Sex Pheromone of <Emphasis Type="BoldItalic">Agriotes acuminatus</Emphasis> (Stephens, 1830) (Coleoptera: Elateridae)

The click beetle species Agriotes acuminatus is distributed in open deciduous forests throughout a large area in Europe. In order to identify its sex pheromone, gland extracts of female beetles were investigated by using GC/MS. Neryl butanoate and 2,6-dimethyl-(Z,E)-2,6-octadien-1,8-diol dihexanoate, in a ratio of approximately 1:5, were the only volatile compounds present in the extracts. Structures of both esters were confirmed by synthesis. Field experiments revealed a strong attraction of A. acuminatus males towards neryl butanoate, which could be synergistically enhanced by addition of 2,6-dimethyl-(Z,E)-2,6-octadien-1,8-diol dihexanoate. The latter compound alone did not show any attractive effect. While all Agriotes spp. investigated to date use geranyl and/or (E,E)-farnesyl esters as sex pheromones, the nerol derivatives of A. acuminatus are the first (Z)-2-configurated pheromones within this genus.     

Electroantennogram responses of grape borerXylotrechus pyrrhoderus bates (Coleoptera: Cerambycidae) to its male sex pheromone components

Electroantennograms were recorded from the grape borerXylotrechus pyrrhoderus in response to serial dilutions of male sex pheromone components, (2S,3S)-octanediol and (2S)-hydroxy-3-octanone, and to 100 g of their optical isomers and host plant substances. Female antennae always responded more strongly than male antennae. Antennae of both sexes were highly sensitive to (2S)-hydroxy-3-octanone. F/M ratio (female to male EAG value) was greater for male sex pheromone components, especially (2S,3S)-octanediol, and their optical isomers than plant substances. Antennal sensitivity to optical isomers (2R,3R-octanediol and 2S,3R-octanediol) was lower than true pheromone components.     

Sex Pheromone of the Click Beetle Agriotes pilosellus (Schönherr, 1718)

Agriotes pilosellus is a fairly common click beetle species distributed in open deciduous and mixed forests throughout a large area in Europe. To identify its sex pheromone, gland extracts of female beetles were analyzed using gas chromatography-mass spectrometry (GC-MS). The only volatile compounds present in the extracts were geranyl butanoate and (E)-8-hydroxygeranyl dibutanoate in a 1:3 ratio, identified by comparison with synthetic samples. Field experiments revealed a clear attraction of A. pilosellus - males towards traps baited with geranyl butanoate, which could be synergistically enhanced by the factor of almost ten by addition of (E)-8-hydroxygeranyl dibutanoate. The latter compound alone did not show any attractive effect. Both compounds correspond well to the structures known from other Agriotes species and may serve as an effective monitoring tool for entomofaunistic research.

     

Synthesis and characterization of hydroxy-terminated poly(alkylene oxides) by condensation polymerization of diols

Acid-catalysed condensation polymerization of 1,6-hexanediol, 1,8-octanediol and 1,10-decanediol was carried out in the 150–190°C temperature range in the presence of sulphuric acid or Nafion-H resin, and the polymerizations were monitored by size-exclusion chromatography. The products were identified as hydroxy-terminated poly(alkylene oxides) by ¹H and ¹³C NMR and IR spectroscopy. The polymers were obtained in 66–81% yield from both catalysts in the polymerizations of 1,8-octanediol and 1,10-decanediol. With 1,6-hexanediol the polymer yields were 30 and 42-56% in the presence of Nafion and sulphuric acid, respectively. These low yields were due to the formation of oxepane as confirmed by gas chromatographic analysis of volatile condensation products. Vapour pressure osmometry showed the number-average molecular weight of polymers to be in the range 700-2400, depending on the reaction time and temperature. The hydroxy functionality of the poly(alkylene oxides) was 2.0 as determined by vapour pressure osmometry and ¹H NMR spectroscopy.     

Identification and Field Evaluation of Sex Pheromone Components of the Pear Barkminer Moth, <Emphasis Type="Italic">Spulerina astaurota</Emphasis>

The pear barkminer moth, Spulerina astaurota Meyrick (Gracillariidae: Gracillariinae), is a harmful pest of the Asian-pear tree. Pheromone components of the female were analyzed by gas chromatography (GC) with an electroantennographic (EAG) detector and GC coupled with mass spectrometry. The analyses of a crude pheromone extract and those of a fractionated extract on a Florisil column indicated three EAG-active components, tetradecadien-1-ol, its acetate, and an aldehyde derivative. Characteristic fragment ions in the mass spectra of the dienyl compounds and derivatives with 4-methyl-1,2,4-triazoline-3,5-dione revealed double bonds at the 9- and 11-positions. By comparing the chromatographic behaviors to those of four authentic geometrical isomers, which were synthesized by three different routes starting from 1,8-octanediol or 1,9-nonanediol, the configuration of each natural component was assigned to be 9Z,11Z; i.e., it was concluded that the S. astaurota females secreted (9Z,11Z)-9,11-tetradecadien-1-ol (Z9,Z11-14:OH) as a main pheromone component, and the acetate and aldehyde derivatives (Z9,Z11-14:OAc and Z9,Z11-14:Ald) as minor components. This identification was confirmed by a field evaluation of the synthetic pheromone. While the male moths could be attracted to a lure baited with Z9,Z11-14:OH alone, Z9,Z11-14:OAc showed a strong synergistic effect on the attraction. Among the lures tested, the mixture of alcohol and acetate in a ratio of 7:3 exhibited the strongest attraction. Addition of Z9,Z11-14:Ald in the mixture did not significantly increase the number of males attracted. Furthermore, the field test indicated that some contamination of a geometrical isomer of the alcohol did not impair the activity of the binary mixture with the 9Z,11Z configuration.     

Aggregation pheromone ofCarpophilus dimidiatus (F.) (Coleoptera: Nitidulidae) and responses toCarpophilus pheromones in South Carolina

The major component of the male-produced aggregation pheromone ofCarpophilus dimidiatus (F.) is (3E, 5E, 7E, 9E)-6,8-diethyl-4-methyl-3,5,7,9-dodecatetraene. It attracts beetles of both sexes in the field and is synergized by odors from fermenting bread dough; mean trap catches for the tetraene alone, tetraene plus dough, dough alone, and control were 24.5, 48.3, 0.02, and 0.00, respectively. In the laboratory, individual males produced 0.58 µg±0.35 µg (SD) of the tetraene per day, but males in groups of 10–50 produced <2% as much per beetle. A second male-specific compound, (3E, 5E, 7E, 9E)-5,7-diethyl-9-methyl-3,5,7,9-tridecatetraene, was also identified fromC. dimidiatus and is about 5% as abundant as the major pheromone component.Carpophilus flight activity was monitored for one year in South Carolina corn fields with the pheromones forC. dimidiatus, C. freemani Dobson,C. mutilatus Erichson,C. hemipterus (L.),C. lugubris Murray, andC. obsoletus Erichson, all in combination with bread dough. The first four of these species accounted for 18, 70, 5.7, and 0.03%, respectively, of the totalCarpophilus trapped, but noC. lugubris orC. obsoletus were captured. Captures ofC. freemani were as high as 11,400/trap/week. Species specificity for the first four pheromones was high, except that a synthetic impurity in theC. dimidiatus pheromone was somewhat attractive toC. freemani andC. mutilatus. Three other species captured.C. antiques Melsheimer,C. marginellus Motschulsky, andC. humeralis (F.), accounted for 0.005, 5.0, and 1.3% of the total catch, respectively.C. antiquus was attracted primarily to the pheromone ofC. dimidiatus, butC. marginellus andC. humeralis responded to most of the test pheromones. There were two major periods ofCarpophilus flight activity: February through June and September through November.Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the names by USDA implies no approval of the product to the exclusion of others that may also be suitable.     

Drones of the Dwarf Honey Bee <Emphasis Type="Italic">Apis Florea</Emphasis> Are Attracted to (2E)-9-Oxodecenoic Acid and (2E)-10-Hydroxydecenoic Acid

The queen mandibular gland component (2E)-9-oxodecenoic acid (9-ODA) has been suggested to function as the major sex pheromone component in all honey bee species. In contrast to this hypothesis, chemical analyses showed that in the Asian dwarf honey bee species, Apis florea, a different decenoic acid, (2E)-10-hydroxydecenoic acid (10-HDA), is the major component in the mandibular gland secretion. We show here that A. florea drones are attracted to 9-ODA as well as to 10-HDA. However, 10-HDA attracted higher numbers of drones at lower dosages than 9-ODA, and also was more attractive when directly compared to 9-ODA in a dual attraction experiment. We conclude that 10-HDA has to be viewed as the major sex pheromone in A. florea. The result that both pheromone components are capable of attracting drones when presented alone was unexpected with regard to existing sex pheromone attraction experiments in honey bees.     

Sex Pheromone of the Azalea Mealybug With a Non-Terpene Structure

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.

     

Multispecies trapping ofHelicoverpa (Heliothis) zea,Spodoptera frugiperda,Pseudaletia unipuncta,andAgrotis ipsilon (Lepidoptera: Noctuidae)

Multispecies sex pheromone trapping (trapping of more than one species in the same trap) for the bollworm,Helicoverpa (Heliothis) zea (Boddie); fall armyworm,Spodoptera frugiperda (J.E. Smith); armyworm,Pseudaletia unipuncta (Haworth); and the black cutworm,Agrotis ipsilon (Hufnagel) was evaluated. Baiting of individual traps with all possible combinations of the four species taken two at a time caused a reduction in the catches of at least one of any two species involved when compared to traps baited for only one species. These results demonstrated the species specificity of sex pheromones identified for these species. Although the effects were reduced in some cases, the interaction between species also was observed when adjacent traps were baited with the sex pheromone dispensers of the different species. These results indicate that the spacing between pheromone traps when more than one species are being trapped at the same site affects trap capture and should be evaluated further.This paper reports the results of research only. Mention of a commercial or proprietary product does not constitute an endorsement by the USDA.     

Aggregation pheromone ofCarpophilus antiquus (Coleoptera: Nitidulidae) and kairomonal use ofC. lugubris pheromone byC. antiquus

Males ofCarpophilus antiquus Melsheimer (Coleoptera: Nitidulidae) emit an aggregation pheromone that was found to be a novel hydrocarbon, (3E,5E,7E,9E)-6,8-diethyl-4-methyl-3,5,7,9-dodecatetraene. A synthetic scheme and spectra (mass and proton NMR) are given for the compound. Beetles produced the pheromone when feeding on a variety of media, including the brewer's yeast-based artificial diet, fermenting whole-wheat bread dough, corn, and prunes; live baker's yeast was generally added to the food media. Males held individually produced, on average, 25 × more pheromone per beetle than males held in groups of 10 or more. Pheromone was not produced until males were at least 5 days old but was still detected from the oldest beetles tested (47 days). In field tests, the pheromone was attractive to both sexes ofC. antiquus, and it was synergized by food volatiles: A combination of pheromone and fermenting whole wheat dough attracted 2.5× more beetles than pheromone alone, but dough by itself was not significantly more attractive than the control. Semiochemical interactions were studied amongC. antiquus and two other sympatric species for which pheromones are known,C. lugubris Murray andC. freemani Dobson.C. antiquus responded readily to the pheromone ofC. lugubris, but all other interspecific responses to the pheromones were weak. In a sample of naturally infested corn ears, the presence ofC. antiquus was strongly associated with the presence ofC. lugubris, as would be expected if the pheromone ofC. lugubris serves as a kairomone forC. antiquus.     

Sex pheromone of the western hemlock looper,Lambdina fiscellaria lugubrosa (Hulst) (Lepidoptera: Geometridae)

The sex pheromone of the western hemlock looper (WHL),Lambdina fiscellaria lugubrosa (Hulst), comprises three methylated hydrocarbons: 5,11-dimethylheptadecane (5,11), 2,5-dimethylheptadecane (2,5), and 7-methylheptadecane (7). Compounds extracted from female pheromone glands were identified by coupled gas chromatographic-electroantennographic (GC-EAD) analysis and coupled GC-mass spectroscopy in selected ion monitoring mode. In trapping experiments, (5,11) alone attracted male moths, but addition of either (7) or (2,5) significantly enhanced attraction. (5,11) combined with both (7) and (2,5) was significantly most attractive. (5,11) and (2,5) are also sex pheromone components of the eastern hemlock looper (EHL),Lambdina fiscellaria fiscellaria (Guen.). Although (7) is produced by the EHL, it is a pheromone component only in the WHL. It constitutes the first behaviorally active monomethyl-branched hydrocarbon to be found in a geometrid and is a novel lepidopteran sex pheromone component. The different 2- versus 3-component sex pheromone supports taxonomic division of EHL and WHL.     

Role of sex pheromone components in behavioral reproductive isolation betweenAutographa gamma (L.) and eitherTrichoplusia ni (Hübner) ORChrysodeixis chalcites (Esp.) (Lepidoptera: Noctuidae: Plusiinae)

The composition of theAutographa gamma sex pheromone was reexamined and only (Z)-7-dodecenyl acetate and (Z)-7-dodecenol were identified by capillary GC, GC-MS, and dimethyl disulfide derivatization and subsequent GC-MS analysis. The fatty acid content of the pheromone glands was also studied, and a series of saturated and unsaturated acids was identified. However, most of the related pheromonal compounds were not detected. The male response to the pheromone components was studied in a flight tunnel and compared with the response to calling females. The best synthetic baits evoked a response similar to that observed to the virgin females, but males spent significantly more time at calling females than at the synthetic baits. The preferred synthetic baits consisted of (Z)-7-dodecenyl acetate alone or of a blend with 5% (Z)-7-dodecenol. Increasing the relative amount of the alcohol caused a gradual reduction in male response, particularly in the last steps of the courtship sequence. The addition of the minor sex pheromone components of the sympatric Plusiinae species,Trichoplusia ni andChrysodeixis chalcites, to theA. gamma pheromone was also investigated in the flight tunnel. Some of these components exhibited a significantly antagonistic effect on theA. gamma male courtship behavior. The most potent antagonists were (Z)-5-dodecenyl acetate and (Z)-9-tetradecenyl acetate. The response ofA. gamma andT. ni males to conspecific and heterospecific females was also compared in the flight tunnel. WhereasA. gamma males were attracted only to their conspecific females, a small percentage ofT. ni males were also attracted toA. gamma females and 11% performed the whole courtship sequence.Contribution from the Agricultural Research Organization (ARO), No. 3459-E, 1992 series.     

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.     

Contact Sex Pheromone Components of the Cowpea Weevil, Callosobruchus maculatus

The cowpea weevil, Callosobruchus maculatus, is a major pest of stored pulses. Females of this species produce a contact sex pheromone that elicits copulation behavior in males. Pheromone was extracted from filter-paper shelters taken from cages that housed females. Crude ether extract stimulated copulation in male C. maculatus. Initial fractionation showed behavioral activity in acidic and neutral fractions. Furthermore, bioassay-guided fractionation and gas chromatography-mass spectroscopy (GC-MS) analysis of active fractions revealed that the active components of the acidic fraction were 2,6-dimethyloctane-1,8-dioic acid and nonanedioic acid. These components along with the hydrocarbon fraction, a mixture of C₂₇–C₃₅ straight chain and methyl branched hydrocarbons, had a synergistic effect on the behavior of males. Glass dummies treated with an authentic pheromone blend induced copulation behavior in males. The potential roles of the contact sex pheromone of C. maculatus are discussed.     

TOXICOKINETICS OF POLYCYCLIC AROMATIC HYDROCARBONS FROM CONTAMINATED SEDIMENT BY THE AMPHIBIAN LARVAE (PLEURODELES WALTL)

The molecular phototransformation mechanism of nitroarenes, genotoxic and ubiquitous pollutants in the atmosphere, is still under debate. With increasing exposure to radiation 1,6- and 1,8-dinitropyrene (DNP) in acetonitrile showed a decrease in their characteristic absorption bands (396 and 411 nm, respectively) in the presence of O ₂ , N ₂ and H ₂ O, and an increase in the 220–390 nm region and above 450 nm, indicating their photodegradation and transformation. The resulting photoproducts were highly fluorescent, presenting a broad emission band around 520–540 nm. Oxygen reactive species did not seem to be produced in the principal photodegradation pathways, since photodegradation rates were similar to those in anaerobic samples. In the presence of O ₂ or N ₂ 1,6-DNP photodegraded 4 times faster than 1,8-DNP, while in the presence of water is 1.5 times faster. Two chromatographic fractions were separated, and identified as pyrenediones using authentic samples and reported spectral data for hydroxy-nitropyrenes. Other chromatographic fractions are still to be identified. The properties of the identified products suggested that these were formed through a nitro-nitrite rearrangement.     

Effects of host plant,Gossypium hirsutum L., on sexual attraction of cabbage looper moths,Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae)

Unmated female or male cabbage looper moths,Trichoplusia ni (Hübner), were attracted more often in a flight tunnel to a cage with moths of the opposite sex and a bouquet of cotton foliage. Increased sexual attractiveness of females with plants may be a result of stimulation of pheromone release in response to plant odor, since more males were attracted when odor of cotton foliage was passed over females than when odor of females was passed over cotton foliage before venting into the flight tunnel. Increased sexual attractiveness of males with plants is due in part to host odor enhancement of female attraction to male pheromone, since more females were attracted to synthetic male pheromone (a blend of enantiomers of linalool and isomers of cresol) and a cotton leaf extract than were attracted to male pheromone alone. A short synthesis procedure was developed for (S)-(+)-linalool, the major component of the male sex pheromone, isolated from hair pencils, used in these tests.     

(E)-11,13-tetradecadienal: Major sex pheromone component of the eastern blackheaded budworm,Acleris variana (Fern.) (Lepidoptera: Tortricidae)

(E)-11,13-Tetradecadienal (E11,13–14:Ald) is the major sex pheromone component of the eastern blackheaded budworm (EBB),Acleris variana (Fern.). The compound was identified in female pheromone gland extracts by coupled gas chromatographic-electroantennographic detection (GC-EAD), coupled GC-mass spectrometry in selected ion monitoring mode, and retention index calculations of candidate pheromone components.E11,13–14:Ald alone as trap bait was very attractive to male EBB. Addition of the corresponding diene alcohol or acetate or both did not enhance attraction. (Z)-11,13-Tetradecadienal in binary combination with (E)-11,13–14:Ald neither enhanced nor reduced trap catches. Increasing the amounts of pheromone from 0.01 to 10 µg increased trap catches, but increase of pheromone quantity above 100 µg proportionately reduced attraction. Stabilization of slowly polymerizingE11,13–14:Ald and development of a sustained, adequate release rate is required for pheromone-based monitoring of EBB populations.     

Identification of the Major Sex Pheromone Component of the Click Beetle Agriotes ferrugineipennis

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.

     

Evidence of an aggregation pheromone in the flea beetle,Phyllotreta Cruciferae (Goeze) (Coleoptera: Chrysomelidae)

Laboratory olfactometer bioassays and field trapping experiments showed that the flea beetle,Phyllotreta cruciferae (Goeze), was highly attracted by oilseed rape(Brassica napus L.) when flea beetles were on the plant. This attraction was mediated by a flea beetle-produced aggregation pheromone based upon: (1) Oilseed rape damaged mechanically, or byP. cruciferae, or by diamondback moth,Plutella xylostella (L.), did not attractP. cruciferae. (2) Contact with the plants or feeding was required for the production of aggregation pheromone because oilseed rape alone was not attractive when separated from flea beetles by a screen. (3) Equal numbers of males and females were attracted.     

Behavioral responses to food volatiles by two species of stored-product coleoptera,Sitophilus oryzae (curculionidae) andTribolium castaneum (tenebrionidae)

Laboratory experiments were conducted to study the behavioral activity of grain-derived volatiles as attractants and pheromone synergists forSitophilus oryzae, an internal-feeding pest of sound grain, andTribolium castaneum, an external-feeding pest of damaged grains and flour. Behavioral studies with two-choice pitfall bioassays determined that the fresh grain volatiles valeraldehyde, maltol, and vanillin were attractive toS. oryzae at various doses, butT. castaneum were not attracted to any dose of any of these three compounds. When oils from pressed grains were bioassayed, sesame oil was significantly repellent and oat and wheat germ oils were attractive toS. oryzae. However, rice, soybean, oat, wheat germ, and corn oils were all attractive toT. castaneum. A commercial food product composed primarily of soybean oil and wheat germ was highly attractive toT. castaneum, but elicited no response fromS. oryzae. A combination of the three grain volatiles valeraldehyde, maltol, and vanillin with the synthetic pheromone sitophinone was more attractive toS. oryzae than either the pheromone alone or the tripartite grain volatile mix. Similarly, a combination of the commercial food product with the pheromone 4,8-dimethyldecanal was more attractive toT. castaneum than either food alone or pheromone alone. Behavioral responses to grain volatiles may reflect the ecological niche of the granivore:S. oryzae colonizes sound grain and is attracted to volatiles characteristic of fresh grain, whileT. castaneum utilizes damaged or deteriorated grains and responds best to oils characteristic of damaged or fungus-infested grain. Synergism of food odors and pheromones suggests that more effective traps can be devised for management of these pest insects.