A Selective Method of Estimation of Bacitracin in the Presence of Other Antibiotics and Growth Factors

The plum cankerworm moth, Cystidia couaggaria couaggaria (Geometridae: Ennominae), is a defoliator of Chinese plum trees (Prunus mume). The pheromone components of the female were analyzed by gas chromatography (GC) with an electro-antennographic (EAG) detector and GC coupled with mass spectrometry. The crude pheromone extract included several EAG-active components, i.e., trienyl, dienyl, and saturated hydrocarbons, with a C₂₁–C₂₅ straight chain. The characteristic mass spectra indicated the unsaturated hydrocarbons to be (3Z,6Z,9Z)-3,6,9-trienes and (6Z,9Z)-6,9-dienes. In the fields, mixtures of the synthetic C₂₁ and C₂₃ trienes in a ratio of 2:3 and 1:4 successfully attracted males of this diurnal species during daytime. While the male antennae responded to the C₂₅ triene and saturated hydrocarbons, their synergistic effects were not observed on the male attraction in the fields. Addition of the C₂₁ diene interestingly inhibited the activity of the triene mixture. Males of Cystidia truncangulata, a sympatric diurnal congener of C. c. couaggaria, showed similar EAG responses to the unsaturated hydrocarbons, but no C. truncangulata males were attracted by the lures tested for C. c. couaggaria males, indicating that the identified hydrocarbons comprised the species-specific pheromone of C. c. couaggaria females.     

Sex pheromone analysis and effective attraction of males of the cabbage webworm,Hellula undalis,inhabiting the Mekong Delta of Vietnam

Hellula undalis is a harmful insect pest of green mustard in the Mekong Delta of Vietnam. In order to establish a tool for a sustainable pest control program, the sex pheromone of H. undalis inhabiting the Mekong Delta was examined. GC-EAD and GC–MS analyses of pheromone gland extracts from the virgin females elucidated three new components, (Z)-11-tetradecenyl acetate (Z11-14:OAc), (Z)-11-hexadecenal (Z11-16:Ald), and (11E,13E)-11,13-hexadecadien-1-ol, in addition to the known pheromone component (11E,13E)-11,13-hexadecadienal (E11,E13-16:Ald). Double bond positions of the two monoenyl components were determined by GC–MS analysis of the pheromone extract treated with dimethyl disulfide. On the other hand, GC–MS analysis of the female body extract detected the unsaturated hydrocarbon (3Z,6Z,9Z)-3,6,9-tricosatriene (Z3,Z6,Z9-23:H). Field examinations of their synthetic compounds indicated the significant role of E11,E13-16:Ald as a major component and a clear synergistic effect of the two monoenyl compounds as a minor component. Although the 3:3:7 mixture of Z11-14:OAc, E11-16:Ald, and E11,E13-16:Ald captured the largest number of males among the tested mixtures, the activity was still quite a bit lower than that of virgin females. However, the 3:3:7:1 mixture, which was prepared by adding a small amount of Z3,Z6,Z9-23:H to the 3:3:7 ternary lure, succeeded in attracting males more powerfully than the females did. This strong synergistic effect was not observed when the triene was added to unmixed E11,E13-16:Ald, indicating important roles of not only the triene but also the two monoenyl compounds as natural pheromone components.     

Geographic variation of sex pheromone and mitochondrial DNA in Diatraea saccharalis (Fab., 1794) (Lepidoptera: Crambidae)

(9Z,11E)-hexadecadienal and (Z11)-hexadecenal, the main sex pheromone components of the sugarcane borer, Diatraea saccharalis, were identified and quantified from four Brazilian and one Colombian populations using GC-EAD, GC-MS and GC analyses. Three different ratios were observed, 9:1, 6:1, and 3:1. The pheromone concentration for the major component, (9Z,11E)-hexadecadienal, varied from 6.8 ng/gland to 21.9 ng/gland and from 1.7 ng/gland to 6.5 to the minor component, (Z11)-hexadecenal. The 25 D. saccharalis cytochrome oxidase II sequences that were analyzed showed low intra-specific variation and represented only 11 haplotypes, with the most frequent being the one represented by specimens from São Paulo, Paraná, and Pernambuco states. Specimens from Colombia showed the highest genetic divergence from the others haplotypes studied. Data on the genetic variability among specimens, more than their geographic proximity, were in agreement with data obtained from analyses of the pheromone extracts. Our data demonstrate a variation in pheromone composition and a covariation in haplotypes of the D. saccharalis populations studied.     

Substrate specificity of the epoxidation reaction in sex pheromone biosynthesis of the Japanese giant looper (Lepidoptera: Geometridae)

Female moths of the Japanese giant looper (Ascotis selenaria cretacea, Lepidoptera: Geometridae) secrete (Z,Z)-6,9-cis-3,4-epoxynonadecadiene as a sex pheromone component. To the pheromone glands of the decapitated females, [19,19,19-D₃](Z,Z,Z)-3,6,9-nonadecatriene was applied after an injection of pheromone biosynthesis activating neuropeptide. GC-MS analysis of the gland extract showed its specific conversion into the pheromonal cis-3,4-epoxide indicating that the C₁₉ triene which had been identified in the gland was a precursor of the pheromone. In order to examine the substrate specificity of the enzyme catalyzing this epoxidation step, several unsaturated hydrocarbons not occurring in the gland were applied to it. Not only (Z,Z,Z)-3,6,9-trienes with varying chain lengths (C₁₇, C₁₈ and C₂₀ to C₂₂) but (Z,Z)-3,6-dienes (C₁₇, C₁₉ and C₂₀) were converted into the corresponding cis-3,4-epoxides in a rather good yield, while no 6,7- and 9,10-epoxides could be detected. (Z)-3-Nonadecene was also changed to the cis-epoxide, but (E)-3-, (Z)-2- and (Z)-4-double bonds in the C₁₉ chain were not oxidized. These in vivo experiments revealed that the monooxygenase regiospecifically attacked the (Z)-3-double bond of straight chain hydrocarbons regardless of their length and degree of unsaturation.     

Male-specific (Z)-9-tricosene stimulates female mating behaviour in the spider Pholcus beijingensis

Chemical signals play an important role in spider sexual communication, yet the chemistry of spider sex pheromones remains poorly understood. Chemical identification of male-produced pheromone-mediating sexual behaviour in spiders has also, to our knowledge, not been reported before. This study aimed to examine whether chemically mediated strategies are used by males of the spider Pholcus beijingensis for increasing the probability of copulation. Based on data from gas chromatography–mass spectrometry analysis, electroantennography assay and a series of behavioural tests, we verified that (Z)-9-tricosene is a male-specific compound in the spider P. beijingensis. This compound acts as an aphrodisiac: it increases the likelihood that a female will mate. Mate-searching males release (Z)-9-tricosene to stimulate sexual behaviour of conspecific females. In the two-choice assay, however, sexually receptive females show no preference to the chambers containing (Z)-9-tricosene. This indicates that the male pheromone of P. beijingensis is not an attractant per se to the conspecific females. This is, to our knowledge, the first identification of a male-produced aphrodisiac pheromone in spiders.     

Biosynthetic pathways of the sex pheromone components and substrate selectivity of the oxidation enzymes working in pheromone glands of the fall webworm, Hyphantria cunea

The fall webworm, Hyphantria cunea Drury (Lepidoptera: Arctiidae), is a harmful polyphagous defoliator. Female moths produce the following four pheromone components in a ratio of about 5:4:10:2; (9Z,12Z)-9,12-octadecadienal (I), (9Z,12Z,15Z)-9,12,15-octadecatrienal (II), cis-9,10-epoxy-(3Z,6Z)-3,6-henicosadiene (III), and cis-9,10-epoxy-(3Z,6Z)-1,3,6-henicosatriene (IV). Although ¹³C-labeled linolenic acid was not converted into trienal II at the pheromone glands of H. cunea females, GC-MS analysis of an extract of the pheromone gland treated topically with ¹³C-labeled linolenyl alcohol showed the aldehyde incorporating the isotope. Other C₁₈ and C₁₉ fatty alcohols were also oxidized to the corresponding aldehydes in the pheromone gland, indicating a biosynthetic pathway of IIvia linolenyl alcohol and low substrate selectivity of the alcohol oxidase in the pheromone gland. On the other hand, epoxydiene III was expected to be produced by specific 9,10-epoxidation of the corresponding C₂₁ trienyl hydrocarbon, which might be biosynthesized from dietary linolenic acid in oenocytes and transported to the pheromone gland. The final biosynthetic step in the pheromone gland was confirmed by an experiment using deuterated C₂₁ triene, which was synthesized by the chain elongation of linolenic acid and LiAlD₄ reduction as key reactions. When the labeled triene was administered to the female by topical application at the pheromone gland or injection into the abdomen, deuterated III was detected in a pheromone extract by GC-MS analysis. Furthermore, the substrate selectivity of epoxidase and selective incorporation by the pheromone glands were examined by treatments with mixtures of the deuterated precursor and other hydrocarbons such as C₁₉-C₂₃ trienyl, C₂₁ dienyl, and C₂₁ monoenyl hydrocarbons. The 9,10-epoxy derivative of each alkene was produced, while the epoxidation of the C₂₁ monoene was poorer than those of the trienes and diene. The low selectivity indicated that the species-specific pheromone of the H. cunea female was mainly due to the critical formation of the precursor of each component.     

Gastrophysa polygoni herbivory on Rumex confertus: single leaf VOC induction and dose dependent herbivore attraction/repellence to individual compounds

We report large induction (>65_fold increases) of volatile organic compounds (VOCs) emitted from a single leaf of the invasive weed mossy sorrel, Rumex confertus Willd. (Polygonaceae), by herbivory of the dock leaf beetle, Gastrophysa polygoni L. (Coleoptera: Chrysomelidae). The R. confertus VOC blend induced by G. polygoni herbivory included two green leaf volatiles ((Z)-3-hexenal, (Z)-3-hexen-1-yl acetate) and three terpenes (linalool, ß-caryophyllene, (E)-ß-farnesene). Uninjured leaves produced small constitutive amounts of the GLVs and barely detectable amounts of the terpenes. A Y-tube olfactometer bioassay revealed that both sexes of adult G. polygoni were attracted to (Z)-3-hexenal and (Z)-3-hexen-1-yl acetate at a concentration of 300 ng h⁻¹. No significant G. polygoni attraction or repellence was detected for any VOC at other concentrations (60 and 1500 ng h⁻¹). Yet, G. polygoni males and females were significantly repelled by (or avoided) at the highest test concentration (7500 ng h⁻¹) of both GLVs and (E)-ß-farnesene. Mated male and female G. polygoni might be attracted to injured R. confertus leaves, but might avoid R. confertus when VOC concentrations (especially the terpene (E)-ß-farnesene) suggest high overall plant injury from conspecifics, G. viridula, or high infestations of other herbivores that release (E)-ß-farnesene (e.g., aphids). Tests in the future will need to examine G. polygoni responses to VOCs emitted directly from uninjured (constitutive) and injured (induced) R. confertus, and examine whether R. confertus VOC induction concentrations increase with greater tissue removal on a single leaf and/or the number of leaves with feeding injury.     

Optimization of pheromone lure and trap design for monitoring the fir coneworm, Dioryctria abietivorella

The major components of the sex pheromone of Dioryctria abietivorella (Groté) (Lepidoptera: Pyralidae) were recently identified as (9Z,11E)‐tetradecadien‐1‐yl acetate (9Z,11E‐14:Ac) and a polyunsaturated, long‐chain hydrocarbon (3Z,6Z,9Z,12Z,15Z)‐pentacosapentaene (C25 pentaene). The optimal ratio of these components and the role of potential minor components were not fully determined in the initial short report on the pheromone's identification. We tested different ratios of the two major components loaded into grey halobutyl rubber septum dispensers, placed in sticky traps deployed in conifer breeding arboreta. The optimal ratio of the two components was 200 µg 9Z,11E‐14:Ac to 2000 µg C25 pentaene. (Z)‐9‐Tetradecen‐1‐yl acetate, which had been identified previously in female pheromone gland extracts, and five other potential minor pheromone components, were tested individually as additions to the optimized two‐component lure blend. None of the ternary blends were more attractive than the optimized two‐component blend, at the ratios tested. Two lure adjuvants, a UV stabilizer (Sumisorb 300) and the antioxidant butylated hydroxytoluene, added individually or together, did not affect the attractiveness of the optimized lure blend. The Pherotech diamond sticky trap baited with the optimized lure blend was the most effective trap design among eight types of sticky trap and a bucket style trap that were tested. Traps baited with synthetic lures were as attractive as traps baited with virgin female moths. The optimized two‐component lure blend in the Pherotech diamond trap is recommended for monitoring fir coneworm infestations. The availability of an effective synthetic pheromone opens the possibility for control tactics using mating disruption or attract‐and‐kill techniques.     

Discovery of a disused desaturase gene from the pheromone gland of the moth Ascotis selenaria, which secretes an epoxyalkenyl sex pheromone

Female Ascotis selenaria (Geometridae) moths use 3,4-epoxy-(Z,Z)-6,9-nonadecadiene, which is synthesized from linolenic acid, as the main component of their sex pheromone. While the use of dietary linolenic or linoleic fatty acid derivatives as sex pheromone components has been observed in moth species belonging to a few families including Geometridae, the majority of moths use derivatives of a common saturated fatty acid, palmitic acid, as their sex pheromone components. We attempted to gain insight into the differentiation of pheromone biosynthetic pathways in geometrids by analyzing the desaturase genes expressed in the pheromone gland of A. selenaria. We demonstrated that a Δ11-desaturase-like gene (Asdesat1) was specifically expressed in the pheromone gland of A. selenaria in spite of the absence of a desaturation step in the pheromone biosynthetic pathway in this species. Further analysis revealed that the presumed transmembrane domains were degenerated in Asdesat1. Phylogenetic analysis demonstrated that Asdesat1 anciently diverged from the lineage of Δ11-desaturases, which are currently widely used in the biosynthesis of sex pheromones by moths. These results suggest that an ancestral Δ11-desaturase became dysfunctional in A. selenaria after a shift in pheromone biosynthetic pathways.     

Research of the (E/Z)-isomerization of carotenoids in Pécs since the 1970s

Geometrical configuration of the polyene chain of approximately 40 mono- and di-cis carotenoids was determined from 1970 through 1990. Subsequently, the kinetic, equilibrium and thermodynamic parameters (k, K, A, E_A, ΔH^#, ΔG^#, ΔS^#) of the reversible thermal isomerization of several symmetrical and unsymmetrical carotenoids were calculated. The rate of the iodine-catalyzed photoisomerization of (all-E)-, (9Z)- and (13Z)-zeaxanthin was compared and the ‘specific rate’ (per unit light energy at given wavelengths) of the iodine-catalyzed photoisomerization for several (13Z)-carotenoids was investigated. As the missing links of the biosynthetic pathway of paprika-carotenoids, carotenoids containing new end groups were isolated; their sterically unhindered mono-cis isomers were also prepared and their geometrical configuration was determined. The investigation concentrated on the substrate specificity of the enzyme violaxanthin-deepoxidase, the light-induced formation of (13Z)-violaxanthin in green leaves, the binding of xanthophylls to the bulk light-harvesting complex (LHC) of photosystem II in higher plants, the biochemical basis of color as an aesthetic quality in Citrus-fruits and the (9Z)-epoxycarotenoid cleavage enzyme activity for ABA biosynthesis. Recently (9Z)-capsanthin-5,6-epoxide and capsoneoxanthin, two novel carotenoids have been isolated from natural sources.     

The structural basis of chain length control in Rv1086

In Mycobacterium tuberculosis, two related Z-prenyl diphosphate synthases, E,Z-farnesyl diphosphate synthase (Rv1086) and decaprenyl diphosphate synthase (Rv2361c), work in series to synthesize decaprenyl phosphate (C₅₀) from isopentenyl diphosphate and E-geranyl diphosphate. Decaprenyl phosphate plays a central role in the biosynthesis of essential mycobacterial cell wall components, such as the mycolyl-arabinogalactan-peptidoglycan complex and lipoarabinomannan; thus, its synthesis has attracted considerable interest as a potential therapeutic target. Rv1086 is a unique prenyl diphosphate synthase in that it adds only one isoprene unit to geranyl diphosphate, generating the 15-carbon product (E,Z-farnesyl diphosphate). Rv2361c then adds a further seven isoprene units to E,Z-farnesyl diphosphate in a processive manner to generate the 50-carbon prenyl diphosphate, which is then dephosphorylated to generate a carrier for activated sugars. The molecular basis for chain-length discrimination by Rv1086 during synthesis is unknown. We also report the structure of apo Rv1086 with citronellyl diphosphate bound and with the product mimic E,E-farnesyl diphosphate bound. We report the structures of Rv2361c in the apo form, with isopentenyl diphosphate bound and with a substrate analogue, citronellyl diphosphate. The structures confirm the enzymes are very closely related. Detailed comparison reveals structural differences that account for chain-length control in Rv1086. We have tested this hypothesis and have identified a double mutant of Rv1086 that makes a range of longer lipid chains.     

Identification and field evaluation of the sex pheromone components of a Korean population of Glossosphecia romanovi

Glossosphecia romanovi (Leech) (Lepidoptera: Sesiidae) is a pest of grape in northeast Asia. We analyzed pheromone gland extracts of female moths and compared attractiveness of various pheromone blends to male moths in the field. Two major components from pheromone gland extracts were identified as (Z,Z)‐3,13‐octadecadien‐1‐ol (Z3,Z13‐18:OH) and (Z,Z)‐3,13‐octadecadienyl acetate (Z3,Z13‐18:OAc) in a ratio of approximately 9:1. Field tests showed that male G. romanovi were attracted to Z3,Z13‐18:OH alone, but the maximum number of males was attracted to the binary blend of Z3,Z13‐18:OH and Z3,Z13‐18:OAc mimicking the blend found in female extracts. In addition to these components, small amounts of (E,Z)‐3,13‐octadecadien‐1‐ol (E3,Z13‐18:OH) were detected in the pheromone gland of females, but addition of this component inhibited attraction to the primary binary blend. The blend of Z3,Z13‐18:OH and Z3,Z13‐18:OAc at the natural ratio should provide a sensitive and effective lure for monitoring populations of this pest.     

Intermittent exposure to traces of green leaf volatiles triggers the production of (Z)-3-hexen-1-yl acetate and (Z)-3-hexen-1-ol in exposed plants

Intermittent exposure during a period of 3 weeks of undamaged Arabidopsis plants to trace amounts of volatiles emitted by freshly damaged Arabidopsis plants resulted in an increase of subsequent artificial-damage-induced production of (Z)-3-hexen-1-yl acetate and (Z)-3-hexen-1-ol in the exposed Arabidopsis plants when compared with Arabidopsis plants exposed to undamaged Arabidopsis plant volatiles (control plants). We previously showed that (Z)-3-hexen-1-yl acetate attracts a parasitic wasp, Cotesia glomerata. Thus, the induced production of this volatile explained our previously reported finding that, when artificially damaged, the exposed plants were more attractive to C. glomerata than control plants.     

Feeding and hemolymph trehalose concentration influence sex pheromone production in virgin Heliothis virescens moths

Previously, we demonstrated that sex pheromone production in mated female Heliothis virescens moths is dependent upon hemolymph trehalose concentration (HTC), which is influenced by activities such as the feeding of adults on sucrose. In this paper we demonstrate, for the first time, that this effect also occurs in starved (i.e., sugar-stressed) virgin females. Females allowed to feed on sugar for 6 days, following eclosion, had significantly greater titers than females that had fed only on water (i.e., were starved). No differences in pheromone titer were observed between sugar- and water-fed females at shorter (1 or 3 days) periods following eclosion. The relatively short-term effects of HTC on sex pheromone titer of virgins, were demonstrated by feeding experiments, in which starved (for 4 days) virgins fed on 10% sucrose solution had significantly greater HTC and pheromone titers than ones fed only on water; an increase in HTC was apparent within an hour, while the increase in pheromone titer was apparent within 2.5 h, of sugar feeding. Starvation also showed similar effects on titers of pheromone gland fatty acids (pheromone intermediates) and HTC. Over 6 days of starvation, fatty acid titers and HTC declined gradually. After feeding on sucrose, titers of hexadecanoic, (Z)-9-hexadecanoic, (Z)-11-hexadecanoic and (Z)-9-octadecanoic, acids, as well as HTC, increased significantly 24 h later, but titers of octadecanoic and (Z,Z)-9,12-octadecanoic (linoleic) acids did not. Lepidoptera cannot biosynthesize polyunsaturated acids, but the lack of change in octadecanoic acid titer suggests this acid may not participate in pheromone biosynthesis. In addition to these short-term changes in pheromone and fatty acid production, mediated by HTC, a longer-term effect of age, regardless of HTC, on pheromone titer was observed. Overall, these results are consistent with hemolymph trehalose and glandular fatty acids acting as twin metabolite reservoirs for pheromone biosynthesis. Hemolymph trehalose, able to be refilled through feeding on exogenous sugars, has a one-way flow of metabolites for synthesis of glandular free fatty acids (FFAs) and pheromone, while glandular glycerolipids provide a reversible reservoir for metabolites, accepting surplus FFAs when glandular concentrations are high, and providing FFAs for pheromone biosynthesis when concentrations are low.     

CYP341B14: A cytochrome P450 involved in the specific epoxidation of pheromone precursors in the fall webworm Hyphantria cunea

Two of the four sex pheromone components in the fall webworm Hyphantria cunea (Lepidoptera: Arctiidae), cis-9,10-epoxy-(3Z,6Z)-3,6-henicosadiene and cis-9,10-epoxy-(3Z,6Z)-1,3,6-henicosatriene, possess an epoxy ring within their molecules. These compounds have been suggested to be biosynthesized from dietary linolenic acid via the following enzymatic reactions; chain elongation, terminal desaturation (in the case of the latter component), decarboxylation, and epoxidation. The last step of this biosynthesis, epoxidation, is known to occur specifically in the sex pheromone gland of females. We identified the enzyme involved in the epoxidation of pheromone precursors by focusing on cytochromes P450, which are known to catalyze the oxidation of various compounds. Three P450-like sequences (Hc_epo1, Hc_epo2, and Hc_epo3) were identified in the cDNA library prepared from the sex pheromone gland of H. cunea. Among these clones, only Hc_epo1 was specifically expressed in the pheromone gland. The full-length sequence of Hc_epo1 contained an ORF of 1527 bp, which encoded a protein of 509 amino acids with a predicted molecular weight of 57.9 kDa. The deduced Hc_epo1 amino acid sequence possessed the characteristics of P450. A phylogenetic analysis of the sequence indicated that Hc_epo1 belonged to the CYP341B clade in the CYP341 family. Therefore, it was named CYP341B14. A subsequent functional assay using Sf-9 cells transiently expressing CYP341B14 demonstrated that this P450 protein was able to specifically epoxidize a (Z)-double bond at the 9th position in the pheromone precursor, (3Z,6Z,9Z)-3,6,9-henicosatriene.     

Responses of male winter moths (Operophtera brumata) to their sex attactant (3Z,6Z,9Z)-1,3,6,9 nonadecatetraene and to some structural analogues

Conclusion (3Z,6Z,9Z)-1,3,6,9-nonadecatetraene, the synthetic sex pheromone of the female of O. brumata is highly active in attracting males of this species in the field (Germany and Switzerland). No analogous compounds possessing attractivity to O. brumata males have been found up to now, nor did they show any inhibitory effects to the same species.Therefore (3Z,6Z,9Z)-1,3,6,9-nonadecatetraene (I) can be recommended as a good attractant in the prognosis or monitoring of this lepidopteran pest.     

The egg parasitoid <Emphasis Type="Italic">Telenomus euproctidis</Emphasis> (Hymenoptera: Scelionidae) uses sex pheromone released by immobile female tussock moth <Emphasis Type="Italic">Orgyia postica</Emphasis> (Lepidoptera: Lymantriidae) as kairomone

Egg parasitoids Telenomus euproctidis Wilcox (Hymenoptera: Scelionidae) were attracted to egg masses laid by wingless immobile female Orgyia postica (Lepidoptera: Lymantriidae). Virgin females, a solvent extract of pheromone glands, and a synthetic sex pheromone, (6Z,9Z,11S,12S)-11,12-epoxyhenicosa-6,9-diene (posticlure), also attracted this parasitoid in the field, demonstrating that T. euproctidis uses the sex pheromone of female Org. postica as a kairomone to locate host eggs.     

Ketone components in the contact sex pheromone of the white-spotted longicorn beetle, Anoplophora malasiaca, and pheromonal activity of synthetic ketones

Two active fractions were found during the isolation of contact sex pheromone of female elytra of the white‐spotted longicorn beetle, Anoplophora malasiaca (Thomson) (Coleoptera: Cerambycidae), in addition to fraction of hydrocarbons that had previously been identified. One fraction was essential to evoke a series of precopulatory behaviors of males toward a glass dummy when coated together with the hydrocarbon blend. The other fraction enhanced this activity when added to the mixture. From the latter synergistic fraction, we isolated five novel compounds and identified them as 10‐heptacosanone, (Z)‐18‐heptacosen‐10‐one, (18Z,21Z)‐heptacosa‐18,21‐dien‐10‐one, (18Z,21Z,24Z)‐heptacosa‐18,21,24‐trien‐10‐one, and 12‐heptacosanone by GC‐MS and NMR analyses. A blend of four of these synthetic ketones, without 12‐heptacosanone, in the ratio and concentration found in female elytra extract (250 : 400 : 1000 : 180 ng FE^?1) showed greater synergistic effect than the natural fraction containing the ketones. This effect was canceled out by further addition of 12‐heptacosanone (100 ng FE^?1), which was still comparable to the effect of the natural ketone fraction.