Secondary pheromone components and synergism in stored-products phycitinae

Attraction of maleEphestia cautella (Walker), in a warehouse population, to traps baited with the synthetic sex pheromone (Z,E)-9,12-tetradecadienyl acetate was greatly enhanced in the presence of the synthetic secondary pheromone (Z)-9-tetradecenyl acetate. Lower levels of enhancement were observed with five compounds related to the secondary pheromone, and the synergistic effect followed a simple chemical pattern. These results are discussed in relation to the possible role of secondary pheromones in species-recognition by males and in interspecific competition.     

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     

Identification and field testing of additional components of female sex pheromone of African armyworm,Spodoptera exempta (Lepidoptera: Noctuidae)

Ovipositor washings from virgin femaleSpodoptera exempta (Walker) (Lepidoptera: Noctuidae) were analyzed by high-resolution gas chromatography (GC) linked to a male electroantennogram (EAG). GC retention times of the two major EAG responses observed were consistent with their assignment as (Z)-9-tetradecenyl acetate and (Z,E)-9,12-tetradecadienyl acetate, as previously identified. However, three other EAG responses were also noted that had GC retention times consistent with (Z)-9-tetradecenal, (Z)-9-tetradecen-1-o 1, and (Z)-11-hexadecenyl acetate. The components were present in the ratio of 10051.53.54, respectively. Further analysis of the ovipositor washings by GC linked to a mass spectrometer (GC-MS) confirmed these findings and indicated the presence of a sixth component consistent with (Z)-11-tetradecenyl acetate present at 2 % of the major component. In field tests carried out in Kenya, (Z)-11-hexadecenyl acetate was the only newly identified component to enhance the catch of the original two-component mixture when presented in their natural ratio. The addition of (Z)-9-tetradecen-1-ol reduced catch, while (Z)-9-tetradecenal and (Z)-11-tetradecenyl acetate had no apparent effect.     

Identification of new sex pheromone components inTrichoplusia ni,predicted from biosynthetic precursors

In addition to the previously identified components (Z)-7-dodecenyl acetate and dodecyl acetate, sex pheromone glands ofTrichoplusia ni release (Z)-5-dodecenyl acetate, 11-dodecenyl acetate, (Z)-7-tetradecenyl acetate, and (Z)-9-tetradecenyl acetate. Bioassays in a flight tunnel showed that a synthetic blend of these six compounds elicited complete flights to the source from 95% of the males tested and elicited hairpenciling responses at the end of the flights from 88% of the males tested. This blend was not significantly different from intact pheromone glands, which elicited complete flights to the source from 98% of the males tested and hairpenciling responses from 91% of the males tested. In contrast, the previously identified two-component blend elicited significantly fewer complete flights to the source (33%) and did not elicit hairpenciling responses from any of the males tested. The search for additional sex pheromone components was prompted by our previous identification of unusual fatty acyl moieties in the gland that seemed to be possible biosynthetic intermediates.     

Calling behavior of almond moth (Ephestia cautella) females kept in glass cages and airborne pheromone deposited on glass surfaces by airstream

The airborne pheromone emitted by calling almond moth (Ephestia cautella) females kept in individual glass cages was mainly adsorbed on the cage surface (60–65%), but sufficient pheromone was transferred by the airflow to the extended capillaries to be measured. Four calling positions of almond moth females in the glass cages were defined. The position in which the female faced the upwind flow and the gland was free to release the pheromone was the more commonly adopted position (39% of calling females). No significant difference was found in the blend proportion between capillary and cage washings in each calling position or between calling positions. The pheromone blend and amount emitted from each of five individual females was measured on three consecutive nights and both fluctuated during the 11 hr of collection, starting 3 hr before the onset of scotophase and continuing for 8 hr into it.     

Intraspecific variation of two components in sex pheromone gland ofPlanotortrix excessana sibling species

Two components, (Z)-5- and (Z)-7-tetradecenyl acetates, in the sex pheromone gland of aPlanotortrix excessana sibling species, were found to vary continuously from a ratio of 397 to 7129 in individual female moths reared from wild larvae collected around New Zealand. Two laboratory colonies were established from populations representing extremes of these ratios. Although both the ratios and the total quantities of the components in individual female moths from both colonies were significantly different from each other, there was a small number of females that overlapped in both ratio and quantity. The variation was confirmed as intraspecific in a field cage experiment with male moths from both populations mating with tethered female moths from both populations.Lepidoptera: Tortricidae: Tortricinae.     

Identification of volatile sex pheromone components released by the southern armyworm,Spodoptera eridania (Cramer)

Analysis of sex pheromone gland extracts and volatile pheromone components collected from the calling female southern armyworm,Spodoptera eridania (Cramer), by high-resolution capillary gas chromatography and mass spectroscopy indicated that a number of 14-carbon mono- and diunsaturated acetates and a monounsaturated 16-carbon acetate were produced. Gland extracts also indicated the presence of (Z)-9-tetradecen-1-ol. However, this compound was not found in collections of volatiles. Field trapping studies indicated that the volatile blend composed of (Z)-9-tetradecen-1-ol acetate (60%), (Z)-9-(E)-12-tetradecadien-1-ol acetate (17%), (Z)-9-(Z)-12-tetradecadien-1-ol acetate (15%), (Z)-9-(E)-11-tetradecadien-1-ol acetate (5%), and (Z)-11-hexadecen-1-ol acetate (3 %) was an effective trap bait for males of this species. The addition of (Z)-9-tetradecen-1-ol to the acetate blends tested resulted in the capture of beet armyworm,S. exigua (Hubner), males which provides further evidence that the alcohol is a pheromone component of this species.     

Variation in relative quantities of airborne sex pheromone components from individual femaleEphestia cautella (Lepidoptera: Pyralidae)

The airborne sex pheromone components (Z,E)-9,12-tetradeca-dien-1-yl acetate and (Z)-9-tetradecen-1-y1 acetate from single calling females ofEphestia cautella (Walker) were trapped within glass capillary tubes and were measured by gas chromatography-mass spectrometry. Broad and similar distributions of relative quantities were found for a laboratory strain and three Australian field strains, and means differed strongly from those reported previously for this species. The overall mean proportion of the two components found for Australian females was 8812. The composition in individuals ranged from 6327 to 973. The proportions for individuals appeared to vary slightly in a random fashion from day to day, and proportions for first-generation progeny were influenced by the maternal blend.Author order in this paper is alphabetical     

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.     

Identification of sex pheromone of bristly cutworm,Lacinipolia renigera (Stephens)

The sex pheromone of the bristly cutworm moth,Lacinipolia renigera was identified as a blend of (Z)-9-tetradecenyl acetate (itZ9–14): Ac and (Z, E)-9,12-tetradecadienyl acetate (ZE-9,12–14: Ac). Extracts of female glands were analyzed by capillary gas chromatography on three columns of different polarities. In each analysis, peaks with retention times identical to Z9–14:Ac andZE–9, 12–14: Ac were observed. GC-MS analysis of gland extracts supported the identification of these two compounds. Volatiles emitted from female sex pheromone glands during 10-min collection periods contained 7.8 ±2.01 ng ofZ9- 14: Ac. On average the blend contained 3.8 ± 1.43%ZE-9,12–14: Ac. Blends ranging from 1% to 10%ZE- 9,12–14: Ac in Z9-14: Ac (1 mg) were effective in capturing males in the field. The number of males captured in traps baited with a 3 % blend ofZE- 9,12-14: Ac in Z9-14: Ac was not significantly different than the number caught in traps containing two virgin females.     

Identification of sex pheromone components from pheromone gland volatiles of the tomato looper,Plusia chalcites (Esp.)

The sex pheromone glands ofPlusia chalcites release, dodecyl acetate, (Z)-7-dodecenyl acetate, (Z)-9-dodecenyl acetate, 11-dodecenyl acetate, (Z)-8-tridecenyl acetate, and (Z)-9-tetradecenyl acetate. A combination of capillary GC, GC-MS, and dimethyl disulfide derivatization enabled a rigorous identification of all these compounds, some of which were previously found in gland extracts. Bioassays in a flight tunnel showed that a ternary blend of (Z)-7-dodecenyl acetate, (Z)-9-dodecenyl acetate, and (Z)-9-tetradecenyl acetate elicited directed flights from 85 to 100% of the males tested and elicited copulation attempts, at the end of the flights, from 44 to 74% of the males tested. This blend was equal in activity to the natural gland extract. Addition of the other acetates had only a slight influence on the activity of this mixture. Substitution of either (Z)-9-dodecenyl acetate or (Z)-9-tetradecenyl acetate in this blend by 11-dodecenyl acetate gave two ternary mixtures which also elicited high levels of courtship activity, almost as high as that of the original blend. Addition of (Z)-7-dodecenyl alcohol inhibited almost totally the flight activity of males.Lepidoptera: Noctuidae.Contribution from the Agricultural Research Organization (ARO) No. 1701-E, 1986 series.     

The female sex pheromone of sugarcane stalk borer,Chilo auricilius identification of four components and field tests

Four pheromonal components have been detected in ovipositor washings and volatiles from female sugarcane stalk borers,Chilo auricilius Dudgeon (Lepidoptera: Pyralidae), using combined gas chromatography-electroantennography. The components have been identified as (I) (Z)-7-do-decenyl acetate, (II) (Z)-8-tridecenyl acetate, (III) (Z)-9-tetradecenyl acetate, and (IV) (Z)-10-pentadecenyl acetate by comparison of their gas chromatographic behavior with that of synthetic standards. In field tests carried out in northern India during 1982–1984, a combination of II, III, and IV in their naturally occurring ratio (841) was shown to provide a highly attractive synthetic source for trap use. (Z)-7-Dodecenyl acetate was found to reduce catches of maleC. auricilius, both when dispensed with the other three components and when released from dispensers surrounding a trap baited with the other three components.     

Sex pheromone of femaleMyelois cribrella Hübner (Lepidoptera: Pyralidae)

Females ofMyelois cribrella contain about 20 ng/gland of the primary sex pheromone components (Z)-9-tetradecenyl acetate, (9Z,12E)-9,12-tetradecadienyl acetate, and (Z)-11-hexadecenyl acetate in proportions of 4115, respectively. These physiologically active components are accompanied by a number of related compounds such as (Z)-9-tetradecen-1-ol, hexadecyl acetate, (9Z,12E)-9,12-tetradecadien-1-ol, (Z)-11-hexadecen-1-ol, octadecyl acetate, octadecan-1-ol, and eicosyl and docosyl acetates. Octadecyl acetate, the most abundant component, represents about 42 ng/female moth; however, no physiological activity could be attributed to it. In field tests, a trap baited with a 1-mg mixture of (Z)-9-tetradecenyl acetate, (9Z,12E)-9,12-tetradecadienyl acetate, and (Z)-11-hexadecenyl acetate in a ratio of 121 caught more male moths than three live female moths.Pheromones, 58. Pheromones, 57: Bestmann et al. (1987).     

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.     

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.     

Replacement of carcinogenic solvent HMPA by DMI in insect sex pheromone synthesis

Hexamethylphosphoric triamide (HMPA) is a good solvent for the alkylation of terminal acetylenes; however, it has been proven to be a carcinogen towards rats and should be considered as a serious risk to man when a large-scale synthesis is involved. Thus the search for a safe alternative is important. The physical properties of 1,3-dimethyl-2-imidazolidinone (DMI) are similar to DMPU (1,3-dimethyl-2-oxo-hexahydropyrimidine) and HMPA, but the potential toxicological risk of DMI is less than DMPU and HMPA. When used in the alkylation of terminal acetylenes, DMI is comparable with HMPA, thus it is a good alternative solvent to the carcinogen HMPA in the alkylation because it provides a safer working environment than DMPU and HMPA.     

Sex pheromone of European corn borer.

Sex gland extracts ofOstrinia nubilalis females collected in the wild or laboratory-reared from Switzerland, Italy, and Hungary were analyzed. Individuals collected in the north of Switzerland contained (Z)- and (E)-11-tetradecenyl acetate at the approximate ratio of 973 (Z type), in accordance with field responses of males and previous findings. On the other hand, females from a laboratory culture derived from field collections made in the same area and reared for four to five generations contained theZ andE isomers at ratios of ca. 397 and 3565, respectively. In the south, one of the eight wild females analyzed was of theZ type and the rest intermediate, whereas males were predominantly trapped with blends of the two isomers containing 60 to 97E. In a laboratory culture reared for one to two generations from corn borers collected in Hungary, three of nine females were of the intermediate type and the restZ. Small amounts of (Z)-11-hexadecenyl acetate were detected in female glands of theE strain; however, no effect of this compound could be observed in the field.     

Bidirectional Selection for Novel Pheromone Blend Ratios in the Almond Moth, <Emphasis Type="Italic">Cadra cautella</Emphasis>

The sex pheromone of the almond moth, Cadra cautella, is a blend of (Z,E)-9,12-tetradecadienyl acetate (Z9,E12–14:Ac, the major component capable of inducing attraction alone) and (Z)-9-tetradecenyl acetate (Z9–14:Ac, the minor component, which is unattractive alone but augments attraction of the major component). In this study, the ratio of the two components responded to artificial directional selection in five of six selected lines, whereas no change was observed in the three control lines. The mean ratio (±SE) of Z9,E12–14:Ac to Z9–14:Ac went from 13.72 ± 1.02:1 to 20.13 ± 0.68:1 in high line 1, an increase of 47%. In the second high-selected line, the mean ratio (±SE) increased from 9.87 ± 0.54:1 to 15.89 ± 0.85:1, an increase of 61%. In low line 1, the mean ratio (±SE) in the parental generation was 10.74 ± 0.78:1 and 7.35 ± 0.41:1 in the last selected generation, a decrease of 32%. The response to selection was greater in low line 2, as the mean ratio (±SE) decreased from 10.11 ± 0.66:1 to 5.65 ± 0.55:1 in the last generation, a decrease of 44%. In low line 3, the mean ratio (±SE) in the parental generation was 13.63 ± 0.82:1 and 6.47 ± 0.26:1 in the last generation, a decrease of 53%. The response to selection was approximately symmetrical with a mean increase of 54% and a mean decrease of 43%. The increases in ratio observed in the high lines were caused by an increase in the titer of the Z9,E12–14:Ac component with no concurrent change in the titer of the component Z9–14:Ac. Among the low selected lines, the titers of both components increased; however, there was a greater relative increase in the titer of the component Z9–14:Ac. The absolute and relative titers of the sex pheromone components had decreased significantly in the F10 generation in some of the selected lines, five generations after the discontinuation of selection.     

Sugar beet crown borer,Hulstia undulatella (Clemens) 1: Identification and field tests of female sex pheromone gland components

Electroantennogram profiles of saturated and monounsaturated 12-, 14-, and 16-carbon acetates, and 12- and 14-carbon alcohols implicated (Z)-9-tetradecen-1-ol acetate (Z9-14: Ac) as a component of the female sex pheromone ofHulstia undulatella (Clemens). Gas chromatography-mass spectrometric analysis of extract of the female sex pheromone glands showed the presence of Z9-14:Ac (8.5 ng/female), (Z)-9-tetradecen-1-ol (Z9-14:OH), and (Z)-11-hexadecen-1-ol acetate (Z11-16:Ac) in a ratio of 100421, respectively. In tests in sugar beet fields, Z9-14:Ac alone produced some trap catch. Addition of Z9-14: OH did not increase catch while addition of Z11-16:Ac eliminated catch, but addition of both Z9-14:OH and Z11-16: Ac increased catch sevenfold. A combination of Z9-14: OH and Z11-16: Ac without Z9-14: Ac did not produce trap catch. A lure of 200 g Z9-14:Ac+16 g Z9-14:OH+42 g Z11-16:Ac is suggested for use in monitoring traps.Lepidoptera: Pyralidae: Phycitinae.     

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.