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BACKGROUND: The chafer beetle, Holotrichia parallela, causes damage to numerous economically significant crops worldwide. Adult beetles exhibit aggregation behavior likely mediated by a male‐produced pheromone. Advancements in biological research technology have facilitated the identification of insect aggregation pheromones and promoted their applications as bait for trapping and monitoring pests. Currently, only a few active components of aggregation pheromones from Holotrichia species have been identified. However, the specific components of aggregation pheromones produced by H. parallela remain unknown. RESULT: In this study, we initially observed from Y‐tube olfactometer assays that both male and female H. parallela were significantly attracted to volatiles emitted by males, but not to those from females. We then collected hindgut crude extracts of male adults and carried out gas chromatography–mass spectrometry analysis to identify potential aggregation pheromone components. Pentadecyl acetate, cis‐13‐docosenol, and behenic acid were identified as male‐specific compounds in comparison to female extracts, serving as components of the aggregation pheromone in H. parallela. We further evaluated their attractiveness to H. parallea in both laboratory and field experiments. In laboratory settings, pentadecyl acetate, cis‐13‐docosenol, and behenic acid evoked significant responses to both males and females at specific concentrations, as evidenced by both electroantennography tests and behavioral bioassays. Under field conditions, traps baited with these three compounds captured significantly more H. parallela adults compared to control traps. CONCLUSION: In this study, we found that pentadecyl acetate, cis‐13‐docosenol, and behenic acid are specifically present in male H. parallela, serving as aggregation pheromones. Both laboratory and field‐trapping experiments suggest their potential as monitoring and controlling tools against H. parallela adults. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: The harmonious operation of many insect societies depends upon colony-wide dissemination of a non-volatile pheromone produced by a single queen, which informs workers of her presence. This represents a major challenge in large colonies. Honeybee colonies, which can exceed 60,000 bees, are believed to solve this challenge using 'messenger' workers that actively relay the queen pheromone throughout the hive. However, little is known about the structure and effectiveness of the underlying relay network or the biology of messaging. Results: Here, we combine automated tracking with modelling to address these outstanding questions. We find that both queen movement and worker messaging play fundamental roles in queen pheromone dissemination. Fine-grained analyses of worker behaviour confirmed the existence of active messaging, as physical contacts with the queen caused workers to move faster and straighter, thereby accelerating pheromone transmission. Finally, we show that messaging follows a stereotypical developmental trajectory, resulting in an age-dependent hierarchical relay network, with the most intense messaging observed between three and five days of age, when workers undergo a suite of physiological changes associated with queen rearing. Conclusions: These results suggest that the individuals that contribute most to advertising the presence of the queen are also the ones that control queen production. [ABSTRACT FROM AUTHOR]

Environmental cues that predict increased risk of herbivory can prime plant defenses; however, few studies have explored how such cues elicit broader plant responses, including potential effects on plant growth and other resource allocations that may affect tolerance to herbivore damage. We exposed goldenrod plants (Solidago altissima) to varying concentrations of the putative sex pheromone of a gall‐inducing herbivore, which has previously been implicated in defense priming. In experiments with two plant genotypes and three herbivore populations, any level of exposure to the pheromone enhanced tolerance of galling, rescuing flower production to levels observed for ungalled plants. Exposure to low doses of the pheromone elicited greater resistance to galling than exposure to high doses, with unexposed plants exhibiting intermediate resistance, suggesting a nonlinear relationship between exposure and defense priming. These findings suggest plant responses to environmental cues associated with biotic stressors are broader and more complex than previously appreciated. [ABSTRACT FROM AUTHOR]

The spiroketal moiety is an important substructure within many biological natural products. One method to access them is via the oxidative cyclisation of a pendant hydroxyl group on to a pre‐formed pyran. However applications of this methodology have been severely limited by requiring the use of toxic oxidants, such as lead (IV) tetraacetate or mercuric oxide. Herein we report a high yielding photochemical route to prepare complex spiroketals using an oxidative photochemical approach employing iodine monochloride and sodium acetate and demonstrate the methodology to the synthesis of a number of insect pheromones. [ABSTRACT FROM AUTHOR]

The blister beetle Epicauta atomaria (Germar) (Coleoptera: Meloidae) is a phytophagous pest of various agricultural crops, especially in Amaranthaceae, Solanaceae, and Fabaceae. Currently, this insect is managed through the spraying of synthetic insecticides that cause serious human health and environmental damage. To reduce the use of synthetic insecticides, the integrated pest management (IPM) programs for other crop pests rely on the use of semiochemical compounds, such as pheromones, kairomones, and allomones, to manipulate the insects' behavior to prevent crop damage. However, studies on semiochemical compounds related to E. atomaria have never been carried out. For this reason, the aim of this study was to explore the chemical communication of E. atomaria. This includes the existence of (i) a sex and/or an aggregation pheromone, (ii) attractant volatile kairomones from host plants, and (iii) repellent volatile allomones from non‐host plants. Tests were carried out using olfactometers and an experimental arena. First, olfactometer tests failed to show the existence of volatile sex and/or aggregation pheromones of these insects. Second, olfactometer and experimental arena tests failed to demonstrate attraction of E. atomaria via volatile kairomonal compounds from host plants (chard, bell pepper, and cock's‐eggs). However, olfactometer tests showed that non‐host plants of E. atomaria (thyme and lavender) emit allomonal volatile compounds with repellent activity. This work represents a first step toward the elucidation of the chemical ecology of E. atomaria and suggests that volatiles from non‐host plants help shape the host preferences of these insects. Those volatiles could be used as a "push" component in a "push–pull" strategy against this pest. [ABSTRACT FROM AUTHOR]

Background: Helopeltis cinchonae (Hemiptera: Miridae) is a major pest of tea plantations in Asia. Conventional control of pests with pesticides is unsustainable. Therefore, safe and eco‐friendly alternatives, such as pheromones, are required to manage the pest. Results: In gas chromatography–electroantennographic detection (GC–EAD) analysis of whole‐body extracts of virgin female H. cinchonae, two compounds elicited electroantennogram (EAG) responses from male antennae. These were identified as hexyl (R)‐3‐acetoxybutyrate and (R)‐1‐acetoxy‐5‐butyroxyhexane using gas chromatography–mass spectrometry (GC–MS) analysis compared to synthetic compounds. This is the first study to report 1‐acetoxy‐5‐butyroxyhexane as an insect pheromone component. The synthetic compounds elicited dose‐dependent EAG responses from the antennae of male H. cinchonae. In two field trapping experiments, the individual compounds were highly attractive to male H. cinchonae when dispensed from polyethylene vials. However, higher catches were obtained with blends of the two compounds in a 1:10 ratio. The blend of racemic compounds was as attractive as the blend of (R)‐enantiomers. Conclusions: We reported that 1‐acetoxy‐5‐butyroxyhexane and hexyl 3‐acetoxybutyrate are components of the female‐produced sex pheromone of H. cinchonae, but further work is required on the blend and loading of pheromone and on trap design to provide an optimized system for monitoring and control of this pest. The results may also facilitate the identification of the pheromones of other Helopeltis species, which are major pests in many crops. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The red palm weevil (RPW), Rhynchophorus ferrugineus (Olivier), also known as the Asian palm weevil, is an invasive pest that causes widespread damage to palm trees around the globe. As pheromone communication is crucial for their mass attack and survival on palm trees, the olfactory concept of pest control strategies has been widely explored recently. We aim to understand the molecular basis of olfaction in RPW by studying one of the key olfactory proteins in insect pheromone communication, sensory neuron membrane proteins (SNMPs). SNMPs belong to the CD36 (cluster of differentiation 36) family that perform two distinct olfactory roles in insects, either in pheromone (odorant) transfer to the odorant receptors (SNMP1) or in the pheromone clearing process (SNMP2). In this study, we performed antennal transcriptomic screening and identified six SNMPs, mapping them on the R. ferrugineus genome, and confirmed four distinct SNMPs. Both SNMP1 proteins in RPW, viz., RferSNMPu1 and RferSNMPu2, were mapped onto the same scaffold in different loci in the RPW genome. To further understand the function of these proteins, we first classified them using phylogenetic analysis and checked their tissue-specific expression patterns. Further, we measured the relative transcript abundance of SNMPs in laboratory-reared, field-collected adults and pheromone-exposure experiments, ultimately identifying RferSNMPu1 as a potential candidate for functional analysis. We mapped RferSNMPu1 expression in the antennae and found that expression patterns were similar in both sexes. We used RNAi-based gene silencing to knockdown RferSNMPu1 and tested the changes in the RPW responses to aggregation pheromone compounds, 4-methyl-5-nonanol (ferrugineol) and 4-methyl-5-nonanone (ferrugineone), and a kairomone, ethyl acetate using electroantennogram (EAG) recordings. We found a significant reduction in the EAG recordings in the RferSNMPu1 knockdown strain of adult RPWs, confirming its potential role in pheromone detection. The structural modelling revealed the key domains in the RferSNMPu1 structure, which could likely be involved in pheromone detection based on the identified ectodomain tunnels. Our studies on RferSNMPu1 with a putative role in pheromone detection provide valuable insight into understanding the olfaction in R. ferrugineus as well as in other Curculionids, as SNMPs are under-explored in terms of its functional role in insect olfaction. Most importantly, RferSNMPu1 can be used as a potential target for the olfactory communication disruption in the R. ferrugineus control strategies. [ABSTRACT FROM AUTHOR]

Simple Summary: Entomopathogenic nematodes and their symbiotic bacteria are widely utilized for biological control. However, whether nematode-derived signals influence the immune response of insects remains unexplored. In this study, we provide comprehensive insight into the interactions among symbiotic bacteria, nematode pheromone ascarosides, and the G. mellonella insect host. Our findings reveal that under the induction of Photorhabdus bacteria, ascarosides enhance the host's immunity response. Specifically, they suppress the intensity of body color change and increase the expression of related-immunity gene expression. Additionally, ascarosides reduce the Photorhabdus cell load and delay G. mellonella larval mortality. These results imply that G. mellonella larvae may employ nematode pheromones to enhance insect immunity in the presence of symbiotic bacteria, thereby enhancing the resistance to invasive bacteria. Insects protect themselves through their immune systems. Entomopathogenic nematodes and their bacterial symbionts are widely used for the biocontrol of economically important pests. Ascarosides are pheromones that regulate nematode behaviors, such as aggregation, avoidance, mating, dispersal, and dauer recovery and formation. However, whether ascarosides influence the immune response of insects remains unexplored. In this study, we co-injected ascarosides and symbiotic Photorhabdus luminescens subsp. kayaii H06 bacteria derived from Heterorhabditis bacteriophora H06 into the last instar larvae of Galleria mellonella. We recorded larval mortality and analyzed the expressions of AMPs, ROS/RNS, and LPSs. Our results revealed a process in which ascarosides, acting as enhancers of the symbiotic bacteria, co-induced G. mellonella immunity by significantly increasing oxidative stress responses and secreting AMPs (gallerimycin, gloverin, and cecropin). This led to a reduction in color intensity and the symbiotic bacteria load, ultimately resulting in delayed host mortality compared to either ascarosides or symbiotic bacteria. These findings demonstrate the cross-kingdom regulation of insects and symbiotic bacteria by nematode pheromones. Furthermore, our results suggest that G. mellonella larvae may employ nematode pheromones secreted by IJs to modulate insect immunity during early infection, particularly in the presence of symbiotic bacteria, for enhancing resistance to invasive bacteria in the hemolymph. [ABSTRACT FROM AUTHOR]

Ant physiology has been fashioned by 100 million years of social evolution. Ants perform many sophisticated social and collective behaviors yet possess nervous systems similar in schematic and scale to that of the fruit fly Drosophila melanogaster, a popular solitary model organism. Ants are thus attractive complementary subjects to investigate adaptations pertaining to complex social behaviors that are absent in flies. Despite research interest in ant behavior and the neurobiological foundations of sociality more broadly, our understanding of the ant nervous system is incomplete. Recent technical advances have enabled cutting-edge investigations of the nervous system in a fashion that is less dependent on model choice, opening the door for mechanistic social insect neuroscience. In this review, we revisit important aspects of what is known about the ant nervous system and behavior, and we look forward to how functional circuit neuroscience in ants will help us understand what distinguishes solitary animals from highly social ones. [ABSTRACT FROM AUTHOR]

As a new vector insect of pine wood nematodes in China, the Monochamus saltuarius (Coleoptera: Cerambycidae) vectors pine wilt nematodes into healthy pine trees through feeding and oviposition, resulting in huge economic losses to forestry. A promising control strategy is to develop safe and efficient attractants. This study aims to screen for the key active volatiles of Pinus koraiensis (Pinales: Pinaceae), Pinus tabuliformis (Pinales: Pinaceae), and Picea asperata (Pinales: Pinaceae) that can attract M. saltuarius, and to study the synergistic attraction of the main attractant plant volatiles with ethanol and insect aggregation pheromones. The preference of M. saltuarius for three hosts is P. koraiensis > P. tabuliformis > Picea asperata. We detected 18 organic volatiles from three host plants. Through EAG assays and indoor Y-tube behavioral experiments, 3-carene, (-)-camphor, β-pinene, α-phellandrene, terpinolene, α-pinene, D-limonene, and myrcene were screened to have attractive effects on M. saltuarius. We found that 3-carene, β-pinene, and α-pinene are the most attractive kairomones in field experiments, which may play a crucial role in the host localization of M. saltuarius. Ethanol has a synergistic effect on the attractant activity of 3-carene and β-pinene, and the synergistic effect on β-pinene is the best. The mixture of ethanol, 2-undecyloxy-1-ethanol, and ipsdienol can significantly enhance the attraction effect of β-pinene on M. saltuarius. These new findings provide a theoretical basis for the development of attractants for adult M. saltuarius and contribute to the green control of M. saltuarius. [ABSTRACT FROM AUTHOR]

Simple Summary: Mass outbreaks of the pine sawfly Diprion pini can cause severe damage to pine forests. The larvae of this herbivorous insect feed selectively on the needles of pine trees, notably Pinus sylvestris. During mass outbreak periods, the females release large amounts of sex pheromones. A prior study revealed that the survival rate of sawfly eggs laid on pheromone-exposed pine needles was lower than that of eggs on unexposed pine. In our study, we found that D. pini females avoided oviposition on pheromone-exposed pine, possibly as a counter-adaptation to the enhanced defenses of previously pheromone-exposed trees against sawfly eggs. The females only discriminated between pheromone-exposed and unexposed trees when they had the chance to touch the needles, but not when exposed to the odor of these types of trees. However, the performance of larvae did not significantly differ on pheromone-exposed and unexposed trees. These results underscore the complexity of the chemical ecology of sawfly–pine interactions and highlight the nuanced roles that pheromones play in shaping the relationships between herbivores and their host plants. Insect pheromones have been intensively studied with respect to their role in insect communication. However, scarce knowledge is available on the impact of pheromones on plant responses, and how these in turn affect herbivorous insects. A previous study showed that exposure of pine (Pinus sylvestris) to the sex pheromones of the pine sawfly Diprion pini results in enhanced defenses against the eggs of this sawfly; the egg survival rate on pheromone-exposed pine needles was lower than that on unexposed pine. The long-lasting common evolutionary history of D. pini and P. sylvestris suggests that D. pini has developed counter-adaptations to these pine responses. Here, we investigated by behavioral assays how D. pini copes with the defenses of pheromone-exposed pine. The sawfly females did not discriminate between the odor of pheromone-exposed and unexposed pine. However, when they had the chance to contact the trees, more unexposed than pheromone-exposed trees received eggs. The exposure of pine to the pheromones did not affect the performance of larvae and their pupation success. Our findings indicate that the effects that responses of pine to D. pini sex pheromones exert on the sawfly eggs and sawfly oviposition behavior do not extend to effects on the larvae. [ABSTRACT FROM AUTHOR]

Pheromones play an important role in mate choice in insects, and pheromone synthesis pathways are potential targets for the control of harmful insects, among which desaturation is of great significance in pheromone structural diversity. However, little is known about the desaturase genes regulating pheromone synthesis in Coleoptera. In this study, taking the internationally significant pest Anoplophora glabripennis as a research object, we identified 6 AglaFAD genes, all of which were mapped to the endoplasmic reticulum and shared a highly similar distribution of conserved domains. A phylogenetic analysis showed that AglaFAD1–2 and AglaFAD3–6 exerted desaturation at different positions of the acyl chain, respectively. In regard to the expression levels of these six AglaFADs in both sexes, six tissues and three developmental stages were analyzed by qPCR. Combined with the chemical composition of the female pheromones that have been identified, two candidate genes, AglaFAD2 and AglaFAD5, which are specifically expressed in females, were screened, showing higher expression levels before mating and significantly decreasing after mating. It is speculated that they may be involved in the biosynthesis of contact pheromones in females. These results provide a basis for detailed functional studies of candidate genes in insect pheromone synthesis. [ABSTRACT FROM AUTHOR]

Semiochemicals such as pheromones play a major role in communication between insects, influencing their spatial orientation, aggregation, defense, and mating. The rational chemical design of precision pheromone‐releasing materials are increased the efficiency of pheromone‐based plant protection agents. Decades of research is begun to unravel the complex communication structures regulated by semiochemicals, from the neuronal perception of specific chemical substances to the behavioral responses in hundreds of species, including many devastating pest insects. This article summarizes the most effective uses of semiochemicals in agriculture, the behavioral responses of selected target species, and controlled‐release strategies based on formulations such as novel fibrous polymer carriers. This study helps scientists, decision‐makers, farmers, and the public understand the importance of appropriate mating disruption techniques that reduce the need for broad‐spectrum insecticides and limit their impact on non‐target and beneficial insects. [ABSTRACT FROM AUTHOR]

Pheromone-binding proteins (PBPs) are specific odorant-binding proteins that can specifically recognize insect pheromones. Through transcriptional analysis of the antennae of adult Endoclita signifer, EsigPBP3 was discovered and identified, and EsigPBP3 was found to be highly expressed in the antennae of male moths. Based on the binding characteristics and ability of EsigPBP3, we can find the key ligands and binding site to consider as a target to control the key wood bore E. signifier. In this study, the fluorescence competitive binding assays (FCBA) showed that EsigPBP3 had a high binding affinity for seven key eucalyptus volatiles. Molecular docking analysis revealed that EsigPBP3 had the strongest binding affinity for the sexual pheromone component, (3E,7E)-4,7,11-trimethyl-1,3,7,10-dodecatetraene. Furthermore, same as the result of FCBA, the EsigPBP3 exhibited high binding affinities to key eucalyptus volatiles, eucalyptol, α-terpinene, (E)-beta-ocimene, (−)-β-pinene, and (−)-α-pinene, and PHE35, MET7, VAL10, PHE38, ILE52, and PHE118 are key sites. In summary, EsigPBP3 exhibits high binding affinity to male pheromones and key volatile compounds and the crucial binding sites PHE35, MET7, VAL10, PHE38, ILE52, and PHE118 can act as targets in the recognition of E. signifier pheromones. [ABSTRACT FROM AUTHOR]

Herbivorous insects use plant volatiles to locate hosts, find food, and identify oviposition sites to aid survival and reproduction. Plant volatiles not only regulate the synthesis and release of sex pheromones in insects, but also help them in the search and orientation of sources of sex pheromones. However, after prolonged exposure to plant volatiles, the changes mediating the mating behavior of diamondback moth (DBM) [Plutella xylostella (L.) (Lepidoptera: Plutellidae)] are unclear. DBMs treated with allyl isothiocyanate, a volatile from cruciferous vegetables, did not show improved rates of mating with a limited effect on mating rhythm. This treatment inhibited mating behaviors in 3-day-old DBMs and decreased mating duration in 5-day-old DBMs. After prolonged exposure to allyl isothiocyanate, the total mating duration of DBM was not significantly different from that after prolonged exposure to n-hexane (control). The longest mating duration after emergence in DBM after prolonged exposure to allyl isothiocyanate was delayed by 1 day compared with exposure to n-hexane. Prolonged exposure to plant volatiles intensified the response behavior of DBM to sex pheromones. However, the amount of Z11-16: Ald, a major component of the sex pheromone blend exhibited no change in female pheromone glands. Pheromone biosynthesis activating neuropeptide gene (PBAN) was down-regulated in DBMs after prolonged exposure to plant volatiles. These findings suggest that prolonged exposure (6 h) to plant-derived volatiles have little effect on the mating behavior of DBM. This study provides practical guidance for applying phytochemicals in pest control by regulating insect behavior. [ABSTRACT FROM AUTHOR]

Background: Aedes aegypti is a vector that transmits various viral diseases, including dengue and Zika. The radiation-based sterile insect technique (SIT) has a limited effect on mosquito control because of the difficulty in irradiating males without reducing their mating competitiveness. In this study, the insect sex pheromone heptacosane was applied to Ae. aegypti males to investigate whether it could enhance the mating competitiveness of irradiated males. Methods: Heptacosane was smeared on the abdomens of Ae. aegypti males that were allowed to mate with untreated virgin females. The insemination rate was used to assess the attractiveness of heptacosane-treated males to females. The pupae were irradiated with different doses of X-rays and γ-rays, and the emergence, survival time, egg number, and hatch rate were detected to find the optimal dose of X-ray and γ-ray radiation. The males irradiated at the optimal dose were smeared with heptacosane, released in different ratios with untreated males, and mated with females. The effect of heptacosane on the mating competitiveness of irradiated mosquitoes was then evaluated by the hatch rate, induced sterility, and mating competitiveness index. Results: Applying heptacosane to Ae. aegypti males significantly increased the insemination rate of females by 20%. Pupal radiation did not affect egg number but significantly reduced survival time and hatch rate. The emergence of the pupae was not affected by X-ray radiation but was affected by γ-ray radiation. Pupae exposed to 60 Gy X-rays and 40 Gy γ-rays were selected for subsequent experiments. After 60 Gy X-ray irradiation or 40 Gy γ-ray irradiation, the average hatch rate was less than 0.1%, and the average survival time was more than 15 days. Moreover, at the same release ratio, the hatch rate of the irradiated group perfumed with heptacosane was lower than that of the group without heptacosane. Conversely, the male sterility and male mating competitiveness index were significantly increased due to the use of heptacosane. Conclusions: The sex pheromone heptacosane enhanced the interaction between Ae. aegypti males and females. Perfuming males irradiated by X-rays or γ-rays with heptacosane led to a significant increase in mating competitiveness. This study provided a new idea for improving the application effect of SIT. [ABSTRACT FROM AUTHOR]

Global crop productivity is reduced by 20–40% annually due to agricultural pests. Mass trapping with insect sex-pheromones have been the major option for the pest control because of non-negative impact on both natural enemy and environment. In addition to this, we can lure and record a wide variety of insect pests with low concentrations of the insect sex pheromone which is released by female insects. However, the lack of understanding regarding the mechanism of how insect sex pheromone lures and traps work in the field has negatively affected the application of these techniques in countries like China and Pakistan. This lack of understanding hinders growers' ability to accurately comprehend the effectiveness and proper utilization of insect sex pheromone lures in pest management. This review summarizes recent advancements in molecular understanding of insect sex pheromones (their relevant structures and compositions), mass trapping, mating disruption and peptide biosensors, various forms of insect sex pheromone traps with a focus on the integration of artificial intelligence, machine learning, deep learning, and smart trap technologies used in Asia. According to this review, the insect sex pheromone technique is not only well understood but can also be effectively utilized for agricultural pest management. [ABSTRACT FROM AUTHOR]

BACKGROUND: Insect pheromones are highly effective and environmentally friendly, and are widely used in the monitoring and trapping of pests. However, many researchers have found that various factors such as ultraviolet light and temperature in the field environment can accelerate the volatilization of pheromones, thus affecting the actual control effect. In recent years, electrospinning technology has demonstrated remarkable potential in the preparation of sustained carriers. Moreover, the utilization of biodegradable materials in electrospinning presents a promising avenue for the advancement of eco‐friendly carriers. RESULTS: In this study, homogeneous and defect‐free pheromone carriers were obtained by electrospinning using fully biodegradable polyhydroxybutyrate materials and pheromones of Spodoptera litura. The electrospun fibers with porous structure could continuously release pheromone (the longest can be ≤80 days). They also had low light transmission, hydrophobic protection. More importantly, the pheromone‐loaded electrospun fiber carriers showed stable release and good trapping effect in the field. They could trap pests for at least 7 weeks in the field environment without other light stabilizers added. CONCLUSION: Sustained‐release carriers constructed by electrospinning and green materials could improve the efficacy of pheromones and ensure environmental friendliness, and provided a tool for the management of S. litura and other pests and sustainable development of agricultural. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Plant volatiles, particularly biogenic volatile organic compounds (BVOCs), emitted in urban areas have attracted attention as olfactory signals between plants and other organisms, including insects. However, in urban areas, elevated ozone (O3) levels inhibit plant growth and degrade olfactory signals, including both insect pheromones and BVOCs, resulting in disrupted biological communication. In this article, we review recent findings on how O3 modifies olfactory interactions, focusing on both the emitters and receivers of these signals. The influence of O3 on herbivorous insects and their enemies alters the pressure caused by herbivorous damage in the field, which can affect the development of the defensive capacities of plants at the hereditary level. To address the challenges posed by O3 in biological interactions, BVOC characteristics (e.g., emission rate and species, blend composition, O3 reactivity, and oxidative products) and O3 effects on insects (e.g., preference and antennal detectivity) should be clarified. At the same time, BVOC emissions are expected to increase with rising temperatures, which will likely increase the impact of BVOCs on O3 formation in the future. Therefore, it is necessary to devise strategies, such as selecting non- or low BVOC emitters, to regulate BVOC emissions from urban greening plants and mitigate O3 risks to olfactory interactions and plant health. [ABSTRACT FROM AUTHOR]

Simple Summary: The whitemarked tussock moth is a pest of balsam fir in the Maritime provinces of Canada, and also poses a threat to human health because the hairs on the larvae are urticating (i.e., they irritate the skin). In this manuscript, we improve a known lure, based on the pheromone of this insect, with the aim to use it as a widespread monitoring/detection method. Because the female-produced sex pheromone of this moth is unstable, lures containing this pheromone only last a day or two in the field; however, our detection method takes advantage of a synthetic propheromone, or pheromone precursor, that is converted to the pheromone by acid within the lure and releases it over time, circumventing the problem of its instability. We found that our lure formulation and pheromone delivery method is more effective as a lure for whitemarked tussock moth than the control treatments in our field study. The whitemarked tussock moth (WMTM), Orgyia leucostigma (J.E. Smith) (Lepidoptera: Erebidae), is an economic pest in Nova Scotia, Canada, where it undergoes periodic outbreaks defoliating several tree species of economic value, including balsam fir, Abies balsamea (L.) Miller (Pinaceae). Herein is described a releasing device for the WMTM sex pheromone (Z,Z)-6, 9-heneicosadien-11-one based on a rubber septum, which converts pheromone precursors, such as acetals, namely (Z,Z)-11,11-dimethoxy-6,9-heneicosadiene and (Z,Z)-6,9-heneicosadien-11-one ethylene ketal, to the pheromone itself by the action of acetic acid and releases it over time. The pheromone is unstable in nature and, consequently, lures made with this compound will only attract WMTM for a day or two. The two pheromone precursors, however, are more stable, and are converted slowly into the pheromone by acetic acid impregnated in the releasing device, or by acidic conditions in the environment. The two pheromone precursors were synthesized in 2019 using a modified, previously published approach. Field trapping studies conducted from 2019–22 showed that traps baited with rubber septa loaded with either (Z,Z)-11,11-dimethoxy-6,9-heneicosadiene by itself or (Z,Z)-6,9-heneicosadien-11-one ethylene ketal plus acetic acid consistently caught significantly more WMTM than traps baited with blank septa in most experiments. [ABSTRACT FROM AUTHOR]

Insect olfactory receptors (iORs) with atypical 7‐transmembrane domains, unlike Chordata olfactory receptors, are not in the GPCR protein family. iORs selectively bind to volatile ligands in the environment and affect essential insect behaviors. In this study, we constructed a new platform (iORbase, https://www.iorbase.com) for the structural and functional analysis of iORs based on a combined algorithm for gene annotation and protein structure prediction. Moreover, it provides the option to calculate the binding affinities and binding residues between iORs and pheromone molecules by virtual screening of docking. Furthermore, iORbase supports the automatic structural and functional prediction of user‐submitted iORs or pheromones. iORbase contains the well‐analyzed results of approximately 6 000 iORs and their 3D protein structures identified from 59 insect species and 2 077 insect pheromones from the literature, as well as approximately 12 million pairs of simulated interactions between functional iORs and pheromones. We also built 4 online modules, iORPDB, iInteraction, iModelTM, and iOdorTool to easily retrieve and visualize the 3D structures and interactions. iORbase can help greatly improve the experimental efficiency and success rate, identify new insecticide targets, or develop electronic nose technology. This study will shed light on the olfactory recognition mechanism and evolutionary characteristics from the perspectives of omics and macroevolution. [ABSTRACT FROM AUTHOR]

Detection of sex pheromones of insects relies on the antennae. The female pheromone signal transmission in the male antennae ultimately initiates the courtship and mating behaviors of males. To investigate the proteins and metabolites involved in this neural transduction, integrative proteomics and metabolomics analysis including tandem mass tag (TMT) proteomic quantification and liquid chromatography tandem mass spectrometry (LC/MS)-based metabolomics was adopted for comparing proteomic and metabolic changes between the antennae of male moths following stimulation by females and the non-stimulated males of Antheraea pernyi (Guérin-Méneville, Lepidoptera: Saturniidae) in this study. A total of 92 differentially expressed proteins (DEPs) containing 52 upregulated and 40 downregulated proteins and 545 differentially expressed metabolites (DEMs) including 218 upregulated and 327 downregulated metabolites were identified from the antennae of female-stimulated male moths based on the proteome and metabolome data, respectively. Bioinformatics analysis was performed for the 45 DEPs and 160 DEMs, including Gene Ontology (GO), Clusters of Orthologous Groups (COG), and Kyoto Encylopaedia of Genes and Genomes (KEGG) enrichment analysis and Human Metabolome Database (HMDB) annotation. A number of DEPs and DEMs related to neural transmission of female pheromone signals in the male antennae of A. pernyi were screened, including tyrosine hydroxylase, cryptochrome-1, tachykinin, arylalkylamine N -acetyltransferase, cadherin-23, glutathione S -transferase delta 3, tyramine, tryptamine, n-oleoyl dopamine, n-stearoyl dopamine, and n-stearoyl tyrosine. The altered expression levels of those proteins or metabolites were speculated involved in regulating the neuron activity for enhanced transmission of neural impulses and continuous perception, reception, and transduction of female pheromone signals. Our findings yielded novel insights into the potential mechanisms in the antennae of male A. pernyi responding to female attraction. [ABSTRACT FROM AUTHOR]

In the current ecological context, use of insect sex pheromones as an alternative to conventional pesticides is in constant growth. In this report, we discuss the recent contributions brought by our groups in the field of iron-catalyzed cross-couplings applied to the synthesis of insect pheromones. The pivotal question of the development of sustainable synthetic procedures involving cheap, non-toxic and efficient additives is also discussed, as well as the mechanistic features guiding the reactivity of such catalytic systems.

Summary: Previous work has demonstrated that plants can be used as production platforms for molecules used in health, medicine, and agriculture. Production has been exemplified in both stable transgenic plants and using transient expression strategies. In particular, species of Nicotiana have been engineered to produce a range of useful molecules, including insect sex pheromones, which are valued for species‐specific control of agricultural pests. To date, most studies have relied on strong constitutive expression of all pathway genes. However, work in microbes has demonstrated that yields can be improved by controlling and balancing gene expression. Synthetic regulatory elements that provide control over the timing and levels of gene expression are therefore useful for maximizing yields from heterologous biosynthetic pathways. In this study, we demonstrate the use of pathway engineering and synthetic genetic elements for controlling the timing and levels of production of Lepidopteran sex pheromones in Nicotiana benthamiana. We demonstrate that copper can be used as a low‐cost molecule for tightly regulated inducible expression. Further, we show how construct architecture influences relative gene expression and, consequently, product yields in multigene constructs. We compare a number of synthetic orthogonal regulatory elements and demonstrate maximal yields from constructs in which expression is mediated by dCas9‐based synthetic transcriptional activators. The approaches demonstrated here provide new insights into the heterologous reconstruction of metabolic pathways in plants. [ABSTRACT FROM AUTHOR]

The review describes low-temperature reduction of (–)-mentholactone with diisobutylaluminum hydride in methylene chloride. Depending on the conditions, three products are formed: (2S,4R,7S)-7-isopropyl-4-methyloxepan-2-ol [(–)-mentholactol), (6R)-8-hydroxy-2,6-dimethyloctan-3-one, and (2S,4R,7S)-2-iso-butoxy-7-isopropyl-4-methyloxepane. Possible ways of formation of each product have been proposed, and conditions for their selective formation have been found. The synthesis of oxepan-2-ol isobutyl acetals via low-temperature (–70°C) reduction of 7-membered lactones with diisobutylaluminum hydride in methylene chloride is considered. The synthesis of a number of low-molecular-weight bioregulators, including optically active pheromones of insect pests in agriculture and forestry, based on (–)-mentholactol, its aluminate, and (6R)-8-hydroxy-2,6-dimethyloctan-3-one is discussed. [ABSTRACT FROM AUTHOR]

Insect sex pheromones are volatile chemicals that induce mating behavior between conspecific individuals. In moths, sex pheromone biosynthesis is initiated when pheromone biosynthesis-activating neuropeptide (PBAN) synthesized in the suboesophageal ganglion binds to its receptor on the epithelial cell membrane of the pheromone gland. To investigate the function of PBAN receptor (PBANR), we identified two PBANR isoforms, MviPBANR-B and MviPBANR-C, in the pheromone glands of Maruca vitrata. These two genes belong to G protein-coupled receptors (GPCRs) and have differences in the C-terminus but share a 7-transmembrane region and GPCR family 1 signature. These isoforms were expressed in all developmental stages and adult tissues. MviPBANR-C had the highest expression level in pheromone glands among the examined tissues. Through in vitro heterologous expression in HeLa cell lines, only MviPBANR-C-transfected cells responded to MviPBAN (≥5 µM MviPBAN), inducing Ca2+ influx. Sex pheromone production and mating behavior were investigated using gas chromatography and a bioassay after MviPBANR-C suppression by RNA interference, which resulted in the major sex pheromone component, E10E12-16:Ald, being quantitatively reduced compared to the control, thereby decreasing the mating rate. Our findings indicate that MviPBANR-C is involved in the signal transduction of sex pheromone biosynthesis in M. vitrata and that the C-terminal tail plays an important role in its function. [ABSTRACT FROM AUTHOR]

Dodecyl acetate (DDA), a volatile compound present in insect sex pheromones, was incorporated into alginate-based granules to obtain controlled-release formulations (CRFs). In this research, not only was the effect of adding bentonite to the basic alginate-hydrogel formulation studied, but also that of the encapsulation efficiency on the release rate of DDA in laboratory and field experiments. DDA encapsulation efficiency increased as the alginate/bentonite ratio increased. From the preliminary volatilization experiments, a linear relationship was found between the DDA release percentage and the amount of bentonite present in the alginate CRFs. Laboratory kinetic volatilization experiments showed that the selected alginate-bentonite formulation (DDAB75A10) exhibited a prolonged DDA release profile. The value of the diffusional exponent obtained from the Ritger and Peppas model (n = 0.818) indicated that the release process follows a non-Fickian or anomalous transport mechanism. Field volatilization experiments showed a steady release of DDA over time from the alginate-based hydrogels tested. This result, together with those obtained from the laboratory release experiments, allowed the obtainment of a set of parameters to improve the preparation of alginate-based CRFs for the use of volatile biological molecules, such as DDA, in agricultural biological control programs. [ABSTRACT FROM AUTHOR]

Pheromone cues released from hosts or prey are of crucial importance to natural enemies for prey and habitat location. The use of herbivorous insect sex pheromones has long been considered as a potential pest control alternative that is non-toxic and harmless to beneficials. We hypothesized that Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), a major predatory coccinellid beetle of the devastating migratory pest Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae), could perceive and use the sex pheromone of S. frugiperda to locate its habitat. Here we tested the electrophysiological and behavioral responses of H. axyridis to the two components Z7-12:Ac and Z9-14:Ac of S. frugiperda sex pheromone by using electroantennography (EAG) and Y-tube bioassay. The 3D modeling of H. axyridis odorant-binding proteins (HaxyOBPs) and molecular docking were also performed. The results showed that both female and male H. axyridis exhibited significantly higher electrophysiological and behavioral responses to Z9-14:Ac at the concentrations of 0.001, 0.01, and 0.1 μg/μL, while no significant electrophysiological and behavioral responses of H. axyridis were observed to Z7-12:Ac. The blend of Z7-12:Ac and Z9-14:Ac at the ratio of 1: 100 had a significant attraction to both male and female H. axyridis at the concentrations of 0.01 and 0.1 μg/μL based on electrophysiological and behavioral assays, but no significant behavioral responses were observed at the ratios of 1:9. According to the 3D modeling of HaxyOBPs and molecular docking, HaxyOBP12 has a good affinity with Z9-14:Ac. Z9-14:Ac is bound to the HaxyOBP12 by hydrogen bonding and hydrophobic interactions. However, there were no credible docking results between HaxyOBPs and Z7-12:Ac. Our findings revealed that H. axyridis can perceive Z9-14:Ac and could use it as a chemical cue to locate prey habitat. We speculated that Z7-12:Ac, which showed some antagonistic effect toward the response of H. axyridis to Z9-14:Ac, could improve the adaptability of S. frugiperda in the presence of predators. This study provides new insights into the application of pheromones to manipulate natural enemy behavior for pest control. [ABSTRACT FROM AUTHOR]

Covering: 2013 to June 2022 Pheromones are usually produced by insects in sub-microgram amounts, which prevents the elucidation of their structures by nuclear magnetic resonance (NMR). Instead, a synthetic reference material is needed to confirm the structure of the natural compounds. In addition, the provision of synthetic pheromones enables large-scale field trials for the development of environmentally friendly pest management tools. Because of these potential applications in pest control, insect pheromones are attractive targets for the development of synthetic procedures and the synthesis of these intraspecific chemical messengers has been at the core of numerous research efforts in the field of pheromone chemistry. The present review is a quick reference guide for the syntheses of insect pheromones published from 2013 to mid-2022, listing the synthesized compounds and highlighting current methodologies in organic synthesis, such as carbon–carbon coupling reactions, organo-transition metal chemistry including ring-closing olefin metathesis, asymmetric epoxidations and dihydroxylations, and enzymatic reactions. [ABSTRACT FROM AUTHOR]

Ants are eusocial insects with a complex adaptive foraging system regulated by trail pheromones. This review summarizes ants' pheromone-producing exocrine glands, the chemical composition of ant trail pheromones, and their function and functional characteristics. Glands that secrete trail pheromones include Dufour's gland, poison glands, Pavan's gland and the pygidial gland. Trail pheromones are mostly volatile substances with complex and diverse structures, including hydrocarbons, alkaloids, organic acids, aldehydes, alcohols, ketones and esters. Their functions include orientation and recruitment. Prospects for the future application of trail pheromones in pest ant management are discussed. [ABSTRACT FROM AUTHOR]

The increasing application of solid phase microextraction (SPME) technology has improved the development of various fields. The advantages of this technology are that it facilitates on-site sampling and sample preparation, realizes high-throughput automatic operation, and can be combined with gas chromatography and mass spectrometry for remote monitoring. Further improvements to the speed, efficiency and specificity of this technology are, however, still required. SPME has now been applied to plant and insect volatiles, insect sex pheromones and egg volatiles. Here, we summarize the methods, disadvantages and advantages of solid-phase microextraction, and the optimal extraction materials for different insect semio-chemicals. The purpose of this review is to provide a reference for the selection of optimal methods and materials, thereby increasing the speed and efficiency of sample preparation. [ABSTRACT FROM AUTHOR]

Pheromones are widely used to monitor and control insect pests. Without considering specific pheromones, this paper discusses key considerations for deploying insect pheromone attractants, including dosage, height, position, product categories, influencing factors, dispensers, coverage and duration. Suggestions for further research and future prospects for the application of insect pheromones are provided to improve the effectiveness of insect pheromone products. [ABSTRACT FROM AUTHOR]

Insect sex pheromones are chemicals generated by sexually mature individuals that stimulate the opposite sex to mate. Due to their high transmissibility, ease of detection and harmlessness to natural enemies, sex pheromone products have been widely used in mass trapping and monitoring, and to disrupt the mating of target pests. Using pheromones to disrupt mating is an environmentally-friendly plant protection strategy that plays an important role in integrated pest control. Research on pheromone formulations is a prerequisite for the successful application of these to disrupt mating. However, such research is deficient in our country, which seriously restricts the application of this technology. This paper introduces methods for preparing and applying more than 10 types of pheromone formulations to disrupt the mating of pest insects and suggests directions for future research in this field. [ABSTRACT FROM AUTHOR]

The cyanide‐catalyzed ring‐transformation of α‐hydroxy‐β‐oxoesters to δ‐lactones with exocyclic ester moiety is the key transformation for the preparation of racemic 5‐hexadecanolide (15 % over nine steps) and 6‐acetoxy‐5‐hexadecanolide (22 % over eight steps), two insect pheromones. The benzyloxycarbonyl moiety is transformed via the acid chloride to the undecanoyl side chain. After reduction of the ketone to the secondary alcohol, this functional group was either reduced via the chloro compound to furnish the 5‐hexadecanolide. On the other hand, stereoselective reduction of the ketone gave secondary alcohol with the wrong relative configuration, which was established by X‐ray single‐crystal structure. Inversion was achieved by reaction of the methanesulfonate with cesium acetate yielding (R*,S*)‐6‐acetoxy‐5‐hexadecanolide with the relative configuration also present in the natural product. [ABSTRACT FROM AUTHOR]

Protein feeding is critical for male reproductive success in many insect species. However, how protein affects the reproduction remains largely unknown. Using Bactrocera dorsalis as the study model, we investigated how protein feeding regulated sex pheromone synthesis. We show that protein ingestion is essential for sex pheromone synthesis in male. While protein feeding or deprivation did not affect Bacillus abundance, transcriptome analysis revealed that sarcosine dehydrogenase (Sardh) in protein-fed males regulates the biosynthesis of sex pheromones by increasing glycine and threonine (sex pheromone precursors) contents. RNAi-mediated loss-of-function of Sardh decreases glycine, threonine, and sex pheromone contents and results in decreased mating ability in males. The study links male feeding behavior with discrete patterns of gene expression that plays role in sex pheromone synthesis, which in turn translates to successful copulatory behavior of the males. [ABSTRACT FROM AUTHOR]

Glutathione transferases (GSTs) are ubiquitous key enzymes with different activities as transferases or isomerases. As key detoxifying enzymes, GSTs are expressed in the chemosensory organs. They fulfill an essential protective role because the chemosensory organs are located in the main entry paths of exogenous compounds within the body. In addition to this protective function, they modulate the perception process by metabolizing exogenous molecules, including tastants and odorants. Chemosensory detection involves the interaction of chemosensory molecules with receptors. GST contributes to signal termination by metabolizing these molecules. By reducing the concentration of chemosensory molecules before receptor binding, GST modulates receptor activation and, therefore, the perception of these molecules. The balance of chemoperception by GSTs has been shown in insects as well as in mammals, although their chemosensory systems are not evolutionarily connected. This review will provide knowledge supporting the involvement of GSTs in chemoperception, describing their localization in these systems as well as their enzymatic capacity toward odorants, sapid molecules, and pheromones in insects and mammals. Their different roles in chemosensory organs will be discussed in light of the evolutionary advantage of the coupling of the detoxification system and chemosensory system through GSTs. [ABSTRACT FROM AUTHOR]

Chemical signals are important mediators of interactions within forest ecosystems. In insects, pheromone signals mediate intraspecific interactions such as mate location and acceptance. The evolution of pheromones in insects has been mostly studied from a theoretical perspective in the Lepidoptera. With this study, we aimed to broaden our understanding of pheromone communication in bark beetles. We first demonstrated that the enantiomeric ratios of ipsdienol produced by male I. avulsus, showed little variation. Subsequently, with field trapping trials we characterized the influence of the enantiomeric ratio of ipsdienol (pheromone component of I. avulsus) on I. avulsus captures and observed a great amount of variation in the receiver preference function. Most importantly, we demonstrated that responding individuals responded indiscriminately to all the enantiomeric ratios produced by the emitting individuals. These observations are consistent with the asymmetric tracking model which postulates that if the limiting sex is the emitting sex, responding individuals should not discriminate between emitted ratios. Consequently, responding individuals do not constrain the evolution of the signal. Our data suggest that, in I. avulsus, the composition of the aggregation pheromone signal might be more responsive to external selection forces, such as predation and metabolic constraints, as suggested by the asymmetric tracking model. [ABSTRACT FROM AUTHOR]

This brief review covers and systematizes the key results acquired using metal complex catalysts in both fundamental and applied research aimed at the development of methods and approaches for the production of practically important cyclic and linear isoprenoids, including vitamins, insect pheromones, and flavorants. Own works of the authors on the use of previously discovered novel reactions of homo- and cross-cyclomagnesiation of 1,2-dienes for the synthesis of compounds of isoprenoid structure are considered separately. [ABSTRACT FROM AUTHOR]

It was the late Professor Kenji Mori, the giant of pheromone synthesis and pioneer of pheromone stereochemistry, who laid the foundation for the practical application of insect pheromones, which play an important role in Integrated Pest Management, one of the key concepts of agriculture in the 21st century. Therefore, it would be meaningful to retrace his achievements at this time, three and a half years after his death. In this review, we would like to introduce some of his notable synthetic studies from his Pheromone Synthesis Series and reconfirm his contributions to the development of pheromone chemistry and their impacts on natural science. [ABSTRACT FROM AUTHOR]

Sex pheromone-binding proteins (PBPs) play an important role in sex pheromone recognition in Lepidoptera. However, the mechanisms of chemical communication mediating the response to sex pheromones remain unclear in the diurnal moths of the superfamily Zygaenoidea. In this study, Phauda flammans (Walker) (Lepidoptera: Zygaenoidea: Phaudidae) was used as a model insect to explore the molecular mechanism of sex pheromone perception in the superfamily Zygaenoidea. Two novel pheromone-binding proteins (PflaPBP1 and PflaPBP2) from P. flammans were identified. The two pheromone-binding proteins were predominantly expressed in the antennae of P. flammans male and female moths, in which PflaPBP1 had stronger binding affinity to the female sex pheromones Z-9-hexadecenal and (Z, Z, Z)-9, 12, 15-octadecatrienal, PflaPBP2 had stronger binding affinity only for (Z, Z, Z)-9, 12, 15-octadecatrienal, and no apparent binding affinity to Z-9-hexadecenal. The molecular docking results indicated that Ile 170 and Leu 169 are predicted to be important in the binding of the sex pheromone to PflaPBP1 and PflaPBP2. We concluded that PflaPBP1 and PflaPBP2 may be responsible for the recognition of two sex pheromone components and may function differently in female and male P. flammans. These results provide a foundation for the development of pest control by exploring sex pheromone blocking agents and the application of sex pheromones and their analogs for insect pests in the superfamily Zygaenoidea. [ABSTRACT FROM AUTHOR]

Sex pheromones are pivotal for insect reproduction. However, the mechanism of sex pheromone communication remains enigmatic in hymenopteran parasitoids. Here we have identified the sex pheromone and elucidated the olfactory basis of sex pheromone communication in Campoletis chlorideae (Ichneumonidae), a solitary larval endoparasitoid of over 30 lepidopteran pests. Using coupled gas chromatography-electroantennogram detection, we identified two female-derived pheromone components, tetradecanal (14:Ald) and 2-heptadecanone (2-Hep) (1:4.6), eliciting strong antennal responses from males but weak responses from females. We observed that males but not females were attracted to both single components and the blend. The hexane-washed female cadavers failed to arouse males, and replenishing 14:Ald and 2-Hep could partially restore the sexual attraction of males. We further expressed six C. chlorideae male-biased odorant receptors in Drosophila T1 neurons and found that CchlOR18 and CchlOR47 were selectively tuned to 14:Ald and 2-Hep, respectively. To verify the biological significance of this data, we knocked down CchlOR18 and CchlOR47 individually or together in vivo and show that the attraction of C. chlorideae to their respective ligands was abolished. Moreover, the parasitoids defective in either of the receptors were less likely to court and copulate. Finally, we show that the sex pheromone and (Z)-jasmone, a potent female attractant, can synergistically affect behaviors of virgin males and virgin females and ultimately increase the parasitic efficiency of C. chlorideae. Our study provides new insights into the molecular mechanism of sex pheromone communication in C. chlorideae that may permit manipulation of parasitoid behavior for pest control. [ABSTRACT FROM AUTHOR]

Plant biofactories are a promising platform for sustainable production of high-value compounds, among which are insect sex pheromones, a green alternative to conventional insecticides in agriculture. Recently, we have constructed transgenic Nicotiana benthamiana plants ("Sexy Plants", SxP) that successfully produce a blend of moth (Lepidoptera) sex pheromone compounds (Z)-11-hexadecen-1-ol and (Z)-11-hexadecenyl acetate. However, efficient biosynthesis of sex pheromones resulted in growth and developmental penalty, diminishing the potential for commercial use of SxP in biomanufacturing. To gain insight into the underlying molecular responses, we analysed the whole-genome transcriptome and evaluated it in relation to growth and pheromone production in low- and high-producing transgenic plants of v1.0 and v1.2 SxP lines. In our study, high-producing SxPv1.2 plants accumulated the highest amounts of pheromones but still maintained better growth compared to v1.0 high producers. For an in-depth biological interpretation of the transcriptomic data, we have prepared a comprehensive functional N. benthamiana genome annotation as well as gene translations to Arabidopsis thaliana, enabling functional information transfer by using Arabidopsis knowledge networks. Differential gene expression analysis, contrasting pheromone producers to wild-type plants, revealed that while only a few genes were differentially regulated in low-producing plants, highproducing plants exhibited vast transcriptional reprogramming. They showed signs of stress-like response, manifested as downregulation of photosynthesisrelated genes and significant differences in expression of hormonal signalling and secondary metabolism-related genes, the latter presumably leading to previously reported volatilome changes. Further network analyses confirmed stress-like response with activation of jasmonic acid and downregulation of gibberellic acid signalling, illuminating the possibility that the observed growth penalty was not solely a consequence of a higher metabolic burden imposed upon constitutive expression of a heterologous biosynthetic pathway, but rather the result of signalling pathway perturbation. Our work presents an example of comprehensive transcriptomic analyses of disadvantageous stress signalling in N. benthamiana biofactory that could be applied to other bioproduction systems. [ABSTRACT FROM AUTHOR]

Background: The nose of most animals comprises multiple sensory subsystems, which are defined by the expression of different olfactory receptor families. Drosophila melanogaster antennae contain two morphologically and functionally distinct subsystems that express odorant receptors (Ors) or ionotropic receptors (Irs). Although these receptors have been thoroughly characterized in this species, the subsystem-specific expression and roles of other genes are much less well-understood. Results: Here we generate subsystem-specific transcriptomic datasets to identify hundreds of genes, encoding diverse protein classes, that are selectively enriched in either Or or Ir subsystems. Using single-cell antennal transcriptomic data and RNA in situ hybridization, we find that most neuronal genes—other than sensory receptor genes—are broadly expressed within the subsystems. By contrast, we identify many non-neuronal genes that exhibit highly selective expression, revealing substantial molecular heterogeneity in the non-neuronal cellular components of the olfactory subsystems. We characterize one Or subsystem-specific non-neuronal molecule, Osiris 8 (Osi8), a conserved member of a large, insect-specific family of transmembrane proteins. Osi8 is expressed in the membranes of tormogen support cells of pheromone-sensing trichoid sensilla. Loss of Osi8 does not have obvious impact on trichoid sensillar development or basal neuronal activity, but abolishes high sensitivity responses to pheromone ligands. Conclusions: This work identifies a new protein required for insect pheromone detection, emphasizes the importance of support cells in neuronal sensory functions, and provides a resource for future characterization of other olfactory subsystem-specific genes. [ABSTRACT FROM AUTHOR]

Insect sex pheromones are trace chemicals generated and released by mature individuals, which seduce or stimulate opposite-sex individuals to mating. Due to trace characteristics, high efficiency, high sensitivity, harmlessness to natural enemies, and environmental friendliness, sex pheromone products have been widely used in pest quarantine and monitoring, mating disruption, and mass trapping. In recent years, the research on insect sex pheromones has been further developed along with the improvement of technology, diversity, and sensitivity of detection. Based on the extensive literature investigation, this review summarizes the biological research, structural characteristics, extraction, identification, synthesis, and application prospect of insect sex pheromones. It provides a technical reference and a theoretical basis for the research, development, and application of insect sex pheromones. [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]

A preliminary chemical analysis of the OLFE extract did not detect any of the four known pheromone components or precursors, but further study is needed to understand the interaction between the pheromone and the kairomone attractants. In several species, host volatiles mediate male attraction to mating sites in advance of female emissions of sex pheromones or can synergistically increase the attraction of males when they co-occur with the pheromones [[38], [40], [42]]. When tests 1 and 2 were pulled together, no significant differences were noticeable between the concentrated kairomone and the pheromone lures, while the kairomone lure attracted more than the unbaited traps (H SB 3,60 sb = 24.748; I p i = 0.000) (Figure 3). Keywords: cocoa pod borer; Conopomorpha cramerella; kairomone; pheromone; lure development; monitoring tool EN cocoa pod borer Conopomorpha cramerella kairomone pheromone lure development monitoring tool N.PAG N.PAG 11 09/27/22 20220901 NES 220901 1. [Extracted from the article]