Roles of minor components in pheromone-mediated behavior of western spruce budworm male moths

The behavior of male western spruce budworm moths,Choristoneura occidentalis Freeman, was observed in a flight tunnel in response to virgin females and synthetic sex pheromone components, alone and in blends. Pheromone blends were also compared in the field using sticky trap bioassays. Pheromones were incorporated into small rods of polyvinyl chloride. The blend of 928 (E/Z)-11-tetradecenal-8911 (E/Z)-11-tetradecenyl acetate-8515 (E/Z)-11-tetradecenol (AldAcOH) that approximated that released from a virgin female moth elicited levels of response similar to those elicited by the female. This blend induced a significantly greater percentage of moths to fly upwind and land at the lure than did the Ald lure. In contrast to the flight-tunnel bioassays, the numbers of moths caught in Ald-baited sticky traps in the field were not significantly increased by the addition of Ac and OH lures. The net upwind groundspeed of flight in response to the 0.05% Ald lure was lower than that in response to the virgin females and was significantly increased by the addition of Ac + OH lures in two of three bioassays. The flight-tunnel bioassays support the hypothesis that the natural blend of major (Ald) and minor (Ac + OH) components stimulates the precopulatory behavior of western spruce budworm male moths at long range (> 1 m downwind) as well as at close range.     

Sex pheromone evidence for two distinct taxa withinGraphania mutans (Walker)

The sex pheromones of two populations ofGraphania mutans (Walker) were analyzed. Females from an Auckland population produced (Z)-9-tetradecenol (Z9-14OH), (Z)-9-tetradecenyl acetate (Z9-14OAc), (Z)-7-tetradecenol (Z7-14OH) and (Z)-7-tetradecenyl acetate (Z7-14OAc), while females from a Lincoln population produced these four compounds and a large amount of (Z)-9-tetradecenal (Z9-14Ald). Significant differences, paralleling the difference between females, were observed when the responses of males of both populations to the above and other related compounds were tested by electroantennogram, field-trapping, and wind-tunnel bioassays. The most distinct difference was observed in the wind tunnel. Males from both taxa flew upwind and touched pheromone sources containing sex pheromone extract of females of their own taxon, but either did not initiate upwind flight or arrested upwind flight shortly after taking flight in response to extract from females of the other taxon. The difference between the pheromone systems of the two populations is probably due to the presence and importance of Z9-14Ald in the pheromone blend of the Lincoln population. Thus the addition of a relatively large amount of Z9-14Aid to a four-component pheromone blend (i.e., Z9-14OH, Z9-14OAc, Z7-14OH, andZ7-14OAc) attractive to Auckland males completely suppressed trap catches of male G.Mutans in Auckland but large numbers of males were caught at both Lincoln and Nelson in traps baited with this five-component blend. In wind-tunnel studies, the addition of even small (1% of amount of Z9-14OH) amounts ofZ9-14Ald to the four-component blend resulted in a significantly greater proportion of Auckland males arresting upwind flight than to the four-com ponent blend. It is suggested that these two populations of G. nations represent distinct sibling species within the described concept.LepidopteraNoctuidaeHadeninae.     

Identification of sex pheromone of calendula plume mothPlatyptilia williamsii

The sex pheromone of the calendula plume moth,Platyptilia williamsii was identified as (Z)-11-hexadecenal (Z11–16Aid). Extracts of female sex pheromone glands contained several compounds when analyzed by capillary and packed-column GLC. However, airborne collections of volatiles from glands contained only one of these compounds, having the same retention time asZ11–16Ald. GC-MS and microozonolysis analyses of the natural product were consistent with those of syntheticZ11–16Ald. In a flight tunnel, males oriented upwind and touched sources ofZ11–16Ald and gland extract with equal frequency. Field tests of syntheticZ11–16Ald already have shown it to be a potent sex attractant for males of this species. This study further supports the hypothesis thatP. williamsii and a sympatric species,Platyptilia carduidactyla, are not reproductively isolated by chemical differences in the composition of the sex pheromone, but rather by temporal differences in sexual activities.     

Attraction ofCacoecimorpha pronubana male moths to synthetic sex pheromone blends in the wind tunnel

Attraction ofCacoecimorpha pronubana male moths to blends of four sex pheromone components was studied in the wind tunnel.Z11–14Ac alone did not elicit upwind flight, admixture of 10%Z11–14OH or more led to successful attraction of males to the source. Attractivity of these binary blends was further enhanced by addition ofE11–14Ac orZ9–14Ac; the optimum was a blend ofZ11–14Ac,Z11–14OH,E11–14Ac, andZ9–14Ac at the proportion of 1003033. In ternary and quaternary blends, the effect ofZ11–14OH andE11–14Ac was strongest at 30% and 3%, respectively. By contrast,Z9–14Ac increased behavioral responses over a wide range.     

Redundancy in a chemical signal: Behavioral responses of maleTrichoplusia ni to a 6-Component sex pheromone blend

The flight response of maleTrichoplusia ni was observed in a flight tunnel to a sex pheromone blend composed of six components:Z7–12Ac, 12Ac,Z5-12Ac, 11-12Ac,Z7-14Ac, and Z9-14Ac. The number of males reaching a 3000-g source of this blend was > 95%, equal to that observed to female glands and significantly greater than with the previously identified two-component blend (Z7-12Ac + 12Ac). In subtraction tests, all five-component blends, with the exception of the blend lacking the primary componentZ7-12Ac, and several four-component blends elicited similar peak levels of upwind flight, source contacts, and hairpencil displays to that observed with the six-component blend. We characterize the substitution of certain minor components for one another as a form of redundancy in the chemical signal and suggest that it contributes to response specificity and signal recognition in males. The results also support the concept that the full blend of components acts as a unit to influence male behavior at all phases of the response. Individual minor components were not responsible for eliciting specific behaviors in the sequence.     

Aggregation pheromone characterization and comparison inDrosophila ananassae andDrosophila bipectinata

(Z)-11-Octadecenyl acetate (Z11–18Ac) and (Z)-11-eicosenyl acetate (Z11–20Ac) were identified as the aggregation pheromones ofDrosophila ananassae, andZ11–20Ac was identified as the aggregation pheromone ofDrosophila bipectinata. Z11–18Ac andZ11–20Ac were not attractive alone; however, in combination with fermenting food odors, the acetates attracted flies of both sexes in a wind-tunnel olfactometer. The pheromones were present in the ejaculatory bulb of sexually mature male flies and transferred to the female during mating. MaleD. bipectinata released little if anyZ11–20Ac to the food; however, recently mated females releasedZ11–20Ac to the surrounding surfaces in just a few hours after mating.D. ananassae males, on the other hand, appeared to release moreZ11–18Ac andZ11–20Ac to the surroundings than mated females. AlthoughD. bipectinata males had noZ11–18Ac, flies were as attracted toZ11–18Ac as to an equal quantity ofZ11–20Ac.D. ananassae were attracted toZ11–18Ac but not toZ11–16Ac orZ11–20Ac. However,Z11–20Ac in combination withZ11–18Ac was significantly more attractive thanZ11–18Ac alone.     

Sex pheromone of the saltmarsh caterpillar moth,Estigmene acrea

Three compounds have been identified as components of the sex pheromone emitted by females of the saltmarsh caterpillar moth,Estigmene acrea (Drury). These are (Z,Z)-9,12-octadecadienal (I), (Z,Z,Z)-9,12,15-octadecatrienal (II), and (Z,Z)-3,6-cis-9,10-epoxyheneicosadiene (III). In female tip extract they were found in a ratio of 1625, respectively, and in trapped female effluvia the ratio was 1627, respectively. Combinations of III with either I or II elicited sustained upwind flight in a wind tunnel, but none of these compounds by themselves did so. There is evidence that the antennal acceptor site for III is chiral.Lepidoptera: Arctiidae.Supported in part by the Rockefeller Foundation and by National Science Foundation Grants GB-38020 and PCM 78-13241.     

Influence of (Z)-11-hexadecen-1-ol on field performance ofHeliothis virescens pheromone in a PVC dispenser as evidenced by trap capture

Field studies were conducted to determine the effect of (Z)-11-hexadecen-1-ol (Z11-16 OH) on capture of tobacco budworm (TBW),Heliothis virescens (F.), males when added to two-component (HV-2) and six-component (HV-6) pheromone blends dispensed from a polyvinyl chloride (PVC) substrate. Numbers of males caught in traps baited with PVC dispensers containing 0.25% Z11-16 OH, relative to total pheromone content, were significantly higher than numbers caught with dispensers containing noZ11-16 OH. Catches of TBW were also increased significantly in some tests whenZ11-16 OH was formulated in the bait at a 1% concentration. Catches were significantly reduced with dispensers containing 5.95%Z11-16 OH compared with those containing noZ11-16 OH. There were no differences in catch between traps baited with HV-2 vs. HV-6 or HV-2 + 0.25%Z11-16 OH vs. HV-6 + 0.25%Z11-16 OH when formulated in PVC substrate.Mention of a commercial or proprietary product does not constitute an endorsement by the USDA.     

Sex pheromone chemistry of the western spruce budwormChoristoneura occidentalis Free

SCOT capillary Chromatographic and SCOT capillary chromatographic-mass spectrometic analyses of gland washes and effluvia of virgin femaleChoristoneura occidentalis Free, have been conducted with both a diapausing and nondiapausing strain of this insect. The following compounds were identified in gland washes and effluvia in both strains:E andZ11–14Ald,E andZ11–14Ac,E andZ11–14OH and 14Ald, 14Ac, and 14OH. The average aldehyde: acetate: alcohol ratio found by analysis of single glands by virgin females (nondiapausing strain) was 170.73. Analysis of virgin female effluvia gave this ratio as 1038 (diapausing strain: %Z=8, 11, 15, respectively) and 1036 (nondiapausing strain: %Z=8, 11, 12, respectively). The saturated components were generally 1–2% of theE isomer in each case. Comparisons of EAG responses of bothC. occidentalis andC. fumiferana toE11–14Ald,E11–14Ac andE11–14OH were made. Correlations with both laboratory and field data previously published were also made betweenC. fumiferana andC. occidentalis.Lepidoptera: Tortricidae.     

Sex pheromone ofEupoecilia ambiguella female: Analysis and male response to ternary blend

Sex gland extracts and washes ofEupoecilia ambiguella contain 10–20 ng/female of the primary sex pheromone componentZ-9-dodecenyl acetate (Z9–12Ac), accompanied by a number of related compounds. These areE-9-dodecenyl acetate (E9–12Ac),Z-9-dodecen-1-ol (Z9–12OH), saturated acetates of 12, 16, 18, and 20 carbons, and traces of a doubly unsaturated acetate, tentatively identified as a 9,11-dodecadienyl acetate. Octadecyl acetate predominates among the pheromone-related components, making up 1–2, occasionally 20–30 times the amount ofZ9–12Ac. The same compounds were also found in field-collected females and in effluvia.Z-9-Undecenyl acetate, which is a male attractant on its own, was also found in a sample of female effluvia. A hierarchy is observed in the ethological function of the pheromone components.Z9–12Ac is an attractant forE. ambiguella males. Dodecyl acetate (12Ac) is not attractive on its own but augments male catch when added to the main attractant. Addition of 18Ac augments attraction only when bothZ9–12Ac and 12Ac are present. Windtunnel tests demonstrate that 18Ac also raises the disorientation threshold, as previously shown for 12Ac. Other compounds, with the possible exception of additional saturated acetates, had either no effect on trap catch or, in the case ofE9–12Ac,Z9–12OH, andE-9,11-dodecadienyl acetate, were inhibitory above a certain level. A blend of roughly equal parts ofZ9–12Ac, 12Ac, and 18Ac provides the best attractant blend forE. ambiguella known to date.     

Temporal patterns of sex pheromone titers and release rates inHolomelina lamae (Lepidoptera: Arctiidae)

Six hydrocarbon components (2-methylhexadecane,n-heptadecane, 2-methylheptadecane, 2-methyloctadecane,n-nonadecane, and 2-methylnonadecane) were identified in sex-pheromone gland extracts and in airborne collections ofHolomelina lamae. Low variability in the ratio of components among individuals indicates tight regulation of blend composition. Minor changes were evident in the quantity and ratio of the blend as a function of time of day. Based on gland extracts, the total quantity of the six components increased from day 1 (X = 6299 ng) to day 4 (X = 7498 ng) and subsequently decreased. No significant correlations were found between total gland contents and wet or dry weights of moths. Emission rates ofH. lamae females were determined from pheromone adsorbed onto Porapak Q. Quantities released peaked shortly after the onset of calling and decreased rapidly as calling continued. Peak release rates ranged from 13 to 350 ng/10 min, and from 37 to 835 ng/60 min. Noncalling females did not emit detectable quantities of pheromone. Based on release rates and the rate of pulsation of the abdominal tip, the average amount released per pulse is not constant. The mean ratio of components released (0.787.45 84.802.842.591.53) was not very different from the ratio of components in gland extracts of 2-day-old females (0.704.1990.12 1.651.911.42). We propose that the blend is atomized rather than volatilized from the gland, thus retaining nearly the same ratios in the female's effluvium as in her gland.     

Development of pheromone lure for monitoring field populations ofEoreuma loftini (Lepidoptera: Pyralidae)

Formulations of Mexican rice borer (MRB) pheromone components were more effective in capturing males in fields of sugarcane when dispensed from rubber septa than when evaporated from four other substrates. Concentrations of 0.63–10.0 mg of total pheromone per lure were effective over a 112-day period when formulated in rubber septa in a ratio of 811.3 of (Z)-13-octadecenyl acetate, (Z)-11-hexadecenyl acetate, and (Z)-13-octadecenal, respectively. Component ratios of 411.3 and 811.3 were equally effective in capturing male MRB, but efficacy decreased with higher relative concentrations of (Z)-13-octadecenyl acetate.Mention of a commercial or proprietary product does not constitute an endorsement by the USDA.     

Components of female sex pheromone of cocoa pod borer moth,Conopomorpha cramerella

The cocoa pod borer,Conopomorpha cramerella (Snellen) (Lepidoptera: Gracillariidae), is the most serious pest of cocoa in Southeast Asia. Analyses of ovipositor washings and entrained volatiles from virgin female moths by gas chromatography (GC) linked to electroantennography (EAG), and comparison of EAG responses from the male moth to synthetic compounds indicated the presence of theE,Z,Z andE,E,Z isomers of 4,6,10-hexadecatrienyl acetate and the corresponding alcohols, and of hexadecyl alcohol. Amounts of pheromone produced were less than 0.1 ng/female, and no peaks for the unsaturated components were observed on GC analysis. Extensive field testing of synthetic mixtures in Sabah, East Malaysia, showed that traps baited with a polyethylene vial impregnated with 1.2 mg of a mixture of the above five components in 40604610 ratio caught more maleC. cramerella moths than traps baited with a virgin female moth.     

Identification of sex pheromone components of jack pine budworm,Choristoneura pinus pinus freeman

Chemical identification and field-trapping experiments have shown that a blend of 8515 (E,Z)-11-tetradecenyl acetates and 8515 (E,Z)-11-tetradecen-1-ols (in a 91 ratio) are female sex pheromone components for jack pine budworm,Choristoneura pinus pinus. This blend of chemicals, formulated in PVC (0.1 %, w/w) sources is as effective a trap bait as virgin females. Preliminary wind tunnel observations have indicated that this blend, effective as a trap bait, is not equivalent to females.Lepidoptera: Tortricidae.     

Sex pheromone ofGrapholita funebrana occurrence ofZ-8- andZ-10-Tetradecenyl acetate as secondary components

Z-8-Dodecenyl acetate (Z8–12Ac),E-8-dodecenyl acetate (E8–12Ac),Z-8-tetradecenyl acetate (Z8–14Ac),Z-10-tetradecenyl acetate (Z10–14Ac), andZ-8-dodecen-1-ol (Z8–12OH) were identified in the proportions 10013052 in female sex gland extracts ofGrapholita funebrana, accompanied by saturated acetates from 12 to 20 carbons with tetradecyl acetate predominating.Z10–14Ac has not previously been described as a lepidopteran sex pheromone component. Best attraction of males is obtained withZ8–12Ac in the presence of a higher proportion ofE8–12Ac than in the female. Inclusion of the 14-carbon acetates did not augmentG. funebrana catches but inhibitedG. molesta. On the other hand, addition ofZ8–12OH at the level optimal forG. molesta reduced attraction ofG. funebrana.     

Nantucket pine tip moth,Rhyacionia frustrana: Identification of two sex pheromone components

Two compounds identified as components of the sex pheromone system ofRhyacionia frustrana are (E)-9-dodecen-1-yl acetate (I) and (E)-9,11-dodecadien-1-yl acetate (II), which were found in female gland extracts in the ratio of 964, respectively. The identifications were based on chemical and instrumental analyses, electroantennogram studies, and field trapping tests. The optimum ratio for trapping maleR. frustrana is the range of 955 to 97.52.5 (III), when dispensed from rubber septa at a loading of ca. 1000/g/lure. In addition to these two compounds, evidence was obtained for the presence of dodecan-1-ol and (E)-9-dodecen-1-ol in female tip extracts and in female effluvium, and for dodecan-1-yl acetate in female tip extracts.Lepidoptera: Tortricidae: Olethreutinae.Supported in part by the Rockefeller Foundation and by National Science Foundation grants GB-38020 and PCM 78-13241.     

Determination of the enantiomeric composition of several insect pheromone alcohols

Details are given for the determination of the enantiomeric composition of several insect pheromone alcohols. The two methods used in the determination were: formation of the derivative with (+)--methoxy--trifluoromethylphenylacetyl chloride and the use of chiral lanthanide shift reagents. The five alcohols studied and their enantiomeric compositions are: sulcatol fromGnathotrichus sulcatus 6535 (+)/(–),trans-verbenol fromDendroctonus frontalis 6040 (+)/(–), 4-methyl-3-heptanol fromScolytus multistriatus 100% (–), seudenol fromDendroctonus pseudotsugae 5050 (+)/(–), and ipsdienol fromIps pini (Idaho) 100% (–). Determinations were done on 50–500 g substrate.     

Effect of sex-pheromone concentration on behavior of three strains of western spruce budworm male moths

The responses of male western spruce budworm moths,Choristoneura occidentalis Freeman, to a range of concentrations of the major sex pheromone, 928 (E/Z)-11-tetradecenal (Ald), in polyvinyl chloride lures, were observed using the electroantennogram technique, a flight tunnel, and field-trapping bioassays. The responses to virgin female moths were also observed in the flight tunnel and field bioassays. The moths were from three strains: a nondiapausing laboratory colony; field-collected wild budworm; and laboratory-wild crosses. The mean peak amplitude of antennal response and the time required for the electroantennogram signal to return to the baseline after stimulation (lag) increased with Ald concentration in both laboratory and wild moths. However, at Ald concentrations of 0.005% and greater, the lag period of the wild male's antennae was significantly shorter than that of the laboratory male's. The mean number of moths caught in the field in delta sticky traps increased with Ald concentration, but the number of moths caught per trap was not significantly different between concentrations of 0.005 % and 0.5 %. The threshold concentration required to elicit upwind flight in the flight tunnel was between 0.0005 and 0.005% Ald; peak response occurred to 0.05 % Ald but was not significantly different from that to 0.005 % or 0.5% Ald. Moths from all three populations significantly reduced their net upwind groundspeed as they approached the pheromone lure. When pheromone concentration was increased, the net upwind groundspeed of laboratory and lab-wild moths, but not wild moths, was significantly reduced between 2 m and 1 m downwind from the pheromone lure. The three populations of moths differed significantly in the percentage of wing-fanning and copulatory attempts, and in the net upwind groundspeed of flight from 2 m to 1 m downwind from the lure.     

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.     

Behavioral responses of maleArgyrotaenia velutinana (Lepidoptera: Tortricidae) to components of its sex pheromone

Males of the redbanded leafroller,Argyrotaenia velutinana (Walker) (Lepidoptera: Tortricidae), were studied for their behavioral responses in laboratory olfactometers and in the field to the 3 components of the female-produced sex pheromone:cis-11-tetradecenyl acetate (c11–14Ac),trans-11-tetradecenyl acetate (t11–14Ac), and dodecyl acetate (12Ac). Dodecyl acetate, when evaporated with c11–14Ac (8%trans) in the field, modified the behavior of feral males nearby the chemical source, causing an increase in the frequency of landing and close approach to the pheromone dispenser. Apparently, an inflight behavioral modification concerning landing or not landing occurs within 60 cm of the source and is mediated by 12Ac. In laboratory olfactometers, c11–14Ac (8%trans) demonstrated a lower threshold for male activation than pure c11- and t11–14Ac and blends of the two isomers. Additionally, over a wide range of dosages, males responded with optimum wing-fanning response to c11–14Ac (8%trans) compared to pure c11–14Ac, c11–14:Ac (30%trans), and pure t11–14Ac, suggesting that thecistrans ratio rather than absolute amounts of either isomer, is a crucial factor in eliciting male response. When presented with c11–14Ac (8%trans) (11), dodecyl acetate caused a significant prolongation of wing-fanning over c11–14Ac (8%trans) alone and resulted in a greater percentage of males moving upwind to the source. Since the increase in wing-fanning and orientation occurred at higher concentrations of the 3-component mixture, the effect of 12Ac in the laboratory may reflect the close-range role of 12Ac in the field.