Stereoselective synthesis of dominicalure 1 and 2: Components of aggregation pheromone from male lesser grain borerRhyzopertha dominica (F.)

Dominicalure 1 (9a) and dominicalure 2 (9b), were synthesized by esterification of ,-unsaturated acids4a and4b with (S)-(+)-2-pentanol (8). The key step was the asymmetric reduction of 3-penten-2-one (5) to give the chiral intermediate6, which, upon diimide reduction, DNB derivatization, recrystallization, and hydrolysis, yielded8 in 63% ee. Acids4a and4b were prepared in a simple and efficient three-step synthesis with an overall yield of 54% and 62%, respectively, in stereoisomerically pure form.     

Dominicalure 1 and 2: Components of aggregation pheromone from male lesser grain borerRhyzopertha dominica (F.) (Coleoptera: Bostrichidae)

Volatiles from lesser grain borers,Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae), were collected on Porapak Q, and those from the male beetles were shown to contain two compounds, that were attractive individually and in combination to both sexes. These compounds were identified as (S)-(+)-1-methylbutyl (E)-2-methyl-2-pentenoate and (S)-(+)-1-methylbutyl (E)-2,4-dimethyl-2-pentenoate by spectrometry and comparison with synthesized compounds. The two compounds have been assigned the trivial names dominicalure 1 and dominicalure 2, respectively. Synthesized samples of these compounds, individually and in combination, were effective in trapping both sexes in field studies.Presented in part at the Northeastern Regional Meeting of the American Chemical Society, June 25–28, 1978, Boston.Approved as TA-14927 by the director of the Texas Agricultural Experiment Station in cooperation with the USDA-FR-SEA.     

Phenotypic plasticity of Rhyzopertha dominica pheromone signaling: the effects of different hosts and presence of conspecific females on male produced aggregation pheromone

Male Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) release an aggregation pheromone consisting of a blend of two components, dominicalure 1 (D1) and Dominicalure 2 (D2). Pheromone from single insects, in different contexts, was collected and measured to determine if this signal is phenotypically plastic. Release rates were lowered when males were moved from maize grains to groundnut kernels or when moved from solitary occupation of maize grain to grain occupied by seven females. The pheromone release was increased again once these moves were reversed. The release of D1 was more affected than D2: thus, on groundnuts or in the presence of females, less pheromone was released and the proportion of D1 in the blend was lowered. Possible reasons for the modifications of the signal are discussed.     

Behavior of the lesser grain borerRhyzopertha dominica (Coleoptera: Bostrichidae)

Adult males of the lesser grain borer,Rhyzopertha dominica (F.), produce a pheromone that attracts both sexes. The volatiles from males collected on filter paper or Porapak-Q were attractive in two laboratory bioassays. The mating behavior is described and the function of the phen infested with the borer.Mention of a commercial product does not constitute an endorsement by the USDA.     

Identification of major component of male-produced aggregation pheromone of larger grain borer,Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae)

Male beetles of the larger grain borer,Prostephanus truncatus Horn (Coleoptera: Bostrichidae) were shown to produce material causing an electroantennographic (EAG) response from both male and female beetles. Volatiles from mixed sex cultures were collected on Porapak Q and fractionated by liquid chromatography (LC) with gradient elution. The total volatiles and the fractions were analyzed by gas chromatography (GC) linked to EAG, and two compounds eluting in the same LC fraction elicited EAG responses from male and female beetles. These were assumed to be components of the male-produced aggregation pheromone. Amounts of these compounds obtained were very low and less than 10^–3 times the amounts of the aggregation pheromone components produced by the related species,Rhyzopertha dominica, under similar conditions. The most abundant of these EAG-active compounds was identified as 1-methyiethyl (2E)-2-methyl-2-pentenoate by comparison of its GC retention times and mass spectrum with those of synthetic analogs. The synthetic compound elicited electrophysiological and behavioral responses in both male and female beetles significantly greater than those to structural analogs. This compound is attractive toP. truncatus beetles in the field, and has been given the trivial name of trunc-call 1.     

Response to pheromone traps and disruption of pheromone communication in the lesser peachtree borer and the peachtree borer (Lepidoptera: Sesiidae)

The sex pheromone communication of the lesser peachtree borer,Synanthedon pictipes (Grote and Robinson), and the peachtree borer,Sanninoidea exitiosa (Say), can be disrupted by permeation of the atmosphere with their respective sex pheromones, (E,Z)- and (Z,Z)-3,13-octadecadien-1-ol acetate. The two isomers seemed equally effective against both species. Disruption was greatest when the pheromone was evaporated from the tops of the peach trees; also, pheromone traps placed in the tree tops captured significantly more males than did traps placed lower in the trees. Neither the color nor the directional placement in a tree (NE, NW, SE, SW) of pheromone-baited traps influenced captures of male lesser peachtree borers.Mention of a commercial or proprietary product in this paper does not constitute a recommendation or an endorsement of that product by the USDA.     

Laboratory and field evidence for maleproduced aggregation pheromone inRhynchophorus cruentatus (F.) (Coleoptera: Curculionidae)

Laboratory and field assays were conducted to determine if palmetto weevil,Rhynchophorus cruentatus (F.), adults produce an aggregation pheromone. Attraction of females in a Y-tube olfactometer to conspecific males was greater than to clean air. Male and female attraction to conspecific male volatiles combined with host-palm,Sabal palmetto (Walter), volatiles was greater than to host-palm volatiles alone. Similarly, more weevils were caught in the field in traps baited with conspecific males plus host-palm tissue than in similar traps baited with only males, or palm tissue, or females, or females plus palm tissue. These results suggest thatR. cruentatus males produce an aggregation pheromone(s) that is highly attractive to conspecific adults of both sexes when combined with host-palm volatiles. This study is an important step towards understanding the chemical ecology ofR. cruentatus.     

Aggregation pheromone of square-necked grain beetle,Cathartus quadricollis (Guér.)

When feeding on rolled oats, male square-necked grain beetles,Cathartus quadricollis (Guér.), produced the aggregation pheromone (3R,6E)-7-methyl-6-nonen-3-yl acetate, for which the trival name quadrilure is proposed. The pheromone was highly attractive to both sexes in a two-choice, pitfall olfactometer modified to retain responding beetles by placing a food stimulus (an oat flake) in the glass vials containing the experimental and control stimuli. TheS enantiomer of the pheromone was inactive. Males also produced small amounts of (E)-7-methyl-6-nonen-3-one, (E)-7-methyl-6-nonen-3-ol, and (6E)-7-methyl-3-propyl-2,6-nonadienyl acetate, but these compounds were inactive in the laboratory bioassay. Segregated males and females both produced (R)-(–)-1-octen-3-ol, which by itself was repellent to both sexes but did not diminish beetle response to the aggregation pheromone.Coleoptera: Cucujidae.Research supported by the Natural Sciences and Engineering Research Council of Canada, Strategic Grant G1039 and Operating Grants A3881 and A3706.     

Male-produced aggregation pheromone in pea and bean weevil,Sitona lineatus (L.)

The attraction ofS. lineatus to live baits comprisingS. lineatus feeding onVicia faba (L.) was studied in a field experiment in the early spring. There was clear evidence that maleS. lineatus produced an aggregation pheromone which attracted approximately equal numbers of both sexes from overwintering sites. No evidence was obtained for the production, in the spring, of any semiochemical by female weevils.Coleoptera: Curculionidae.     

Aggregation pheromone of palmetto weevil,Rhynchophorus cruentatus (F.) (Coleoptera: Curculionidae)

5-Methyl-4-octanol is the major aggregation pheromone of the palmetto weevil,Rhynchophorus cruentatus (F.). The pheromone (cruentol) was identified by coupled gas chromatographic-electroantennographic (GC-EAD) analysis of male-produced volatiles, coupled GC-mass spectrometry (MS) in electron impact and chemical ionization mode, and coupled GC-high resolution MS. In laboratory and field assays, a diastereomeric mixture of synthetic cruentol greatly enhanced attraction of weevils to cabbage palmetto,Sabal palmetto (Walter), stem tissue, indicating that cruentol and host volatiles are synergistically attractive. An attractive lure in combination with efficient traps should facilitate development of semiochemical-based management forR. cruentatus.     

Lasioderma chemistry sex pheromone of cigarette beetle (Lasioderma serricorne F.)

A chemical study of the sex pheromone of the cigarette beetle was carried out. Seven components were isolated from active fractions of column chromatography of the female extract, and their structures were elucidated by spectroscopic evidence and confirmed by synthesis to be (4S,6S,7S)-4,6-di-methyl-7-hydroxynonan-3-one (serricornin) (I), 2,6-diethyl-3,5-dimethyl-3,4-dihydro-2H-pyran (anhydroserricornin) (II), 4,6-dimethylnonan-3,7-dione (III), 4,6-dimethylnonan-3,7-diol (IV), 4,6-dimethyl-7-hydroxy-4-nonen-3-one (V), (2S,3R)-2,3-dihydro-3,5-dimethyl-2-ethyl-6-(l-methyl-2-oxobutyl)-4H-pyran-4-one (serricorone) (VI) and (2S,3R)-2,3-dihydro-3,5-dimethyl-2-ethyl-6-(1-methyl-2-hydroxybutyl)-4H-pyran-4-one (serricorole) (VII).These structural features suggested that the occurrence of these components might be related to the polyketide biosynthesis. The behavioral bioassay and BAG experiments revealed the biological role of each component in the copulatory behavior of this insect.     

The pheromone of the eastern tent caterpillar,Malacosoma americanum (F.) (lepidoptera,Lasiocampidae)

The pheromone system of the eastern tent caterpillar,M. americanum, has been identified as a mixture of (E,Z)-5,7-dodecadienal and the corresponding alcohol. Field data on the attractiveness of the aldehyde alone were not consistent, but mixtures of aldehyde and alcohol in varying proportions were attractive to males. Addition of small amounts ofE,Z acetate toE,Z aldehyde had no effect on male response, but larger amounts reduced trap catch. Traps baited withZ,E, E,E, orZ,Z aldehydes were not more attractive than blank traps. Pherocon IC traps fortified with extra adhesive and baited with lures consisting of 500 µg (E,Z)-5,7-dodecadienal with either 250 or 100 µg of the corresponding alcohol trapped as many as 100 males/trap/night with means of 15–20. Lures prepared from purified (94%E,Z) aldehyde and alcohol were more attractive than those prepared from unpurified (58%E,Z) materials.DeceasedMention of a company name or proprietary product does not constitute an endorsement by the U.S. Department of Agriculture.     

Sex pheromone of the pea moth,Cydia nigricana (F.) (Lepidoptera: Olethreutidae)

The sex pheromone of the pea moth,Cydia nigricana (F.), was identified as (E,E)-8,10-dodecadien-1-ylacetate (E,E8,10–12Ac) (approximately 0.1 ng/abdominal tip), in vacuum distillates of virgin female abdominal tips and volatiles emitted by calling females, from its chemical properties and capillary gas chromatography and mass spectrometry data. SyntheticE,E8,10–12Ac and the natural pheromone elicited similar quantitative electrophysiological and behavioral responses from male moths. Other related compounds which also attract male moths in the field,viz., (E)-10-dodecen-1-yl acetate, (E,E)-8,10-dodecadien-1-ol, and (E,E)-8,10-dodecadienal, were not detected in the pheromone andE,E8,10–12Ac was not found in male moths.     

Sex pheromone of tomato fruit borer, Neoleucinodes elegantalis

Five candidate pheromone components were identified by analyzing pheromone gland extracts by gas chromatography (GC), coupled GC-electroantennographic detection (EAD), and coupled GC-mass spectrometry (MS): (E)-11-hexadecenol(E11–16 : OH), (Z)-11-hexadecenol (Z11–16 : OH),(E)-11-hexadecenal, (E)-11-hexadecenyl acetate, and (Z)-3,(Z)-6,(Z)-9-tricosatriene (Z3,Z6,Z9–23 : Hy). In electroantennogram (EAG) recordings, synthetic E11–16 : OH elicited stronger antennal responses at low doses than other candidate pheromone components. Field tests demonstrated that synthetic E11–16 : OH as a trap bait was effective in attracting males, whereas addition of Z11–16 : OH inhibited the males' response. Z3,Z6,Z9–23 : Hy strongly enhanced attractiveness of E11–16 : OH, but was not attractive by itself. A pheromone blend with synergistic behavioral activity of an alcohol (E11–16 : OH) and hydrocarbon (Z3,Z6,Z9–23 : Hy) component is most unusual in the Lepidoptera. The synthetic two-component pheromone is approximately 60 times more attractive than the female-produced blend and might facilitate the control of this pest.     

Female sex pheromone of iris borer,Macronoctua onusta (Lepidoptera: Noctuidae)

Chromatographic and mass spectrometry studies of heptane extracts of the ovipositors of the iris borer,Macronoctua onusta, showed that the females produce several compounds that are the same as those produced by females of the tobacco budworm,Heliothis virescens. In trapping experiments, a mixture of (Z)-11-hexadecenal, (Z)-11-hexadecen-1-ol, and (Z)-9-tetradecenal (9442) proved to be the minimum set of compounds required to cause effective capture of iris borer males in the field.     

Effect of chirality, release rate, and host volatiles on response of Tetropium fuscum (F.), Tetropium cinnamopterum Kirby, and Tetropium castaneum (L.) to the aggregation pheromone, fuscumol

The male-produced aggregation pheromones of Tetropium fuscum (F.) and T. cinnamopterum Kirby were identified as (2S,5E)-6,10-dimethyl-5,9-undecadienol by chemical analysis, synthesis, electronantennography, and field trapping; the compound is here renamed “fuscumol”. The effect of fuscumol chirality, alone or with host volatiles, and fuscumol release rate on Tetropium spp. was tested in field-trapping experiments in Nova Scotia and Poland. Both (S)-fuscumol and racemic fuscumol synergized trap catches of male and female T. fuscum, T. cinnamopterum, and T. castaneum (L.) when combined with a blend of host monoterpenes and ethanol. Without added host volatiles, fuscumol was either unattractive (in Nova Scotia) or only slightly so (in Poland). (R)-Fuscumol, alone or in combination with host volatiles, did not elicit increases in trap capture of any Tetropium species, relative to the controls. Fuscumol synergized attraction of both sexes to host volatiles, thus indicating it acts as an aggregation pheromone. Sex ratio was often female-biased in traps baited with fuscumol plus host volatiles, and was either unbiased or male-biased in traps with host volatiles alone. In traps with host volatiles and racemic fuscumol, mean catches of Tetropium species were unaffected by fuscumol release rates ranging from 1 to 32 mg/d. The attraction of three different Tetropium species to the combination of (S)-fuscumol and host volatiles suggests that cross-attraction may occur where these species are sympatric, and that reproductive isolation possibly occurs via differences in close-range cues. These results have practical applications for survey and monitoring of T. fuscum, a European species established in Nova Scotia since at least 1980, and for early detection of T. castaneum, a European species not presently established in North America.     

Evidence for male-produced aggregation pheromone in American palm weevil,Rhynchophorus palmarum (L.) (Coleoptera: Curculionidae):

Field trapping of the American palm weevil (APW),Rhynchophorus palmarum, showed that the combination of caged male APWs and palm stem was much more attractive to APWs of both sexes than palm stem alone. Caged female APWs did not enhance the attractiveness of the palm. Caged APWs without palm stem were not attractive. Virgin laboratory-bred males were highly attractive to APWs of both sexes in a two-choice pitfall olfactometer, whereas virgin laboratory-bred females were not. Adsorbenttrapped volatiles from virgin laboratory-bred males reproduced the effect of living males, giving evidence for a male-produced aggregation pheromone in this species. Wild-mated APWs of both sexes were as responsive to the aggregation pheromone as virgin laboratory-bred APWs. This is the first record of chemical communication in this species. These results have prompted investigations into the chemical identification of the aggregation pheromone.     

Identification,synthesis, and bioactivity of a male-produced aggregation pheromone in assassin bug,Pristhesancus Plagipennis (Hemiptera: Reduviidae)

Pristhesancus plagipennis, a large Australian assassin bug, possesses three pairs of dorsal abdominal glands (DAGs). In the male, the anterior and posterior glands are hypertrophied and secrete an attractant pheromone. Gas chromatography-mass spectrometry (GC-MS) analyses of male DAG extracts and airborne volatiles emitted from calling males showed the pheromone signature to be dominated by a novel component. Subsequent chemical manipulations, GC-MS, and chiral-column analyses established its identity as (Z)-3-hexenyl (R)-2-hydroxy-3-methylbutyrate. Minor components included 3-methylbutanol, 2-phenylethanol, (Z)-3-hexenol, decanal, (E)-2-hexenoic acid, and three minor hexenyl esters. Bioactivity studies using laboratory olfactometers and outdoor flight cages demonstrated attraction by femaleP. plagipennis to calling males, heptane extracts of male posterior DAGs and a synthetic formulation of the (Z)R enantiomer of the major ester, alone or in combination with other components of male anterior and posterior DAGs. Males were also attracted to the major ester. The racemate andS enantiomer of the ester were not attractive. Contamination of the (Z)R enantiomer with 30–60% of theE isomer also made the compound nonattractive. This is the first report of an aggregation pheromone in the Reduviidae. The prospects for pheromonal manipulation ofP. plagipennis populations to enhance the value of this predator in horticultural ecosystems, are discussed.     

Sex pheromone of tobacco stem borer,Scrobipalpa heliopa (Lower) (Lepidoptera: Gelechiidae)

The major volatile component in the extract of the female sex pheromone gland ofScrobipalpa heliopa was shown to be (E)-3-tridecen-1-ol acetate (V). The identification was based on mass spectral analyses, comparison of retention times with those of synthetic compounds on polar, nonpolar, and liquid crystal gas chromatographic columns and microchemical studies. The latter included hydrolysis and reacetylation, and mass spectral studies of the derivatives formed by epoxidation and methoxymercuration-demercuration. Analysis of gland extracts by gas chromatography linked to electroantennography showed this component to be the only one with significant biological activity, similar to that of the synthetic compound. (E)-3-Tridecenyl acetate (V) attracted male moths to traps in the field while addition of theZ isomer (III) reduced the numbers of moths caught.     

Structure,chirality, and field testing of a male-produced aggregation pheromone of Asian palm weevilRhynchophorus bilineatus (Montr.) (Coleoptera: Curculionidae)

4-Methyl-5-nonanol is a male-produced aggregation pheromone of the Asian palm weevil,Rhynchophorus bilineatus (Montr.). The pheromone was identified by coupled gas chromatographic-electroantennographic detection (GC-EAD) and coupled GC-mass spectrometric (MS) analyses of male-and female-produced volatiles. Analyses by GC-EAD and GC-MS of weevil-produced and stereoselectively synthesized isomers of 4-methyl-5-nonanol on a Cyclodex B column, which separated isomers with baseline resolution, revealed that only (4S,5S)-4-methyl-5-nonanol is EAD active and produced by the males. In field experiments in Papua New Guinea, (4S,5S)-4-methyl-5-nonanol and a racemic mixture of disatereoisomers of it enhanced attraction of male and female weevils to sugarcane-baited traps. (4S,5S)-4-Methyl-5-nonanol is also an aggregation pheromone of two other Asian palm weevils.R. ferrugineus (Oliv.) andR. vulneratus (Panz.). The stereoisomeric mixture of 4-methyl-5-nonanol is currently used to manage populations ofR. bilineatus in Papua New Guinea.