Methyl Salicylate,a Soybean Aphid-Induced Plant Volatile Attractive to the Predator <Emphasis Type="Italic">Coccinella septempunctata</Emphasis>

Induced volatiles provide a signal to foraging predatory insects about the location of their prey. In Iowa, early in the growing season of soybean, Glycine max, many predacious seven-spotted lady beetles, Coccinella septempunctata, were observed on plants with heavy infestations of soybean aphid, Aphis glycines. We studied whether the attraction of this beetle is caused by the release of specific volatile compounds of soybean plants infested by aphids. Volatile compounds emitted by soybean plants infested by aphids were compared with those of undamaged, uninfested, and artificially damaged plants. Gas chromatography–mass spectrometry analyses revealed consistent differences in the profiles of volatile compounds between aphid-infested soybean plants and undamaged ones. Significantly more methyl salicylate was released from infested plants at both the V1 and V2 plant growth stages. However, release patterns of two other induced plant volatiles, (d)-limonene and (E,E)-α-farnesene, differed between the two plant growth stages. Gas chromatographic–electroantennographic detection of volatile extracts from infested soybean plants showed that methyl salicylate elicited significant electrophysiological responses in C. septempunctata. In field tests, traps baited with methyl salicylate were highly attractive to adult C. septempunctata, whereas 2-phenylethanol was most attractive to the lacewing Chrysoperla carnea and syrphid flies. Another common lady beetle, the multicolored Asian lady beetle, Harmonia axyridis, showed no preference for the compounds. These results indicate that C. septempunctata may use methyl salicylate as the olfactory cue for prey location. We also tested the attractiveness of some selected soybean volatiles to alate soybean aphids in the field, and results showed that traps baited with benzaldehyde caught significantly higher numbers of aphids.     

Sex Pheromone of Nuttall's Sheep Moth, Hemileuca nuttalli, from the Eastern Sierra Nevada Mountains of California

The sex attractant pheromone blend of Hemileuca nuttalli (Lepidoptera: Saturniidae) from the eastern slope of the Sierra Nevada Mountains in California was determined to be a combination of E10,Z12-hexadeca-10,12-dien-1-yl acetate (E10,Z12–16:Ac) and E10,E12-hexadeca-10,12-dien-1-yl acetate (E10,E12–16:Ac). Ratios of the compounds in extracts of female pheromone glands varied around a mean of 100:48, although the ratio was not critical in field trials. Blends of synthetic E10,Z12–16:Ac and E10,E12–16:Ac in 100:50, 50:100, and 100:100 ratios attracted equal numbers of male moths. Field trials also indicated that E10,Z12–hexadeca-10,12-dien-1-ol (E10,Z12–16:OH) and E10,Z12-hexadeca-10,12-dienal (E10,Z12–16:Ald) were antagonistic at rates of 3.3% and 10%, respectively, of the E10,Z12–16:Ac, despite being found in female moth extracts. E10,E12–16:Ac, E10,Z12–16:OH, and E10,Z12–16:Ald all appear to have roles in maintenance of reproductive isolation between H. nuttalli and H. eglanterina.     

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 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.     

Geographic Variation in Sex Pheromone Blend of Hemileuca electra from Southern California

Differences were found in the pheromonally mediated mate location systems of two subspecies of Hemileuca electra, H. electra electra (Hee) and H. e. mojavensis (Hem), from southern California. Hem female pheromone gland extracts contained eight times as much (10E,12Z)-hexadeca-10,12-dienal (E10,Z12–16:Ald) and half as much hexadecyl acetate (16:Ac) as Hee extracts. Relative amounts of the other major component of the pheromone blends, (10E,12Z)-hexadeca-10,12-dien-1-ol (E10,Z12–16:OH) did not differ between the two subspecies. In coupled gas chromatography–electroantennogram studies, responses of male antennae to 1:1:1 mixtures of the three principal components (E10,Z12–16:Ac, E10,Z12–16:OH, E10,Z12–16:Ald) also differed, with Hem antennae producing significantly larger responses to E10,Z12–16:Ald and significantly smaller responses to 10E,12Z–16:Ac than Hee. In field trials, male Hem were attracted to Hem females in preference to Hee females. Males of a second species, H. burnsi, which is sympatric with Hem but not Hee, also were attracted to females of Hee transported to their range. Field tests of blends of synthesized pheromone components confirmed that male Hem preferred E10,Z12–16:Ald ratios of 10–100% of the major component, E10,Z12–16:Ac, whereas males of Hee and H. burnsi responded optimally to ratios of 0.3–1% E10,Z12–16:Ald to E10,Z12–16:Ac. 16:Ac added to lures increased attraction of Hee but not Hem males. The data presented are consistent with reproductive character displacement, whereby the Hem subspecies has modified its pheromone-based mating system to reduce interference from sympatric H. burnsi.     

Sex Attractant Pheromone of Saturniid Moth Coloradia velda

The female-produced sex attractant pheromone of Coloradia velda has been identified by a combination of analytical methods and field tests as a blend of (10E,12Z)-hexadecadien-1-yl acetate (10E,12Z–16:Ac), (10E,12E)-hexadecadien-1-yl acetate (10E,12E–16:Ac), and (10E,12Z)-hexadecadien-1-ol (10E,12Z–16:OH) in a 10:1:0.33 ratio, respectively. The corresponding aldehyde (10E,12Z–16:Ald) was also found in extracts of female pheromone glands, but in blends with 10E,12Z–16:Ac and 10E,12E–16:Ac at low doses did not significantly increase the attractiveness of baits to male moths.     

Green Leaf Volatiles Interrupt Pheromone Response of Spruce Bark Beetle, Ips typographus

A synthetic mixture of nine green leaf volatiles (GLVs) including linalool was tested on antennae of Ips typographus (L.) with coupled gas chromatographic–electroantennographic detection (GC-EAD). Strong responses were found to 1-hexanol, (Z)-3-hexen-1-ol, and (E)-2-hexen-1-ol. Weak responses were recorded to (E)-3-hexen-1-ol, (Z)-2-hexen-1-ol and linalool, while hexanal, (E)-2-hexenal and (E)-3-hexenyl acetate elicited no EAD responses. In a laboratory walking bioassay, the attraction of I. typographus females to a synthetic pheromone source was significantly reduced when a mixture of the three most EAD-active GLV alcohols was added to the source. Further reduction in response was obtained when these three alcohols were combined with verbenone (Vn). In field trapping experiments, a blend of 1-hexanol, (Z)-3-hexen-1-ol, and (E)-2-hexen-1-ol reduced I. typographus trap catches by 85%, while ca. 70% reduction of trap catch was achieved by Vn or a blend of (E)-3-hexen-1-ol, (Z)-2-hexen-1-ol, and linalool. The strongest disruptive effect was found when Vn plus a blend of the three most EAD active GLV alcohols was added to the pheromone trap (95% catch reduction). Adding the blend of the three most EAD active alcohols to pheromone-baited traps significantly reduced the proportion of males captured. These three GLV alcohols were also disruptive in the laboratory and in the field when tested individually. Hexanal, (E)-2-hexenal, and (Z)-3-hexenyl acetate were inactive both in the lab and in the field. Our results suggest that these nonhost green leaf alcohols may explain part of the host selection behavior of conifer-attacking bark beetles and may offer a source of inhibitory signals for alternative management strategy for forest protection.     

Characterization of Pheromone Blend for Grapevine Moth, Lobesia botrana by Using Flight Track Recording

The behavioral responses of Lobesia botrana males to calling females, pheromone gland extracts, and synthetic sex pheromones were recorded in a wind tunnel. Gland extracts and synthetic pheromones were released from a pheromone evaporator. The numbers of males reaching the source and their flight tracks in response to calling females and pheromone gland extracts were compared to those of synthetic blends. Upwind flights to natural sex pheromone were straighter and faster than to a three-component blend of (E)-7,(Z)-9-dodecadienyl acetate (E7,Z9–12:Ac), (E)-7,(Z)-9-dodecadien-1-ol (E7,Z9–12:OH), and (Z)-9-docecenyl acetate (Z9–12:Ac) (100:20:5). The optimum ratio of E7,Z9–12:OH and Z9–12:Ac to E7,Z9–12:Ac was found to be 5% and 1%, respectively. An additional seven compounds identified in the sex pheromone gland were investigated for their biological activity. Two unsaturated acetates, i.e., (E)-9-dodecenyl acetate (E9–12:Ac) and 11-dodecenyl acetate (11–12:Ac), increased the number of males reaching the source as well as straightness, linear velocity, and decreased the track angle of upwind flight. Optimum response was obtained by releasing 10 pg/min E7,Z9–12:Ac in a mixture with 0.5 pg/min E7,Z9–12:OH, 0.1 pg/min Z9–12:Ac, 0.1 pg/min E9– 12:Ac and 1 pg/min 11-12–Ac. The saturated acetates previously identified in the female glands were biologically inactive.     

Sex pheromone components of female smaller tea tortrix moth,Adoxophyes sp. (Lepidoptera: Tortricidae) in Taiwan

(Z)-11-Teiradecenyl acetate (Z11-14: Ac) and (Z)-9-tetrade-cenyl acetate (Z9–14: Ac) were isolated as major sex pheromone components from the female tips of the smaller tea tortrix moth,Adoxophyes sp., in Taiwan. The average amount ofZ11- andZ9–14: Ac in each female gland was 24.9 and 14.1 ng, in a ratio of 6436, respectively. When compared to a closely related Japanese strain, which used theZ9-14: Ac,Z11-14 Ac,E11–14:Ac, 10-Me-12:Ac four-component system (in a ratio of 633142), the Taiwan formulation of two components caught significantly more Taiwan males than the Japanese formulation of four components.     

Sex pheromone ofStenoma cecropia Meyrick (Lepidoptera: Elachistidae)

(Z,E)-9,11-tetradecadienal (Z9,E11–14: Ald; 11%), (Z,E)-9,11,13-tetradecatrienal (Z9,E11, 13–14: Ald; 67%), (Z,E)-9,11-tetradecadienyl acetate (Z9,E11–14: Ac, 5.5%), and (Z,E)-9,11,13-tetradecatrienyl acetate (Z9,E11,13–14: Ac; 16.5%) were identified in the extracts of female pheromone glands ofStenoma cecropia (Lepidoptera: Elachistidae). From electroantennograms and single sensillum recordings, receptors toZ9,E11,13–14:Ald andZ9,E11–14: Ald were found on male antenna. Behavioral data were obtained from olfactometric tests in the laboratory and field trapping experiments in Colombia. It appeared that a blend ofZ9,E11,13–14:Ald (83%) andZ9,E11–14:Ald (17%) was attractive to males. These aldehydes are assumed to be components of the sex pheromone ofS. cecropia, whereas the acetates found in gland extracts might be precursors of the pheromone.     

Accumulation of Glucosinolates by the Cabbage Aphid Brevicoryne brassicae as a Defense Against Two Coccinellid Species

Brassica nigra plants, characterized by high levels of sinigrin, and artificial aphid diets to which sinigrin was selectively added were used to rear the crucifer specialist, Brevicoryne brassicae. Aphids were provided as a food source to two species of polyphagous ladybird, Adalia bipunctata and Coccinella septempunctata. First instar A. bipunctata were unable to survive when fed with B. brassicae reared on B. nigra or diets containing 0.2% sinigrin, but when fed with aphids reared on diets containing 0% sinigrin, survival rates were high. By contrast, first instar C. septempunctata were able to survive when fed with aphids reared on B. nigra or artificial diets containing up to 1% sinigrin. However, the presence of sinigrin in the aphid diet decreased larval growth and increased the time necessary for larvae to reach second instar for this species of ladybird. These results indicate that the presence of sinigrin in the diet of B. brassicae makes this aphid unsuitable as a food source for A. bipunctata but not for C. septempunctata, although for this ladybird species, there appear to be costs associated with feeding on aphids that contain this secondary metabolite.     

Sex pheromone components of the buck moth Hemileuca maia

The sex attractant pheromone blend of Hemileuca maia (Lepidoptera: Saturniidae) from the vicinity of Baton Rouge, Louisiana, has been identified. The major component of the blend is (E10,Z12)-hexadeca-10,12-dienal (E10,Z12–16:Ald), in combination with the minor components (E10,Z12)-hexadeca-10,12-dien-1-ol (E10,Z12–16:OH), and (E10,Z12)-hexadeca-10,12-dien-1-yl acetate (E10,Z12–16:Ac). Ratios of the compounds in extracts of female pheromone glands varied around a mean of 100:7.4:6.3. None of the three components were attractive to male moths when tested as single components. Several other compounds were tentatively identified from female pheromone gland extracts, including E10,E12–16:Ald, E10,E12–16:OH, and E10,E12–16:Ac, but addition of these components, either alone or in combination, at biologically relevant rates, did not significantly increase the attractiveness of lures. The saturated analogs, hexadecanal, hexadecanol, and hexadecyl acetate, also were identified in gland extracts, but had no apparent effect as pheromone components.     

Sex Pheromone Components of Nettle Caterpillar, Setora nitens

Gas chromatographic–electroantennographic detection (GC-EAD) analyses of pheromone gland extracts of female nettle caterpillars, Setora nitens, revealed four compounds that consistently elicited responses from male moth antennae. Retention indices on three fused silia columns (DB-5, DB-23, and DB-210) of two EAD-active compounds were almost identical to those of (E)-9-dodecenal (E9–12 : Ald) and (E)-9,11-dodecadienal (E9,11–12 : Ald), two pheromone components previously identified in congeneric Setothosea asigna. However, comparative GC, GC-EAD, and GC-mass spectrometry of extracted S. nitens compounds and authentic standards revealed that the candidate pheromone components were (Z)-9-dodecenal (Z9–12 : Ald) and (Z)-9,11-dodecadienal (Z9,11–12 : Ald). The two other EAD-active compounds in pheromone gland extracts proved to be the corresponding alcohols to these aldehydes. In field-trapping experiments in Tawau, Malaysia, synthetic Z9–12 : Ald and Z9,11–12 : Ald at a 1 : 1 ratio, but not singly, attracted male S. nitens. Attractiveness of these two aldehydes could not be enhanced through the addition of their corresponding alcohols. Whether these differences in pheromone biology and chemistry between S. nitens and S. asigna are sufficient to prevent cross-attraction of heterospecific males or whether nonpheromonal mechanisms are required to maintain reproductive isolation is currently being studied.     

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.     

Sex-Related Perception of Insect and Plant Volatiles in Lygocoris pabulinus

We recorded electroantennograms of male and female Lygocoris pabulinus antennae to 63 insect and plant volatiles. EAGs were between 100 and 500 V. Overall, male EAGs were about twice the size of female EAGs. In both sexes, largest EAGs were recorded to (E)-2-hexenyl butanoate and (E)-2-hexen-1-ol. Response profiles were similar in both sexes. However, male antennae were more sensitive to a number of esters, especially the butanoates and pentanoates. Female antennae were more sensitive to nine of the 19 plant volatiles, i.e., to hexan-1-ol, heptan-1-ol, 1-octen-3-ol, 2-heptanone, (R)-carvone, linalool, geraniol, nerol, and methyl salicylate. Sexual differences in responses suggest that males are more sensitive to insect-produced pheromone-type compounds, whereas females are more sensitive to plant compounds for their orientation towards oviposition sites.     

Sex pheromone of cranberry fruitworm,Acrobasis vaccinii riley (Lepidoptera: Pyralidae)

The following compounds and (approximate ratios) were identified in sex pheromone gland extracts of femaleAcrobasis vaccinii Riley by comparison of gas chromatography-mass spectrometric traces with those of synthetic standards: (E,Z)-, (Z,E)-, (Z,Z), and (E,E)-8, 10-pentadecadien-l-ol acetates (100:1:2:12), a dodecen-l-ol acetate (8), (Z)-8-, (Z)-9-, and (E)-9-pentadecen-l-ol acetates (3:23:4), two heptadecen-l-ol acetates (4:4), tetradecyl, pentadecyl, hexadecyl, and heptadecyl acetates (3:15:10:8), dodecan-l-ol (6), tetradecan-l-ol (5), and hexadecan-l-ol (23). The amount of (E,Z)-8, 10-pentadecadien-l-ol acetate (E8,Z10–15:Ac) in the extract was about 0.5 ng/female. Electroantennographic analysis of gas chromatographic fractions of female sex pheromone gland extract showed that the fraction containingE8,Z10–15:Ac elicited the greatest response. Alone,E8,Z10–15:Ac failed to elicit upwind flight of males in flight-tunnel tests, and traps baited with it did not catch males in field experiments. WhenE8,Z10–15:Ac was combined with (E)-9-pentadecen-l-ol acetate (100:4), male upwind flight response in flight-tunnel tests was equivalent to those obtained with extract of female sex pheromone glands (synthetic, 62%; natural, 51%), but the percent of males flying upwind that contacted the source was lower (synthetic, 47%; natural, 88%). The lower percent of source contact elicited by the synthetic pheromone could be a result of the difference in isomer ratios of 8,10–15:Ac in the natural and synthetic pheromone or could indicate that the synthetic pheromone is incomplete. Traps baited with the 100:4 combination caught large numbers of males in field experiments.     

Production and release of (Z,E)-9,12-tetradecadienal by sex pheromone glands of females ofPlodia interpunctella (lepidoptera: pyralidae)

Extracts of sex pheromone glands obtained from females ofPloida interpunctella contained detectable amounts of (Z,E,)-9,12-tetradecadien-1-ol acetate (Z9,E12–14:Ac) and (Z,E.)-9,12-tetradecadien-1-ol (Z9,E12–14:OH) 4 hr prior to the first scotophase after adult emergence. The amount of pheromone increased during the first 4 hr of the scotophase and then declined to low levels during the subsequent photophase. Decapitation of females immediately after emergence, prior to expansion of the wings, inhibited production of pheromone during the subsequent 48 hr. Injection of extracts of the heads of 1-day-old females ofP. interpunctella of partially purified extracts of the cephalic ganglia of females of the corn earworm moth into decapitated females stimulated production of bothZ9,E12–14:Ac andZ9,E12–14:OH as well as production of (Z,E)-9,12-tetradecadienal (Z9,E12–14:Al). This aldehyde was subsequently identified from extracts of pheromone glands obtained from naturally calling females as well as from volatiles emitted by calling females. Studies on the terminal steps in biosynthesis of the pheromone showed thatZ9,E12–14:OH was produced from the corresponding acetate and thatZ9,E12–14:Al was produced from the alcohol via the action of an oxidase(s).     

Electrophysiologically and Behaviorally Active Volatiles of Buffalo Gourd Root Powder for Corn Rootworm Beetles

The dried, powdered roots of buffalo gourd, Cucurbita foetidissima, were tested in a cornfield and shown to attract adult northern and southern corn rootworm beetles. Coupled gas chromatography–electroantennography (GC-EAG) analyses of headspace samples of the root powder showed several GC-EAG-active compounds on the antennae of female northern, southern, and western corn rootworms. Among other techniques, solid-phase microextraction and GC-mass spectrometry identified the following GC-EAG-active compounds: hexanol, nonanal, 1-octen-3-ol, benzaldehyde, benzyl alcohol, (E)-3-octen-2-one, (E,E)-3,5-octadien-2-one, and (E,Z)-3,5-octadien-2-one. EAG dose–response studies of several of the identified root powder volatiles also were performed and compared with results from known attractants. Field tests of synthetic root powder volatiles in commercial cornfields showed that northern corn rootworm adults were attracted to (E,E)-3,5-octadien-2-one. The antennae of the Diabrotica species and the field tests showed specificity for different geometrical isomers of 3,5-octadien-2-one, with a behavioral preference for (E,E)-3,5-octadien-2-one. In addition, we have shown that the efficacy of buffalo gourd root powder as a feeding stimulant and arrestant can be enhanced for northern and western corn rootworm adults by augmenting buffalo gourd root powder with additional (E,E)-3,5-octadien-2-one.     

The Tea Weevil, <Emphasis Type="Italic">Myllocerinus aurolineatus</Emphasis>, is Attracted to Volatiles Induced by Conspecifics

The tea weevil, Myllocerinus aurolineatus (Voss) (Coleoptera: Curculionidae), is a leaf-feeding pest of Camellia sinensis (O.Ktze.) with aggregative behaviors that can seriously reduce tea yield and quality. Although herbivore-induced host plant volatiles have been shown to attract conspecific individuals of some beetle pests, especially members of the Chrysomelidae family, little is known about the volatiles emitted from tea plants infested by M. aurolineatus adults and their roles in mediating interactions between conspecifics. The results of behavioral bioassays revealed that volatile compounds emitted from tea plants infested by M. aurolineatus were attractive to conspecific weevils. Volatile analyses showed that infestations dramatically increased the emission of volatiles, (Z)-3-hexenal, (Z)-3-hexenol, (E)-β-ocimene, linalool, phenylethyl alcohol, benzyl nitrile, indole, (E, E)-α-farnesene, (E)-nerolidol, and 31 other compounds. Among the induced volatiles, 12 chemicals, including γ-terpinene, benzyl alcohol, (Z)-3-hexenyl acetate, myrcene, benzaldehyde, (Z)-3-hexenal, and (E, E)-α-farnesene, elicited antennal responses from both sexes of the herbivore, whereas (E)-β-ocimene elicited antennal responses only from males. Using a Y-tube olfactometer, we found that six of the 13 chemicals, γ-terpinene, benzyl alcohol, (Z)-3-hexenyl acetate, myrcene, benzaldehyde, and (Z)-3-hexenal, were attractive to both males and females; two chemicals, (E/Z)-β-ocimene and (E, E)-α-farnesene, were attractive only to males; and four chemicals, (E)-4,8-dimethyl-1,3,7-nonatriene, phenylethyl alcohol, linalool, and (Z)-3-hexenol, were attractive only to females. The findings provide new insights into the interactions between tea plants and their herbivores, and may help scientists develop new strategies for controlling the herbivore.     

Identification of Sex Pheromone of Adzuki Bean Borer,Ostrinia scapulalis

By means of gas chromatography with electroantennographic detection (GC-EAD), gas chromatography–mass spectrometry (GC-MS), and a series of bioassays, (Z)-11-tetradecenyl acetate (Z11–14:OAc) and (E)-11-tetradecenyl acetate (E11–14:OAc) at a ratio of 100:3 were identified as the female sex pheromone of the adzuki bean borer,Ostrinia scapulalis. The average amounts ofZ11–14: OAc andE11–14:OAc in a single sex pheromone gland were 6.6 ± 2.4 ng and 0.2 ± 0.1 ng, respectively. In a wind-tunnel bioassay, the binary blend ofZ11- andE11–14:OAc elicited almost the same male behavioral responses as did virgin females and sex pheromone gland extract. In field trapping experiments, rubber septa impregnated with the binary blend (50 g/septum) attracted more males than virgin females. The sex pheromone ofO. scapulalis thus turned out to be similar to that of theZ-type European corn borer,O. nubilalis, in both components and their ratio.