(Z)-11-Eicosenyl acetate,an aggregation pheromone inDrosophila malerkotliana

(Z)-11-Eicosenyl acetate (Z11–20:Ac) was identified as the aggregation pheromone inDrosophila malerkotliana. The pheromone (200–300 ng/fly) was isolated from hexane extracts of the ejaculatory bulb of sexually mature male flies. Males released very little, if any,Z11–20:Ac to the food at any time. During mating there was a transfer of ca. 100 ng ofZ11–20:Ac to the female's reproductive tract. The mated female fly transferred theZ11–20:Ac to the surrounding surfaces in just a few hours after mating. In bioassay in a wind-tunnel olfactometer,Z11–20:Ac was not attractive alone, but was synergistic with fermenting food or with acetone. AlthoughD. malerkotliana has no (Z)-11-octadecenyl acetate (Z11–18:Ac), it was as attracted toZ11–18:Ac as to an equal quantity ofZ11–20:Ac.D. melanogaster andD. simulans, however, responded to theZ11–18: Ac that they produced and did not respond toZ11–20:Ac.     

Biocatalytic synthesis of (S)-2-tridecanyl acetate and (S)-2-pentadecanyl acetate,aggregation pheromone components ofDrosophila mulleri andD. busckii,by enantioselective hydrolysis with lipase

The two chiral pheromone acetates, (S)-2-tridecanyl acetate and (S)-2-pentadecanyl acetate, were synthesized with an enantiomeric excess (e.e.) of almost 100% byPseudomonas cepacia lipase-catalyzed hydrolysis of their corresponding racemic acetates in an acetone-water solvent system.     

(Z)-11-octadecenyl acetate,an aggregation pheromone inDrosophila simulans

Existence of a male-produced pheromone, which attracts both males and females in a wind-tunnel olfactometer, has been demonstrated inDrosophila simulans (Sturtevant). A pheromone component was identified as (Z)-11-octadecenyl acetate (Z11-18: Ac), also known ascis-vaccenyl acetate. The pheromone is synergized by food volatiles. In bioassay ca. 1/1000 of a mature male equivalent of Z11-18: Ac is attractive and activity increases with increased amounts of Z11-18: Ac. Flies do not begin responding to Z11-18: Ac until after they have been away from food for at least 2 hr. Z11-18: Ac is transferred from the male to the female during mating, and the female emits the majority of the transferred Z11-18: Ac within 6 hr after mating.     

(S)-2-pentadecyl acetate and 2-pentadecanone Components of aggregation pheromone ofDrosophila busckii

(S)-2-Pentadecyl acetate and 2-pentadecanone were identified as the major aggregation pheromone components, inDrosophila busckii. Both sexes of flies were attracted equally in a wind-tunnel olfactometer. The flies also responded to racemic 2-pentadecyl acetate but not to the pureR enantiomer. In bioassay, (S)-2-pentadecyl acetate and 2-pentadecanone were each active alone, and a mixture of both increased the number of flies responding ca. twofold. The aggregation pheromone components are found in the ejaculatory bulb of sexually mature males and are transferred primarily to the female cuticle during mating. One third of the pheromone transferred is released by the female to the surrounding environment in a few hours after mating. None of the aggregation pheromone components remained on the mated female's cuticle, leaving two thirds unaccounted for. The same results were obtained when racemic 2-pentadecyl acetate was topically applied to immature and mature virgin males and females. BothD. mulleri andD. busckii were attracted to (S)-2-acetates of 13, 14 and 15 carbons, butD. mulleri preferred (S)-2-tridecyl acetate andD. busckii preferred (S)-2-pentadecyl acetate.     

(Z,Z)-5,27-Tritriacontadiene: Major sex pheromone ofDrosophila pallidosa (Diptera; Drosophilidae)

A crude cuticular extract from both sexes of 3660 fruit flies (Drosophila pallidosa) was subjected to SiO₂ and AgNO₃/SiO₂ column chromatography, accompanied by bioassay for the sex pheromone activity. After three chromatographic steps, the active fraction was obtained. The main component of the active fraction was determined to be (Z,Z)-5,27-tritriacontadiene [(Z,Z)-5,27-C_33:2, on the basis of gas-liquid chromatographic analysis, chemical derivatization and gas chromatography-mass spectrometry. Synthetic (Z,Z)-5,27-C_33:2 at 5 female equivalents (FE) elicited a clear courtship response with a high courtship index amongD. pallidosa males. Therefore it was concluded that (Z,Z)-5,27-C_33:2 was a major sex pheromone component in this species.     

Ester and ketone components of aggregation pheromone ofDrosophila hydei (Diptera: Drosophilidae)

Existence of an aggregation pheromone inDrosophila hydei was demonstrated by laboratory bioassay. The pheromone was produced by mature males, but both sexes responded. The nonpolar components consisted of three esters: the methyl, ethyl, and 1-methylethyl (isopropyl) esters of 2-methyl-(E)-2 butenoic (tiglic) acid, and two ketones: 2-tridecanone and 2-pentadecanone. The ketones and esters alone were only minimally active in the laboratory bioassay, but 2-tridecanone was highly synergistic with each of the esters, mixtures attracting 3–60 times more flies than the single components. 2-Pentadecanone was less active, but it did cause significant increases in activity when added to synthetic mixtures. The nonpolar portion of an extract of mature males and an equivalent mixture of the synthetic components were not significantly different in bioassay. Neither the esters nor the ketones were detected in sexually immature males or in females of any age. In extracts of mature males, ethyl tiglate was usually the most abundant ester component, with a mean of 8 ± 5 (SD) ng/male. The absolute and relative levels of the other esters were more variable. The mean level of methyl ketones in the extracts was 122 ± 106 (SD) ng/male, of which 85–93% was 2-tridecanone.     

Aggregation pheromones ofDrosophila immigrans,D. phalerata,andD. subobscura

Aggregation pheromones ofDrosophila immigrans, D. phalerata andD. subobscura were demonstrated by testing attraction of adult flies to hexane extracts of the flies in a windtunnel bioassay. Extracts of adult males of all species attracted conspecific males and females. However,D. subobscura flies were attracted only when the extract (cVA) in the extracts of adult maleD. immigrans andD. phalerata. Both species were attracted to synthetic cVA. Male and femaleD. phalerata. Both species were attracted to synthetic cVA. Male and femaleD. subobscura produced 5,9-pentacosadiene, 5-pentacosene, 2-methylhexacosene and 5,9-heptacosadiene, while only maleD. subobscura produced (Z)-5-tricosene and minor amounts of cVA.     

Ester components of aggregation pheromone ofDrosophila virilis (Diptera: Drosophilidae)

The male-produced aggregation pheromone ofDrosophila virilis was found to contain five ester components, in addition to a previously identified hydrocarbon, (Z)-10-heneicosene (Z10–21). The five esters were: the methyl, ethyl, and 1-methylethyl (isopropyl) esters of 2-methyl-(E)-2-butenoic (tiglic) acid and the methyl and ethyl esters of hexanoic acid. The esters were not detected in females. Each ester was active by itself in laboratory bioassay tests, and each increased the number of flies responding toZ10–21 ca. 4–5 times. In comparisons among the five esters at 10 ng per compound, ethyl tiglate was the most active, and methyl tiglate, the least. No mixture of esters was found to be significantly more active than ethyl tiglate alone. In a doseresponse study, bioassay activity increased with dose for both ethyl tiglate andZ10–21. Newly emerged males did not have detectable levels of the esters. All five esters increased as sexual maturity was approached. Ethyl tiglate and ethyl hexanoate were the most abundant in mature males, usually over 15 ng per individual. Ratios among the esters were variable. Male flies also contained an as yet unidentified attractant(s) still more polar than the esters, which was synergistic with the esters and hydrocarbon. Food odors also synergized the synthetic compounds.     

(Z,Z)-6,9-heneicosadien-11-one,labile sex pheromone of the whitemarked tussock moth,Orgyia leucostigma

The whitemarked tussock moth (WMTM), Orgyia leucostigma (J. E. Smith), is a major pest of coniferous and deciduous trees in eastern Canada. Chemical identification of its sex pheromone depended primarily on GC-EAD and HPLC analysis, with confirmation of behavioral activity by wind tunnel and field tests. We identified (Z,Z)-6,9-heneicosadien-11-one (Z,Z-6,9-ket) at 4–5 ng/female as the only essential sex pheromone component. Also detected in female extracts were (Z)-6-heneicosen-11-one (Z6-ket) at 2.5 ng/female, (Z,E)-6,8-heneicosadien-11-one (Z,E-6,8-ket) at about 0.5 ng/female, and a trace amount of (Z,E)-6,9-heneicosadien-11-one. Traps containing as little as 1 g of Z,Z-6,9-ket attracted males at low population levels, indicating it is a potent sex attractant. Traps baited with Z6-ket attracted few males, and in wind-tunnel bioassays it was at least 100-fold less attractive to males than Z,Z-6,9-ket. No improvement in trap catch occurred with the addition of Z6-ket in various binary mixtures with Z,Z-6,9-ket, including the female ratio, and a ternary mixture of Z,Z-6,9-ket, Z6-ket, and Z,E-6,8-ket in the 9:5:1 ratio detected in females was no better than Z,Z-6,9-ket alone. We attribute the presence of Z,E-6,8-ket and Z,E-6,9-ket in female extracts to the spontaneous and rapid stereospecific isomerization of Z,Z-6,9-ket at room temperature. Male flight began at sunset but peaked during the second half of the night.     

Aggregation pheromone components inDrosophila mulleri

Existence of an aggregation pheromone was demonstrated inDrosophila mulleri. Mature males produce at least two compounds that are lacking from females and newly emerged males and that attract both males and females in a wind-tunnel bioassay. These compounds are (S)-(+)-2-tridecanol acetate and (Z)-10-heptadecen-2-one. Both were synthesized, and the flies responded to the synthetic compounds as well as to fly-derived preparations. The flies also responded to racemic 2-tridecanol acetate but not to the pureR enantiomer. A more polar, very volatile attractant was also extracted from both sexes ofD. mulleri but was not identified.     

Aggregation pheromone ofDrosophila mauritiana,Drosophila yakuba,andDrosophila rajasekari

(Z)-11-Octadecenyl acetate (Z11–18Ac) was identified as the aggregation pheromone ofDrosophila mauritiana, D. yakuba, andD. rajasekari. The amount of pheromone in the ejaculatory bulb of male flies increased with age, reaching plateau levels of ca. 240, 800, and 1100 ng/fly forD. mauritiana, D. yakuba, andD. rajasekari, respectively. Thirty to 50% of the pheromone in the ejaculatory bulb was transferred to the female during mating, with the majority transferred to the female's reproductive tract. In the subsequent 6-hr period, over half the pheromone in the female's reproductive tract was transferred to the surroundings. In a wind-tunnel olfactometer,Z11–18Ac was attractive toD. yakuba andD. mauritiana; however,D. rajasekari required food or food odors in combination withZ11–18Ac to demonstrate aggregation activity.Z11–16Ac andZ11–20Ac were not attractive forD. mauritiana, D. yakuba, andD. rajasekari. For all three species, food was synergistic withZ11–18Ac and both sexes were attracted.     

Sex pheromone ofAdoxophyes orana: Additional components and variability in ratio of (Z)-9- and (Z)-11-tetradecenyl acetate

Twelve products related to the sex pheromone main components (Z)-9- and (Z)-11-tetradecenyl acetate (Z9–14Ac andZ11–14Ac, respectively), were identified in female pheromone gland extracts of the laboratory-reared summerfruit tortrix moth,Adoxophyes orana F.v R. These are the geometric isomers and the alcohols of the main components, (Z)-9-dodecenyl acetate, (Z)-11-hexadecenyl acetate, and saturated acetates of 12–22 carbons. The ratio ofZ9–14Ac toZ11–14Ac in individuals varied from 3.51 to 111 with an average of 6.2; their total added up to 462 ng/female with an average of 182 ng for 2- to 7-day-old individuals. No qualitative or quantitative differences were observed between laboratory and field insects.Z9–14Ac,Z11–14Ac and the corresponding alcohols were also found in female effluvia. Addition of either of the two alcohols to a blend of the two acetates augmented trap catch in the field. The same was true for (Z)-9,(E)-12-tetradecadienyl acetate which was not detected in gland extracts.     

(E)- and (Z)-6-nonen-2-one: Biosynthetic precursors ofEndo- andexo-brevicomin in two bark beetles (Coleoptera: Scolytidae)

The ability of (E)- and (Z)-6-nonen-2-one to serve as precursors of the common scolytid pheromonesEndo- andexo-brevicomin was examined in vivo. When mountain pine beetles (MPB),Dendroctonus ponderosae Hopkins, or western balsam bark beetles (WBBB),Dryocoetes confusus Swaine, were exposed to [6,7-D₂](E)-6-nonen-2-one, theEndo-brevicomin produced was enriched with two deuterium atoms per molecule (as determined by GC-MS), indicating that (E)-6-nonen-2-one served as a precursor of this pheromone. Similarly, when the beetles were exposed to [4,4-D₂](Z)-6-nonen-2-one, theexo-brevicomin produced was enriched with two deuterium atoms per molecule. Evidence in support of biological relevance of the latter observation include: (1) (Z)-6-nonen-2-one was found in the volatiles of male MPBs and WBBBs, indicating that this is a natural metabolite; (2) theexo-brevicomin produced by MPB was shown to be of natural (+) chirality by complexation chromatography; and (3) female WBBBs and MPBs (which are not known to produceexo-brevicomin) produced significantly lessexo-brevicomin when exposed to the precursor than did the males.     

(Z,Z)-4,7-tridecadien-(S)-2-yl acetate: sex pheromone of Douglas-fir cone gall midge,Contarinia oregonensis

Our objectives were to identify and field test the sex pheromone of female Douglas-fir cone gall midge, Contarinia oregonensis (Diptera: Cecidomyiidae). Coupled gas chromatographic–electroantennographic detection (GC-EAD) analyses of pheromone extract revealed a single compound (A) that elicited responses from male antennae. Hydrogenation of pheromone extract, followed by renewed GC-EAD analysis, revealed a new EAD-active compound with chromatographic characteristics identical to those of tridecan-2-yl acetate on five fused silica columns (DB-5, DB-210, DB-23, SP-1000, and Cyclodex-B). Syntheses, chromatography, and retention index calculations of all possible tridecen-2-yl acetates suggested that the candidate pheromone A was a tridecadien-2-yl acetate with nonconjugated double bonds. Synthetic candidate pheromone component (Z,Z)-4,7-tridecadien-2-yl acetate (Z4Z7) cochromatographed with A on all analytical columns and elicited comparable antennal activity. In GC-EAD analyses that separated the enantiomers (Z,Z)-4,7-tridecadien-(S)-2-yl acetate (2S-Z4Z7) and (Z,Z)-4,7-tridecadien-(R)-2-yl acetate (2R-Z4Z7) with baseline resolution, only 2S-Z4Z7 as a component in a racemic standard or in pheromone extract elicited antennal responses. In Douglas-fir seed orchards, sticky traps baited with 2S-Z4Z7 captured male C. oregonensis, whereas 2R-Z4Z7 was behaviorally benign. Comparable catches of males in traps baited with racemic Z4Z7 (50 g) or virgin female C. oregonensis suggested that synthetic pheromone baits could be developed for monitoring C. oregonensis populations in commercial Douglas-fir seed orchards.     

cis-Vaccenyl acetate as an aggregation pheromone inDrosophila melanogaster

Pentane extracts of matureDrosophila melanogaster males substantially increased the attractiveness of food odors to both males and females in a wind-tunnel olfactometer. Extracts of females caused no such increase. An active component of the extract was isolated and identified as (Z)-11-octadecenyl acetate (cis-vaccenyl acetate, cVA), and synthetic cVA was active in bioassay. Hydrolysis of the ester linkage or movement of the double bond to the 9 position destroyed the activity. Mature virgin males released cVA into their feeding vials, and amounts of synthetic CVA equal to that released per male caused significant bioassay responses. Females, which were known to receive cVA from males during copulation, were found to emit relatively large amounts of the ester into their feeding vials within 6 hr after mating. cVA had been demonstrated previously to be a close-range pheromone inD. melanogaster, discouraging males from courting other males or recently mated females; it now appears to have a longer-range function as well.     

Sustained Production of the Labile Pheromone Component, (Z,Z)-6,9-Heneicosadien-11-one, from a Stable Precursor for Monitoring the Whitemarked Tussock Moth

The principal sex pheromone component of the whitemarked tussock moth (WMTM), Orgyia leucostigma, was recently identified as (Z,Z)-6,9-heneicosadien-11-one (Z6Z9-11-one-21Hy). However, it is thermally unstable and quickly degrades under field conditions so that baited traps are effective for only one night. We have developed a solution to this problem that combines two techniques: (1) the use of a stable pheromone precursor, (Z,Z)-6,9-heneicosadien-11-one ethylene ketal, which is hydrolyzed to the dienone by an acidic aqueous solution (2% p-toluenesulfonic acid in 35% aqueous sorbitol), and (2) use of a small, off-the-shelf, autonomous pump (the Med-e-Cell Infu-disk™) to deliver the precursor continuously to a suitable substrate where it is converted rapidly into the attractive dienone pheromone component. The pump and hydrolysis substrate fit inside sticky traps and because generation and release of pheromone is continuous, the instability of the pheromone is not an issue. In electroantennogram bioassays, dose-dependent responses were obtained with 1 to 1000 ng of hydrolyzed ketal on filter paper, but no response was obtained to 1000 ng of the ketal itself. In wind tunnel bioassays, males were attracted to lures emitting the dienone pheromone component generated from 0.1 to 100 ng of the hydrolyzed ketal. Field tests in 2004 and 2005 showed that sticky traps fitted with the pump delivering the ketal (0.1–1 μg/μL in heptane) at 10 μL/hr to a cotton pad soaked with the hydrolyzing solution were attractive to male WMTM. No moths were caught in controls or traps baited with (Z)-6-heneicosen-11-one. An average of 0.51 moths per trap night was caught over an 18-night period in 2005. The results represent a first step toward developing a sensitive and practical monitoring tool for the WMTM by using a ketal precursor of its unstable dienone pheromone component.     

(Z)-7-Tricosene and Monounsaturated Ketones as Sex Pheromone Components of the Australian Guava Moth Coscinoptycha improbana: Identification, Field Trapping, and Phenology

Pheromone gland extracts of the Australian guava moth Coscinoptycha improbana (Lepidoptera: Carposinidae), contained four compounds that elicited responses from male moth antennae in gas chromatography-electroantennogram detection (GC-EAD) analyses. These were identified by GC-mass spectrometry as (Z)-7-tricosene (Z7-23Hy), (Z)-7-octadecen-11-one (Z7-11-one-18Hy), (Z)-7-nonadecen-11-one (Z7-11-one-19Hy), and (Z)-7-tricosen-11-one (Z7-11-one-23Hy) at a ratio of 65:23.5:1.5:10, respectively. Z7-23Hy, Z7-11-one-18Hy, and Z7-11-one-23Hy have not previously been reported as lepidopteran sex pheromone components. Z7-11-one-18Hy was active as a single component, and was synergized by Z7-11-one-23Hy but not Z7-11-one-19Hy, although the latter compound was weakly attractive as a single component. Addition of Z7-23Hy further increased attraction. The amount of the major pheromone component, Z7-11-one-18Hy in female pheromone gland extracts was estimated to be 16.4 ng/female (N = 8). Phenological data gathered over a 12-mo period in 2002 and 2003 using the binary blend indicated that moths are active throughout the year. The pheromone has already been employed to monitor the spread of C. improbana in New Zealand and detect its presence in Queensland, Australia.     

Evaluation of the Major Female Eurytoma amygdali Sex Pheromone Components, (Z,Z)-6,9-Tricosadiene and (Z,Z)-6,9-Pentacosadiene for Male Attraction in Field Tests

We evaluated the attraction of male almond seed wasp Eurytoma amygdali to the synthetic alkadienes (Z,Z)-6,9-tricosadiene and (Z,Z)-6,9-pentacosadiene and their blend in almond orchards using baited rubber septa attached to cardboard rectangular adhesive traps. The two alkadienes were recently isolated from virgin female whole body extracts and SPME collected volatiles. The alkenes (Z)-9-tricosene, (Z)-9-pentacosene, and (Z)-9-heptacosene, present in female extracts, were also added to the blend of the alkadienes and tested. The alkadienes tested individually attracted males when the traps were baited with doses ranging from 10 to 30 mg/trap. The maximum number of males was attracted to traps baited with 10 mg of a (Z,Z)-6,9-C(23:2):(Z,Z)-6,9-C(25:2) blend at a ratio of 7:3. Results with the three alkenes added to the blend were inconclusive because of low populations. The present study on E. amygdali is the first one reporting attraction of males to synthetic sex pheromone components in field trials for a Eurytomidae species. The synthetic alkadienes blend offers the potential to develop an effective system for monitoring populations of the almond seed wasp in almond orchards.     

Sex pheromone components of three species ofSemiothisa (Geometridae), (Z,Z,Z)-3,6,9-heptadecatriene and two monoepoxydiene analogs

Adult males ofSemiothisa signaria dispuncta (Walker) were attracted to field traps baited with (Z,Z,Z)-3,6,9-octadecatriene and (Z,Z)-6,9-cis-3,4-epoxy-octadecadiene. However, analyses of sex pheromone gland extracts of females of this species by GC-MS and by GC in combination with an electroantennograph detector (GC-EAD) showed the pheromone to be comprised of a mixture of the next lower homologs: (Z,Z,Z)-3,6,9-heptadecatriene and (Z,Z)-6,9-cis-3,4-epoxy-heptadecadiene. Blends of these two C₁₇ compounds were subsequently found to be more attractive to males in the field than the corresponding C₁₈ mixtures. Sex pheromones of two otherSemiothisa species were also found to contain C₁₇ components. (Z,Z,Z)-3,6,9-Heptadecatriene, detected by GC-EAD analysis of a female abdominal tip extract ofS. bicolorata (Fabricius), attracted conspecific males, and this attraction was significantly reduced by additions of (Z,Z)-6,9-cis-3,4-epoxyheptadecadiene, the major pheromone component ofS. signaria dispuncta, to the lure. (Z,Z)-3,9-cis-6,7-Epoxy-heptadecadiene was detected by GC-EAD analysis as the primary male antennal stimulatory component present in abdominal tip extracts ofS. ulsterata (Pearsall), and males of this species were attracted to traps baited with this epoxide. Each of these three C₁₇ compounds constitute previously unknown lepidopteran sex pheromone components. Blends of (Z,Z, Z)-3,6,9-heptadecatriene and (Z,Z)-3,9-cis-6,7-epoxyheptadecadiene attracted males of a fourth species,S. delectata Hulst, but no females of this species were obtained to permit analysis of its sex pheromone. The occurrence of (Z,Z,Z)-3,6,9-heptadecatriene inS. neptaria (Guenee) females was indicated by GC-MS analysis of an abdominal tip extract; however, no males were attracted to any of the fielded mixtures containing this hydrocarbon.     

(Z)-11-Hexadecenal and (3Z,6Z,9Z)-tricosatriene: sex pheromone components of the red banded mango caterpillar Deanolis sublimbalis

The sex pheromone of the red banded mango caterpillar, Deanolis sublimbalis (Lepidoptera: Crambidae), a serious pest of the mango Mangifera indica (Anacardiaceae) in India and Southeast Asia and a recent invader into northern Australia, has been identified. Three candidate compounds were identified from pheromone gland extracts of female moths, using gas chromatography (GC), GC-electroantennographic detection and GC-mass spectrometric analyses, in conjunction with dimethyldisulfide derivatization. Field bioassays established that both (Z)-11-hexadecenal (Z11-16:Ald) and (3Z,6Z,9Z)-tricosatriene (3Z,6Z,9Z-23:Hy) were required for attraction of male D. sublimbalis moths, and 1,000 μg of a 1:1 mix of Z11-16:Ald and 3Z,6Z,9Z-23:Hy was more attractive to male moths than caged virgin females. However, the binary blend was only attractive when the isomeric purity of the monounsaturated aldehyde was >99%, suggesting that the (E)-isomer was inhibitory. Although (Z)-11-hexadecen-1-ol (Z11-16:OH) was tentatively identified in gland extracts, the addition of this compound to the binary blend did not increase the numbers of moths captured. The pheromone can now be used in integrated pest management strategies. Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.