Identification of Floral Volatiles From Ligustrum japonicum that Stimulate Flower-Visiting by Cabbage Butterfly, Pieris rapae

Floral scent compounds of Ligustrum japonicum that affect the foraging behavior of Pieris rapae adults were examined by means of chemical analyses, electroantennogram (EAG) responses, and behavioral bioassays; the behavioral biossays consisted of two tests: reflex extension of proboscis (REP) in response to odor, and attraction to scented and unscented artificial flowers. More than 30 compounds, including 2-phenylethanol, benzyl alcohol, and methyl phenylacetate as the major components were identified from L. japonicum flowers. Of these, 22 compounds were tested for their effect on foraging behavior. Phenylacetaldehyde (PA), 2-phenylethanol (PE), and 6-methylhept-5-en-2-one (MHO) elicited the highest REP responses, and benzaldehyde (BA) and methyl phenylacetate (MPA) evoked intermediate REP responses. EAG responses were not necessarily correlated with REP activities; the three high-REP compounds gave only moderate EAG responses, whereas two other compounds (ethyl phenylacetate and 2-phenylethyl acetate) that released high EAG responses showed low REP activities. In two-choice behavioral bioassays, flower models scented with any one of these high-REP compounds attracted significantly more adults, while compounds with low REP activities exhibited weak or no appreciable attractiveness. This suggests that the REP responsiveness closely reflects the attractiveness of a compound and could be an effective measure in elucidating which chemical attractants are involved in flower-visiting. A synthetic blend of five floral chemicals (PA, PE, MHO, BA, and MPA) displayed an attractiveness that was comparable to that of the floral extract and was more effective in attractiveness than the compounds tested singly. Consequently, it is highly likely that the flower-visiting by P. rapae to L. japonicum is mediated largely by floral scent chemicals and that a synergistic effect of the five floral components would be most responsible for attraction of the butterfly to this flower. The present results also strongly suggest that specific floral volatiles may facilitate close-range flower location by P. rapae, could serve in part as a cue for recognizing food sources, and also be profoundly implicated in flower preference.     

Fragrance of Canada Thistle (Cirsium arvense) Attracts Both Floral Herbivores and Pollinators

The evolution of floral scent as a plant reproductive signal is assumed to be driven by pollinator behavior, with little attention paid to other potential selective forces such as herbivores. I tested 10 out of the 13 compounds emitted by dioecious Cirsium arvense, Canada thistle, including 2-phenylethanol, methyl salicylate, p-anisaldehyde, benzaldehyde, benzyl alcohol, phenylacetaldehyde, linalool, furanoid linalool oxides (E and Z), and dimethyl salicylate. Single compounds (and one isomer) set out in scent-baited water-bowl traps trapped over 10 species of pollinators and 16 species of floral herbivores. The two dominant components of the fragrance blend of C. arvense, benzaldehyde and phenylacetaldehyde, trapped both pollinators and florivores. Other compounds attracted either pollinators or florivores. Florivores of C. arvense appear to use floral scent compounds as kairomones; by advertising to pollinators, C. arvense also attracts its own enemies.     

Discrimination of oilseed rape volatiles by honey bee: Novel combined gas chromatographic-electrophysiological behavioral assay

A novel technique for the simultaneous monitoring of electroan-tennogram (EAG) and conditioned proboscis extension (CPE) responses of honey bees to the effluent from a gas chromatograph (GC) was developed to locate biologically active components in blends of plant volatiles and to investigate odor recognition at the peripheral and behavioral levels. A six-component mixture, comprising compounds previously identified as oilseed rape floral volatiles, was used as the stimulus. Standard CPE and EAG recordings were done as a reference. EAG responses were elicited from unconditioned bees by all the components presented either in the coupled or the standard mode. Conditioned bees gave larger EAG responses than unconditioned bees, suggesting that antennal sensitivity is enhanced by conditioning. At the behavioral level, in both the standard and the coupled modes, only conditioned bees showed the proboscis extension response, with the majority of individuals responding to linalool, 2-phenylethanol, and benzyl alcohol.     

Electroantennogram responses ofHyles lineata (Sphingidae: Lepidoptera) to volatile compounds fromClarkia breweri (Onagraceae) and other moth-pollinated flowers

Electroantennograms (EAGs) from field-collectedHyles lineata moths were recorded in response to 10 individual floral volatiles identified fromClarkia breweri (Onagraceae), to 22 scent compounds produced by other moth-pollinated flowers and to eight ubiquitous green leaf volatiles. Females' EAGs were generally 1.5- to 2-fold greater than those observed for male moths. Female:male EAG rank orders were significantly correlated, but marked differences in order were observed for some compounds (e.g., benzyl alcohol, cinnamic aldehyde, geraniol, and linalool). Linalool, benzyl acetate, methyl salicylate, and pyranoid linalool oxide elicited the largest EAG responses (–1.2 to –0.8 mV) among scent compounds fromC. breweri. EAG responses were significantly lower for monoterpenes as a pooled compound class than for aromatic esters, alcohols and aldehydes, fatty acid derivatives, N-bearing compounds and oxygenated terpenoids. EAG responses to structurally related scent compounds were not significantly different in most cases. Both male and femaleH. lineata were sensitive to mostC. breweri scent compounds at 10^–2 to 10^–4 µg/µl doses, and rank order in potency varied with the dose/concentration tested.H. lineata's olfactory sensitivity to diverse volatile compounds across a range of doses/concentrations suggests that a broad array of volatiles could function as floral attractants for foraging hawkmoths.     

Effects of Volatile Compounds Emitted by Protea Species (Proteaceae) on Antennal Electrophysiological Responses and Attraction of Cetoniine Beetles

Evolutionary shifts in pollination systems within a plant genus are commonly associated with changes in floral scent, reflecting selection mediated through the sensory systems of various pollinators. The most common cetoniine beetle pollinator of grassland Protea species in South Africa, Atrichelaphinis tigrina, previously has been shown to have a strong preference for the fruity floral scent of these plants over the weak scent of their bird-pollinated congeners. However, it is not known which of the many compounds found in the scent of beetle pollinated Protea species play a role for pollinator attraction. Electroantennograms (EAG) from A. tigrina beetles were recorded in response to 15 compounds emitted by Protea flower heads. EAG responses to all 15 compounds were significantly greater than those to the paraffin solvent in which they were diluted. The greatest responses were observed for aromatics (anisole, methyl benzoate, methyl salicylate, benzaldehyde) followed by the monoterpene β-linalool, which can comprise up to 66 % of fruity Protea scents. Five compounds that elicited EAG responses (benzaldehyde, β-linalool, (E/Z)-linalool oxide (furanoid), methyl benzoate, and methyl salicylate) were tested in commercially available yellow bucket traps in the field to test their attractiveness to beetles. Traps baited with methyl benzoate, β-linalool, (E/Z)-linalool oxide (furanoid), and methyl salicylate caught significantly more insects than did those containing paraffin only. Methyl benzoate also was more specifically attractive to A. tigrina than was (E/Z)-linalool oxide (furanoid) and paraffin baited controls. A second field experiment using a combination of linalool vs. paraffin baited yellow or green traps showed that trap color had a significant effect on the number of trapped beetles. Yellow traps yielded a ten-fold higher number of insect catches than did green traps. However, the combination of yellow color and the scent compound linalool yielded the highest number of catches. This study has shown that the cetoniine beetle A. tigrina can detect a variety of floral compounds and is attracted to compounds comprising a large proportion of the blend that makes up fruity Protea scents, adding support for the hypothesis that change in scent chemistry during the shift from bird to cetoniine beetle pollination in this genus were mediated by beetle sensory preferences.     

Identification of odors from overripe mango that attract vinegar flies,Drosophila melanogaster

Bioassays with a variety of overripe fruits, including mango, plum, pear, and grape, and their extracts showed that odors from overripe mango were most attractive to adult vinegar flies, Drosophila melanogaster. Combined gas chromatography–electroantennographic detection (GC-EAD) analyses of solid-phase microextraction (SPME) and Tenax extracts of overripe mango odors showed that several volatile compounds, including ethanol, acetic acid, amyl acetate, 2-phenylethanol, and phenylethyl acetate elicited significant EAG responses from antennae of female flies. Most of the volatile compounds in the extracts were identified by mass spectral and retention index comparisons with synthetic standards. In cage bioassays, lures with a blend of ethanol, acetic acid, and 2-phenylethanol in a ratio of 1:22:5 attracted six times more flies than any single EAG-active compound. This blend also attracted four times more flies than traps baited with overripe mango or unripe mango. However, in field trials, the blend was not as attractive as suggested by the laboratory bioassay.     

Chemical and Chromatic Bases for Preferential Visiting By the Cabbage Butterfly, Pieris rapae, to Rape Flowers

Scent and coloration of corolla were examined as floral attributes responsible for preferential visiting by the cabbage butterfly, Pieris rapae, to rape flower, Brassica rapa. Floral volatile components that release the flower-visiting behavior of the butterfly were identified by chemical analyses, electroantennography (EAG), and two behavioral bioassays: proboscis extension reflex (PER) in response to odor and attraction to artificial flowers. GC and GC-MS analyses of the headspace volatiles from the flowers revealed the presence of six aromatic compounds, benzaldehyde, phenylacetaldehyde, benzyl alcohol, 2-phenylethanol, phenylacetonitrile, and indole in decreasing order of quantity. Of these, phenylacetaldehyde elicited the highest response in the PER assay. While benzyl alcohol, 2-phenylethanol, benzaldehyde, and phenylacetonitrile evoked moderate responses, the PER-eliciting activity of indole was very weak. In two-choice behavioral bioassays, artificial flowers scented with any one of these PER-active compounds attracted significantly more butterflies than control (unscented) flowers, whereas those treated with indole were almost inactive. The EAG activities of the six chemicals were not high and were about the same at a low dose (1 g), but phenylacetaldehyde elicited a much stronger response from both sexes at higher doses (10 and 100 g). An overall profile of EAG responses at a dose of 100 g was analogous to that of PER performance, suggesting that floral volatiles may be involved in close-range location or recognition of flowers rather than long-range attraction. By spectroscopic and UV-photographic examinations of rape flower, the central part of the corolla was found to absorb UV rays in marked contrast to the other parts, which reflected near-UV rays (_max = 350 nm). This indicates that the flower is endowed with a conspicuous nectar guide that is probably an important visual stimulus for attracting foraging adults of P. rapae. Consequently, the present findings strongly suggest that this elaborate pollination strategy of rape flower, characterized by its good combination of olfactory and visual attractiveness, accounts for preferential visiting by the cabbage butterfly to the flower.     

Electrophysiological and Behavioral Responses of Sorghum Shoot Fly, <Emphasis Type="Italic">Atherigona soccata</Emphasis>, to Sorghum Volatiles

The sorghum shoot fly, Atherigona soccata, is an economically important pest of sorghum in Asia, Mediterranean Europe and Africa. Field observations have suggested that shoot fly susceptible sorghum varieties emit attractive volatiles, but the compounds involved were unknown. The objective of the present study was to identify plant-derived attractants for A. soccata. Headspace samples were collected from the susceptible cultivar ‘Swarna,’ and when female A. soccata were exposed to the volatiles in an olfactometer bioassay, a strong positive behavioral response was observed. Coupled GC-EAG with female A. soccata revealed eight compounds that elicited an EAG response, which were identified by coupled GC-MS and GC peak enhancement on two GC columns of different polarity as (Z)-3-hexen-1-yl acetate, (-)-α-pinene, (-)-(E)-caryophyllene, methyl salicylate, octanal, decanal, 6-methyl-5-hepten-2-one and nonanal. When an eight-component synthetic blend of the EAG active compounds, at the same concentration (2.64 μg) and ratio as in the natural headspace sample, was tested, A. soccata spent more time in the treated region of the olfactometer than controls (P = 0.001). Furthermore, when this synthetic blend and the natural headspace sample were tested in a choice test, the shoot flies did not show any preference for either of the two treatments, demonstrating that the synthetic blend had similar activity to the natural sample. Results are discussed in relation to breeding sorghum varieties less attractive to this pest.     

Odor compound detection in male euglossine bees

Male euglossine bees collect fragrances from various sources, which they store and use for as yet unknown purposes. They are attracted, often specifically, to single odor compounds and blends thereof. We used gas chromatography with electroantennographic detection (GC-EAD) and electroantennography (EAG) to investigate the response to 8 odor compounds by males of two euglossine species, Euglossa cybelia Moure and Eulaema polychroma (Mocsàry). In E. cybelia, we recorded EAD reactions in response to 1,8-cineole, methyl benzoate, benzyl actetate, methyl salicylate, eugenbl, and methyl cinnamate. E. polychroma responded to the same compounds in EAG experiments, while (ls)(-)-pinene and -pinene failed to trigger EAD or EAG responses in the bees. Blends of two compounds triggered larger responses than single compounds in EAG experiments with E. polychroma, however, when -pinene was added, reactions decreased. In the light of existing data on the bees' behavior towards these odor compounds, our work indicates that both peripheral and central nervous processes influence the attraction of euglossine bees to odors.     

Isolation and Identification of Host Cues from Mango, <Emphasis Type="Italic">Mangifera indica</Emphasis>, That Attract Gravid Female Oriental Fruit fly, <Emphasis Type="Italic">Bactrocera dorsalis</Emphasis>

The oriental fruit fly, Bactrocera dorsalis, is an economically damaging, polyphagous pest of fruit crops in South-East Asia and Hawaii, and a quarantine pest in other parts of the world. The objective of our study was to identify new attractants for B. dorsalis from overripe mango fruits. Headspace samples of volatiles were collected from two cultivars of mango, ‘Alphonso’ and ‘Chausa’, and a strong positive behavioral response was observed when female B. dorsalis were exposed to these volatiles in olfactometer bioassays. Coupled GC-EAG with female B. dorsalis revealed 7 compounds from ‘Alphonso’ headspace and 15 compounds from ‘Chausa’ headspace that elicited an EAG response. The EAG-active compounds, from ‘Alphonso’, were identified, using GC-MS, as heptane, myrcene, (Z)-ocimene, (E)-ocimene, allo-ocimene, (Z)-myroxide, and γ-octalactone, with the two ocimene isomers being the dominant compounds. The EAG-active compounds from ‘Chausa’ were 3-hydroxy-2-butanone, 3-methyl-1-butanol, ethyl butanoate, ethyl methacrylate, ethyl crotonate, ethyl tiglate, 1-octen-3-ol, ethyl hexanoate, 3-carene, p-cymene, ethyl sorbate, α-terpinolene, phenyl ethyl alcohol, ethyl octanoate, and benzothiazole. Individual compounds were significantly attractive when a standard dose (1 μg on filter paper) was tested in the olfactometer. Furthermore, synthetic blends with the same concentration and ratio of compounds as in the natural headspace samples were highly attractive (P < 0.001), and in a choice test, fruit flies did not show any preference for the natural samples over the synthetic blends. Results are discussed in relation to developing a lure for female B. dorsalis to bait traps with.     

Defensive Secretions in Three Species of Polydesmids (Diplopoda,Polydesmida, Polydesmidae)

Nine compounds were detected in three different millipede species: Polydesmus complanatus (L.), Brachydesmus (Stylobrachydesmus) avalae Ćurčić & Makarov, and Brachydesmus (Stylobrachydesmus) dadayi Verhoeff. Benzaldehyde, benzyl alcohol, benzoylnitrile, benzyl methyl ketone, benzoic acid, benzyl ethyl ketone, mandelonitrile, and mandelonitrile benzoate were identified by GC-FID and GC-MS analyses. Hydrogen cyanide was detected qualitatively by the picric acid test. Benzyl ethyl ketone, benzyl methyl ketone, and benzyl alcohol were detected for the first time in polydesmidan millipedes. Benzoylnitrile was the major component in all three hexane extracts. These compounds are suspected to be active in the defensive secretions of these millipede species.     

Field Attraction of Hoplia communis to 2-Phenylethanol, A Major Volatile Component from Host Flowers, Rosa spp.

The attractiveness of volatile compounds from the floral scent of Rosa, one of the most preferred plants for adult Hoplia communis, was evaluated under field conditions. The beetles were attracted to most compounds tested, but 2-phenylethanol exhibited the highest capture rate. Catches increased with increasing emissions of between 9.1 and 287.2 mg/day. Catches in white traps were significantly larger (17.4-fold) than those in green traps when both were baited with anethole, an already known attractant; however, the trap color was not significant when a more attractive lure, 2-phenylethanol, was used. The use of a single funnel trap baited with 2 g of 2-phenylethanol at a heavily infested nursery exhibited promising results for mass trapping. Approximately 90,000 beetles of both sexes, which nearly corresponds to the estimated maximum population per 1000 m², were captured within six days.     

Female-Biased Attraction of Oriental Fruit Fly, Bactrocera dorsalis (Hendel), to a Blend of Host Fruit Volatiles From Terminalia catappa L.

Coupled gas chromatography-electroantennogram detection (GC-EAD) analysis of volatiles from tropical almond fruit, Terminalia catappa L., revealed 22 compounds that were detected by antennae of oriental fruit fly females, Bactrocera dorsalis (Hendel). Both solid-phase microextraction (SPME) and Porapak Q were used for sampling odors in fruit headspace, with SPME collections producing larger EAD responses from a greater number of compounds. Geranyl acetate and methyl eugenol elicited the largest EAD responses. A synthetic blend containing SPME collected, EAD stimulatory compounds showed female-biased attraction in laboratory wind tunnel bioassays, but heavily male-biased trap captures in a larger olfactometer arena. A nine-component subset of compounds eliciting relatively small EAD responses (EAD minor) and consisting of equal parts ethanol, ethyl acetate, ethyl hexanoate, hexyl acetate, linalyl acetate, ethyl nonanate, nonyl acetate, ethyl cinnamate, and (E)-β-farnesene, attracted mainly females. This EAD minor blend was as attractive to females and much less attractive to males when compared to torula yeast in field cage experiments using glass McPhail traps. Similar results were obtained with outdoor rotating olfactometer tests in which the EAD minor blend was almost completely inactive for males.     

Electroantennogram Responses of a Predator, Perillus bioculatus, and its Prey, Leptinotarsa decemlineata, to Plant Volatiles

The two-spotted stinkbug, Perillus bioculatus, is a predator of the Colorado potato beetle (CPB), Leptinotarsa decemlineata. Behavioral tests revealed that P. bioculatus is attracted to potato plants, Solanum tuberosum L. (Solanaceae), infested by the CPB. Electroantennograms from the antennae of P. bioculatus were recorded in response to compounds present in the headspace of CPB-infested potato plants. (Z)-3-Hexen-1-ol and 2-phenylethanol elicited the highest EAG amplitudes. Linalool, 4,8-dimethyl-1,3(E),7-nonatriene, nonanal, decanal, and (R)-(+)-limonene evoked lower EAG amplitudes. The major headspace components -caryophyllene and -selinene produced only weak EAG responses. Antennal sensitivity of the CPB to (Z)-3-hexen-1-ol was higher than that of P. bioculatus, whereas the stinkburg was more sensitive to 2-phenylethanol, -caryophyllene, (R)-(+)-limonene, and decanal. Among these compounds, 2-phenylethanol is of special interest since it was observed to be emitted by potato foliage only after being damaged by CPBs.     

Olfactory Reactions of the Twelve-Spotted Lady Beetle, Coleomegilla maculata and the Green Lacewing, Chrysoperla carnea to Semiochemicals Released from Their Prey and Host Plant: Electroantennogram and Behavioral Responses

Electroantennograms (EAGs) were recorded from two predatory insect species, the twelve-spotted lady beetle, Coleomegilla maculata and the green lacewing, Chrysoperla carnea in response to semiochemicals emitted from one of their prey species, the pea aphid Acyrthosiphon pisum and their host plant. EAG responses were also recorded from C. maculata in response to extracts from individuals of the opposite sex and to extracts from an herbaceous plant, catnip Nepeta cataria. Extracts of catnip and two sex pheromone components of aphids, (4aS,7S,7aR)-nepetalactone and (1R,4aS,7S,7aR)-nepetalactol, elicited significant EAG responses from the antennae of both predatory species. Of 10 corn volatile compounds tested, C. carnea adults responded most strongly to 2-phenylethanol and (E)--farnesene. A significant difference in EAG response to extracts of corn leaf collections was observed between male and female C. carnea. In C. maculata, significant EAG responses were elicited by most of the tested corn volatile compounds, except -pinene and (E)-2-hexenal. The highest EAG responses were observed in response to (E)--farnesene, -terpineol, 2-phenylethanol, and -caryophyllene. Sexual differences in EAG responses of C. maculata were only found in response to 1-octen-3-ol. Male antennae of C. maculata produced significant EAG responses to extracts from conspecific females, but not to males, which indicates that some chemicals from females could be involved in sexual communication. A significant EAG response also was recorded in response to the extracts of fluids produced during reflex bleeding. Male and female antennae of both species exhibited similar dose–response curves to most of the selected compounds, although female C. maculata antennae exhibited higher thresholds in response to several compounds including -terpineol, (Z)-3-hexenol, and (4aS,7S,7aR)-nepetalactone. Field tests showed that 2-phenylethanol was highly attractive to both sexes of the two investigated species. Only C. maculata was attracted to traps baited with -terpineol.     

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.     

Optimization of a Phenylacetaldehyde-Based Attractant for Common Green Lacewings (<Emphasis Type="Italic">Chrysoperla carnea s.l.</Emphasis>)

In field trapping tests, the catch of Chrysoperla carnea sensu lato (Neuroptera: Chrysopidae) increased when acetic acid was added to lures with phenylacetaldehyde. The addition of methyl salicylate to the binary mixture of phenylacetaldehyde plus acetic acid increased catches even further. The ternary blend proved to be more attractive than β-caryophyllene, 2-phenylethanol, or 3-methyl eugenol (compounds previously described as attractants for chrysopids) on their own, and no influence on catches was recorded when these compounds were added as fourth components to the ternary blend. There were minimal changes in activity when (E)-cinnamaldehyde or methyl anthranylate (both evoking large responses from female or male antennae of C. carnea in this study) were added, although both compounds showed significant attraction on their own when compared to unbaited traps. In subtractive field bioassays with the ternary mixture, it appeared that the presence of either phenylacetaldehyde or methyl salicylate was important, whereas acetic acid was less so in the ternary mixture. The ternary blend attracted both female and male lacewings at sites in southern, central, and northern Europe. Possible applications of a synthetic attractant for lacewings are discussed.     

Further Field Evaluation Of Synthetic Herbivore-Induced Plan Volatiles As Attractants For Beneficial Insects

Fifteen synthetic herbivore-induced plant volatiles (HIPVs) were field-tested for attractivity to beneficial insects in two experiments conducted in an open field and a hop yard in Washington State. Eleven insect species or families showed significant attraction to 13 HIPVs. The ladybeetle, Stethorus punctum picipes, was attracted to sticky traps baited with methyl salicylate (MeSA), cis-3-hexen-1-ol (He), and benzaldehyde (Be). The minute pirate bug, Orius tristicolor, was attracted to traps baited with MeSA, He, Be, and octyl aldehyde (Oa), and the bigeyed bug, Geocoris pallens, responded to MeSA, indole, and trans-2-hexen-1-al. The mymarid wasp, Anagrus daanei, was attracted to He, Oa, and farnesene. The chloropid fly, Thaumatomyia glabra, was highly attracted to methyl anthranilate. Insect families responding to HIPVs included Syrphidae (MeSA, He), Braconidae ((Z)-3-hexenyl acetate, He, cis-jasmone (J), methyl jasmonate (MeJA), methyl anthranilate (MeA)), Empididae (MeSA), Sarcophagidae (MeSA, Be, J, nonanal and geraniol), Tachinidae (Be), and Agromyzidae (MeSA). Micro-Hymenoptera (primarily parasitic wasp families) were attracted to MeSA, He, and indole. These results are discussed with respect to known properties and bioactivity of the tested HIPVs and to their potential as tools for recruiting natural enemies into agroecosystems.     

Sex Pheromone of the Persimmon Fruit Moth, Stathmopoda masinissa: Identification and Laboratory Bioassay of (4E, 6Z)-4,6-Hexadecadien-1-ol Derivatives

Three electroantennogram (EAG)-active components were detected by gas chromatography coupled to an electroantennographic detector (GC–EAD) analysis of a hexane extract of the pheromone glands of the persimmon fruit moth, Stathmopoda masinissa. These compounds were identified as (4E,6Z)-4,6-hexadecadienal (E4,Z6-16:Ald) and the corresponding acetate (E4,Z6-16: OAc) and alcohol (E4,Z6-16:OH) by mass spectral, GC retention time (RT), and microchemical test data. The characteristic base peak of the aldehyde at m/z 84 provided a crucial piece of information suggesting the possibility of a 4,6-diene structure. The (4E,6Z)-isomer elicited the strongest EAG responses among the four geometrical isomers of each synthetic 4,6-hexadecadienyl compound. In a laboratory bioassay, only E4,Z6-16:OAc elicited male moth behavioral activity significantly different from the control; the activity of the acetate was not affected by addition of the aldehyde and alcohol. A preliminary field trial confirmed that E4,Z6-16:OAc as a single component attracted male moths. The possible roles of E4,Z6-16:Ald and E4,Z6-16:OH as components of lures for field use remain to be determined.     

Identification of floral compounds fromAbelia grandiflora that stimulate upwind flight in cabbage looper moths

Four major volatile components emitted from flowers ofAbelia grandiflora were identified based on retention time using two capillary columns of different polarities and electron impact mass spectrometry. These are phenylacetaldehyde, benzaldehyde, 2-phenylethanol, and benzyl alcohol. A blend of these compounds was as effective as a cluster of flowers in stimulating upwind flight by maleTrichoplusia ni to the source in a wind-tunnel test. Phenylacetaldehyde or 2-phenylethanol were each as effective as the complete blend in stimulating source location by male moths. Attraction to a source of the synthetic blend was demonstrated in virgin males and females and mated males and females, but virgin moths of both sexes were more likely than mated moths to complete the sequence of behavioral responses necessary to locate the odor source.