Relationship of sexual maturation rate to response of oriental fruit fly strains (Diptera: Tephritidae) to methyl eugenol

Laboratory-reared and wild, fruit-reared adults of the Oriental fruit fly,Dacus dorsalis Hendel, were tested for response to methyl eugenol at various ages. Virgin laboratory (2, 4, 6, 8, and 10 days old) and wild (7, 11, 15, 19, and 23 days old) flies were released into an outdoor field cage and trapped over a two-day period. Response of males increased with age as ca. 32% and 22% of laboratory and wild males responded at 2 and 7 days of age, respectively, while ca. 93% of both strains responded at 10 and 23 days of age, respectively. These correspond approximately to the ages at which they reach sexual maturity. Female response did not increase with age and fluctuated between 15% and 29% for the laboratory strain and 10% and 45% for the wild strain. The age-related response profiles, when integrated with sexual maturation curves, indicate that one of the major reasons the male-annihilation technique is effective is because methyl eugenol is able to attract 40–50% of male flies prior to the onset of sexual maturation.     

Sex Pheromone of Apple Blotch Leafminer, Phyllonorycter crataegella, and Its Effect on P. mespilella Pheromone Communication

(Z)-10,(Z)-12-Tetradecadienyl acetate (Z10,Z12–14:OAc) and (E)-10,(E)-12-tetradecadienyl acetate (E10,E12–14:OAc) are sex pheromone components of the apple blotch leafminer (ABLM), Phyllonorycter crataegella. Compounds extracted from female pheromone glands were identified by coupled gas chromatographic–electroantennographic detection (GC-EAD) analyses, retention index calculations of EAD-active compounds, and by comparative GC-EAD analyses of female ABLM-produced and authentic (synthetic) compounds. In field experiments in apple Malus domestica orchards in Connecticut, Z10,Z12–14:OAc alone attracted ABLM males. Addition of E10,E12–14:OAc to Z10,Z12–14:OAc at 0.1:10 or 1:10 ratios enhanced attractiveness of the lure. Geometrical isomers Z10,E12- or E10,Z12–14:OAc at equivalent ratios were behaviorally benign and slightly inhibitory, respectively. In field experiments in British Columbia, Z10,Z12–14:OAc plus E10,E12–14:OAc did not attract Phyllonorycter moths, supporting the contention that ABLM is not present in the fruit growing regions of British Columbia. Z10,Z12–14:OAc added to P. mespilella pheromone, (E)-4,(E)-10-dodecadienyl acetate, strongly inhibited response by P. mespilella males. Recognition of the ABLM pheromone blend by allopatric P. mespilella males suggests a phylogenetic relationship and previous sympatry of these two Phyllonorycter spp. If pheromonal attraction of ABLM males were reciprocally inhibited by P. mespilella pheromone, a generic Phyllonorycter pheromone blend could be tested for pheromone-based mating disruption of the apple leaf-mining Phyllonorycter guild in North America.     

Interspecific response to sex pheromones,and calling behavior of severalAttagenus species (Coleoptera: Dermestidae)

Females of severalAttagenus species demonstrated calling behaviors similar to those previously reported forA. elongatulus. Attagenus rufipennis females did not call until they were 12–14 days old. OtherAttagenus species called at approx. 4 days of age. All species exhibited diurnal periods of calling activity. Interspecific pheromone responses were tested, withA. megatoma megatoma, A. megatoma canadensis, A. megatoma japonicus, andA. schaefferi spurcus showing equal cross-responses. Male response to females was demonstrated inA. rufipennis andA. bicolor. Attagenus rufipennis, bicolor, andelongatulus males responded only to female extracts of their own species.Mention of a proprietary product does not constitute an endorsement by the USDA.     

Responsiveness ofPseudaletia unipuncta (Lepidoptera: Noctuidae) males,maintained as adults under different temperature and photoperiodic conditions,to female sex pheromone

Different-agedPseudaletia unipuncta (Haworth) males, maintained as adults at 10 and 25°C under 16∶8 and 12∶12 light-dark photoperiodic regimes, were flown to a 30-μg pheromone source in a wind tunnel at 20°C. While the responsiveness of individuals reared under both photoperiodic conditions at 25 °C was similar by day 5 (65–75%), response levels of younger males showed that those reared at 16∶8 light-dark matured more rapidly than those under 12∶12 light-dark. A significant delay in the onset of responsiveness was observed for males reared under 10°C with less than 25% of individuals responding to the pheromone, even at 25 days old. At this temperature, photoperiodic conditions had no significant effect on male receptivity. When males are transferred from 10°C to 25°C 16∶ 8 light-dark, their level of responsiveness after five days was similar to control 5-day-old males reared at 25°C, 16∶8 light-dark. These results are discussed relative to the hypothesis that this species migrates in response to seasonal cues that indicate a predictable habitat deterioration.     

Sex Pheromone Components in Defense of Melon Fly, Bactrocera cucurbitae Against Asian House Gecko, Hemidactylus frenatus

The Asian house gecko, Hemidactylus frenatus, after being acclimatized to feeding on the melon fly, Bactrocera cucurbitae, consumed fewer numbers of 15-day-old (DO) and older male melon flies compared to sexually immature flies 10 DO and younger. The first male melon fly that performed mating did so on the 10th day after eclosion (DAE), but >80% of the males performed their first mating between 10 and 15 DAE. This confirmed that between 10 and 15 DAE most male melon flies are already sexually mature and producing sex pheromone. Synthetic 1,3-nonanediol, a component of male melon fly sex pheromone produced endogenously, when topically applied onto the thorax of housefly Musca domestica at ca. 80 or 320 ng/fly, reduced consumption by geckos compared with untreated flies in subsequent days after the first day in a four-day feeding test. Raspberry ketone (RK) is consumed and sequestered into the pheromonal gland and later released as a pheromonal component of male melon fly. Houseflies topically treated with 2.6 g RK/fly did not deter predation by geckos. However, houseflies treated with 5.1 g RK/fly caused geckos to consume fewer flies, especially on the third and fourth days during a four-day feeding test, compared with the period when they were offered untreated flies.     

Seasonal Variation in Volatile Compound Profiles of Preen Gland Secretions of the Dark-eyed Junco (<Emphasis Type="Italic">Junco hyemalis</Emphasis>)

Quantitative stir bar sorptive extraction methodology, followed by gas chromatography-mass spectrometry (GC-MS) and element-specific atomic emission detection (AED) were utilized to analyze seasonal changes in volatile components of preen oil secretions in Junco hyemalis. Juncos were held in long days to simulate breeding conditions, or short days to simulate nonbreeding conditions. Linear alcohols (C₁₀–C₁₈) were the major volatile compounds found in preen oil, and in both sexes their levels were higher when birds were housed on long as opposed to short days. Methylketones were found at lower levels, but were enhanced in both sexes during long days. Levels of 2-tridecanone, 2-tetradecanone, and 2-pentadecanone were also greater on long days, but only in males. Among carboxylic acids (C₁₂, C₁₄, and C₁₆), linear but not branched acids showed some differences between the breeding and nonbreeding conditions, although the individual variation for acidic compounds was large. Qualitatively, more sulfur-containing compounds were found in males than females during the breeding season. Functionally, the large increase in linear alcohols in male and female preen oil during the breeding season may be an indication of altered lipid biosynthesis, which might signal reproductive readiness. Linear alcohols might also facilitate junco odor blending with plant volatiles in the habitat to distract mammalian predators. Some of the volatile compounds from preen oil, including linear alcohols, were also found on the wing feather surface, along with additional compounds that could have been of either metabolic or environmental origin.     

Sex Pheromones and Reproductive Isolation of Three Species in Genus <Emphasis Type="Italic">Adoxophyes</Emphasis>

We tested differences in female pheromone production and male response in three species of the genus Adoxophyes in Korea. Females of all three species produced mixtures of (Z)-9-tetradecenyl acetate (Z9–14:OAc) and (Z)-11-tetradecenyl acetate (Z11–14:OAc) as major components but in quite different ratios. The ratio of Z9–14:OAc and Z11–14:OAc in pheromone gland extracts was estimated to be ca. 100:200 for Adoxophyes honmai, 100:25 for Adoxophyes orana, and 100:4,000 for Adoxophyes sp. Field tests showed that males of each species were preferentially attracted to the two-component blends of Z9–14:OAc and Z11–14:OAc mimicking the blends found in pheromone gland extracts of conspecific females. The effects of minor components identified in gland extracts on trap catches varied with species. Addition of 10-methyldodecyl acetate (10me-12:OAc) or (E)-11-tetradecenyl acetate (E11–14:OAc) to the binary blend of Z9–14:OAc and Z11–14:OAc significantly increased captures of A. honmai males, whereas E11–14:OAc exhibited a strongly antagonistic effect on catches of Adoxophyes sp. males. Moreover, (Z)-9-tetradecen-1-ol (Z9–14:OH) or (Z)-11-tetradecen-1-ol (Z11–14:OH) added to the binary blends increased attraction of male A. orana but not A. honmai and Adoxophyes sp. males, suggesting that these minor components, in addition to the relative ratios of the two major components, play an important role in reproductive isolation between Adoxophyes species in the southern and midwestern Korea where these species occur sympatrically.     

Accumulation ofDendrobium superbum (orchidaceae) fragrance in the rectal glands by males of the melon fly,Dacus cucurbitae

4-(4-Hydroxyphenyl)-2-butanone was characterized from flowers of the orchidDendrobium superbum as a specific attractant factor for the male melon fly,Dacus cucurbitae. The male flies compulsively licked the flower surface and sequestered the compound in significant quantities in their rectal glands. The compound was detected within 6 hr after ingestion and was retained for more than six days in the rectal gland sacs.     

Field Tests of Synthetic Sex Pheromone of the Apple Leafminer Moth, Phyllonorycter ringoniella

The apple leafminer moth, Phyllonorycter ringoniella, is becoming a more serious insect pest on apple trees with four to five generations a year in Korea. In order to devise a forecasting method for more accurate estimation of their numbers and development timing, the sex attractant was studied. Various ratios, from 10:0 to 0:10, of the two components, (Z)-10-tetradecenyl acetate (Z10–14:Ac) and (E,Z)-4,10-tetradecadienyl acetate (E4,Z10–14:Ac), identified from the sex pheromone gland (Jung and Boo, 1997), were tested for attractivity in terms of behavioral response (taxis, approach, and landing) against P. ringoniella males in a wind tunnel. The lure with Z10–14:Ac/E4,Z10–14:Ac in a ratio of 4:6 elicited the highest response in two (taxis and approach) measurement categories. For eliciting landing behavior, the two blends of 5:5 and 4:6 were best. The single component, Z10–14:Ac, elicited taxis behavior, but a combination of two chemicals was needed for eliciting all three behaviors. In the field, male attraction to various lure mixtures in Pherocon IC traps was usually greater than attraction to virgin females. The best field activity was in the lure baited with a 4:6 ratio of Z10–14:Ac and E4,Z10–14:Ac. Similar results were obtained from tests conducted in a net house. This optimum ratio for attracting P. ringoniella males in Korea is different from those reported in Japan (10:3) or China (7:3 to 6:4). The isomer E10–14:Ac neither improved nor depressed the number of catches when added at up to 10% of the total mixture to lures of the two components in the 4:6 ratio. The attractivity of the lures increased with higher amounts of the pheromones, up to 10 g in the wind-tunnel experiment and 5 mg in the apple orchard. The number of males captured was not significantly different among traps installed at 0.3, 1.5, or 2 m above the ground, or among wing, delta, or water traps. A rubber septum dispenser impregnated with 1 mg of the 4:6 mixture maintained its field attractivity for up to eight weeks.     

Isolation,identification, and synthesis of sex pheromone components of female tea cluster caterpillar,Andraca bipunctata walker (Lepidoptera: Bombycidae) in Taiwan

Octadecanal (18:Ald), (E)-11-octadecenal (E11–18:Ald), (E)-14-octadecenal (E14–18:Ald) and (E,E)-11,14-octadecadienal (E11,E14–18:Ald) were isolated and identified as major components from the pheromone glands of the tea cluster caterpillar,Andraca bipunctata, in Taiwan by analyzing the mass spectra of gland components and their DMDS adducts. GC retention times and mass spectra of the components were in agreement with those of authentic synthetic compounds. The average amount of 18:Ald,E11–18:Ald,E14–18:Ald andE11,E14–18:Ald per female gland (1 to 3 days old) was 121±76, 50±20, 187±75, and 237±110 ng, respectively, in a ratio of 20:8:31:41. SyntheticE11,E14–18:Ald caught more males than each of the other three components or blank control in field trapping tests.E11,E14–18:Ald is reported as an insect sex pheromone for the first time. Male antenna responded toE11,E14–18:Ald strongly in an EAG analysis. Furthermore, 4 hr after the injection of PBAN (pheromone biosynthetic activating neuropeptide) into decapitated female moths (2 days old), the percentage of theE11,E14–C18 Ald in the gland extract increased from 0% to 75.5%, which was also significantly more than that of unligated and uninjected control at 55.1%. All these data indicated thatE11,E14–18:Ald is the sex pheromone of theAndraca bipunctata in Taiwan.     

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.     

Floral synomone of a wild orchid,Bulbophyllum cheiri,lures Bactrocera fruit flies for pollination

The major fruit fly attractant component in the floral fragrance of Bulbophyllum cheiri (fruit fly orchid) is methyl eugenol (ME). In the lowland rain forest of Malaysia, the solitary and nonresupinate flowers of the fruit fly orchid attract only males of the ME-sensitive fruit fly species (Bactrocera carambolae, B. papayae, and B. umbrosa. During the morning, the fruit fly orchid flower is visited by many fruit flies, which can sometimes cover the whole flower. The number of visitors dwindles in the afternoon. Headspace analysis of the flower shows a high ME peak in the morning, a small one between 12:00 and 14:00 hr, and no detectable ME peak after 14:00 hr. The process of pollination in the wild is initiated by attraction of fruit flies to floral ME. The flower, with the aid of its specialized hinged see-saw lip (labellum), temporarily traps (<1 min) a fruit fly pollinator between its lip and column. Just prior to this, the fly is rewarded by the opportunity to feed on the floral attractant found on surfaces of petals, sepals, and lip. The pollinaria borne by two wild B. papayae males (caught on and near the fruit fly orchid flower) are identical in morphology and structure with those obtained from the flower. Many of the B. papayae males (17 of 22 analyzed) attracted to the fruit fly orchid already possessed both ME metabolites, trans-coniferyl alcohol and 2-allyl-4,5-dimethoxyphenol, in their rectal glands, indicating that they had previously consumed ME. In this orchid–fruit fly association, both organisms gain direct reproductive benefits: the orchid flower gets pollinated without having to offer nectar, while the fruit fly boosts its pheromone and defense system, as well as its sexual competitiveness by feeding on the ME produced by the flower.     

Differences in sex pheromone communication systems of closely related species:Spodoptera latifascia (walker) andS. descoinsi lalannecassou & silvain (Lepidoptera: Noctuidae)

S. latifascia andS. descoinsi are closely related species that occur sympatrically over limited areas in French Guiana. We examined allopatric populations,S. latifascia originating from Barbados andS. descoinsi from French Guiana. Studies on nocturnal activity cycles showed temporal partitioning of female calling behavior, male sexual activity, and mating behavior.S. descoinsi were sexually active in the first half of the scotophase whereasS. latifascia were sexually active in the second half. Seven compounds (Z9–14: Ac,Z9,E12–14: Ac,Z11–16: Ac,E9,E12–14: Ac,Z9–14: Ald,Z9,E11–14: Ac andZ11–14: Ac) were identified in females of bothS. latifascia andS. descoinsi extracts.Z9–14: Ac was a main pheromone component for the two species. The major difference between the pheromones ofS. latifascia andS. descoinsi was the proportion ofZ9,E12–14: Ac in the extracts: 7% forS. latifascia and 42% forS. descoinsi. The proportion ofZ9,E12–14: Ac relative to the sum ofZ9–14: Ac andZ9,E12–14: Ac in individual gland extracts was 4±1% (mean ± standard deviation) forS. latifascia and 44.8±6% forS. descoinsi. Electrophysiological studies showed no major differences between species in the morphology and physiology of the pheromone receptors of males. Receptors were identified forZ9–14: Ac andZ9,E12–14: Ac, but no receptor was found for the other compounds. In the wind tunnel, synthetic blends withZ9–14: Ac andZ9,E12–14: Ac gave the same behavioral responses as conspecific female extracts for the males of the two species. Some cross-attraction was observed with synthetic blends and female extracts. Nethertheless, previous field trapping experiments in French Guiana were species-specific and suggested differences in the attractivity of males. In the laboratory,S. latifascia andS. descoinsi could hybridize in both reciprocal crosses. FemaleS. descoinsi × maleS. latifascia mating rate was significantly lower than for the reciprocal cross, and 26.7% of femaleS. descoinsi could not separate from maleS. latifascia after mating. These copulatory problems may involve genital incompatibilities between males and females. Several barriers against interbreeding betweenS. latifascia andS. descoinsi seem to combine including differences in nocturnal activity cycles, pheromone differences, and genital barriers. The study of sympatric populations will be necessary to define the role of sex pheromones in the reproductive isolation ofS. latifascia andS. descoinsi.     

Comparative Study of Pheromone Production and Response in Swedish and Zimbabwean Populations of Turnip Moth, Agrotis segetum

Analysis of female sex pheromone gland extracts of the turnip moth (or common cutworm), Agrotis segetum, from Zimbabwe revealed three compounds previously identified as sex pheromone components in the Swedish population, namely (Z)-5-decenyl acetate (Z5–10:OAc), (Z)-7-dodecenyl acetate (Z7–12:OAc), and (Z)-9-tetradecenyl acetate (Z9–14:OAc). However, the proportions from the Zimbabwean population (1:0.25:0.03) differ from those in the Swedish population (1:5:2.5). In addition, gas chromatography–mass spectrometric (GC-MS) analysis of the Zimbabwean female gland extracts revealed a trace of (Z)-5-dodecenyl acetate (Z5–12:OAc). This compound has recently been identified as a fourth sex pheromone component for the Swedish population. Single-sensillum recordings from both Zimbabwean and Swedish populations showed the presence of two types of antennal receptors responding to either Z5–10:OAc or Z7–12:OAc. In Zimbabwean males the Z7–12:OAc receptor neuron appeared to be confined to the basal and medial thirds of the antennal branches, while in Swedish males it was distributed along the entire antennal branch. Dose–response curves of Z5–10:OAc or Z7–12:OAc specific receptor neurons from males of both populations showed similar response profiles, but the neurons of the Zimbabwean population showed higher maximal responses. In flight tunnel tests with Zimbabwean males, the three-component Zimbabwean blend of Z5–10:OAc, Z7–12:OAc and Z9–14:OAc elicited significantly greater responses than the Swedish blend, but not significantly greater than pheromone glands from calling Zimbabwean females. (Z)-5-decenol (Z5–10:OH), a constituent of gland extracts, exerted an antagonistic effect in the flight tunnel. In field tests conducted in Sweden, local males were preferentially attracted to local females, while in Zimbabwe preferential attraction to local females was less pronounced. Local response to the Swedish and Zimbabwean synthetic four-component blends mirrored the responses to the local females. Zimbabwean males are much more strongly attracted to Z5–10:OAc alone than are Swedish males and the high concentrations of Z7–12:OAc and/or Z9–14:OAc present in the Swedish blend reduced attraction of Zimbabwean males. This reduced attraction appears to be counteracted by the trace amounts of Z5–12:OAc found in the Swedish four-component blend. Addition of Z5–12:OAc to the three-component Zimbabwean blend did not, however, significantly increase the trap catches of Zimbabwean males.     

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.     

Thet complex of the mouse: Chemical characterization by urinary volatile profiles

Urine samples from C3H congenic house mice (Mus domesticus) differing only at thet complex were examined by capillary gas chromatography to assess variations in the volatile components that may cause olfactory discrimination between animals bearingt lethal and+(wild-type) haplotypes. Urine was collected from 192 males and females varying in age from 1 to 9 months. C3H congenic mice that have the same genetic background at all loci but differed in theirt complex genotypes: +/ +, +/t_w1,T/t _w1, T/+ were used. No urinary volatiles were unique to thet complex. However, significant differences amongt complex genotypes and among ages occurred for concentrations of 12 male volatiles and four female volatiles. Usually young males (1–2 months of age) had significantly higher concentrations of cyclic enol ethers and ketones than older males (4–9 months of age). Moreover, some urinary volatiles (cyclic enol ethers, one ketone, dehydrobrevicomin, and thiazoline) were excreted in the urine of T/+and/orT/t males in significantly higher concentration than in the urine of +/+ males. Age andt complex genotype influences on the urinary volatiles in females were observed for four ketones. Gas chromatography of urinary components has the potential to be used in field studies of thet complex because the two t complex genotypes found in wild populations, +/+ and +/t, had significant differences in concentration for two males volatiles and three female volatiles.We dedicate this paper to the memory of Dorothea Bennett.On leave from the Environmental Protection Institute, Ministry of Light Industry, Beijing, China.A.E.M.B. supported in part by NSF BSR 8909172.     

Mating disruption of pea mothCydia nigricana F. (lepidoptera: Tortricidae) by a repellent blend of sex pheromone and attraction inhibitors

Synthetic sex pheromone of the pea mothCydia nigricana, (E,E)-8,10-dodecadien-1-yl acetate (E8,E10–12: Ac), was applied in polyethylene dispensers at a rate of 30 g/ha and 600 dispensers/ha in a 0.6-ha pea field. The release rate ofE8,E10–12: Ac was 140 mg/ha/day after six days, and 82 mg/ha/day after 20 days. Aerial concentrations ofE8,E10–12: Ac, as measured by a portable EAG apparatus, ranged from 2 ± 2 to 7 ± 3 ng/m³. The antennal signal was high and rather constant within pea canopy, but was lower and fluctuated strongly above canopy. Initially, >99% isomerically pureE8,E10–12: Ac was released, and male moths were attracted to dispensers. After nine days, isomeric blend composition had equilibrated to approx. 92%E8,E10–12: Ac and 8% of the inhibitory isomersE,Z-,Z,E-, andZ8,Z10–12: Ac. Males were then repelled from the pheromone-permeated field. Traps baited with 100 µgE8,E10–12: Ac caught 258 ± 133C. nigricana males/trap in the control, but no males at all in the disruption field.     

Identification and Synthesis of Male-Produced Sex Pheromone Components of the Stink Bugs Chlorochroa ligata and Chlorochroa uhleri

The reproductive behaviors of the stink bugs Chlorochroa ligata and C. uhleri were studied in the laboratory. Adults of both species became sexually mature about 12–14 days after the final molt, and both sexes mated multiple times during their lifetimes. The mean duration of copulation was 54 ± 24 min for virgin bugs and 46 ± 33 min for experienced bugs for C. ligata and 78 ± 55 min for field-collected C. uhleri of unknown mating status. Male C. ligata were found to transfer a significant fraction of their body mass (19%) to females during mating. Sexually mature C. uhleri males produced three sex-specific compounds, methyl (R)-3-(E)-6-2,3-dihydrofarnesoate, methyl (2E,6E)-farnesoate, and methyl (E)-5-2,6,10-trimethyl-5,9-undecadienoate, in a ratio of 100:0.9:0.6. These three compounds were also produced by sexually mature male C. ligata in a ratio of 100:0.5:0.4. Identifications of the compounds were confirmed by synthesis. Production of the male-specific compounds peaked in late afternoon to early evening, coincident with the peak period of reproductive activity. Laboratory and field bioassays demonstrated that female bugs were attracted to odors from live males and to reconstructed blends of the male-specific compounds.     

Identification and Field Evaluation of Components of Female Sex Pheromone of Millet Stem Borer, Coniesta ignefusalis

Five active compounds were detected during analyses of ovipositor washings and effluvia from virgin female Coniesta ignefusalis moths by gas chromatography (GC) linked to electroantennographic (EAG) recording from a male moth. These were identified as (Z)-7-dodecen-1-ol (Z7–12:OH), (Z)-5-decen-1-ol (Z5–10:OH), (Z)-7-dodecenal (Z7–12:Ald), (Z)-7-dodecenyl acetate (Z7–12:Ac), and (Z)-9-tetradecen-1-ol (Z9–14:OH) by comparison of their GC retention times, mass spectra, and EAG activities with those of synthetic standards. Laboratory tests of dispensers for these compounds showed that release rates from polyethylene vials increased to relatively uniform values after three to four days, but release from septa was very rapid and nonuniform and decreased to low levels after two to three days. Trapping tests in Niger showed that the major component, Z7–12:OH, and two of the minor components, Z5–10:OH and Z7–12:Ald, were essential for attraction of male C. ignefusalis moths. The most attractive blend contained these three components in a 100:5:3.3 ratio in a polyethylene vial, which emitted the components in similar proportions to those produced by the female C. ignefusalis moth. Water traps baited with this blend containing 1 mg of Z7–12:OH caught more male C. ignefusalis moths than traps baited with newly emerged female moths. Addition of up to 10% of the corresponding E isomers of the pheromone components had no effect on catches, but addition of the other two minor components detected, Z7–12:Ac and/or Z9–14:OH, to the attractive blend at naturally occurring levels caused significant reductions in trap catch.     

Aggregation pheromone ofCarpophilus antiquus (Coleoptera: Nitidulidae) and kairomonal use ofC. lugubris pheromone byC. antiquus

Males ofCarpophilus antiquus Melsheimer (Coleoptera: Nitidulidae) emit an aggregation pheromone that was found to be a novel hydrocarbon, (3E,5E,7E,9E)-6,8-diethyl-4-methyl-3,5,7,9-dodecatetraene. A synthetic scheme and spectra (mass and proton NMR) are given for the compound. Beetles produced the pheromone when feeding on a variety of media, including the brewer's yeast-based artificial diet, fermenting whole-wheat bread dough, corn, and prunes; live baker's yeast was generally added to the food media. Males held individually produced, on average, 25 × more pheromone per beetle than males held in groups of 10 or more. Pheromone was not produced until males were at least 5 days old but was still detected from the oldest beetles tested (47 days). In field tests, the pheromone was attractive to both sexes ofC. antiquus, and it was synergized by food volatiles: A combination of pheromone and fermenting whole wheat dough attracted 2.5× more beetles than pheromone alone, but dough by itself was not significantly more attractive than the control. Semiochemical interactions were studied amongC. antiquus and two other sympatric species for which pheromones are known,C. lugubris Murray andC. freemani Dobson.C. antiquus responded readily to the pheromone ofC. lugubris, but all other interspecific responses to the pheromones were weak. In a sample of naturally infested corn ears, the presence ofC. antiquus was strongly associated with the presence ofC. lugubris, as would be expected if the pheromone ofC. lugubris serves as a kairomone forC. antiquus.