Intrapopulational changes in sex pheromone composition during scotophase in oriental tobacco budworm,Helicoverpa assulta (Guenée) (Lepidoptera: Noctuidae)

Solvent extracts of individual pheromone glands were prepared from femaleHelicoverpa assulta (Guenée) at 2-hr intervals throughout the scotophase. The amounts of female sex pheromone components, (Z)-9-hexadecenal, (Z)-11-hexadecenal, (Z)-9-hexadecenyl acetate, and (Z)-11-hexadecenyl acetate, in the extracts were determined by gas chromatographic analysis. Although females called from early scotophase (2 hr) until late scotophase (6 hr) the quantity of extracted pheromone remained high at 8 hr, the end of the scotophase. More than 70% of the pheromone gland extracts contained sex pheromone components regardless of whether the donor females had been called or resting. Pheromone components were absent from gland extracts prepared at the onset of the scotophase. The quantity of (Z)-9-hexadecenal and (Z)-11-hexadecenal increased rapidly to reach a maximum of approximately 260 and 30 ng/female, respectively, that was maintained for up to 8 hr, the duration of the scotophase. The quantity of (Z)-9-hexadecenyl acetate and (Z)-11-hexadecenyl acetate increased continuously during the scotophase to peak at 600 and 30 ng/female, respectively, 8 hr into the scotophase. At the end of scotophase the quantity of all pheromone components decreased significantly.     

Identification of the sex attractant pheromone of the southwestern corn borerDiatraea grandiosella Dyar

We report the identification of the southwestern corn borer,Diatraea grandiosella Dyar (Lepidoptera: Pyralidae), female sex attractant pheromone as a mixture of (Z)-9-hexadecenal, (Z)-11-hexadecenal, and (Z)-13-octadecenal in the ratio 21.570.67.9. Initially, six 16- and 18-carbon aldehydes includingn-hexadecanal, (Z)-9-octadecenal, (Z)-11-octadecenal, and the three above were isolated from female gland rinses and evaluated as potential pheromone components by GLC-MS and laboratory bioassays. By laboratory flight chamber and field tests, the stated mixture of (Z)-9-hexadecenal, (Z)-11-hexadecenal, and (Z)-13-octadecenal was shown to be as effective as the female for male attraction. Electrophysiological studies confirmed the requirement for these three compounds, but not forn-hexadecanal, (Z)-9-octadecenal, and (Z)-11-octadecenal.Lepidoptera: Pyralidae.Mention of a commercial or proprietary product in this paper does not constitute endorsement of this product by USDA.     

Identification of Sex Pheromone Components of the Box Tree Pyralid,Glyphodes perspectalis

Analysis of ovipositor extracts of the box tree pyralid, Glyphodes perspectalis (Lepidoptera: Crambidae), by coupled gas chromatography-electroantennogram detection and gas chromatography yielded three candidate pheromone compounds. Gas chromatography-mass spectrometry, and reaction with dimethyl disulfide (DMDS), identified these compounds as (Z)-11-hexadecenal (Z11-16:Ald), (E)-11-hexadecenal (E11-16:Ald), and (Z)-11-hexadecenol (Z11-16:OH). The ratio of these three compounds in crude extract was 5:1.25:1, and the total amount was approximately 100 ng/female. In laboratory bioassays, Z11-16:Ald alone was attractive to males. In field bioassays, however, Z11-16:Ald alone was not attractive to males, but a mixture of Z11-16:Ald and E11-16:Ald was. The addition of Z11-16:OH to the two aldehydes, significantly reduced attractiveness to male moths in a field trial. From these results, we conclude that the aldehyde compounds comprise the sex pheromone components of G. perspectalis. A rubber septum containing 0.6 mg of the two aldehydes at the natural ratio was an effective lure for monitoring this pest.     

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.     

Pheromone reception in tobacco budworm moth,heliothis virescens

Eleclrophysiological recordings from single olfactory receptor cells were carried out in the male tobacco budworm moth,Heliothis virescens. Recordings were made primarily from the sensilla trichodea type 1, which are located in the characteristic circumferential rows on the antennae. They possess the longest sensilla hairs as revealed by scanning electron microscopy (SEM). The sensory cells of these sensilla responded specifically to pheromones. Only three types of receptor neurons were found, each tuned to one of the female-produced components. The majority (58%) of the neurons were tuned to the major component (Z)-11-hexadecenal (Z11-16:A1). Another large group (27%) responded specifically to stimulation with (Z)-9-tetradecenal (Z9-14: Al). These two compounds are the most important components of the pheromones as judged by their influence on the behavioral responses of the males. The third type of neurons responded specifically to (Z)-11-hexadecen-1-ol (Z11-16: OH), which may act either as a pheromone component or as an interspecific cue. None of the receptor neurons in the long sensilla trichodea responded specifically to the minor aldehyde components of the pheromone, which have subtle effects on behavior. Mixture experiments provided no evidence that minor components influence the receptor responses to the major components. Olfactory sensilla outside the crosswise rows were also characterized morphologically by SEM. Included in these were sensilla of different lengths, corresponding to a classification as s. basiconica and s. trichodea type 2. Electrophysiological recordings from these sensilla showed that they are involved primarily in host odor reception. However, a few of these neurons responded to pheromones.     

Sex pheromone chemistry of the female tobacco budworm moth,Heliothis virescens

(Z)-11 -Hexadecenal (77–91%), (Z)-7-hexadecenal (0.1–2%), (Z)-9-hexadecenal (0.3–2%), hexadecanal (3–19%), (Z)-11-hexadecen-1-ol (1–5%), tetradecanal (1–3%), and (Z)-9-tetradecenal (1–3%) were identified from the heptane washes of the ovipositor of femaleHeliothis virescens (F.) females. In field bioassays, a 152-g mixture of these seven compounds deployed in an insect trap exceeded the attractiveness of 4 virgin femaleH. virescens for males and was 5–6 times more attractive than a mixture of (Z)-1 1-hexadecenal and (Z)-9-tetradecenal (virelure) that was previously reported as the sex pheromone of the species. Four of the seven compounds produced byH. virescens females are also produced byH. zea (Boddie). Specificity of pheromonal signals among the two species is ostensibly dependent upon one or more of the three additional compounds [tetradecanal, (Z)-9-tetradecenal, and (Z)-1 1-hexadecen-1-ol] produced by femaleH. virescens.     

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 chemistry of female corn earworm moth,Heliothis zea

Glass open-tubular capillary Chromatographic and combined glass open-tubular capillary chromatographic-mass spectrometric analyses of ovipositor washes of femaleHeliothis zea, chemical characterization, chemical synthesis, and laboratory and field bioassays showed that the ovipositor wash of the species is made up of 90–95% (Z)-11-hexadecenal, 1–2% (Z)-9-hexadecenal, 0.4–2% (Z)-7-hexadecenal, and 2–7% hexadecanal. Stimuli containing a binary mixture of (Z)-11-hexadecenal and (Z)-9-hexadecenal or the binary mixture in combination with any of the other aldehydes identified from the females elicited intense attraction and close-range precopulatory reactions fromH. zea males.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.     

Changes in pheromone titer of oblique-banded leafroller,Choristoneura rosaceana,virgin females as a function of time of day,age, and temperature

Under a 16:8 hr light-dark photoperiod and 20C constant temperature, the titers of (Z)-11-tetradecenyl acetate (Z11–14:Ac), (E)-11-tetradecenyl acetate (E11–14:Ac) and (Z)-11-tetradecenol (Z11–14:OH) produced by different-agedChoristoneura rosaceana virgin females varied significantly during the scotophase, with the maximum titer occurring before the onset of calling in day-0 and day-3 females, while in day-5 females the titer remained constant throughout the calling period. There was a significant decrease in the titer of all pheromone components with age, explaining the lesser attractiveness of day-5 females relative to day-0 and day-3 females observed in the field. Under a cold thermocycle simulating condition during the second flight period in the fall, the titers of all pheromone components did not vary with time of day. There was a significant decrease in the amount ofZ11–14:Ac with age but no changes occurred in the minor components. Furthermore, for any given age tested, the amount of each component produced during the period of maximal calling activity remained relatively similar at the two temperature regimes. However, as with the expression of calling behavior, pheromone production was initiated earlier at cooler than at warmer temperatures. At both temperature regimes, female age and time of day influenced the ratio of each pheromone component. These results are discussed in relation to the hypothesis that by calling earlier, less attractive older females may increase their probability of mating.     

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.     

Calling behavior and pheromone titer in the smaller tea tortrix moth,Adoxophyes sp. (Lepidoptera: Tortricidae)

The calling behavior and pheromone titer in the female smaller tea tortrix moth,Adoxophyes sp., were investigated under a 1410-hr light-dark photoperiod. Quantitative gas chromatographic analysis of ovipositor extract for (Z)-11-tetradecenyl acetate (Z11–14Ac) and (Z)-9-tetradecenyl acetate (Z9–14Ac), the major pheromone components of this species, obtained on the third day postemergence, indicated that extractable amounts of sex pheromone were present throughout the period of observation. Maximal pheromone titer and calling activity was reached at 8 and 10 hr after onset of scotophase, respectively. The ratio ofZ11–14Ac toZ9–14Ac through the 24-hr period varied significantly. The significance of the sex pheromone component ratio variation on the attraction of males was tested in a field experiment. The ratio of males trapped by the most attractive blend versus the least attractive one was 2.16.     

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.     

Heliothis virescens: Response characteristics of receptor neurons in Sensilla Trichodea type 1 and type 2

Partial electroantennograms (EAGs) and single cell recordings fromHeliothis virescens males have demonstrated the presence of pheromones receptor neurons in sensilla trichodea type 2 as well as in type 1. This is supported by cobalt tracing experiments, showing that primary axons from the distal flagellum, containing only s. trichodea type 2, project into the macrogiomerulus complex in the male antennal lobes. Four types of finely tuned pheromone receptor neurons were found in males, whereas in females the corresponding neurons responded mainly to host odors. In males the majority (75 and 18%, respectively) were tuned to the majorHeliothis virescens pheromone components (Z)-11-hexadecenal (Z11-16A1) and (Z)-9-tetradecenal (Z9-14A1). The others (5 and 2%, respectively) responded specifically to (Z)-1 1-hexadecen-1-ol (Z1 1-16OH) and (Z)-1 1-hexadecen-1-ol acetate (Z1 1-16Ac). No neurons responding selectively to the minor pheromone components were found. The Z11-16A1 neurons of both sensilla types possessed similar specificity. However, the sensitivity decreased toward the medial and distal part of the flagellum, where s. trichodea type 2 are located. This suggests that the pheromone concentrations can be detected peripherally by a spatial as well as a temporal mechanism. Differences in temporal response patterns (pronounced phasic vs. tonic component) were found within the same type of neurons, suggesting different ability to encode intermittency of the pheromone plume as well as to mediate maintenance of flight.     

Sex pheromone of fall armyworm,Spodoptera frugiperda (J.E. Smith)

Analyses of extracts of pheromone glands and of volatiles from calling female fall armyworm moths,Spodoptera frugiperda (J.E. Smith), revealed the presence of the following compounds: dodecan-1-ol acetate, (Z)-7-dodecen-1-ol acetate, 11-dodecen-1-ol acetate, (Z)-9-tetradecenal, (Z)-9-tetradecen-1-ol acetate, (Z)-11-hexadecenal, and (Z)-11-hexadecen-1-ol acetate. The volatiles emitted by calling females differed from the gland extract in that the two aldehydes were absent. Field tests were conducted with sticky traps baited with rubber septa formulated to release blends with the same component ratios as those emitted by calling females. These tests demonstrated that both (Z)-7-dodecen-1-ol acetate and (Z)-9-tetradecen-1-ol acetate are required for optimum activity and that this blend is a significantly better lure than either virgin females or 25 mg of (Z)-9-dodecen-1-ol acetate in a polyethylene vial, the previously used standard. Addition of the other three acetates found in the volatiles did not significantly increase the effectiveness of the two-component blend as a bait for Pherocon 1C or International Pheromones moth traps.Mention of a commercial or proprietary product does not constitute an endorsement by the USDA.     

Individual variation in sex pheromone of smaller tea tortrix moth,Adoxophyes sp. (Lepidoptera: Tortricidae)

Female smaller tea tortrix mothsAdoxophyes sp. (Lepidoptera: Tortricidae), which initiated calling at 1, 2, or 3 days old, respectively, were analyzed individually for (Z)-11-tetradecenyl acetate (Z11-14:OAc) and (Z)-9-tetradecenyl acetate (Z9–14: OAc) in the pheromone gland via GLC. Among different age groups, broad and similar distributions were found for pheromone quantity (¯X=58.6±52.9 ng/female; range 1.3–219.8 ng/female). The ratio of the two pheromone components averaged 6535 but ranged from 8416 to 4060. The significance of the pheromone blend variation to the attraction of males was tested in a field experiment. The ratio of males trapped by the most attractive blend versus the least attractive one was 2.2.     

Identification of sex pheromone components of darksided cutworm,Euxoa messoria,and modification of sex attractant blend for adult males

Eleven pheromone-like compounds were identified in excised abdomen tip extracts of calling adult females of darksided cutworm,Euxoa messoria (Harris). The essential pheromone components were (Z)-7- and (Z)-11-hexadecenyl acetates in a ratio of 140, which agreed with an attractant blend developed empirically by field testing the attractancies of synthetic blends. The pheromone component, (Z)-11-hexadecenol, improved the attraction of darksided cutworm males whereas the components (Z)-9-tetradecenyl acetate and (Z)-7-dodecenyl acetate inhibited their attraction. The other pheromone-like compounds identified in the female extracts had no obvious effect on the attraction of darksided cutworm males. Three compounds that functioned as parapheromones when substituted for (Z)-7-hexadecenyl acetate in the two-component blend were (Z)-7-pentadecenyl, (Z)-7-tetradecenyl, and (Z)-7-tridecenyl acetates. (Z)-11-hexadecenal was not detected in the female extracts, but it had a synergistic effect on the attraction of darksided cutworm moths and inhibited the attraction of male moths of a nontarget species,Helotropha reniformis (Grote). As a trap bait for monitoring purposes, we recommend a four-component blend of (Z)-7-hexadecenyl acetate, (Z)-11-hexadecenyl acetate, (Z)-11-hexadecenol, and (Z)-11-hexadecenal at 12.5, 500, 1, and 10 g/red rubber septum dispenser containing 5 g of antioxidant 2,6-tert-butyl-4-methyl phenol. This blend is effective under field conditions for at least six weeks.     

Specificity of laboratory trail following by the argentine ant,Iridomyrmex humilis (Mayr), to (Z)-9-hexadecenal,analogs, and gaster extract

In laboratory trail-following bioassays of Argentine ant workers,Iridomyrmex humilis (Mayr), the geometric isomer, (E)-9-hexadecenal, of the trail pheromone component (Z)-9-hexadecenal elicited insignificant trail following as did the potentially more stable formate analogs, (Z)-7-tetradecenyl formate, (E)-7-tetradecenyl formate, and tetradecyl formate. Further, in direct choice tests, workers showed no preference for gaster extract trails (0.002 ant equiv/cm) over trails of (Z)-9-hexadecenal (0.2 ng/cm). Moreover, a 10-fold increase in synthetic trail concentration to 2.0 ng/cm caused (Z)-9-hexadecenal trails to be significantly preferred over gaster extract trails by trail-following ants.     

Trail-following responses of the Argentine ant,Iridomyrmex humilis (Mayr), to a synthetic trail pheromone component and analogs

Behavioral evidence indicates that (Z)-9-hexadecenal (Z9-16ALD) is a trail pheromone component ofIridomyrmex humilis, and that the true trail pheromone may be multicomponent. Trail-following responses ofI. humilis workers to several concentrations of syntheticZ9-16ALD, a constituent of the Pavan's gland, were found to be comparable to responses to gaster extract trails containing ca. 100 times lessZ9-16ALD. Of the five aldehyde analogs tested, only (Z)-7-hexadecenal (Z7-16ALD) elicited significant trail-following. However, following responses to severalZ9-16ALD-Z7-16ALD combinations were lower than responses toZ9-16ALD alone. Trails on filter paper of biologically relevant concentrations ofZ9-16ALD lose activity within 2 hr in the laboratory. The release rate ofZ9-16ALD measured from filter paper trails was 0.25 ± 0.10 pg/cm-sec. This was used to estimate the trail-following threshold for this compound of Argentine ant workers.     

Female sex pheromone of oriental tobacco budworm,Helicoverpa assulta (Guenee) (Lepidoptera: Noctuidae): Identification and field testing

Analysis of ovipositor washings from virgin femaleHelicoverpa assulta (Guenée) (Lepidoptere: Noctuidae) from Korea by gas chromatography (GC) linked to electroantennography and GC linked to mass spectrometry resulted in the identification of nine compounds, hexadecanal, (Z)-9-hexadecenal, (Z)-11-hexadecenal, hexadecyl acetate, (Z)-9-hexadecenyl acetate, (Z)-11-hexadecenyl acetate, hexadecan-l-ol, (Z)-9-hexadecen-l-ol, and (Z)-11-hexadecen-1-ol. However, ovipositor washings from females from Thailand contained mainly the 16-carbon aldehydes with very small amounts of (Z)-9-hexadecenyl acetate. Field tests conducted in Korea, China, and Thailand indicated that a binary blend of (Z)-9-hexadecenal and (Z)-11-hexadecenal was sufficient for attraction, although the most attractive ratio of compounds varied with location. In Korea a 201 blend of compounds was the most attractive, while in Thailand a 7.51 blend was most attractive. In China both blends of hexadecenal isomers were equally attractive. Addition of the hexadecenyl acetates to the 201 blend of hexadecenals in the ratio of 13.3 increased the trap catch of maleH. assulta compared to lures containing the aldehydes alone in Korea but reduced trap catch in China. Addition of the hexadecenyl acetates to the 7.51 blend of hexadecenals had no significant effect on trap catch in Thailand or China compared to the aldehydes alone. The addition of the 16-carbon alcohols to the aldehydes had a significantly inhibitory effect in all three countries, suggesting they are not pheromone components. Taken together these results indicate thatH. assulta is polymorphic with at least two populations responding to different sex pheromones.     

(Z)-11-Hexadecenal and (3Z,6Z,9Z)-tricosatriene: sex pheromone components of the red banded mango caterpillar Deanolis sublimbalis

The sex pheromone of the red banded mango caterpillar, Deanolis sublimbalis (Lepidoptera: Crambidae), a serious pest of the mango Mangifera indica (Anacardiaceae) in India and Southeast Asia and a recent invader into northern Australia, has been identified. Three candidate compounds were identified from pheromone gland extracts of female moths, using gas chromatography (GC), GC-electroantennographic detection and GC-mass spectrometric analyses, in conjunction with dimethyldisulfide derivatization. Field bioassays established that both (Z)-11-hexadecenal (Z11-16:Ald) and (3Z,6Z,9Z)-tricosatriene (3Z,6Z,9Z-23:Hy) were required for attraction of male D. sublimbalis moths, and 1,000 μg of a 1:1 mix of Z11-16:Ald and 3Z,6Z,9Z-23:Hy was more attractive to male moths than caged virgin females. However, the binary blend was only attractive when the isomeric purity of the monounsaturated aldehyde was >99%, suggesting that the (E)-isomer was inhibitory. Although (Z)-11-hexadecen-1-ol (Z11-16:OH) was tentatively identified in gland extracts, the addition of this compound to the binary blend did not increase the numbers of moths captured. The pheromone can now be used in integrated pest management strategies. Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.