Pheromone Components Research Articles

Nearctic female Agriotes pubescens and Palearctic female A. lineatus (Coleoptera: Elateridae) produce the same sex pheromone.

In central Canada, surveys for the three invasive (Palearctic) Agriotes species-A. obscurus, A. lineatus, and A. sputator-commonly collect A. pubescens, a North American native (Nearctic) click beetle (Coleoptera: Elateridae) that generally co-occurs with Nearctic A. mancus. Despite the abundance of A. pubescens on farmland, its life history and potential economic impact remain largely unknown. Here, we report the identification and field testing of the A. pubescens sex pheromone. We collected headspace volatiles from a single female beetle on Porapak Q, then extracted the female's pheromone gland, and analyzed aliquots of both Porapak extract and pheromone gland extract by gas chromatographic-electroantennographic detection (GC-EAD) and by GC-mass spectrometry. In GC-EAD recordings of gland extract, two esters-geranyl butanoate and geranyl octanoate-elicited antennal responses from A. pubescens males. In a field experiment in Quebec, traps baited with a 1:1 blend of these esters captured approximately 100× more A. pubescens males than traps baited with a single ester. This is the same trap lure used for capturing A. lineatus. In this experiment, and in a similar one run in British Columbia, heterospecific pheromone components added to conspecific pheromone lures reduced captures of A. mancus, A. sputator, A. lineatus, and A. obscurus by 29%, 96%, 44%, and 71%, respectively. These data indicate that, in North America, lures containing pheromone components of multiple Agriotes congeners may not be optimally attractive to all target species.

Identification and field verification of the aggregation pheromone components produced by male Holotrichia parallela Motschulsky (Coleoptera: Scarabaeidae).

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. 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. 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.

Comparation of pheromone-binding proteins 1 and 2 of Spodoptera frugiperda in perceiving the three sex pheromone components Z9-14:Ac, Z7-12: Ac and Z11-16: Ac

Pheromone-binding proteins (PBPs) are mainly responsible for binding and transporting hydrophobic pheromone molecules across the aqueous sensilla lymph to the receptor proteins. The preference of each PBP is believed to be different for each pheromone component within a single species. Significantly higher expression level of PBP1 and PBP2 in the male antennae of Spodoptera frugiperda suggesting that SfruPBP1 and SfruPBP2 might play important roles in pheromone perception. However, the preference of these two PBP to the three main pheromone components Z9-14: Ac, Z7-12: Ac and Z11-16: Ac have not been determined. In this study, a fluorescence competitive binding assay revealed that the binding intensities of SfruPBP1 and SfruPBP2 to Z9-14: Ac or Z7-12: Ac was comparable. We then used the CRISPR/Cas9 system to individually or simultaneously knock out PBP1 and PBP2 in S.frugiperda. The result of courtship behavior indicated that SfruPBP1 and SfruPBP2 were indispensable and played equal roles in perceiving the pheromones Z9-14: Ac and Z7-12: Ac for orientation, wing vibration, and hair-pencil display. Compared with Z9-14:Ac and Z7-12: Ac, Z11-16: Ac showed higher or medium binding intensities with SfruPBP1 and SfruPBP2 but played a minor role in inducing the wing vibration behavior. The results of this study are valuable for elucidating the mechanisms involved in sex pheromone perception and may facilitate the development of PBP-targeted pest control techniques.

Identification of a colony- and dose-dependent worker aggregation pheromone in the subterranean termite Reticulitermes virginicus

Collective behaviors of social insects are often regulated by pheromones. In subterranean termites, some workers forage for and exploit decaying wood for new food resources while forming tunnels from their nest. Colonizing new food resources requires workers to build and disinfect tunnels and chambers inside the nest and ingest decaying wood; therefore subterranean termite colonies should have mechanisms to establish and maintain groups of workers to perform these functions. Recently, an aggregation pheromone was identified in workers of the termite Reticulitermes speratus, which induces quick attraction of nestmate workers and prolonged aggregation to the site of attraction. In this study, we extended this work to another species of Reticulitermes and identified a worker aggregation pheromone in the termite R. virginicus. GC–MS analysis and bioassays demonstrated that this pheromone consists of 3-octanone, 3-octanol, and palmitic acid and shows a colony-specific, dose-dependent attractant response but not an arrestant response. Furthermore, these pheromone components were most likely emitted from the surface of the body. This suggests that aggregation pheromone composition and function differ significantly among termite species, even within the same genus. This study advances our understanding of the regulatory mechanisms of termite aggregation behavior.

Identification of alarm pheromone components of the southern giant Asian hornet, Vespa soror, a major pest of honey bees.

The rise of biological invasions threatens biodiversity and food security, with the vespid family, including Vespa soror, being of particular concern. Our study focused on the alarm pheromone components of V. soror. By using gas chromatography-mass spectrometry (GC-MS) chemical analyses, electroantennograms, and field bioassays, we identified 5 compounds-2-pentanol, 3-methyl-1-butanol, 2-heptanol, 2-nonanol (2-N), and isopentyl acetate (IPA)-in hornet sting venom that elicited defensive behavior from hornets. IPA and 2-N also serve as alarm pheromone components in multiple honey bee species that are important prey for V. soror. This shared chemical signaling may allow cross-detection by each species on the other's alarm cues. While it should be advantageous for bees to detect V. soror alarm pheromone, the benefits to V. soror of using IPA and 2-N are unclear. V. soror may manipulate bee behavior, potentially distracting defenders, because they mark victim bee colonies by rubbing their abdomens, which contain their sting glands, at bee hive entrances. Our findings pose new evolutionary questions about the role of manipulation in the arms races.

Efficient Biosynthesis of (+)-α-Pinene and de Novo Synthesis of (+)-cis-Verbenol in Escherichia coli.

Bark beetles, major pests that bore into forest stems, cause significant economic damage to forests globally. (+)-α-Pinene is the precursor to (+)-cis-verbenol, a crucial component of the aggregation pheromones produced by bark beetles. This paper describes the de novo synthesis of (+)-cis-verbenol in Escherichia coli. Initially, the truncation position of (+)-α-pinene synthase (PtPS30 from Pinus taeda) and monoterpene precursor (geranyl diphosphate/neryl diphosphate) synthases were evaluated. Neryl diphosphate synthase from Solanum lycopersicum (SlNPPS1) and truncated (+)-α-pinene synthase (PtPS30-39) were selected as promising candidates. Subsequently, the titer of (+)-α-pinene was significantly increased 8.9-fold by using the fusion tag CM29, which enhanced the solubility of PtPS30-39. In addition, by optimizing expression elements (ribosomal binding sites, linkers, and up elements) and overexpressing CM29*PtPS30-39, a yield of 134.12 mg/L (+)-α-pinene was achieved. Finally, the first de novo synthesis of enantiopure (+)-cis-verbenol was achieved by introducing a cytochrome P450 mutant from Pseudomonas putida (P450camF89W,Y98F,L246A), resulting in a yield of 11.13 mg/L. This study lays the groundwork for developing verbenol-based trapping technology for controlling bark beetles.

Functional Characterization of Peripheral Neurons and a Receptor Recognizing Sex Pheromones in Hyphantria cunea (Erebidae).

Hyphantria cunea (Lepidoptera: Erebidae) is difficult and costly to control as a quarantine pest found globally. Sex pheromone trapping is an effective measure for its population monitoring and control; however, the peripheral neural mechanism of sex pheromone recognition in H. cunea remains unclear. An electrophysiological analysis showed that both male and female moths of H. cunea responded to four components of sex pheromones and the responses of male moths were stronger than those of the female moths. We identified three types of trichoid sensilla (ST) responsive to sex pheromones using the single sensillum recording technique. Each type was involved in recognizing 9R, 10S-epoxy-1, Z3, Z6-heneicosatriene (1, Z3, Z6-9S, 10R-epoxy-21Hy). Four peripheral neurons involved in the olfactory encoding of sex pheromones were identified. Four candidate pheromone receptor (PR) genes, HcunPR1a, HcunPR1b, HcunPR3, and HcunPR4, were screened by transcriptome sequencing. All of them were highly expressed in the antennae of males, except for HcunPR4, which was highly expressed in the antennae of females. Functional identification showed that HcunPR1a responded to sex pheromone. Other HcunPRs were not functionally identified. In summary, neurons involved in sex pheromone recognition of H. cunea were located in the ST, and HcunPR1a recognized secondary pheromone components 1, Z3, Z6-9S, 10R-epoxy-21Hy. Interestingly, PRs that recognize the main components of the sex pheromone may be located in an unknown branch of the olfactory receptor and merit further study. Our findings provide a better understanding of the peripheral neural coding mechanism of type II sex pheromones, and HcunPR1a may provide a target for the subsequent development of highly effective and specific biopesticides for H. cunea.

Preparative Synthesis of 4-Oxooctanoic and 4-Oxodecanoic Acids - Components of Sex Pheromone of Asian Hornet Vespa velutina

Preparative Synthesis of 4-Oxooctanoic and 4-Oxodecanoic Acids - Components of Sex Pheromone of Asian Hornet Vespa velutina

RpedOBP1 plays key roles in aggregation pheromones reception of the Riptortus pedestris

Riptortus pedestris (Hemiptera: Alydidae) is a notable soybean pest, with diapause and non-diapause individuals showing different sensitivities to aggregation pheromones. This study aimed to investigate how R. pedestris detects aggregation pheromones through electroantennogram (EAG) and behavioral experiments, transcriptome sequencing and qRT-PCR, as well as competitive fluorescence-binding assay. Results indicated that diapausing females and males of R. pedestris exhibited a heightened EAG response and were more attracted to the aggregation pheromone components compared to their non-diapause counterparts. Transcriptome sequencing and qRT-PCR analyses revealed significantly higher expression of RpedOBP1 in the antennae of diapause females and males compared to non-diapausing R. pedestris. The competitive fluorescence-binding assay demonstrated that RpedOBP1 displayed the strongest binding affinity to E2HE2H, suggesting its crucial role in recognizing the aggregation pheromone. These findings have the potential to inform the development of integrated pest management strategies utilizing behavioral approaches for bean bug control.

Confirmation that Monochamol is a Male Produced Aggregation-Sex Pheromone for Monochamus maculosus Haldeman (Coleoptera: Cerambycidae).

The recognition of cerambycids as frequent and damaging invaders led to an increase in the interest in the chemical ecology of the group with the identification of pheromones and pheromone-like attractants for well over 100 species. Pheromone components of the Cerambycidae are often phylogenetically conserved, with a single compound serving as a pheromone component for several related species. In the subfamily Lamiinae, the compound 2-(undecyloxy)ethanol (monochamol) has been identified as an aggregation-sex pheromone for several species of the genus Monochamus. In other species, including Monochamus maculosus Haldeman, field trials have demonstrated that monochamol is a pheromone attractant, but at that point it was still unknown as to whether it was a pheromone for this species. Here we report the identification, and laboratory and field trials of a pheromone component produced by adult male M. maculosus. Chemical analyses of headspace volatile collections sampled from field collected beetles of both sexes revealed the presence of one male-specific compound that was identified as 2-(undecyloxy)ethanol. Electroantennography analyses showed that monochamol elicited responses from the antennae of female beetles. Traps baited with monochamol in the field captured M. maculosus adults of both sexes corroborating the identification of monochamol as the sex-aggregation pheromone of this species. The attractivity of monochamol to adult M. maculosus in our field trapping experiment was synergized by the addition of the host volatile α-pinene.

Identification of the Female Sex Pheromone of Grammodes Geometrica (Lepidoptera: Erebidae: Erebinae).

The female sex pheromone of Grammodes geometrica (Lepidoptera: Erebidae: Erebinae) was identified as a 2:100:4 mixture of (3Z,6Z,9Z)-3,6,9-icosatriene (T20), (3Z,6Z,9Z)-3,6,9-henicosatriene (T21), and (3Z,6Z,9Z)-3,6,9-tricosatriene (T23) through chemical and electrophysiological analyses of female gland extracts. T23 is a novel sex pheromone component in Erebinae species. Field trapping tests demonstrated optimal male captures in attractant-baited traps when using a 2:100:4 blend of T20, T21 and T23, with a significant decrease in captures observed when T20 or T23 were removed from the full blend. Traps were set in early August, but males began to be captured in early September. The seasonal prevalence showed a bimodal peak, occurring on September 11 and October 9. These findings provide valuable insights into the chemical communication and ecological dynamics of this species within the subfamily Erebinae.

Synergism of (E)-β-farnesene and Its Analogue to Insecticides against the Green Peach Aphid Myzus persicae.

With high aphid-repellent activity but low stability, (E)-β-farnesene (EβF), the major component of the aphid alarm pheromone, can be used as a synergist to insecticides. Some EβF analogues possess both good aphid-repellent activity and stability, but the synergistic effect and related mechanism are still unclear. Therefore, this study investigated the synergistic effect and underlying mechanism of the EβF and its analogue against the aphid Myzus persicae. The results indicated that EβF and the analogue showed significantly synergistic effects to different insecticides, with synergism ratios from 1.524 to 3.446. Mechanistic studies revealed that EβF and the analogue exhibited effective repellent activity, significantly upregulated target OBP genes by 161 to 731%, increased aphid mobility, and thereby enhanced contact with insecticides. This research suggests that the EβF analogue represents a novel synergist for insecticides, with the potential for further application in aphid control owing to its enhanced bioactivity and the possibility of reducing insecticide doses.

Identification and Functional Analysis of Odorant Binding Proteins in Apriona germari (Hope).

Apriona germari (Hope) presents a significant threat as a dangerous wood-boring pest, inflicting substantial harm to forest trees. Investigating the olfactory sensory system of A. germari holds substantial theoretical promise for developing eco-friendly control strategies. To date, however, the olfactory perception mechanism in A. germari remains largely unknown. Therefore, we performed transcriptome sequencing of A. germari across four distinct body parts: antennae, foreleg tarsal segments, mouthparts (maxillary and labial palps), and abdomen terminals, pinpointing the odorant binding protein (OBP) genes and analyzing their expression. We found eight AgerOBPs (5, 19, 23, 25, 29, 59, 63, 70) highly expressed in the antennae. In our competitive binding experiments, AgerOBP23 showed strong binding abilities to the pheromone component fuscumol acetate, eight plant volatiles (farnesol, cis-3-hexenal, nerolidol, myristol acetate, cis-3-hexenyl benzoate, (-)-α-cedrene, 3-ethylacetophenone, and decane), and four insecticides (chlorpyrifos, phoxim, indoxacarb, and cypermethrin). However, AgerOBP29 and AgerOBP63 did not show prominent binding activities to these tested chemicals. Through homology modeling and molecular docking, we identified the key amino acid sites involved in the binding process of AgerOBP23 to these ligands, which shed light on the molecular interactions underlying its binding specificity. Our study suggests that AgerOBP23 may serve as a potential target for future investigations of AgerOBP ligand binding. This approach is consistent with the reverse chemical ecology principle, establishing the groundwork for future studies focusing on attractant or repellent development by exploring further the molecular interactions between OBP and various compounds.

Enantioselective Synthesis of the Active Sex Pheromone Components of the Female Lichen Moth, Lyclene dharma dharma, and Their Enantiomers

The Lichen moth, Lyclene dharma dharma (Arctiidae, Lithosiinae), plays a significant role in forest ecosystem dynamics. A concise and novel method to synthesize the active sex pheromone components, (S)-14-methyloctadecan-2-one ((S)-1), (S)-6-methyloctadecan-2-one ((S)-2), and their enantiomers has been developed. Key steps in the synthesis include the use of Evans’ chiral auxiliaries, Grignard cross-coupling reactions, hydroboration–oxidation, and Wacker oxidation. The synthesized sex pheromone components hold potential value for studies on communication mechanisms, species identification, and ecological management.

Functional characterization of two odorant‐binding proteins to sex pheromones in Spodoptera frugiperda

AbstractThe primary function of odorant‐binding proteins (OBPs) is thought to be binding and transporting odorants molecules. The research on the molecular mechanisms of SfruOBPs binding with sex pheromones is beneficial to the prevention and control of Spodoptera frugiperda (S. frugiperda). Herein, two screened SfruOBPs (Sfru10933 and Sfru21187) were knocked down by RNA interference, and then the changes in electroantennogram (EAG) and behavioral responses of male mutants to their main sex pheromone components were recorded. Upon interfering with Sfru10933, the EAG response and behavioural preferences of males to sex pheromones were significantly reduced or eliminated. The interference with Sfru21187 resulted in a weakening of the behavioural preference, while the EAG response remained unchanged. However, the co‐interference of Sfru10933/Sfru21187 led to a significant reduction in the EAG activity of male to sex pheromones. These results reveal that Sfru10933 and Sfru21187 play a crucial role in sex pheromone recognition, and there may be a synergistic effect between them. Furthermore, these results will help clarify the perception of sex pheromones by S. frugiperda, which may provide new targets for the development of mating inhibitors in the future.

Love Hug-Functional Validation of Nuptial Pad-Secreted Pheromone in Anurans.

Chemical communication is an important mode of communication in the courtship and breeding processes of amphibians. In caudates, multiple components of sexual pheromones have been identified and functionally verified. One of these pheromone systems is plethodontid modulating factor (PMF). In anurans, the pheromone called amplexin was found in nuptial pads of ranids and was considered a member of the PMF system, yet its bio-function has not been tested. In this study, we obtained 18 amplexin transcript sequences from nuptial pads of Nidirana pleuraden (Amphibia, Ranidae) by transcriptome sequencing and found that the proteins translated by these transcripts are diversified, hydrophilic, and relatively stable. We also acquired a N. pleuraden amplexin isoform with the highest expression level in the transcriptome analysis through the prokaryotic expression system. Using two different animal behavioral experimental settings, we have tested the bio-function of the recombinant PMF protein (rPMF) in N. pleuraden's reproduction and found that the rPMF does not attract females but shortens the duration of amplexus significantly. This is the first study to verify the function of the PMF pheromone in Anura, indicating the pervasiveness of chemical communication during breeding in amphibians.

Geographic variation in genetic composition, sexual communication and mating compatibility of the False Codling Moth, Thaumatotibia leucotreta for optimisation of area-wide control

Intraspecific variation in sex pheromones is a driver of reproductive isolation and speciation in insects. The False Codling Moth (FCM) Thaumatotibia leucotreta (Lepidoptera: Tortricidae) is a quarantine pest endemic to sub-Saharan Africa (SSA). The currently available precision control measures for FCM use female sex pheromone components to lure males into traps. However, the existing data on the composition of the female sex pheromone, especially the isomer ratios of the main pheromone component (E/Z)-8-dodecenyl acetate, are inconsistent for populations in SSA. This inconsistency led to speculation about possible reproductive isolation between geographically separated FCM populations and the potential need for local adjustment of pheromone-based FCM control tools. This, however, requires a comparative evaluation of geographic variation in FCM sexual communication and inter-population mating compatibility. We therefore investigated genetic isolation and mating compatibility between five geographically isolated FCM populations in South Africa and analysed the ratio of (E)- and (Z)-8-dodecenyl acetate in females from these populations. The five studied populations were found to form three genetically distinct groups with high genetic distances between each other. Mating compatibility tests showed that mating is possible across these groups, however, males preferred females of their own population when given choices; without a choice, males successfully mated with and transferred spermatophores to females from all other populations. The ratio of (E)- and (Z)-8-dodecenyl acetate was similar (c. 4:1) across the populations, indicating that this main female pheromone component does not cause the observed intra-population mating preferences. It remains to be investigated if qualitative/quantitative variation in other sex pheromone components influences intra-population recognition in South African FCM, providing a base for the development of regionally-specific lures for area-wide control programmes.

A Polyketide Male-Produced Aggregation-Sex Pheromone Shared by the North American Cerambycid Beetle Graphisurus fasciatus and the South American Cerambycid Eutrypanus dorsalis.

The longhorn beetle Graphisurus fasciatus (Degeer) ranges from southeastern Canada to Florida and west to Texas, and has frequently been caught during field trials testing attraction of other cerambycid species to their synthesized pheromones. Collections of headspace volatiles from live beetles revealed that males but not females produce a polyketide compound identified as (4R,6S,7E,9E)-4,6,8-trimethylundeca-7,9-dien-3-one ([4R,6S,7E,9E]-graphisurone). Field trials verified that beetles of both sexes were attracted to the synthesized compound, indicating that it is an aggregation-sex pheromone. This structure represents a new structural motif among cerambycid pheromones, and a new natural product. While this study was in progress, the same compound was isolated from males of the South American cerambycid Eutrypanus dorsalis (Germar), in the same subfamily (Lamiinae) and tribe (Acanthocinini) as G. fasciatus. Field trials in Brazil confirmed that (4R,6S,7E,9E)-graphisurone is also an aggregation-sex pheromone for E. dorsalis, and a possible pheromone for two additional sympatric lamiine species, Hylettus seniculus (Germar) (Acanthocinini) and Oreodera quinquetuberculata (Drapiez) (tribe Acrocinini). These results indicate that graphisurone may be shared among a number of related species, as has been found with many components of cerambycid pheromones.

Sex Pheromone of the Saturniid Moth Hemileuca nevadensis from Southern California.

The major and possibly only component of the sex attractant pheromone of the moth Hemileuca nevadensis (Lepidoptera: Saturniidae) from southern California was determined to be (E10,Z12)-hexadecadienal (E10,Z12-16:Ald). Detectable quantities of the analogs (E10,Z12)-hexadecadien-1-yl acetate (E10,Z12-16:Ac) and (E10,Z12)-hexadecadien-1-ol (E10,Z12-16:OH) were also present in solvent extracts of sex pheromone glands, and stimulated male antennae in coupled gas chromatography-electroantennogram detector (GC-EAD) assays. GC-EAD traces from solid phase microextraction (SPME) wipe samples of sex pheromone glands of calling females confirmed the presence of E10,Z12-16:Ald and traces of E10,Z12-16:OH on the gland surface, but E10,Z12-16:Ac was not detected. Despite evidence for the presence of all three compounds in extracts, behavioral responses to synthetic compounds in the field suggested that only E10,Z12-16:Ald is required for optimal attraction.

Genetic Underpinnings of Cuticular Hydrocarbon Biosynthesis in the German Cockroach, Blattella germanica (L.): Progress and Perspectives.

Insect cuticular hydrocarbons (CHCs) serve as important waterproofing barriers and as signals and cues in chemical communication. Over the past 30 years, numerous studies on CHCs have been conducted in the German cockroach, Blattella germanica, leading to substantial progress in the field. However, there has not been a systematic review of CHC studies in this species in recent years. This review aims to provide a concise overview of the chemical composition, storage, transport, and physical properties of different CHCs in B. germanica. Additionally, we focus on the biosynthetic pathway and the genetic regulation of HC biosynthesis in this species. A considerable amount of biochemical evidence regarding the biosynthetic pathway of insect CHCs has been gathered from studies conducted in B. germanica. In recent years, there has also been an improved understanding of the molecular mechanisms that underlie CHC production in this insect. In this article, we summarize the biosynthesis of different classes of CHCs in B. germanica. Then, we review CHCs reaction to various environmental conditions and stressors and internal physiological states. Additionally, we review a body of work showing that in B. germanica, CHC profiles exhibit significant sexual dimorphism, specific CHCs act as essential precursors for female contact sex pheromone components, and we summarize the molecular regulatory mechanisms that underlie sexual dimorphism of CHC profiles. Finally, we highlight future directions and challenges in research on the biosynthesis and regulatory mechanisms of CHCs in B. germanica, and also identify potential applications of CHC studies in the pest control.