Identification of herbivore-induced plant volatiles from selected Rubus species fed upon by raspberry bud moth (Heterocrossa rubophaga) larvae.

Heterocrossa rubophaga (raspberry bud moth) feed on a range of Rubus species, including commercial berryfruit crops where they are a pest. This study aimed to characterize the responses of native and non-native Rubus species to feeding by raspberry bud moth larvae. In a laboratory environment, in situ headspace volatiles of three Rubus species were collected from healthy plants and those fed upon by raspberry bud moth. Rubus cissoides (bush lawyer), the native host of raspberry bud moth, gave a limited response to larval feeding with green leaf volatiles (GLVs) representing the only new headspace constituents of the infested plants. The non-native hosts, Rubus ursinus var. loganobaccus cv Boysenberry (Boysenberry), and Rubus fruticosus (blackberry), gave strong responses to raspberry bud moth herbivory, releasing a number of unique nitrogenous compounds in conjunction with the GLVs. The nitrogenous compounds were identified as 2-methylbutanenitrile, (Z)- and (E)- 2-methylbutanal O-methyloxime, benzyl nitrile, (Z)- and (E)- phenylacetaldehyde O-methyloxime and indole. The four methyloximes and 2-methylbutanenitrile were confirmed by synthesis. Field collected phenology data showed that raspberry bud moth were active year round on both bush lawyer and blackberry.

Synthesis and Electrophysiological Testing of Carbonyl Pheromone Analogues for Carposinid Moths.

Sex pheromone analogues were synthesized and tested on two pest carposinid moth species: the guava moth, Coscinoptycha improbana, and the raspberry bud moth, Heterocrossa rubophaga. The pheromone analogues used for the electroantennogram testing included (Z)-11-methylenenonadec-7-ene, (Z)-nonadec-12-en-9-amine, (Z)-11-methoxynonadec-7-ene, (Z)-1-(octylsulfinyl)-dec-3-ene, and (Z)-nonadec-12-en-9-ol. An imine analogue, N-((Z)-nonadec-12-en-9-ylidene)cyclopropanamine, was also synthesized but was too unstable for testing with the moths. None of the analogue compounds elicited significant responses from the male moth antennae.

Liquid Baits with Oenococcus oeni Increase Captures of Drosophila suzukii.

The spotted-wing drosophila (SWD), Drosophila suzukii Matsumura (Diptera: Drosophilidae), native to Eastern Asia, is an invasive alien species in Europe and the Americas, where it is a severe pest of horticultural crops, including soft fruits and wine grapes. The conventional approach to controlling infestations of SWD involves the use of insecticides, but the frequency of application for population management is undesirable. Consequently, alternative strategies are urgently needed. Effective and improved trapping is important as an early risk detection tool. This study aimed to improve Droskidrink® (DD), a commercially available attractant for SWD. We focused on the chemical and behavioral effects of adding the bacterium Oenococcus oeni (Garvie) to DD and used a new trap design to enhance the effects of attractive lures. We demonstrate that microbial volatile compounds produced by O. oeni are responsible for the increase in the attractiveness of the bait and could be later utilized for the development of a better trapping system. Our results showed that the attractiveness of DD was increased up to two-fold by the addition of commercially available O. oeni when combined with an innovative trap design. The new trap-bait combination increased the number of male and especially female catches at low population densities.

Synthesis and Biological Testing of Ester Pheromone Analogues for Two Fruitworm Moths (Carposinidae).

A range of ester pheromone analogues for carposinid moths were synthesized and evaluated for biological activity. The analogues aimed to take advantage of the structural commonality of (7Z)-alken-11-ones found in this family. Analogues were tested on two pest species: Heterocrossa rubophaga and Coscinoptycha improbana. Two of the analogues, (2Z)-nonenyl nonanoate and (4Z)-heptyl undecenoate, elicited significant electroantennogram responses. Only (4Z)-heptyl undecenoate gave consistent responses with both moth species in single sensillum recording. Field trapping trials were conducted with these two analogues both individually and in combination with the pheromone of each of the two moth species. No attraction was observed to either of the analogues alone, by either moth species. However, when (4Z)-heptyl undecenoate was coupled with the pheromone, it produced a strong inhibitory effect in H. rubophaga, reducing male moth trap catch by over 95%. No inhibitory effect on male moth trap catch was observed in C. improbana.

Olfactory Receptor Neurons for Plant Volatiles and Pheromone Compounds in the Lucerne Weevil, Sitona discoideus.

Antennal olfactory receptor neurons (ORNs) for pheromone-related and plant volatile compounds were identified and characterized in the lucerne weevil, Sitona discoideus (Gyllenhal), using the single sensillum recording technique. Our study using five pheromone-related compounds and 42 plant volatile compounds indicates that S. discoideus have highly specialized ORNs for pheromone and plant volatile compounds. Different groups of ORNs present in both males and females of S. discoideus were highly sensitive to 4-methylheptane-3,5-dione (diketone) and four isomers (RR, RS, SR and SS) of 5-hydroxy-4-methylheptan-3-one, respectively. Our results also indicate that male S. discoideus, using the sensory input from antennal ORNs, can distinguish both diketone and the RR-isomer from others, and RS- and SS-isomers from others, although it was unclear if they can distinguish between RS-isomer and SS-isomer, or between diketone and the SR-isomer. It also appeared that female S. discoideus could distinguish between RS-isomer and SS-isomers. The antennae of S. discoideus thus contain sex-specific sets of ORNs for host- and non-host plant volatile compounds. Both sexes of S. discoideus have highly sensitive and selective ORNs for some green-leaf volatiles, such as (Z)-3-hexenol and (E)-2-hexenal. In contrast, male antennae of S. discoideus house three distinct groups of ORNs specialized for myrcene and (E)-ß-ocimene, 2-phenylethanol, and phenylacetaldehyde, respectively, whereas female antennae contain three groups of ORNs specialized for (±)-linalool and (±)-α-terpineol, myrcene and (E)-ß-ocimene, (±)-1-octen-3-ol, and 3-octanone. Our results suggest that S. discoideus use a multi-component pheromone communication system, and a sex-specific set of ORNs with a narrow range of response spectra for host-plant location.

Selection of key floral scent compounds from fruit and vegetable crops by honey bees depends on sensory capacity and experience.

Flowers have complex odours often comprising hundreds of volatile compounds. Floral scents are species-specific, and vary also among populations, varieties, sexes or lines, as well as with phenology. Honey bees, Apis mellifera, generally associate only a few key compounds among the complex floral scent with the food reward which guides their foraging choices. How these key compounds are selected remains partially unexplained, despite their crucial role in influencing foraging. Using electrophysiological techniques and behavioural assays, we identified the key bioactive compounds that bees detected with their antennae and that were associated with appetitive responses from four fruit crops and three vegetable crops. Three quantities of identified key volatile compounds were assayed with the two methods in each of four different seasons with experienced foragers. Whether the selection of these key compounds is determined by the sensory capability of the bee or influenced by its foraging experience was assessed by comparing experienced and naïve bees. Our results showed that experienced foragers were electrophysiologically-sensitive to a specific set of key compounds for each crop, independent of variation in quantity among several varieties. Experienced foragers responded to these compounds in all seasons, with increased electrophysiological amplitude with increasing quantities. Behavioural appetitive responses varied amongst compounds and seasons, revealing preferences based on associative learning. Naïve bees that were exposed to compounds and subsequently learned them, tended to be overall more sensitive. We discuss our results based on the identity of each bioactive compound and their presence in nature. Preferences for specific floral compounds based on sensory biases exist and associative learning may reinforce behavioural attraction depending on foraging experience in each season.

Will growing invasive arthropod biodiversity outpace our ability for eradication?

The Global Eradication Database documents 811 eradication attempts against invasive arthropods since 1890, in 104 countries. Eradication programs show a greater than exponential increase in the number of programs started in recent decades. In addition, there is a trend of a rapidly diversifying burden of the most severe threats. The species richness showed a three-fold increase in number of species under eradication in the last 50 yr, and all taxonomic levels rose dramatically. The increase in number of eradication programs shows that current management measures for constraining the spread of invasive species are inadequate. A similar surge in the number of governments trying to prevent the establishment of new pests has occurred. Increased biodiversity of arthropod eradication targets includes new pest groups with fewer tools developed for management. We argue that a rapid increase in biodiversity of invasive and economically or environmentally damaging organisms represents a substantial and underestimated challenge for managers wanting to prevent their establishment, requiring a shift in research focus to accelerate delimitation and suppression options with less reliance on insecticides.

Chemical Composition of the Rectal Gland and Volatiles Released by Female Queensland Fruit Fly, Bactrocera tryoni (Diptera: Tephritidae).

The composition of the rectal gland secretion and volatiles emitted by female Queensland fruit fly, Bactrocera tryoni was investigated. Esters were found to be the main compounds in the gland extracts and headspace, while amides were the minor compounds in the gland extracts and headspace. Ethyl dodecanoate, ethyl tetradecanoate, ethyl (Z9)-hexadecenoate and ethyl palmitate were the main esters in the gland extracts, while ethyl dodecanoate and ethyl tetradecanoate were the main esters in the headspace. Four amides (N-(3-methylbutyl)acetamide), N-(2-methylbutyl)propanamide, N-(3-methylbutyl)propanamide, and N-(3-methylbutyl)-2-methylpropanamide were found in the gland extracts and the headspace. Among the amides, N-(3-methylbutyl)acetamide and N-(3-methylbutyl)propanamide were the main amides in the gland extracts and the headspace. Traces of three spiroacetals were found both in the gland extracts and in the headspace. (E,E)-2,8-Dimethyl-1,7-dioxaspiro[5.5]undecane, (E,E)-2-ethyl-8-methyl-1,7-dioxaspiro[5.5]undecane, (E,E)-2-propyl-8-methyl-1,7-dioxaspiro[5.5]undecane. All compounds found in the headspace were present in the extract of the rectal gland suggesting that the rectal gland is the main source of the headspace volatiles, whose function remains to be elucidated. This is the first comprehensive chemical analysis of the rectal gland secretions and volatiles of female B. tryoni, and further laboratory and field bioassays are required to determine the function of compounds identified in this study. Discovery of the same amides previously identified in the male rectal gland in the female rectal gland raises questions about the pheromonal role previously suggested for these compounds.

Leafroller-induced phenylacetonitrile and acetic acid attract adult Lobesia botrana in European vineyards.

We recently identified unique caterpillar-induced plant volatile compounds emitted from apple leaves infested with the larvae of various leafroller species. In subsequent field tests, binary blends of phenylacetonitrile+acetic acid and 2-phenylethanol+acetic acid were found to be attractive to a range of tortricid leafroller species (Tortricidae: Tortricinae) in both the Southern and Northern Hemispheres. In this work, the caterpillar-induced plant volatiles from the apple-leafroller system were tested in two vineyards in Spain and Hungary for their attractiveness to the grape frugivore Lobesia botrana (Tortricidae: Olethreutinae). As seen for Tortricinae species, a binary blend of phenylacetonitrile+acetic acid attracted significantly more male and female L. botrana to traps than acetic acid or blank lures. Traps baited with other caterpillar-induced plant volatile compounds (benzyl alcohol, 2-phenylethanol, indole, and (E)-nerolidol, each as a binary blend with acetic acid) did not catch significantly more moths than traps containing acetic acid alone. The catches of male and female moths support an optimistic future for new products in female tortricid surveillance and control that are based on combinations of kairomone compounds released from larval-damaged foliage.

Honey Norisoprenoids Attract Bumble Bee, Bombus terrestris, in New Zealand Mountain Beech Forests.

Three varieties of honey of different dominant floral origin were found to attract social Hymenoptera, including the large earth bumble bee, Bombus terrestris, in a New Zealand mountain beech forest. This study was undertaken to identify volatile organic compounds that induce the attraction of bumble bees to honeybee ( Apis mellifera) honey. We analyzed the chemical composition of the volatile organic compounds produced in three distinct varieties of honey (i.e., manuka, honeydew, and clover honey). The composition of the chemical profile of the three honey varieties differed in the quality and in the ratio of compounds in the headspace. o-Methoxyacetophenone was the main compound in the headspace of all three honey varieties. Among the 40 compounds identified in the headspace in the three varieties, only seven shared compounds (i.e., benzaldehyde, benzyl alcohol, phenylacetaldehyde, 2-phenylethanol, isophorone, 4-oxoisophorone, and o-methoxyacetophenone) were present in the headspace of the three honey varieties. The relative attractiveness of various blends of the seven common compounds found in the three honey varieties was tested for the attraction to bumble bees in a mountain beech forest. A binary blend of isophorone and 4-oxoisophorone at a ratio of 90:10 was the most attractive blend for both bumble bee workers and queens. A small number of honey bee workers were also attracted to the former binary blend. Our study represents the first identification of a honey-derived attractant for bumble bees and honey bees. The potential application of our finding for monitoring of bumble bees or to enhance crop pollination and help to tackle the current concern of a global pollination crisis is discussed.

Associative Learning of Food Odor by Social Wasps in a Natural Ecosystem.

The ability of insects to associate olfactory cues with food from their environment has been well documented with various insect orders. However, these studies were based on prior training of insects to associate odors with food sources in the laboratory or in the field with almost no evidence for the development of this phenomenon in natural ecosystems. In New Zealand's ancient Fuscospora spp. or beech forests, invasive Vespula social wasps were attracted to odor from honeydew (benzaldehyde and n-octanol) but did not respond to a known wasp attractant (isobutanol and acetic acid). On the other hand, wasps in a rural/suburban area in New Zealand did not respond to honeydew odor but responded instead to the known wasp attractant. Similarly, social wasps in Hungary did not respond to honeydew odor, but responded to the known wasp attractant. DNA sequences of Vespula vulgaris from the two locations in New Zealand were 100% identical. Similarly, DNA sequences of V. germanica from the two locations in New Zealand were 100% identical, indicating little or no intra-specific variation. On the other hand, DNA sequences of V. vulgaris and V. germanica from New Zealand were 99.56 and 99.78% matches with V. vulgaris and V. germanica samples from Hungary, respectively. Electroantennogram (EAG) response profiles of wasps from the three locations to benzaldehyde, isobutanol, acetic acid, n-octanol and heptyl butyrate were similar. The high similarity in DNA sequences and EAG profiles, with only a behavioral difference in the response to odor sources, suggests that social wasps in New Zealand's beech forest have naturally developed associative learning for the odor of the carbohydrate-rich honeydew. This is the first study to provide conclusive evidence of the occurrence and the development of associative learning of food odor by social insects in a natural ecosystem free of human interference. The ability of social wasps to naturally develop associative learning of food odor might in part explain why they are extremely successful invaders of new ecosystems, especially those with rich honeydew resources. The finding of our study will have significant implications for the use of attractants in wasp monitoring and control in different habitats.

The importance of key floral bioactive compounds to honey bees for the detection and attraction of hybrid vegetable crops and increased seed yield.

BACKGROUND: Crop breeding programmes generally select for traits for improved yield and human consumption preferences. Yet, they often overlook one fundamental trait essential for insect-pollinated crops: pollinator attraction. This is even more critical for hybrid plants that rely on cross-pollination between the male-fertile line and the male-sterile line to set seeds. This study investigated the role of floral odours for honey bee pollination that could explain the poor seed yield in hybrid crops. RESULTS: The key floral bioactive compounds that honey bees detect were identified for three vegetable hybrid crops. It was found that 30% of the variation in bioactive compound quantities was explained by variety. Differences in quantities of the bioactive compounds triggered different degrees of olfactory response and were also associated with varied appetitive response. Correlating the abundance of each bioactive compound with seed yield, it was found that aldehydes such as nonanal and decanal can have a strong negative influence on seed yield with increasing quantity. CONCLUSION: Using these methodologies to identify relevant bioactive compounds associated with honey bee pollination, plant breeding programmes should also consider selecting for floral traits attractive to honey bees to improve crop pollination for enhanced seed yield. © 2018 Society of Chemical Industry.

Thigmotaxis Mediates Trail Odour Disruption.

Disruption of foraging using oversupply of ant trail pheromones is a novel pest management application under investigation. It presents an opportunity to investigate the interaction of sensory modalities by removal of one of the modes. Superficially similar to sex pheromone-based mating disruption in moths, ant trail pheromone disruption lacks an equivalent mechanistic understanding of how the ants respond to an oversupply of their trail pheromone. Since significant compromise of one sensory modality essential for trail following (chemotaxis) has been demonstrated, we hypothesised that other sensory modalities such as thigmotaxis could act to reduce the impact on olfactory disruption of foraging behaviour. To test this, we provided a physical stimulus of thread to aid trailing by Argentine ants otherwise under disruptive pheromone concentrations. Trail following success was higher using a physical cue. While trail integrity reduced under continuous over-supply of trail pheromone delivered directly on the thread, provision of a physical cue in the form of thread slightly improved trail following and mediated trail disruption from high concentrations upwind. Our results indicate that ants are able to use physical structures to reduce but not eliminate the effects of trail pheromone disruption.

Identification of in situ flower volatiles from kiwifruit (Actinidia chinensis var. deliciosa) cultivars and their male pollenisers in a New Zealand orchard.

In situ flower volatiles from six kiwifruit cultivars (Actinidia chinensis var. deliciosa); 'Hayward', 'Chieftain', 'M56', 'Zes007' (Green11), 'M36', and 'M43' were collected by dynamic headspace sampling. Forty-five compounds were detected in the headspace of the flowers, with straight chain hydrocarbons and terpenes accounting for >98% of the volatiles emitted quantitatively across the six cultivars. Of these hydrocarbons, (3Z,6Z,9Z)-heptadecatriene is reported for the first time from a floral source while (8Z)-hexadecene and (9Z)-nonadecene are reported for the first time from kiwifruit flowers. All three hydrocarbons were verified by synthesis. Quantitative comparison of the six honey bee perceived compounds from the headspace of the cultivars showed that the males 'M36' and 'M43' closely matched the female cultivar Green11 that they are used to pollinate. Males 'M56' and 'Chieftain' were not as closely matched to the female cultivar 'Hayward' that they are used to pollinate. The male 'M56' in particular differed significantly from the female 'Hayward' in four of the six honey bee perceived compounds.

Caterpillar-induced plant volatiles attract conspecific adults in nature.

Plants release volatiles in response to caterpillar feeding that attract natural enemies of the herbivores, a tri-trophic interaction which has been considered an indirect plant defence against herbivores. The caterpillar-induced plant volatiles have been reported to repel or attract conspecific adult herbivores. To date however, no volatile signals that either repel or attract conspecific adults under field conditions have been chemically identified. Apple seedlings uniquely released seven compounds including acetic acid, acetic anhydride, benzyl alcohol, benzyl nitrile, indole, 2-phenylethanol, and (E)-nerolidol only when infested by larvae of the light brown apple moth, Epiphyas postvittana. In field tests in New Zealand, a blend of two of these, benzyl nitrile and acetic acid, attracted a large number of conspecific male and female adult moths. In North America, male and female adults of the tortricid, oblique-banded leafroller, Choristoneura rosaceana, were most attracted to a blend of 2-phenylethanol and acetic acid. Both sexes of the eye-spotted bud moth, Spilonota ocellana, were highly attracted to a blend of benzyl nitrile and acetic acid. This study provides the first identification of caterpillar-induced plant volatiles that attract conspecific adult herbivores under natural conditions, challenging the expectation of herbivore avoidance of these induced volatiles.

Is the Combination of Insecticide and Mating Disruption Synergistic or Additive in Lightbrown Apple Moth, Epiphyas postvittana?

Pest suppression from combinations of tactics is fundamental to pest management and eradication. Interactions may occur among tactical combinations and affect suppression. The best case is synergistic, where suppression from a combination is greater than the sum of effects from single tactics (AB >> A+B). We explored how mating disruption and insecticide interacted at field scale, additively or synergistically. Use of a pheromone delivery formulation (SPLAT™) as either a mating disruption treatment (i.e. a two-component pheromone alone) or as a lure and kill treatment (i.e. the two-component pheromone plus a permethrin insecticide) was compared for efficacy against the lightbrown apple moth Epiphyas postvittana. Next, four point-source densities of the SPLAT™ formulations were compared for communication disruption. Finally, the mating disruption and lure and kill treatments were applied with a broadcast insecticide. Population assessment used virgin female traps and synthetic pheromone in replicated 9-ha vineyard plots compared with untreated controls and insecticide-treated plots, to investigate interactions. Lure and kill and mating disruption provided equivalent suppression; no additional benefit accrued from including permethrin with the pheromone suggesting lack of contact. The highest point-source density tested (625/ha) was most effective. The insect growth regulator methoxyfenoxide applied by broadcast application lowered pest prevalence by 70% for the first ten weeks compared to pre-trial. Pheromone addition suppressed the pest further by an estimated 92.5%, for overall suppression of 97.7% from the treatment combination of insecticide plus mating disruption. This was close to that expected for an additive model of interactivity between insecticide and mating disruption (AB = A+B) estimated from plots with single tactics as 98% suppression in a combination. The results indicate the need to examine other tactical combinations to achieve the potential cost-efficiencies of synergistic interactions.

Pollinator-prey conflicts in carnivorous plants: When flower and trap properties mean life or death.

Insect-pollinated carnivorous plants are expected to have higher fitness if they resolve pollinator-prey conflicts by sparing insects pollinating their flowers while trapping prey insects. We examined whether separation between flowers and traps of the carnivorous sundew species or pollinator preferences for colours of flowers enable these plants to spare pollinators. In addition, we collected odours from flowers and traps of each carnivorous species in order to identify volatile chemicals that are attractive or repellent to pollinators and prey insects. In Drosera spatulata and D. arcturi, no volatiles were detected from either their flowers or traps that could serve as kairomone attractants for insects. However, behavioural experiments indicated white colour and spatial separation between flowers and traps aid in reducing pollinator entrapment while capturing prey. In contrast, D. auriculata have flowers that are adjacent to their traps. In this species we identified chemical signals emanating from flowers that comprised an eight-component blend, while the plant's traps emitted a unique four-component blend. The floral odour attracted both pollinator and prey insects, while trap odour only attracted prey. This is the first scientific report to demonstrate that carnivorous plants utilize visual, spatial, and chemical signals to spare flower visitors while trapping prey insects.

Eradication of Invading Insect Populations: From Concepts to Applications.

Eradication is the deliberate elimination of a species from an area. Given that international quarantine measures can never be 100% effective, surveillance for newly arrived populations of nonnative species coupled with their eradication represents an important strategy for excluding potentially damaging insect species. Historically, eradication efforts have not always been successful and have sometimes been met with public opposition. But new developments in our understanding of the dynamics of low-density populations, the availability of highly effective treatment tactics, and bioeconomic analyses of eradication strategies offer new opportunities for developing more effective surveillance and eradication programs. A key component that connects these new developments is the harnessing of Allee effects, which naturally promote localized species extinction. Here we review these developments and suggest how research might enhance eradication strategies.

Synthetic pheromones as a management technique - dispensers reduce Linepithema humile activity in a commercial vineyard.

BACKGROUND: Invasive ants, such as the Argentine ant, have often been reported to facilitate honeydew-producing hemipteran pests such as mealybugs, which can be vectors of plant pathogens. Synthetic pheromones may offer a target-specific method to control such ants and consequently lower the abundance of honeydew-producing pests. Here we report the results of a trial to suppress Argentine ants in grapevines using ant pheromone dispensers. RESULTS: Compared with untreated controls, we observed a significant drop in Argentine ant activity on the ground, irrespective of whether pheromone dispensers were placed at ground level, within the canopy or in both locations. Ant counts in the canopy confirmed that Argentine ant abundance was reduced under the influence of the pheromone dispenser placed at ground level compared with untreated controls. However, placing dispensers only in the canopy did not reduce the numbers of ants within the canopy compared with untreated controls. CONCLUSION: Our results showed that pheromone dispensers can significantly reduce Argentine ant foraging in grapevines if they are positioned appropriately. This technique could potentially reduce the abundance of associated mealybugs and potentially attendant virus vectoring areawide.

Invasive Vespula Wasps Utilize Kairomones to Exploit Honeydew Produced by Sooty Scale Insects, Ultracoelostoma.

Vespula wasps are widely distributed invasive alien species that are able to reach high population densities in the 1.2 M ha of beech forests (Fuscospora spp.) of New Zealand's South Island. These endemic temperate forests have an abundance of carbohydrate-rich honeydew produced by native scale insects (Ultracoelostoma spp.). A characteristic aroma is associated with the honeydew in beech forests, which we hypothesized is the signal used by wasps to harvest the vast resources previously exploited by birds and other insects. Volatile collections were taken of black beech tree trunks with honeydew and sooty mold present, and analyzed with a gas chromatograph-mass spectrometer. Eleven compounds (benzaldehyde, benzyl alcohol, 2-phenylethyl acetate, 2-phenylethanol, phenylacetaldehyde, methyl 2-phenylacetate, ethyl 2-phenylacetate, methyl salicylate, n-octanol, octan-3-ol, and 1-octen-3-ol) were positively identified from the headspace, and were shown to elicit an electrophysiological response from Vespula vulgaris worker antennae by using electroantennography (EAG). Field trials with delta traps individually baited with these compounds confirmed wasp attraction to 8 of the 11 compounds tested, with 2-phenylethyl acetate, methyl salicylate, and octan-3-ol capturing the same numbers of wasps as the control. In later trials, attraction to a 1:1 blend of benzaldehyde and n-octanol was significantly higher (45%) than to any other treatment. Many of the chemicals identified are known to be associated with fermenting sugars, or with fungal aroma. Benzaldehyde and n-octanol are common compounds produced by many different species in nature. The ability to respond to generic signals emanating from sugar resources is likely to contribute to the success of V. vulgaris as an invasive species.