attraction of virgin males to P. flammans females suggested the utilization of sex pheromones. We identified Z‐9‐hexadecenal and (Z,Z,Z)‐9,12,15‐octadecatrienal as the primary components and found that they elicited the largest electroantennographic detection responses from the antennae of males. Field tests confirmed that P. flammans males can be captured by the two synthetic pheromone components at a ratio of 1:1. The capture of only males in field tests using the synthetic compounds confirmed the activity of the identified sex pheromone candidates. CONCLUSION: The results provide useful information for the design of standardized sex pheromone traps for the monitoring as well as trapping of P. flammans in the field. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Pheromone‐binding proteins (PBPs) are thought to bind and transport sex pheromones onto the olfactory receptors on the dendrite membrane of olfactory neurons, and thus play a vital role in sex pheromone perception. However, the function of PBPs has rarely been demonstrated in vivo. In this study, two PBPs (PBP1 and PBP3) of Chilo suppressalis, one of the most notorious pyralid pests, were in vivo functionally characterized using insects with the PBP gene knocked out by the CRISPR/Cas9 system. First, through direct injection of PBP‐single guide RNA (sgRNA)/Cas9 messenger RNA into newly laid eggs, a high rate of target‐gene editing (checked with polled eggs) was induced at 24 h after injection, 21.3% for PBP1‐sgRNA injected eggs and 19.5% for PBP3‐sgRNA injected eggs. Second, by an in‐crossing strategy, insects with mutant PBP1 or PBP3 (both with a premature stop codon) were screened, and homozygous mutants were obtained in the G3 generation. Third, the mutant insects were measured for electroantennogram (EAG) response to female sex pheromones. As a result, both PBP mutant males displayed significant reduction in EAG response, and this reduction in PBP1 mutants was higher than that in PBP3 mutants, indicating a more important role of PBP1. Finally, the relative importance of two PBPs and the possible off target effect induced by sgRNA‐injection are discussed. Taken together, our study provides a deeper insight into the function of and interaction between different PBP genes in sex pheromone perception of C. suppressalis, as well as a valuable reference in methodology for gene functional study in other genes and other moth species. [ABSTRACT FROM AUTHOR]

BACKGROUND: Diamondback moth, Plutella xylostella L., is a very important pest of cruciferous vegetables causing excessive economic losses worldwide. Bioactivities of halo‐, diazo‐, and cyclopropane acetates of P. xylostella sex pheromone have been evaluated using electrophysiology and enzyme inhibition assays. RESULTS: A total of 23 sex pheromone analogs of P. xylostella were designed and synthesized and the result shows that (11Z)‐hexadec‐11‐en‐1‐yl 2,2,2‐trifluoroacetate, (11Z)‐hexadec‐11‐en‐1‐yl 2,2,3,3,3‐pentafluoropropanoate, and (11Z)‐hexadec‐11‐en‐1‐yl trifluoromethanesulfonate elicited potential inhibitory effects at all doses tested in the electrophysiology and enzyme inhibition assays. Interference of locating the sex pheromone source was found strongest when these three analogs were mixed with the sex pheromone at a 10:1 ratio. In addition, field test showed that the rate of mating disruption was over 90% when (11Z)‐hexadec‐11‐en‐1‐yl 2,2,2‐trifluoroacetate or (11Z)‐hexadec‐11‐en‐1‐yl 2,2,3,3,3‐pentafluoropropanoate was mixed with the sex pheromone at a 10:1 ratio. CONCLUSION: Two sex pheromone antagonists were screen out by electrophysiology, enzyme inhibition assays, wind tunnel and field tests. We believe that these antagonists could be used to establish a novel eco‐friendly measure to control P. xylostella and provide evidence for clarifying the specific functions and molecular mechanisms of sex pheromone antagonists. © 2018 Society of Chemical Industry Diamondback moth Plutella xylostella L. is a very important pest of cruciferous vegetables causing excessive economic losses worldwide. Bioactivities of halo‐, diazo‐, and cyclopropane acetates of P. xylostellasex pheromone have been evaluated using electrophysiology and enzyme inhibition assays. [ABSTRACT FROM AUTHOR]

Adult males of web‐building spiders often cohabit the webs of sessile sub‐adult (i.e. penultimate instar) females and mate with them as they moult to adults. Often, males accrue benefits from this cohabitation (kleptoparasitism, avoidance of cannibalism, potential polygamy), whereas sub‐adult females may either accrue benefits or incur costs such as curtailed opportunity for mate choice or mate cannibalism. Working with the false black widow spider, Steatoda grossa, we tested the hypothesis that webs of sub‐adult females, unlike those of virgin adult females, lack sex attractant pheromone that mate‐seeking males could detect and exploit for mate location. We tested our hypothesis in laboratory experiments by presenting adult males with binary choices between different types of webs (e.g., webs of adult virgin females, sub‐adult females or sub‐adult males), and methanol extracts of these webs. Males spent more time on webs, or web extracts, of adult virgin females than on webs or web extracts of any other type. Most males (95%) also displayed courtship only on webs, or web extracts, of adult virgin females. Our data demonstrate apparent semiochemical crypsis of sub‐adult females or their webs to mate‐seeking adult males that seem to find sub‐adult females by chance encounter. This crypsis is likely adaptive to sub‐adult females that are in sexual conflict with adult males cohabiting their webs. [ABSTRACT FROM AUTHOR]

In the cockroach Periplaneta americana, to represent pheromone source in the receptive space, axon terminals of sex pheromone‐receptive olfactory sensory neurons (pSNs) are topographically organized within the primary center, the macroglomerulus, according to the peripheral locations of sex pheromone‐receptive single walled (sw)‐B sensilla. In this study, we sought to determine when and where pSNs emerge in the nymphal antenna. We revealed two different pSN proliferation patterns that underlie the formation of topographic organization in the macroglomerulus. In nymphal antennae, which lack sw‐B sensilla, pSNs are identified in the shorter sensilla, termed sw‐A sensilla. Because new sw‐A sensilla emerge on the proximal antenna at every molt, topographic organization in the macroglomerulus must be formed by adding axon terminals of newly emerged pSNs to the lateral region in the macroglomerulus at each molt. At the final molt, a huge number of new sw‐B sensilla appeared throughout the whole antenna. Sw‐B sensilla in the proximal part of the adult antenna were newly formed during the last instar stage, whereas those located in the distal antenna were transformed from sw‐A sensilla. This transformation was accompanied by an increase in the number of pSNs. Axon terminals of newborn pSNs in new sw‐B sensilla were recruited to the lateral part of the macroglomerulus, whereas those of newborn pSNs in transformed sw‐B sensilla were recruited to the macroglomerulus according to the sensillar location. These mechanisms enable an increase in sensitivity to sex pheromone in adulthood while retaining the topographic map formed during the postembryonic development. In the adult male cockroach, axon terminals of sex pheromone‐receptive olfactory sensory neurons (pSNs) are recruited into a macroglomerulus according to the locations of sex pheromone‐receptive single‐walled B (sw‐B) sensilla. We revealed that the two different pSN proliferation patterns underlie the formation of the topographic organization in the macroglomerulus during the postembryonic development. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: Mating disruption (MD) employs high doses of a pest's synthetic sex pheromone in agricultural plots, to interfere with its reproduction. MD is assumed to have few behavioral effects on non‐target arthropods, because sex pheromones are highly species‐specific and non‐toxic. Nevertheless, some natural enemies use their host's sex pheromones as foraging cues, and thus may be attracted to MD plots. To investigate this hypothesis, we compared parasitoid and spider assemblages in paired plots in five Israeli vineyards during 2015. One plot was MD‐treated against two key pests, Lobesia botrana (Denis & Schiffermüller) and Planococcus ficus (Signoret). Both plots were insecticide‐treated as needed. Natural enemies were suction‐sampled and collected from pheromone‐baited monitoring traps. RESULTS: The total abundance, species diversity and species composition of most natural enemies were unaffected by MD. An important exception involved P. ficus' main parasitoid, Anagyrus sp. nr. pseudococci (Girault). Anagyrus sp. nr. pseudococci females were mainly captured in control plots, while male captures were low and not influenced by MD. Parasitized P. ficus occurred only in MD plots. CONCLUSION: Non‐target effects of MD involved mostly A. sp. nr. pseudococci females and hardly affected other natural enemies. These findings support the use of MD as an environmentally friendly pest management strategy. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Abstract: Sahlbergella singularis Haglund and Distantiella theobroma (Distant) (Heteroptera: Miridae) are the key insect pests of cacao in Ghana and elsewhere in West Africa. Since 1954, spraying with synthetic insecticides has been the principal means of controlling these pests. In West Africa, environmental concerns, economic stimuli, and unreliable access to insecticides have stimulated interest in ecologically more benign mirid control strategies as an alternative to a total reliance on insecticides. Males of both mirid species, and those of the less damaging Bryocoropsis laticollis Schumacher, respond to the same synthetic sex pheromone blend, so pheromone‐based strategies may provide control as well as monitoring opportunities. Pheromone traps were deployed for 3 months at nine densities between two and 30 traps per 0.1 ha plot (20–300 traps ha−1) plus an untreated control treatment in a replicated large‐scale field experiment on mature mixed Upper Amazon hybrid cacao in Ghana, in order to determine the optimal dispenser density for mass trapping, lure‐and‐kill, and/or lure‐and‐infect. At the end of the trapping period, mirid populations in the various treatments were assessed by insecticide knockdown on 400 trees and by searches to hand height on 1 200 trees, together with an assessment of mirid damage. In total 781 S. singularis and 235 D. theobroma were captured in the pheromone traps. The optimal dispenser density for S. singularis was 150 traps ha−1. Over 300 traps ha−1 was probably optimal for D. theobroma as a smaller proportion of the population was captured, and numbers caught per trap displayed no decline with increasing trap density. From insecticide knockdowns, mirid population density was estimated at 220–230 ha−1, 63% of which were D. theobroma. Too few pods and orthotropic shoots were damaged by mirids to establish the efficacy of pheromone trapping for mirid control. [ABSTRACT FROM AUTHOR]