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1.
Molecules ; 29(9)2024 May 04.
Article En | MEDLINE | ID: mdl-38731627

A concise synthesis of the sex pheromones of elm spanworm as well as painted apple moth has been achieved. The key steps were the alkylation of acetylide ion, Sharpless asymmetric epoxidation and Brown's P2-Ni reduction. This approach provided the sex pheromone of the elm spanworm (1) in 31% total yield and those of the painted apple moth (2, 3) in 26% and 32% total yields. The ee values of three final products were up to 99%. The synthesized pheromones hold promising potential for use in the management and control of these pests.


Epoxy Compounds , Moths , Sex Attractants , Animals , Sex Attractants/chemical synthesis , Sex Attractants/chemistry , Epoxy Compounds/chemistry , Molecular Structure
2.
Int J Mol Sci ; 25(9)2024 Apr 30.
Article En | MEDLINE | ID: mdl-38732112

The paulownia bagworm, Clania variegata Snell, is an economically important pest of agriculture and forests. The sex pheromone of this pest and its stereoisomers were synthesized, and two of the stereoisomers were prepared for the first time. Our strategy was efficient and mainly included the ring-opening reaction of (S)-2-methyloxirane, the coupling of chiral sulfonate, the oxidative cleavage of olefin, and Yamaguchi esterification. Moreover, the overall yields of our synthesis were 23-29%, with eight steps in the longest route.


Sex Attractants , Sex Attractants/chemical synthesis , Sex Attractants/chemistry , Stereoisomerism , Animals
3.
Sci Rep ; 14(1): 3848, 2024 02 15.
Article En | MEDLINE | ID: mdl-38360933

In the Americas, the fall armyworm (Spodoptera frugiperda) exists in two genetically distinct strains, the corn (C) and rice (R) strains. Despite their names, these strains are not associated with host plant preferences but have been shown to vary in pheromone composition and male responses. Recently, S. frugiperda was detected in Africa as an invasive species, but knowledge about variation in strain types, pheromone composition and inter-strain mating of populations of the pest in the continent has not been fully examined. Therefore, this study aimed to investigate variations, if any in the pheromone composition of female moths, male moth responses, and mating between C and R mitotypes of S. frugiperda populations in Kenya, as well as their geographic distribution. Strains (mitotypes) of S. frugiperda were identified using mitochondrial DNA (mtDNA) markers, and their pheromonal composition determined by coupled gas chromatography-mass spectrometric (GC-MS) analysis. Male moth responses to these compounds were evaluated using GC-electroantennographic detection (EAD), electroantennogram (EAG), and wind tunnel assays. Oviposition assays were used to determine whether R and C mitotype moths could mate and produce eggs. The results showed that both the R and C mitotypes were present, and there were no statistically significant differences in their distribution across all sampled locations. Five pheromone compounds including (Z)-7-dodecenyl acetate (Z7-12:OAc), (Z)-7-tetradecenyl acetate (Z7-14:OAc), (Z)-9-tetradecenyl acetate (Z9-14:OAc), (Z)-11-tetradecenyl acetate (Z11-14:OAc) and (Z)-11-hexadecenyl acetate (Z11-16:OAc), were detected in the pheromone glands of female moths of both mitotypes, with Z9-14:OAc being the most abundant. The relative percentage composition of Z9-14:OAc was similar in both mitotypes. However, the R mitotype had a 2.7 times higher relative percentage composition of Z7-12:OAc compared to the C mitotype moth, while the C mitotype moth had a 2.4 times higher relative percentage composition of Z11-16:OAc than the R mitotype moth. Male moths of both mitotypes exhibited similar responses to the pheromone compounds, showing the strongest responses to Z9-14:OAc and Z7-12:OAc in electrophysiological and behavioural assays. There was mating between R and C mitotypes with egg production comparable to mating within the same mitotype. Our results revealed that differences between the two S. frugiperda mitotypes are characterized by female moth pheromone composition rather than male moth responses to the pheromones, and that this does not prevent hybridisation between the mitotypes, which may have implications for their management.


Moths , Sex Attractants , Animals , Female , Spodoptera/genetics , Sex Attractants/chemistry , Pheromones , Moths/genetics , Moths/chemistry , Kenya
4.
J Agric Food Chem ; 72(8): 3904-3912, 2024 Feb 28.
Article En | MEDLINE | ID: mdl-38303158

The leaf skeletonizer, Pyrausta machaeralis (Lepidoptera: Crambidae), is a serious insect pest of teak (Tectona grandis) in China. The application of insect pheromones is widely applied as an environmentally friendly technology for integrated pest management (IPM). In the present study, crude extracts of sex pheromone glands of calling P. machaeralis females were collected and then analyzed using gas chromatography/electroantennographic detection (GC/EAD) and gas chromatography-mass spectrometry (GC-MS). The combination of infrared spectroscopy (IR) and nuclear magnetic resonance (NMR) spectrometry was used for structure identification. Afterward, their electrophysiological and behavioral activity was evaluated in the laboratory and field. Herein, we eventually determined two active components, E-11-tetradecenyl acetate (E11-14:Ac) and Z-11-tetradecenyl acetate (Z11-14:Ac), at a ratio of 96:4, as the sex pheromone of P. machaeralis. The identification of sex pheromones would facilitate the development of efficient strategies for monitoring and controlling the field populations of P. machaeralis.


Lepidoptera , Moths , Sex Attractants , Animals , Female , Lepidoptera/physiology , Sex Attractants/chemistry , Moths/physiology , Pheromones/chemistry , Gas Chromatography-Mass Spectrometry , Biological Assay
5.
Biosci Biotechnol Biochem ; 88(5): 577-580, 2024 Apr 22.
Article En | MEDLINE | ID: mdl-38378960

(3Z,6Z,9Z)-3,6,9-henicosatriene was identified as a major component of female sex pheromone of Bastilla arctotaenia (Lepidoptera: Erebidae), a pest of cultivated roses, by gas chromatograph-electroantennographic detector( GC-EAD) and gas chromatograph/mass spectrometry (GC/MS) analyses. The single (3Z,6Z,9Z)-3,6,9-henicosatriene (1.0 mg/lure) successfully attracted B. arctotaenia males in the field.


Gas Chromatography-Mass Spectrometry , Lepidoptera , Sex Attractants , Animals , Sex Attractants/chemistry , Sex Attractants/analysis , Female , Male , Lepidoptera/physiology , Moths/physiology , Sexual Behavior, Animal
6.
J Chem Ecol ; 50(3-4): 122-128, 2024 Apr.
Article En | MEDLINE | ID: mdl-38388901

The scarab genus Osmoderma (Coleoptera: Scarabaeidae) includes several large species called hermit beetles that develop within dead and decaying hardwood trees. Males of at least three Palearctic species produce the aggregation-sex pheromone (R)-(+)-γ-decalactone, including the endangered O. eremita (Scopoli). However, hermit beetles have received less attention in the western hemisphere, resulting in a large gap in our knowledge of the chemical ecology of Nearctic species. Here, we identify (R)-( +)-γ-decalactone as the primary component of the aggregation-sex pheromone of the North American species Osmoderma eremicola (Knoch). Field trials at sites in Wisconsin and Illinois revealed that both sexes were attracted to lures containing (R)-(+)-γ-decalactone or the racemate, but only males of O. eremicola produced the pheromone in laboratory bioassays, alongside an occasional trace of the chain-length analog γ-dodecalactone. Females of the congener O. scabra (Palisot de Beauvois) were also significantly attracted by γ-decalactone, suggesting further conservation of the pheromone, as were females of the click beetle Elater abruptus Say (Coleoptera: Elateridae), suggesting that this compound may have widespread kairomonal activity. Further research is needed to explore the behavioral roles of both lactones in mediating behavioral and ecological interactions among these beetle species.


Coleoptera , Lactones , Sex Attractants , Animals , Coleoptera/physiology , Male , Female , Sex Attractants/chemistry , Sex Attractants/pharmacology , Sex Attractants/metabolism , Lactones/chemistry , Lactones/metabolism , Lactones/pharmacology , Pheromones/metabolism , Pheromones/chemistry , Pheromones/pharmacology
7.
Pest Manag Sci ; 80(2): 577-585, 2024 Feb.
Article En | MEDLINE | ID: mdl-37735837

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


Lepidoptera , Moths , Sex Attractants , Female , Male , Animals , Lepidoptera/physiology , Sex Attractants/pharmacology , Sex Attractants/chemistry , Gas Chromatography-Mass Spectrometry , Moths/physiology , Pheromones , Acetates
8.
Pest Manag Sci ; 80(3): 996-1007, 2024 Mar.
Article En | MEDLINE | ID: mdl-37830147

BACKGROUND: The sugarcane borer Diatraea saccharalis (Lepidoptera) is a key pest on sugarcane and other grasses in the Americas. Biological control as well as insecticide treatments are used for pest management, but economic losses are still significant. The use of female sex pheromones for mating disruption or mass trapping in pest management could be established for this species, provided that economical production of pheromone is available. RESULTS: Combining in vivo labelling studies, differential expression analysis of transcriptome data and functional characterisation of insect genes in a yeast expression system, we reveal the biosynthetic pathway and identify the desaturase and reductase enzymes involved in the biosynthesis of the main pheromone component (9Z,11E)-hexadecadienal, and minor components hexadecanal, (9Z)-hexadecenal and (11Z)-hexadecenal. We next demonstrate heterologous production of the corresponding alcohols of the pheromone components, by expressing multiple steps of the biosynthetic pathway in yeast. CONCLUSION: Elucidation of the genetic basis of sex pheromone biosynthesis in D. saccharalis, and heterologous expression in yeast, paves the way for biotechnological production of the pheromone compounds needed for pheromone-based pest management of this species. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Moths , Saccharum , Sex Attractants , Female , Animals , Sex Attractants/chemistry , Saccharomyces cerevisiae , Moths/genetics , Pheromones
9.
J Chem Ecol ; 49(11-12): 611-641, 2023 Dec.
Article En | MEDLINE | ID: mdl-37856061

Pheromones mediate species-level communication in the search for mates, nesting, and feeding sites. Although the role of pheromones has long been discussed by various authors, their existence was not proven until the mid-twentieth century when the first sex pheromone was identified. From this finding, much has been speculated about whether this communication mechanism has acted as a regulatory agent in the process of speciation, competition, and sexual selection since it acts as an intraspecific barrier. Chrysomelidae is one of the major Phytophaga lineages, with approximately 40,000 species. Due to this immense diversity the internal relationships remain unstable when analyzed only with morphological data, consequently recent efforts have been directed to molecular analyses to establish clarity for the relationships and found their respective monophyly. Therefore, our goals are twofold 1) to synthesize the current literature on Chrysomelidae sex pheromones and 2) to test whether Chrysomelidae sex pheromones and their chemical structures could be used in phylogenetic analysis for the group. The results show that, although this is the first analysis in Chrysomelidae to use pheromones as a phylogenetic character, much can be observed in agreement with previous analyses, thus confirming that pheromones, when known in their entirety within lineages, can be used as characters in phylogenetic analyses, bringing elucidation to the relationships and evolution of organisms.


Coleoptera , Sex Attractants , Animals , Pheromones , Phylogeny , Sex Attractants/chemistry
10.
Biomol NMR Assign ; 17(2): 223-227, 2023 12.
Article En | MEDLINE | ID: mdl-37498448

Ostrinia nubilalis, also known as European Corn Borer (ECB), is a serious pest in Europe and North America, as well as in Central Asia and Northern Africa. It damages a variety of agricultural crops such as corn, oats, buckwheat, millet, and soybeans. causing annually at least one billion dollars in loss. The Ostrinia nubilalis pheromone-binding protein3 (OnubPBP3), preferentially expressed in the male moth antenna, has been implicated in the detection of the female-secreted pheromone blend during the mating process. Understanding the structure of and function of OnubPBP3, including the mechanism of pheromone binding and its release at the dendritic olfactory neuron (ORN), is essential if integrated pest management through sensory inhibition is to be achieved. We report here the backbone and side-chain resonance assignments of OnubPBP3 at pH 6.5 using various triple resonance NMR experiments on a 13C, 15N-labeled protein sample. The secondary structure of OnubPBP3 consists of six α-helices and an unstructured C-terminus based on backbone chemical shifts.


Moths , Sex Attractants , Animals , Male , Female , Sex Attractants/chemistry , Sex Attractants/pharmacology , Sex Attractants/physiology , Nuclear Magnetic Resonance, Biomolecular , Moths/metabolism , Pheromones , Agriculture
11.
J Agric Food Chem ; 71(21): 8016-8022, 2023 May 31.
Article En | MEDLINE | ID: mdl-37204042

Rusicada privata (Lepidoptera: Erebidae) is a major pest insect on Hibiscus syriacus L. (Malvaceae: Malvales), which is usually planted in urban landscapes. Insecticidal control of R. privata is not ideal for urban landscaping due to its harmful effects and risk to human health. Therefore, nonchemical and ecofriendly alternatives are needed. To identify the sex pheromone of R. privata, abdominal tip extracts of male and female R. privata were analyzed by gas chromatography-mass spectrometry. The abundance of 7-methylheptadecane (7Me-17Hy) in female R. privata abdominal tip extracts led us to hypothesize that it is the major sex pheromone. The compound was tentatively identified by a mass spectral library and confirmed by matching retention times and mass spectra of the female-produced compound with those of a synthetic standard. The compounds elicited electroantennographic (EAG) activity. In a field trapping experiment, only synthetic lures containing 7Me-17Hy attracted R. privata males. The EAG activity and field trapping results confirmed that 7Me-17Hy is the sex pheromone of female R. privata. The results will aid in developing sex pheromone-based R. privata control techniques, such as mating disruption.


Lepidoptera , Moths , Sex Attractants , Female , Male , Animals , Humans , Sex Attractants/pharmacology , Sex Attractants/chemistry , Gas Chromatography-Mass Spectrometry , Mass Spectrometry , Biological Assay
12.
J Agric Food Chem ; 71(18): 7009-7019, 2023 May 10.
Article En | MEDLINE | ID: mdl-37126455

Like many insects, females of the Noctuid moth Spodoptera litura and Spodoptera exigua release chemical signals to attract males from a long distance for successful mating. In this study, 98 and 86 genes related to the sex pheromone biosynthesis of S. litura and S. exigua were identified. The tissue expression profiles of highly expressed genes in sex pheromone glands (PGs) were further examined by real-time quantitative polymerase chain reaction. The results displayed that only SlitDes5 and SexiDes5 gene were specifically and significantly overexpressed in the PGs of S. litura and S. exigua. The functional study of SlitDes5 gene showed that RNA interference reduced its expression level by 49.42%. In addition, the content of the sex pheromones of S. litura, Z9E11-14:OAc, Z9E12-14:OAc, E11-14:OAc, and Z9-14:OAc, decreased by 41.98% on average. Our findings provide a basis for better understanding the key genes that affect the biosynthesis of sex pheromones and for determining potential gene targets for pest control strategies.


Moths , Sex Attractants , Animals , Female , Male , Spodoptera/genetics , Spodoptera/metabolism , Sex Attractants/chemistry , Gene Expression Profiling , Moths/genetics , RNA Interference
13.
Pest Manag Sci ; 79(9): 3312-3325, 2023 Sep.
Article En | MEDLINE | ID: mdl-37103977

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


Lepidoptera , Moths , Receptors, Odorant , Sex Attractants , Animals , Female , Male , Sex Attractants/chemistry , Odorants , Ligands , Molecular Docking Simulation , Insect Proteins/metabolism , Moths/genetics , Moths/metabolism , Receptors, Odorant/chemistry
14.
Pest Manag Sci ; 79(8): 2831-2839, 2023 Aug.
Article En | MEDLINE | ID: mdl-36935454

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


Moths , Sex Attractants , Animals , Female , Sex Attractants/pharmacology , Sex Attractants/chemistry , Spodoptera , Gas Chromatography-Mass Spectrometry , Pheromones , Aldehydes
15.
J Agric Food Chem ; 71(6): 2795-2803, 2023 Feb 15.
Article En | MEDLINE | ID: mdl-36726240

Sex pheromones play an essential role when moths are searching for mates. Male olfactory receptor neurons (ORNs) are the primary determinant during peripheral pheromone recognition. Here, we identified the sex pheromones of a global agricultural pest, Mythimna loreyi, using gas chromatography coupled with mass spectrometry and electroantennographic detection. Nine pheromone components were identified, including (Z)-9-tetradecen-1-yl acetate (Z9-14:OAc), (Z)-7-dodecen-1-yl acetate (Z7-12:OAc), and (Z)-11-hexadecen-1-yl acetate (Z11-16:OAc), and the first two elicited electrophysiological activities in the male antennae. Trichoid sensilla were classified into four functional types on the basis of neuronal responses to pheromones by single sensillum recording. Five functional ORNs were involved in recognizing pheromones and pheromone analogues. Finally, a field bioassay revealed that a blend of Z9-14:OAc, Z7-12:OAc, and Z11-16:OAc at a ratio of 100:8.8:19.7 was highly efficient for trapping males. Our results uncover the pheromone recognition mechanism in M. loreyi and provide a novel angle for developing efficient sex attractants of pests on the basis of screening the peripheral olfactory neurons.


Moths , Olfactory Receptor Neurons , Sex Attractants , Animals , Male , Pheromones/pharmacology , Pheromones/chemistry , Sex Attractants/pharmacology , Sex Attractants/chemistry , Gas Chromatography-Mass Spectrometry , Moths/chemistry , Olfactory Receptor Neurons/physiology
16.
Pest Manag Sci ; 79(6): 2005-2016, 2023 Jun.
Article En | MEDLINE | ID: mdl-36680502

BACKGROUND: Mythimna separata is a notorious pest causing crop damages at the larval stage. Gaining insight into larval olfaction mechanisms would provide knowledge for olfaction-based management of M. separata larvae. RESULTS: In the present research, (Z)-11-hexadecenal (Z11-16: Ald), a major component of M. separata sex pheromone, was found to attract early-instar larvae of M. separata in a food context. Using a fluorescent binding assay, we found that M. separata general odorant binding protein 2 (MsepGOBP2) exhibited high binding affinity to Z11-16: Ald. Further, silencing of MsepGOBP2 resulted in a sharp reduction of the response to Z11-16: Ald, which could not be mitigated by increasing the concentration of Z11-16: Ald. Additionally, we employed molecular dynamics-based approaches to unravel the interaction details between MsepGOBP2 and Z11-16: Ald, specifically the binding of Z11-16: Ald to MsepGOBP2. CONCLUSION: Z11-16: Ald is attractive to early-instar larvae of M. separata, and MsepGOBP2 is identified to be indispensable in the larval detection of Z11-16: Ald. These results could aid in the development of olfaction-based methods for controlling M. separata in the larval stage. © 2023 Society of Chemical Industry.


Insect Proteins , Moths , Odorants , Sex Attractants , Animals , Larva/metabolism , Moths/physiology , Sex Attractants/chemistry
17.
J Biomol Struct Dyn ; 41(8): 3647-3658, 2023 05.
Article En | MEDLINE | ID: mdl-35352606

Odorant receptors (OR) play a critical role in signal transduction and olfactory recognition in insects. Unfortunately, insect ORs are difficult to express and purify, and limited structural data are available. Computational methods were used to predict models for aphid ORs, and binding interactions with aphid pheromones and other semiochemicals were investigated. Previously functionally characterised ORs from the pea aphid, Acyrthosiphon pisum, ApisOR4 and ApisOR5, were screened against functional ligands. ApisOR5 had a defined binding site, and had predicted interactions with the aphid alarm pheromone, (E)-ß-farnesene. ApisOR4 had multiple distinct binding sites and showed broad tuning to multiple odorants. Screening of six other highly conserved ORs showed some interactions and potential enantiomeric discrimination between the aphid sex pheromone components (4aS,7S,7aR)-nepetalactone and (1R,4aS,7S,7aR)-nepetalactol. These results indicate that specific binding sites may be more critical to understanding olfactory activity of ligands and ORs than kinetic data, and greater knowledge of the method of action of ORs is required.Communicated by Ramaswamy H. Sarma.


Aphids , Receptors, Odorant , Sex Attractants , Animals , Receptors, Odorant/metabolism , Aphids/metabolism , Ligands , Sex Attractants/chemistry , Sex Attractants/metabolism , Pheromones/metabolism
18.
J Chem Ecol ; 48(7-8): 609-617, 2022 Aug.
Article En | MEDLINE | ID: mdl-35945405

Mealybug females release sex pheromones to attract conspecific males for mating. It is critical for mealybug males, which are fragile and short-lived, to respond to the pheromone of their species without time- and energy-consuming cross-attractions to other species. Thus, mealybug pheromone systems are considered to have evolved to be species-specific with unique structures in each species and offer an opportunity to study the diversity of pheromone chemistry that mediates intersexual courtship signals. More than 20 mealybug pheromones are reported to be monoterpenes in general, with only one exception, a hemiterpene alcohol esterified with a medium-chain fatty acid (MCFA), found in the Matsumoto mealybug, Crisicoccus matsumotoi. However, it is unknown whether this is truly exceptional, or if similar compounds are used in other related mealybugs. In this study, we isolated and characterized the pheromone of an allied species, the azalea mealybug C. azaleae. Using gas chromatography-mass spectrometry, nuclear magnetic resonance spectroscopy, and bioassays with synthetics, the pheromone was shown to be composed of isopropyl (E)-7-methyl-4-nonenoate, isopropyl (E)-7-methyl-4-octenoate, and ethyl (E)-7-methyl-4-nonenoate. Surprisingly, the structures of these compounds do not include hemiterpene nor monoterpene motifs but have methyl-branched MCFA parts that are similar to an acid moiety of the C. matsumotoi pheromone. This study implies irregular events for the divergence of pheromone structures in ancestors of the genus Crisicoccus and other mealybugs.


Hemiptera , Sex Attractants , Animals , Female , Gas Chromatography-Mass Spectrometry , Hemiptera/chemistry , Hemiterpenes , Male , Monoterpenes , Pheromones , Sex Attractants/chemistry , Sex Attractants/pharmacology
19.
J Chem Ecol ; 48(5-6): 502-517, 2022 Jun.
Article En | MEDLINE | ID: mdl-35841479

In a previous study, we reported the identification and synthesis of a male-specific sex pheromone component of the stink bug, Pellaea stictica, as the alcohol 2,4,8,13-tetramethyltetradecan-1-ol (1). To establish the correlation between the stereochemistry of the pheromone and its bioactivity, it first was necessary to determine its absolute configuration. For this purpose, a series of syntheses were designed to: (a) furnish a mixture of all possible stereoisomers; (b) a narrowed down group of diastereomers, and (c) one specific enantiomer. A crucial step in the syntheses involved a coupling reaction between two key intermediates: a phosphonium salt and an aldehyde, through a Wittig olefination. Nuclear magnetic resonance data of a mixture of the synthetic pheromone diastereomers and further comparison of GC retention times with that of the natural product by gas chromatography suggested that the methyl branches at C2 and C4 were in a syn relationship, reducing the possibilities to only four of the eight possible stereoisomers. Employing GC analysis, chiral derivatization reagents and synthetic (8R)-2,4-syn-1 it was possible to confirm the configuration of the methyl branch at C8 as R, reducing the number of possible stereoisomers to two. After enantioselective synthesis of (2R,4R,8R)-1, the absolute configurations of all methyl branches of the natural compound were confirmed as R, fully identifying the male-produced sex pheromone of P. stictica as (2R,4R,8R)-2,4,8,13-tetramethyltetradecan-1-ol.


Heteroptera , Sex Attractants , Animals , Fatty Alcohols , Heteroptera/chemistry , Male , Pheromones , Sex Attractants/chemistry , Stereoisomerism
20.
J Chem Ecol ; 48(5-6): 491-501, 2022 Jun.
Article En | MEDLINE | ID: mdl-35895216

Synthetic sex pheromone lures are useful tools to monitor and control populations of adult click beetles (Coleoptera: Elateridae). However, sex pheromones for Agriotes click beetle species native to North America have yet to be identified. Here we report the identification and field testing of the sex pheromone of Agriotes ferrugineipennis. Headspace volatiles from female beetles were collected on Porapak Q, and aliquots of Porapak extract were analyzed by gas chromatographic-electroantennographic detection (GC-EAD) and GC-mass spectrometry. 7-Methyloctyl 7-methyloctanoate (7Me7Me) emitted by females was more abundant and elicited much stronger responses from male antennae than the aldehydes octanal and nonanal and the ketone 6,10,14-trimethyl-2-pentadecanone. In a field experiment, captures of A. ferrugineipennis males in traps baited with candidate pheromone components exceeded those of unbaited control traps, on average by nearly 1,200 times. Neither the ketone nor the aldehydes as lure constituents appeared to alter captures of males in 7Me7Me-baited traps. We conclude that 7Me7Me is the major, and possibly the only, sex attractant pheromone component of female A. ferrugineipennis.


Coleoptera , Sex Attractants , Aldehydes/pharmacology , Animals , Coleoptera/physiology , Female , Gas Chromatography-Mass Spectrometry , Ketones/pharmacology , Male , Pheromones/chemistry , Sex Attractants/chemistry , Sex Attractants/pharmacology
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