Isolation,identification, and synthesis of a female sex pheromone of the navel orangeworm,Amyelois transitella (Lepidoptera: Pyralidae)

A sex pheromone of the navel orangeworm,Amyelois transitella (Walker), was obtained from ether rinses of the sex pheromone gland of calling females. The pheromone was isolated by means of liquid and gas chromatography and was identified as one of four possible geometrical isomers of 11,13-hexadecadienal by means of spectroscopic and microchemical methods. Synthesis and laboratory bioassay of all four isomers revealed that only the (Z,Z) isomer was biologically active. (Z,Z)-11,13-hexadecadienal elicited quantitatively similar activation and attraction responses byA. transitella males as did the natural product.Mention of a commercial or proprietary product in this paper does not constitute an endorsement of that product by the USDA. Accepted for publication February 28, 1979.     

Factors influencing release of hostmarking pheromone byRhagoletis pomonella flies

The effect of fly or fruit treatments on quality and/or quantity of host-marking pheromone (HMP) trail substance released by apple maggot flies (Rhagoletis pomonella) following oviposition was evaluated. Among flies, considerable variation existed in the amount of HMP substance deposited, but overall, the amount of substance released on successively offered fruit (over a day or a week) did not change appreciably. Fly diet did not influence pheromone activity. Older flies (28 days) or smaller flies released less or less active HMP trail substance than younger flies (14 days) or larger flies. Females deposited a similar amount of trail substance on large (18–19 mm diam.) or HMP-marked fruit as on small (12–13 mm) or unmarked fruit. Starvation reduced the amount of measurable trail substance deposited but resulted in a more active HMP deposition. Discrepancy between trail measurement and behavioral bioassay results for the starvation treatment indicated that trail measurement results may be misleading under conditions that reduce gut contents of the fly.     

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

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

A bioassay system for collecting volatiles while simultaneously attracting tephritid fruit flies

A bioassay system was developed that permits the testing of various substrates for biological activity in a flight tunnel, while simultaneously collecting a portion of the volatiles from the attractive source for subsequent chemical identification and quantification. Bioassays of the response of virgin female Caribbean fruit flies,Anastrepha suspensa (Loew) (Diptera: Tephritidae), to volatiles released by calling males were conducted in a greenhouse under natural light cycles and fluctuating environmental conditions, similar to those in the field. Using this system, the periodicity of response of the female flies between 1300 and 1845 hr (EST) was tested. Fifty to 75% response occurred between 1700 and 1845 hr. Male pheromone release was greatest between 1500 and 1800 hr. Videotaped records of insects, taken between 1700 and 1800 hr as flies approached and entered the traps, were analyzed to interpret the communicative role of the volatiles released. Significantly more flies landed on and entered the pheromone-emitting trap than the control trap. There was no difference in the amount of time spent on the trap face, an indication that volatiles were attractants. The system described should be of general utility in determination of the attraction of pest fruit flies to suspected attractants.     

Deterrence of repeated oviposition by fruit-marking pheromone inCeratitis capitata (Diptera: Tephritidae)

During ovipositor dragging on the fruit surface following egg laying in hawthorne fruit,Ceratitis capitata (Wiedemann) females deposit an unidentified pheromone that deters repeated oviposition attempts in that fruit. The pheromone proved water soluble and, when collected and sprayed in aqueous solution onto uninfested fruits in laboratory cages, effectively deterred boring attempts byC. capitata females of wild origin for at least 6 days (termination of test). A laboratory population ofC. capitata cultured on artificial media for more than 200 generations deposited pheromone that proved equally as deterrent to wild fly oviposition as pheromone from wild flies. However, lab fly oviposition was not effectively deterred by the presence of pheromone. The ecological significance of the pheromone is discussed.     

Codling moth,Cydia pomonella, (Lepidoptera: Tortricidae): Is its sex pheromone multicomponent?

When the nine identified components in the effluvium of calling female codling moths were compared to pure synthetic (E,E)-8,10-dodecadien-1-ol in flight-tunnel tests, equal responses were obtained over a concentration range of 300-fold. When synthetic (E,E)-8,10-dodecadien-1-ol was compared to extract of female sex pheromone glands by a male wing-flutter bioassay, or in flight-tunnel tests, equal responses were obtained over a concentration range of 1000-fold. The sum total of these and previous studies indicate that the codling moth sex pheromone consists of only one component.     

Host marking pheromone ofRhagoletis cerasi: Foraging behavior in response to synthetic pheromonal isomers

We studied the foraging behavior ofRhagoletis cerasi females in trees treated with synthetic cherry fruit fly host marking pheromone (HMP) under seminatural conditions (potted trees enclosed in a screen cage). Results show that synthetic HMP (particularly the 8RS-@#@ 15R isomer configuration (racemic mixture)) was highly effective in eliciting behavioral responses similar to those reported in studies using natural HMP. Flies exposed to synthetic pheromone exhibited short tree residence times (i.e., emigrated faster), increased flight frequency rates (measured as number of alightings per/minute), higher irritation indices while on a tree or a fruit, and oviposited fewer eggs per fruit visit than flies exposed to clean trees and fruit (not treated with synthetic HMP). Furthermore, we provide evidence showing that when flies were continuously exposed to an HMP-saturated environment, they exhibited an increased tendency to lay eggs in marked fruit.     

Behavioral responses of female Mexican fruit flies,Anastrepha ludens,to components of male-produced sex pheromone

The behavioral responses of virgin female Mexican fruit flies elicited by components and combinations of the components of male-produced pheromone were measured in a laboratory wind-tunnel bioassay where test chemicals were applied to the undersides of some leaves on a treated tree but to none of the leaves of a control tree. Only treatments containing at least (Z)-3-nonenol and/or (Z,Z)-3,6-nonadienol in combination with (S,S)-(–)-epianastrephin elicited strong behavioral responses. Responses included attraction to the vicinity of the pheromone but not to point sources, increased searching rate, changes in searching strategy, and agonism. The results support a model of pheromone-component function in which components act as a unit to stimulate all behaviors of the pheromone-mediated behavioral repertoire.Diptera: Tephritidae.     

Disruption of male spruce budworm orientation to calling females in a wind tunnel by synthetic pheromone

Male spruce budworm [Chorisloneura fumiferana (Clem.)] moths were held for 3 hr in a wind tunnel and subjected to various concentrations of background synthetic pheromone. They were then exposed to calling females and their response was recorded. The background pheromone was presented either as discrete turbulent plumes or as a uniform permeation throughout the tunnel. The numbers of males wing-fanning and flying in response to the calling females decreased as the concentration of background pheromone increased. Of the males which flew, a higher proportion progressed upwind in the discrete plumes than in the uniform permeation, an indication that structure in the pheromone cloud is necessary for upwind progression. In both discrete plumes and uniform permeation fewer males were able to locate the females (i.e., disruption was greater) as the concentration of synthetic pheromone increased, but for the same total release rates, disruption was greater when the synthetic pheromone was released in discrete plumes rather than in a uniform permeation. This implies that disruption which involves luring males to sources of synthetic pheromone is more effective than masking female plumes by uniform permeation and suggests that it is more efficient to release pheromone from a few potent sources than from numerous low-potency sources.     

Ester and ketone components of aggregation pheromone ofDrosophila hydei (Diptera: Drosophilidae)

Existence of an aggregation pheromone inDrosophila hydei was demonstrated by laboratory bioassay. The pheromone was produced by mature males, but both sexes responded. The nonpolar components consisted of three esters: the methyl, ethyl, and 1-methylethyl (isopropyl) esters of 2-methyl-(E)-2 butenoic (tiglic) acid, and two ketones: 2-tridecanone and 2-pentadecanone. The ketones and esters alone were only minimally active in the laboratory bioassay, but 2-tridecanone was highly synergistic with each of the esters, mixtures attracting 3–60 times more flies than the single components. 2-Pentadecanone was less active, but it did cause significant increases in activity when added to synthetic mixtures. The nonpolar portion of an extract of mature males and an equivalent mixture of the synthetic components were not significantly different in bioassay. Neither the esters nor the ketones were detected in sexually immature males or in females of any age. In extracts of mature males, ethyl tiglate was usually the most abundant ester component, with a mean of 8 ± 5 (SD) ng/male. The absolute and relative levels of the other esters were more variable. The mean level of methyl ketones in the extracts was 122 ± 106 (SD) ng/male, of which 85–93% was 2-tridecanone.     

Behavioral and electrophysiological evidence for volatile sex pheromones in Parcoblatta wood cockroaches

Species within the cockroach genus Parcoblatta are sexually dimorphic for wing length; females have reduced wings and are flightless, while males have long wings that are used in flight. We predicted that Parcoblatta females would release a volatile sex pheromone to attract the more mobile males. Nymphs of the broad wood cockroach, P. lata, and the Caudell's wood cockroach, P. caudelli, were collected in forested areas in North Carolina, USA, and reared in the laboratory for observations of sexual behavior and for pheromone analysis. After several days of sexual maturation, virgin females of both species exhibited distinct calling behaviors. In females of P. lata, calling commenced 6 days after adult emergence. Under a light–dark photoperiod regime, calling behavior in both species was restricted to the scotophase. Calling consisted of a repeated pattern of raising and lowering the abdomen with occasional exposure of the genital vestibulum. To test whether calling behavior is associated with the release of pheromone, volatiles from calling and noncalling females were collected on Super-Q and tested by electroantennogram (EAG) and behavioral assays. Volatile collections from calling females elicited higher male-specific EAG responses than collections from noncalling females of the same physiological stage. In an olfactometer choice test (Y-tube), males preferred volatiles from calling females over those from noncalling females. To determine the anatomical source of the pheromone, solvent extracts of various body parts were analyzed by EAG. The first through seventh tergites were the only body parts that elicited male-specific EAG responses in both species. In P. lata, the activity of the extract increased from 1- to 7-day-old females, but was lower in mated than in virgin females of the same age. The putative pheromone gland appears to consist of numerous class-3 secretory units, each composed of a secretory cell connected to a cuticular pore via a tubular duct. We conclude that female P. lata and P. caudelli produce sex-specific volatile pheromones that are emitted during calling behavior.     

2-Methylthiazolidine and 4-ethylguaiacol,male sex pheromone components of the cockroachNauphoeta cinerea (dictyoptera,blaberidae): A reinvestigation

InNauphoeta cinerea, male calling behavior is associated with sex pheromone release by the sternal glands. The male pheromone that attracts females from a distance is a mixture of 2-methylthiazolidine and 4-ethylguaiacol. It is active at very low concentrations, 0.05 and 0.01 ng, respectively. Two other compounds, 3-hydroxy-2-butanone and 2-methyl-2thiazoline, act at close range, keeping the female in the vicinity of the male. The function of the volatile pheromone and those of previously described contact pheromones are discussed in regard to their possible involvement in the establishment of male dominant-subordinate relationships.     

Sex Pheromone of <Emphasis Type="BoldItalic">Lonomia obliqua</Emphasis>: Daily Rhythm of Production,Identification, and Synthesis

The sex pheromone of Lonomia obliqua Walker (Lepidoptera: Saturniidae) was studied in the laboratory. All female calling occurred during the scotophase. Most females (70.6%) called first within 24 hr of eclosion. Calling varied with age of female, with older (5- to 6-day-old) females calling earlier in the scotophase and for longer durations than younger (0- to 1-day-old) females. The sex pheromone gland of 1- to 3-day-old virgin females was extracted during the calling peak. A Y-olfactometer bioassay showed significant attraction of males to a filter paper containing the female gland extract. Gas chromatographic-electroantennogram detection (GC-EAD) analysis of the extract indicated the presence of at least two possible pheromone components. Gas chromatographic-mass spectrometric analysis of the major GC-EAD-active peak indicated a hexadecenyl acetate; chemical derivatization indicated Δ11 unsaturation. Synthetic samples of (E)- and (Z)-11-hexadecenyl acetate were obtained by coupling 10-bromo-1-decanol and 1-hexyne, utilizing lithium chemistry. The comparison of the retention time of dimethyl disulfide derivatives of the natural compound, to those of synthetic chemicals, confirmed the natural compound as (E)-11-hexadecenyl acetate. The minor component was identified as the related alcohol, (E)-11-hexadecenol. The ratio of the two components in female extract was 100:35. Preliminary tests of males in a Y-olfactometer showed that their response to a mixture of the two compounds was not significantly different from that to gland extract.     

Female sex pheromone of the common furniture beetleAnobium punctatum (Coleoptera: Anobiidae): Extraction,identification, and bioassays

Observations and reports on the common furniture beetleAnobium punctatum suggested that, on emergence, females use a sex pheromone to attract males. GLC analysis of ovipositor extracts showed the presence of a single component, which was found to be active by EAG and coupled GLC-EAG techniques, and to attract males in both walking and flying assays. The pheromone was identified by GC-MS as 2,3-dihydro-2,3,5-trimethyl-6-(1-methyl-2-oxobutyl)-4H-pyran-4-one (stegobinone), which is the sex pheromone of another anobiid, the drugstore beetle,Stegobium paniceum. MaleA. punctatum responded equally to ovipositor extracts of either species, at both the sensory (EAG) and behavioral levels, which poses the question as to how species specificity in mate attraction is achieved.     

(Z,Z)-5,27-Tritriacontadiene: Major sex pheromone ofDrosophila pallidosa (Diptera; Drosophilidae)

A crude cuticular extract from both sexes of 3660 fruit flies (Drosophila pallidosa) was subjected to SiO₂ and AgNO₃/SiO₂ column chromatography, accompanied by bioassay for the sex pheromone activity. After three chromatographic steps, the active fraction was obtained. The main component of the active fraction was determined to be (Z,Z)-5,27-tritriacontadiene [(Z,Z)-5,27-C_33:2, on the basis of gas-liquid chromatographic analysis, chemical derivatization and gas chromatography-mass spectrometry. Synthetic (Z,Z)-5,27-C_33:2 at 5 female equivalents (FE) elicited a clear courtship response with a high courtship index amongD. pallidosa males. Therefore it was concluded that (Z,Z)-5,27-C_33:2 was a major sex pheromone component in this species.     

Ester components of aggregation pheromone ofDrosophila virilis (Diptera: Drosophilidae)

The male-produced aggregation pheromone ofDrosophila virilis was found to contain five ester components, in addition to a previously identified hydrocarbon, (Z)-10-heneicosene (Z10–21). The five esters were: the methyl, ethyl, and 1-methylethyl (isopropyl) esters of 2-methyl-(E)-2-butenoic (tiglic) acid and the methyl and ethyl esters of hexanoic acid. The esters were not detected in females. Each ester was active by itself in laboratory bioassay tests, and each increased the number of flies responding toZ10–21 ca. 4–5 times. In comparisons among the five esters at 10 ng per compound, ethyl tiglate was the most active, and methyl tiglate, the least. No mixture of esters was found to be significantly more active than ethyl tiglate alone. In a doseresponse study, bioassay activity increased with dose for both ethyl tiglate andZ10–21. Newly emerged males did not have detectable levels of the esters. All five esters increased as sexual maturity was approached. Ethyl tiglate and ethyl hexanoate were the most abundant in mature males, usually over 15 ng per individual. Ratios among the esters were variable. Male flies also contained an as yet unidentified attractant(s) still more polar than the esters, which was synergistic with the esters and hydrocarbon. Food odors also synergized the synthetic compounds.     

Aggregation pheromone components inDrosophila mulleri

Existence of an aggregation pheromone was demonstrated inDrosophila mulleri. Mature males produce at least two compounds that are lacking from females and newly emerged males and that attract both males and females in a wind-tunnel bioassay. These compounds are (S)-(+)-2-tridecanol acetate and (Z)-10-heptadecen-2-one. Both were synthesized, and the flies responded to the synthetic compounds as well as to fly-derived preparations. The flies also responded to racemic 2-tridecanol acetate but not to the pureR enantiomer. A more polar, very volatile attractant was also extracted from both sexes ofD. mulleri but was not identified.     

Diel rhythms of calling behavior and pheromone production of oriental tobacco budworm moth,Helicoverpa assulta (Lepidoptera: Noctuidae)

Both calling behavior and titer of (Z)-9-hexadecenal (Z9-16: Al), the major sex pheromone component ofHelicoverpa assulta, in pheromone glands showed distinct diel periodicity, and these two were synchronous. Calling was most actively performed and the pheromone titer reached a maximum from 2 to 6 h after lights-off. During photophase, no calling was shown and only a relatively small amount of Z9-16:A1 was detected. However, there was a time lag of a few days between peak calling activity and maximum pheromone titer. The pheromone titer was maximal from age 1 day to age 5 days and thereafter decreased while calling was most actively performed after age 3 days. Titers of three minor components, hexadecenal, (Z)-11-hexadecenal, and (Z)-9-hexadecenyl acetate, showed similar daily fluctuation patterns to that of Z9-16:Al, but relative to the titer of Z9-16:Al, the titer of the two aldehyde components remained relatively constant whereas that ofZ9-16:Ac increased in the late scotophase.     

Aggregation pheromone of square-necked grain beetle,Cathartus quadricollis (Guér.)

When feeding on rolled oats, male square-necked grain beetles,Cathartus quadricollis (Guér.), produced the aggregation pheromone (3R,6E)-7-methyl-6-nonen-3-yl acetate, for which the trival name quadrilure is proposed. The pheromone was highly attractive to both sexes in a two-choice, pitfall olfactometer modified to retain responding beetles by placing a food stimulus (an oat flake) in the glass vials containing the experimental and control stimuli. TheS enantiomer of the pheromone was inactive. Males also produced small amounts of (E)-7-methyl-6-nonen-3-one, (E)-7-methyl-6-nonen-3-ol, and (6E)-7-methyl-3-propyl-2,6-nonadienyl acetate, but these compounds were inactive in the laboratory bioassay. Segregated males and females both produced (R)-(–)-1-octen-3-ol, which by itself was repellent to both sexes but did not diminish beetle response to the aggregation pheromone.Coleoptera: Cucujidae.Research supported by the Natural Sciences and Engineering Research Council of Canada, Strategic Grant G1039 and Operating Grants A3881 and A3706.     

(S)-2-pentadecyl acetate and 2-pentadecanone Components of aggregation pheromone ofDrosophila busckii

(S)-2-Pentadecyl acetate and 2-pentadecanone were identified as the major aggregation pheromone components, inDrosophila busckii. Both sexes of flies were attracted equally in a wind-tunnel olfactometer. The flies also responded to racemic 2-pentadecyl acetate but not to the pureR enantiomer. In bioassay, (S)-2-pentadecyl acetate and 2-pentadecanone were each active alone, and a mixture of both increased the number of flies responding ca. twofold. The aggregation pheromone components are found in the ejaculatory bulb of sexually mature males and are transferred primarily to the female cuticle during mating. One third of the pheromone transferred is released by the female to the surrounding environment in a few hours after mating. None of the aggregation pheromone components remained on the mated female's cuticle, leaving two thirds unaccounted for. The same results were obtained when racemic 2-pentadecyl acetate was topically applied to immature and mature virgin males and females. BothD. mulleri andD. busckii were attracted to (S)-2-acetates of 13, 14 and 15 carbons, butD. mulleri preferred (S)-2-tridecyl acetate andD. busckii preferred (S)-2-pentadecyl acetate.