Neral and geranial: Components of the sex pheromone of the parasitic wasp,Itoplectis conquisitor

A laboratory investigation of theItoplectis conquisitor sex pheromone was initiated to elucidate the structure(s) of the active component(s) of the system. Functional group tests performed on crude virgin female extract classified the pheromone as unsaturated aldehyde(s) and/or ketone(s). Isolation of active fractions by gas-liquid chromatography (GLC) suggested the existence of a multicomponent pheromone system. Analysis by gas chromatography-mass spectrometry indicated the presence of saturated and unsaturated aldehydes including neral and geranial. When mixtures of neral and geranial were bioassayed independently and in combination with other active GLC fractions, they elicited male sexual activity of intensity comparable to that released by the GLC fraction (DEGS E) from which they were isolated. The authors conclude that neral and/or geranial are components of the sex pheromone system of this species.     

The sex pheromone glands ofDermacentor variabilis (Say) andDermacentor andersoni stiles

Evidence is presented indicating the presence of the tick sex pheromone, 2,6-dichlorophenol in lipid droplets in the foveal glands ofDermacentor variabilis (Say) andDermacentor andersoni Stiles. The pheromone appears to be dissolved in the lipid droplets. The droplets consist of neutral lipids, mostly triacylglycerides and cholesterol esters. The esterified fatty acid profiles of foveal gland triacylgylcerides are different from those of other tissues examined or reported for other ticks. The percentage of shorter chain, mostly saturated fatty acids were decreased, while the longer chain polyunsaturated fatty acids were increased. The biological advantages of lipid solution for storage, translocation, and release of the sex pheromone from the female tick are discussed.Supported by grant AI 10986, from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, U.S. Public Health Service, Department of Health, Education and Welfare, Bethesda, Maryland.     

Chemical communication in the mating behavior ofTrogoderma glabrum (Herbst) (Coleoptera: Dermestidae)

Male mating behavior of the stored product pest beetleTrogoderma glabrum (Herbst) was analyzed into three major phases: arousal/searching, preliminary recognition, and genital (copulatory). Airborne pheromone released by calling females elicits male arousal via antennal sensillae. Contact chemoreception via male mouthpart sensillae appears to be necessary for copulation to occur. A procedure was developed for quantitative bioassay of presumptive pheromone compounds in both airborne and contact chemoreception. (E)-14-methyl-8-hexadecenal, present in airborne pheromone, but not detectable in extracts of whole females, elicits both arousal and attempted copulation. The activity of (E)-14-methyl-8-hexadecenal is equal to that of the total airborne pheromone. Activity of additional possible pheromone component candidates [including (E)-14-methyl-8-hexadecen-1-ol, -caprolactone,n-hexanoic acid, and methyl (Z)-7-hexadecenoate] was investigated. Evidence for a behavioral role forn-hexanoic acid is presented.     

Genital sex pheromones of ixodid ticks: 1. Evidence of occurrence in anterior reproductive tract of American dog tick,Dermacentor variabilis (Say) (Acari: Ixodidae)

The occurrence of a genital sex pheromone in the anterior reproductive tract of partially fed femaleDermacentor variabilis was demonstrated by extraction and bioassay. A new type of bioassay, the neutered female assay, was developed to test the potency of extracts or chemically defined fractions to stimulate males to copulate. Electrophysiological tests confirmed the ability of males to detect the pheromone with sensilla on their cheliceral digits. Males of bothD. variabilis andD. andersoni exhibited neuronal excitation when stimulated with extracts of theD. variabilis reproductive tissues. The pheromone, which is soluble in methanol, was fractionated and found to contain at least two fractions that stimulated copulation by sexually excited males. Evidently, the pheromone is a mixture of two or more compounds. Histologic, ultrastructural, and histochemical studies suggest the vestibular vagina as the site of genital sex pheromone occurrence, presumably from secretions of the surrounding lobular accessory gland. The identity of the compounds that comprise the pheromone remains unknown.Supported by grants AI10986 and AI10987 from the National Institute of Allergy and Infectious Diseases, National Institute of Health, U.S. Public Health Service, Bethesda, Maryland 20205.     

2,6-Dichlorophenol,the sex pheromone of the Rocky Mountain wood tick,Dermacentor andersoni Stiles and the American dog tick,Dermacentor variabilis (Say)

2,6-Dichlorophenol is the only active sex attractant component detected in the extracts of the Rocky Mountain wood tick,Dermacentor andersoni Stiles and the American dog tick,Dermacentor variabilis (Say). It elicits from the male of each species a hierarchy of responses culminating in copulation. This compound probably occurs generally throughout the metastriate Ixodidae. 2,6-Dibromophenol, an artifact, also elicits the same sexual responses from the wood tick, but phenol andp-cresol do not.Supported by grants nos. AI 10,986 and AI 10,987 from the National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20014.     

Evidence for occurrence of mounting sex pheromone on body surface of femaleDermacentor variabilis (Say) AndDermacentor andersoni (Stiles) (Acari: Ixodidae)

MaleDermacentor variabilis andD. andersoni respond to an unknown chemical or chemicals present on the body surfaces of partially engorged conspecific female ticks. Following contact, the males mount the females and apply their mouthparts and legs against the female dorsal body surface. Then, the males turn with these appendages still in close contact and crawl to the female's venter, whereupon they locate the gonopore, probe the vulva, and copulate. Similar responses are elicited by heterospecific as well as conspecific females. However, the response is lost when the female cuticle is cleaned (delipidized) with organic solvents. It can be restored by applying hexane extracts prepared from female cuticle to the previously cleaned females. Males do not use surface texture as the primary stimulus for mate recognition. Male ticks also respond to hexane extracts applied to spherical inanimate objects, (dummy female), suggesting that a chemical or chemicals soluble in organic solvents has been transferred to these objects. These findings suggest the existence of a previously undescribed pheromone, the mounting sex pheromone (MSP). This contact sex pheromone enables males excited and attracted by 2,6-dichlorophenol to identify the female as a potential mating partner. The MSP is the second in the series of three sex pheromones guiding the hierarchy of behavioral responses which constitute tick courtship behavior.Supported by grant AI 10,986 from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, U.S. Public Health Service, Department of Health and Human Services, Bethesda, Maryland 20205.     

Production and release of (Z,E)-9,12-tetradecadienal by sex pheromone glands of females ofPlodia interpunctella (lepidoptera: pyralidae)

Extracts of sex pheromone glands obtained from females ofPloida interpunctella contained detectable amounts of (Z,E,)-9,12-tetradecadien-1-ol acetate (Z9,E12–14:Ac) and (Z,E.)-9,12-tetradecadien-1-ol (Z9,E12–14:OH) 4 hr prior to the first scotophase after adult emergence. The amount of pheromone increased during the first 4 hr of the scotophase and then declined to low levels during the subsequent photophase. Decapitation of females immediately after emergence, prior to expansion of the wings, inhibited production of pheromone during the subsequent 48 hr. Injection of extracts of the heads of 1-day-old females ofP. interpunctella of partially purified extracts of the cephalic ganglia of females of the corn earworm moth into decapitated females stimulated production of bothZ9,E12–14:Ac andZ9,E12–14:OH as well as production of (Z,E)-9,12-tetradecadienal (Z9,E12–14:Al). This aldehyde was subsequently identified from extracts of pheromone glands obtained from naturally calling females as well as from volatiles emitted by calling females. Studies on the terminal steps in biosynthesis of the pheromone showed thatZ9,E12–14:OH was produced from the corresponding acetate and thatZ9,E12–14:Al was produced from the alcohol via the action of an oxidase(s).     

(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.     

Synthesis of the male stable fly polyene (Z,Z)-1,7,13-pentacosatriene and its geometrical isomers

The four geometrical isomers of 1,7,13-pentacosatriene were synthesized from 1,7-octadiyne. Two of the required isomers were synthesized using known methodology. Hydrogenation of acetylenic linkages were employed to produce predominantly cis alkenes, and alkali metal/amine reduction was used to produce a trans alkene. It was thus possible to produce the (Z,Z) and the (Z,E) isomers. Methods for olefin inversion were then employed to obtain the other two isomers.     

Comparing the effectiveness of sexual communication disruption in the oriental fruit moth (Grapholitha molesta) using different combinations and dosages of its pheromone blend

The relative efficacy of disruptant blends comprised of different combinations of the Oriental fruit moth's pheromone components was determined in field tests. Disruption was evaluated by comparing male moth catch at synthetic and female-baited traps in disruptant and non-treatment areas. Three atmospheric dosages of a 8-dodecenyl acetate (93.5%Z6.5%E) blend, representing two successive 10-fold decreases in concentration (2.5 × 10^–2 g/hectare/day to 2.5 × 10^–4 g/hectare/day) were tested alone and in combination with an additional percentage of (Z)-8-dodecen-1-ol. Male moth orientation to traps was eliminated in plots exposed to the two highest binary acetate dosages. However, significantly more males were captured in synthetic-baited traps in the lowest acetate-alone treatment, indicating a diminution of disruption efficiency. In contrast, inclusion of (Z)-8-dodecen-1-ol in the disruptant blend effected essentially complete disruption of orientation at all concentrations tested. Mating success ofG. molesta pairs confined in small cages apparently was not affected by the presence of relatively high concentrations of the binary acetate and the acetate-alcohol blends. This suggests that habituation and/or adaptation of male response, at least for comparatively close-range behaviors, did not occur.Lepidoptera: Tortricidae.Published as Journal Article No. 9569 of the Michigan Agricultural Experiment Station.     

Sexual behavior ofMatsucoccus josephi (Homoptera: Margarodidae)

The daily emergence patterns ofMatsucoccus josephi adults and third-instar male larvae raised on artificially infested saplings ofPinus halepensis were determined. A single peak of emergence was found for adult males between 0300 and 0500 hr. Adult females emerged throughout the day, with maximum emergence between 0500 and 0700 hr. Two daily emergence periods were observed in third-instar male larvae, one between 0300 and 0900 hr and the other between 1700 and 2100 hr. Airborne pheromone emitted by adult virgin females was collected using a flow system. No significant differences were recorded in the attraction of the male to crude pheromone collected at different times of day. A single female, virgin or half an hour after mating, was sufficient to attract the males in an olfactometer system. From minor differences in pheromone release throughout the day, and from the lesser degree of attraction by females half an hour after mating, it is assumed that there is no mechanism controlling the daily release of the female sex pheromone. Reduction of pheromone emission after mating is suggested.Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. No. 2743-E, 1989 series.     

Population-density-dependent mating frequency amongPlodia interpunctella (Lepidoptera: Phycitidae) in the presence of synthetic sex pheromone with behavioral observations

Mating frequency amongPlodia interpunctella (Hübner) held in enclosed environments was reduced in the presence of the synthetic sex pheromone, (Z,E)-9,12-tetradecadien-l-ol acetate. The effectiveness of any dose of pheromone was markedly increased as population densities were decreased from 10 to 0.1 pairs/m² of wall and ceiling surface. Mating behaviors of the insect are described.Mention of a commercial or proprietary product in this paper does not constitute an endorsement of the product by the U.S. Department of Agriculture.Florida employed under a cooperative agreement with the USDA.     

Sex Pheromone of the Leaf-Miner Phyllonorycter Platani: (Z10)-Tetradecenyl Acetate

A female produced sex pheromone of the leaf-miner pest Phyllonorycter platani (Staudinger) (Lepidoptera: Gracillariidae) was identified as (Z10)-tetradecenyl acetate. Field trapping trials confirmed activity of this compound. The presence of the geometrical isomer (E10)-tetradecenyl acetate, a pheromone component of other Phyllonorycter species, reduced trap efficacy.     

Chemically mediated associative learning: An important function in the foraging behavior ofMicroplitis croceipes (Cresson)

When experienced by contact with feces from hosts feeding on cowpeas, laboratory-reared females ofMicroplitis croceipes, a larval parasitoid ofHeliothis spp., orient and fly to odors of the same feces, whereas naive laboratory-reared females do not. Flight-tunnel studies revealed that associative learning occurs during female encounters with hosts and host products. When females antennate host feces, they learn to recognize the volatile odors associated with the feces. Females even can be conditioned to respond to novel and otherwise unattractive odors such as vanilla extract by exposure to these volatile substances in association with a water extract of the feces. They apparently link the volatile odors with a nonvolatile hostspecific recognition chemical found in the feces. The antennating stimulant, 13-methylhentriacontane, was found to be a valuable ingredient, apparently as a facilitator of the initial antennation and subsequent linkage of the volatiles to the nonvolatile host recognition cue.     

Sex pheromone components from asian corn borer,Ostrinia furnacalis (Hubner) (Lepidoptera: Pyralidae) in Taiwan

The female sex pheromone of the Asian com borer,Ostrinia furnacalis, widespread in Taiwan, was confirmed as (Z)-12-tetradecenyl acetate and its geometric isomer (E)-12-tetradecenyl acetate in a ratio of ca. 31 by gas chromatography and gas chromatography-mass spectrometry in selected ion monitoring mode. Males were attracted by the mixture of these two synthetic components in the field, but the attractiveness was less than by virgin females. The presence of minor components in the sex pheromone was therefore suggested.     

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.     

(S)-(+)-Ipsdienol: Interspecific inhibition ofIps latidens (leconte) byIps pini (Say) (Coleoptera: Scolytidae)

In south-central British Columbia, the attraction ofIps latidens (LeConte) to its pheromone, ipsenol, was inhibited by (S)–(+)-ipsdienol, a pheromone forI. pini (Say). (R)-(–)–lpsdienol had no effect onI. latidens. (S)–(+)-lpsdienol probably plays a role in interspecific communication between the two species, facilitating reductions in interspecific competition for breeding material and/or interspecific mating interference.     

Responses of Tea Tussock Moth, Euproctis pseudoconspersa, to Its Pheromone, (R)-10,14-Dimethylpentadecyl Isobutyrate, and to the S-Enantiomer of Its Pheromone

Field trials were conducted with each synthetic enantiomer (>98% ee) and blends of the two synthetic enantiomers of the female-produced sex pheromone (10,14-dimethylpentadecyl isobutyrate) of the tea tussock moth, Euproctis pseudoconspersa. Male moths were attracted to each enantiomer alone and to various blends of them. Short syntheses of both enantiomers of the pheromone from commercially available (R)- and (S)-citronellyl bromide and a method of checking the enantiomeric purity of the citronellyl bromide enantiomers are described.     

(R)-acetoin-female sex pheromone of the summer chafer Amphimallon solstitiale (L.)

Extracts of Amphimallon solstitiale (L.), a well known, widely distributed and rather common European scarab beetle, were analyzed by GC-MS and GC-EAD. Acetoin -(R):(S) < 9:1 - as well as 2,3-butanediol -(2R,3R):(2S,3S) :meso = 1:1:9 - were present in extracts of both males and females. Although (2S,3S)-butanediol did not show any EAD activity, the other compounds elicited strong responses exclusively with male antennae. In contrast, several EAD active green leaf volatiles were detected equally well by male and female antennae. During preliminary field bioassays, (R)-acetoin was highly attractive to swarming males, whereas neither rac-acetoin nor the 2,3-butanediols showed activity. Therefore, (R)-acetoin is the female sex pheromone of A. solstitiale.     

Western avocado leafroller,Amorbia cuneana (Walsingham), (Lepidoptera: Tortricidae)

The most effective lure for maleAmorbia cuneana (Walsingham) in Orange, Ventura, and Riverside counties of California was previously found to be a 11 ratio of (E,E)-10,12- and (E,Z)-10,12-tetradecadien-1-ol acetates. In subsequent field tests in San Diego and Santa Barbara counties, this lure was ineffective. Analysis of sex pheromone glands (SPG) of femaleA. cuneana from these two counties showed theEE:EZ ratio to be about 19 and synthetic lures of this composition were highly attractive in these areas. Analysis of the SPG of a number of females from both areas showed that there were three population types: two in the low ratio areas possessed 37 and 58%EZ, and the third in the high ratio areas possessed 89%EZ.Mention of a commercial or proprietary product does not constitute an endorsement by the USDA.