Sex pheromone blend discrimination by male moths fromE andZ strains of European corn borer

Sex pheromone behavioral responses were analyzed in a flight tunnel with European corn borer,Ostrinia nubilalis (Hübner), males from three distinct populations. Males from a bivoltine and a univoltine biotype using a 97.82.2 blend (Z strains) of (Z)- and (E)-11-tetradecenyl acetate were assayed with treatments containing 0, 0.5, 1, and 3% of theE isomer. Males from neither population oriented in the plume to the 100%Z treatment, but bivoltine males oriented and flew to the source to the other three treatments, whereas univoltine males oriented and flew to the source only to the 1 % and 3 %E treatments. Males from a bivoltine biotype using a 199 blend ofZ/E isomers (E strain) were assayed with sources containing 0, 0.5, 1, and 3% of theZ isomer. Males did not orient to the 0%Z source, but oriented and flew to the source to the other three treatments. In addition to using opposite geometric isomers for the main pheromone component, the bivoltineE strain differed from the bivoltineZ strain by producing and responding better to 1 % of the minor component and by storing 3 times more pheromone in the female glands. Contrary to previous reports, the blend of two pheromone components is significantly better than the main component alone in eliciting oriented flight and close-range behavior with males from all three populations of European corn borer.     

European corn borer sex pheromone

The male sexual behavior-stimulating and inhibiting properties of a series of analogs of the European corn borer sex pheromone were determined in a flight tunnel. The structural requirements for inhibition of pheromonal response were far less restrictive than those for elicitation of that response. Analogs that by themselves elicited upwind flight response from males at a low dose were generally less inhibitory to male response than many of the analogs that had no pheromonal activity. These findings suggest that many pheromone analogs bind to pheromone receptors without provoking behavioral response and possibly undergo slower degradation on the antenna than pheromonally active compounds. The disparity of response to analogs by two pheromonal types of the European corn borer indicates that the pheromone receptor and pheromone catabolic systems are biochemically very different in the two types.     

Three European corn borer populations in New York based on sex pheromones and voltinism

Pheromone blend analyses of glands from individual female European corn borers,Ostrinia nubilalis (Hübner), from field-collected larvae or pupae associated with bivoltine flights in June and August and a univoltine flight in July have shown that: (1) a site in western New York has a bivoltine biotype utilizing (Z)-11-tetradecenyl acetate as its primary pheromone component (designatedZ), (2) two sites in central New York have mixed populations consisting of a bivoltine biotype utilizing theE pheromone isomer (designatedE) and a univoltine biotype utilizingZ, and (3) one site in central New York was found to have only the univoltineZ biotype. The combinations of voltine biotypes and pheromone strains found in New York support the existence of three European corn borer populations designated bivoltineE, bivoltineZ, and univoltineZ.     

Role of (Z)- and (E)-11-tetradecenyl acetate pheromone components in the sexual behavior of the (Z) strain of the european corn borer,Ostrinia nubilalis (Lepidoptera: Pyralidae)

A glass tube olfactometer bioassay was used to examine pheromone response of males of the (Z)-pheromone strain ofOstrinia nubilalis (Hubner). The presence of (E)-11-tetradecenyl acetate at the natural ratio to (Z)-11-tetradecenyl acetate (973; ZE) did not consistently elevate wing-fanning, upwind walking, or clasper extrusion over (Z)-11-tetradecenyl acetate alone. This bioassay did not reveal the behavioral role of (E)-11-tetradecenyl acetate.Published as Journal Article No. 10264 of the Michigan State University Agricultural Experiment Station.     

Iowa European corn borer sex pheromone isolation and identification of four C14 esters

Four C₁₄ straight-chain acetate esters—(Z)-11-tetradecenyl acetate, (E)-11-tetradecenyl acetate, (E)-9-tetradecenyl acetate, and tetradecyl acetate—were isolated and identified from the diethyl ether extracts of the abdominal tips of adult female European corn borers,Ostrinia nubilalis (Hübner). The compounds were isolated using a combination of high-resolution gel-permeation, adsorption highpressure liquid, and micropreparative gas chromatography. Identifications were made by gas chromatography, a combination of gas chromatography and mass spectrometry, and microdegradative chemical methods.Mention of a commercial or proprietary product in this paper does not constitute a recommendation or an endorsement of that product by the U.S. Department of Agriculture or the Energy Research and Development Administration.Joint contribution: Agricultural Research Service, U.S. Department of Agriculture; Energy Research and Development Administration; and Journal Paper No. J-8565 of the Iowa Agriculture and Home Economics Experiment Station. Project 2183.     

Comparative analysis of sex-pheromone-response antagonists in three races of European corn borer

Behavioral responses of males from three New York races of European corn borer,Ostrinia nubilalis (Hübner), to various suspected sexpheromone-response antagonists were investigated with a flight tunnel protocol. Males from a bivoltine (Z) race and from a univoltine (Z) race utilizing a natural pheromone blend of 982 (Z)-(E)-11-tetradecenyl acetates and males from a bivoltine (E) race utilizing a 199 (Z)-(E)-11-tetradecenyl acetate ratio were flown to their natural blends and to blends containing 1 % of one of the following additional compounds: Z9–12OAc,E9–12OAc,Z9–14OAc, andE9–14OAc. In each race, the added components lowered significantly the number of individuals completing the behavioral sequence. The only exception was bivoltineE males flown to a blend withE9–12OAc added. The number completing the sequence in this case was statistically not significantly lower than the number that completed the sequence to the standard blend. In all three races, theZ9–14OAc produced the most dramatic reduction in completed flights, and in the univoltineZ race, this added component was significantly more effective in reducing completed flights than any other added component. The response to the Z9–14OAc is understandable given recently published findings of an electrophysiological study of single sensilla in the European corn borer.     

Biological activity and in vivo degradation of tritiated female sex pheromone in the male European corn borer

Isomers of [11,12-³H₂]-11-tetradecenyl acetate (57 Ci/mM) were synthesized. Behavioral assay of the two compounds using Z- and E-type European corn borer (ECB) males showed that introduction of tritons into the double bond of the pheromone caused a significant isotope effect in the E-type ECB but not in the Z-type ECB. Measurements of tritium associated with the male antennae after a 3-min exposure showed that radioactivity equivalent to 10^–7 mol pheromone was adsorbed onto male antennae. Time-course in vivo metabolic studies with picogram amounts of compound applied topically to antennae of E- and Z-type males and Z-type females showed that they metabolized pheromone similarly but females degraded pheromone more slowly than males. Pheromone was hydrolyzed, and the only other major radiolabeled metabolite observed by combined high-pressure liquid chromatography-radiodetection was tritiated water. Capillary gas chromatography and radiomonitoring permitted detection of a trace amount of 11-tetradecenoic acid, which indicated alcohol oxidase activity is associated with the antennae. Evidence shows that clearing of pheromone from the ECB male antennae involves hydrolysis and oxidation of the alcohol to fatty acid, which in turn is degraded, probably via -oxidation, to carbon dioxide and water.     

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.     

European corn borer: Pheromonal catabolism and behavioral response to sex pheromone

When physiologically excessive amounts of the female sex pheromone of the European corn borer (ECB) or esters analogous to the pheromone were applied to the antennae of males, their behavioral responsiveness to pheromone in a flight tunnel was significantly impaired for 2 hr. Concurrent quantitative analyses of heptane extracts of the male antennae by gasliquid chromatography showed that the compounds applied to antennae were hydrolyzed and, at 2 and 4 hr posttreatment, little or none of the compound applied or hydrolysis product was detectable in the antennal extracts. After 4 hr of in vivo incubation, male responsiveness to pheromone was restored among moths treated with the analogs but not among moths treated with pheromone. Esterase activity on the antennae was moderately inhibited in vivo by a pheromone analog that is a so-called transition-state esterase inhibitor, 1,1, 1-trifluoro-14-heptadecen-2-one. However, the analog did not inhibit male behavior when it was coevaporated with pheromone in a flight-tunnel assay. Therefore, in the presence of pheromone, the analog did not compete well for esterase or the pheromone receptor. Treating the antennae of intact males with tetrahydrofuran obliterated sex pheromone response capability in males, but the treatment did not significantly attenuate esterase and other catabolic activity of the antennae. Indications are that degradation of esters on the ECB antennae involves substrate-nonspecific esterase activity and other metabolic processes that in turn remove hydrolysis products from the antennae. Maintenance of a male's ability to respond to pheromone is linked to these processes.     

Sex pheromone components isolated from china corn borer,Ostrinia furnacalis guenée (lepidoptera: Pyralidae), (E)- and (Z)-12-tetradecenyl acetates

The sex pheromone components from the corn borer spreading widely in China,Ostrinia furnacalis Guenée, have been identified as (E)-and (Z)-12-tetradecenyl acetates (E andZ12–14 Ac). The ratio ofE isomer toZ isomer was 53 47. Traps containing 1 × 10^–7–1 × 10^–5 g of these compounds captured more males than did live females or their tip extract (3–6 female equivalents). Tetradecyl acetate (14 Ac) was also identified in the tip extract. Its quantity was about 1.8 times the sum of the other two isomers. However, including this compound in its natural ratio in pheromone traps resulted in a decrease in trap catches (P< 0.05).     

Moth responses to selectively fluorinated sex pheromone analogs

Partially fluorinated analogs of the European corn borer (Ostrinia nubilalis) female sex pheromone, 11-tetradecenyl acetate (97:3Z:E), having mono- and trifluorsubstitutions at the terminal carbon of the pheromone chain, mimicked the biological activity of the pheromone, while analogs with fluorine at either side of the double bond and a pentafluoro analog were essentially inactive. Comparison of the pheromonal activity of these analogs with the previously reported activity of similarly fluorinated pheromones in five other species of moths revealed an unpredictable relationship between fluorine substitution pattern and pheromone-mimicking activity. Fluorine substitution patterns that rendered pheromonal analogs biologically inactive in the European corn borer had no detrimental influence upon pheromonal activity in other species and the converse was also true. This is evidence that the relative importance of electronic qualities of sites within a pheromone molecule differ from species to species. Furthermore, it indicates that the biochemical components (pheromone receptor proteins, binding proteins, and enzymes) that make up moth olfactory chemosensory systems must also vary structurally from species to species, despite the fact that they are involved in olfactory sensing of compounds having very similar chemical structure.     

Sex pheromone of the chokecherry leafroller moth,Sparganothis directana

(E)-9,11-Dodecadienyl acetate and (Z)-9,11-dodecadienyl acetate in conjunction with (E)-11-tetradecenyl acetate and (Z)-11-tetradecenyl acetate were found to comprise the sex pheromone ofSparganothis directana, based on chemical analysis, electroantennogram tests, and field trapping. (E)-9-Dodecenyl acetate and (Z)-9-dodecenyl acetate were also found in gland extracts but did not influence trap catches. The relative amounts of these compounds in the gland were 3521928 106, in the order named. Only (E)-9,1 1-dodecadienyl acetate, (E)-11-tetradecenyl acetate, and (Z)-11-tetradecenyl acetate were required for attraction of males to traps, dispensed in the relative amounts 501238, respectively.Lepidoptera: Tortricidae.Supported by National Science Foundation grant PCM 78-13241.     

Structure-activity relationship observations for European corn borer moth pheromone and fluoro analogs via computer molecular modeling

Structure-activity relationship (SAR) observations were made for theZ-type European corn borer moth pheromone, (Z)-11-tetradecen-1-ol acetate, and a series of analogs with fluorination in the alcohol portion of the molecule. The attractiveness of these analogs and the pheromone was compared to the electrostatic potential map of the molecular mechanics (MM) minimized lowest energy conformation for each compound. A critical range of electrostatic potential on the protons of the double-bond appears to be essential for optimal acceptor fit and attractiveness.     

Female Sex Pheromone Polymorphism in Adzuki Bean Borer, Ostrinia scapulalis, Is Similar to That in European Corn Borer, O. nubilalis

Individual analysis of the female sex pheromone of the adzuki bean borer, Ostrinia scapulalis, has shown that the sex pheromone of this species comprised (E)-11-tetradecenyl acetate (E11–14:OAc) and (Z)-11-tetradecenyl acetate (Z11–14:OAc) at variable blend ratios. The pheromone blend could be tentatively categorized into three types with respect to the proportion of E11–14:OAc: E type (94–100%, median 99.2%), Z type (0–16%, median 3.0%), and intermediate type (I type, 48–85%, median 63.7%). In addition to the identity of components, the blend ratios in the three types were similar to those of the E strain, Z strain, and hybrid of the European corn borer, O. nubilalis, respectively. This finding suggests that two closely related but morphologically distinct species, O. scapulalis and O. nubilalis, share almost the same sex pheromone communication systems. The significance of this similarity in the two sibling species is discussed.     

Mint root borer,Fumibotys fumalis (Guenee): Identification and field tests of female sex pheromone gland components

Compounds identified in sex pheromone gland extracts of femaleFumibotys fumalis (Guenee) consisted of (E,E)-10,12-tetradecadienyi acetate, (Z)-11-tetradecenyl acetate, (E)-11-tetradecenyl acetate, and (Z)-9-tetradecenyl acetate in a ratio of 100:18: 8:4, respectively. The compounds were identified by electroantennographic, gas Chromatographic, mass spectrometric, and chemical derivatization procedures. In mint fields synthetic components in gray elastomeric septa at ratios found in the sex pheromone gland and at doses of 3 or 10 mg of the diene produced trap catch comparable to traps baited with three females.Lepidoptera: Pyralidae     

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.     

Sex pheromone components of the blueberry leaftier mothCroesia curvalana kearfott (Lepidoptera: Tortricidae)

The GC-MS and GC-EAD analyses of sex-gland components and sex-gland-released volatiles have identified (E)- and (Z)-11-tetradecenal (9010) and (E)- and (Z)-11-tetradecenyl acetate (8515) as components of the sex pheromone chemical communication system ofCroesia curvalana (Kearfott). The aldehyde-to-acetate ratio of 91 was found in the gland-released components. This blend at a 0.1–1 g/day release rate from PVC lures was shown to be as effective as virgin females in the trapping of maleC. curvalana.     

Comparative studies of female sex pheromone components and male response of the corn stalk borer Sesamia nonagrioides in three different populations

Studies to determine possible differences in the pheromone communication system of three different populations of the corn stalk borer Sesamia nonagrioides (Lef.) in France, Spain, and Greece were carried out. The two main pheromone components (Z)-11-hexadecenyl acetate (Z11–16:Ac) and (Z)-11-hexadecenol (Z11–16:OH), were detected in all analyses with very small differences in the three populations. Among the minor components, analyzed by GC-MS on concentrated gland extracts from French and Greek origin females, (Z)-11-hexadecenal (Z11–16:Ald) was detected in minor amounts. Wind-tunnel and field studies revealed similar a male response in the three populations to pheromone glands extracts and synthetic pheromone regardless of the female/male origin. The results do not support the assumption of the existence of different pheromone types of the corn stalk borer S. nonagrioides due to geographic isolation.     

Male european corn borer,Ostrinia nubilalis (Hübner), antennal responses to analogs of its sex pheromone

Experiments were conducted to (1) determine whether the electroantennogram (EAG) can detect differences among the responses of antennae from males derived from the three strains ofOstrinia nubilalis (Hübner), and (2) characterize the EAG responses of each strain to isomeric forms of the natural pheromone, (E)- and (Z)-11-tetradecen-1-ol acetate (TDA), and analogs possessing differences in the terminal alkyl group, cyclopropyl (CPA), ortert-butyl (TBA).EAG responses differed among the strains in two ways: (1) Antennae fromZZ males always produced an EAG to (Z)-TDA with an extended duration of response. This signature EAG response was found to be unique to the antennal response ofZZ males to (Z)-TDA, thus providing a relatively easy method of distinguishing liveZZ males fromEE orZE males. Correlated with this longer EAG response was a longer disadaptation time, i.e., the EAG response ofZZ antennae disadapted more slowly (ca. 10 min) than the response ofEE antennae. (2) Strain differences in the relative EAG amplitudes to isomers and analogs were observed at the stimulus amounts eliciting the peak EAG amplitude as follows: TDA CPA > TBA forZZ males and both isomers; TDA > CPA TBA and CPA TDA > TBA forEE males and theE andZ isomers, respectively; CPA > TBA TDA forZE males and both isomers. Dose—response relationships were seen for all compounds if amplitude (peak height) of the EAG was used as a measure of response. However, if width of the EAG at half the peak height (peak width) was used, then only theZZ antennal response to (Z)-TDA resulted in a meaningful dose-response relationship. For all strains, the EAG amplitudes elicited by theZ isomers of any of the tested compounds were greater than those elicited by the correspondingE isomers. Therefore, correlations between the relative EAG and upwind flight responses were observed in theZZ (r = 0.86) andZE (r = 0.80) strains but were not correlated in theEE strain (r = 0.18). Temporal studies showed that adaptation, not postexcision deterioration, was responsible for the observed decreases in the EAG amplitude after repetitive stimulation or after stimulation with amounts in a descending order. Disa-daptation required at least 20 min for a moderate dose (10 g for 1 sec). Developmental studies showed that antennae from 2-day-old adults had the greatest EAG response.     

Sex pheromone components of the variegated leafroller moth,Platynota flavedana

Female tip extracts of the variegated leafroller moth,Platynota flavedana (Clemens), were analyzed and found to contain a mixture of (E)-11-tetradecen-1-ol and (Z)-11-tetradecen-1-ol (91), as well as a mixture of (E)-11-tetradecenyl acetate and (Z)-11-tetradecenyl acetate (2-31). Small amounts of tetradecen-1-ol and tetradecyl acetate probably are also present. In the field, a mixture of the two alcohols (8416,EZ ratio) attracted significantly more male moths of this species than any other mixture tested. The data indicate that the acetates are probably not used as pheromone components.Lepidoptera:Tortricidae:Tortricinae.This research was supported in part by the Rockefeller Foundation and by NSF Grant No. GB-38020.