Heptyl Butyrate Research Articles

The structure of temperate yellowjacket communities is affected by land development and loss of forest cover

Abstract As anthropogenic disturbance continues to encroach on natural areas, it is imperative to establish how this disturbance affects species assemblages. Yellowjackets are important predators of a wide range of arthropods, acting as natural population control in many ecosystems. This study seeks to explore how Vespinae community structure shifts with increasing land development in a temperate North American environment. Yellowjackets were sampled from May to September 2019 using heptyl butyrate and acetic acid plus isobutanol traps. Sampling sites represented a gradient of developed landscapes, from fully forested to entirely developed. Seven species from the genera Dolichovespula and Vespula were trapped during the study. Yellowjacket community structure was found to be significantly affected by the amount of land development. These results were driven by the replacement of Vespula consobrina with Vespula germanica in urban landscapes. A high level of development, greater than 75%, reduced species abundance relative to the fully forested landscapes, primarily due to the loss of Vespula pensylvanica and V. consobrina. Our results highlight that the replacement of forested areas with urban development causes a shift in yellowjacket community composition, favouring generalist scavengers (e.g. V. germanica) and threatening the abundance of forest specialists such as V. consobrina.

Identification of a novel plant-derived attractant for Acromyrmex lobicornis leaf-cutting ants.

Leaf-cutting ants are considered major pests of agriculture and forestry in the Neotropics. Attractive toxic baits are the prevailing method for managing them. Thus, there is great interest in identifying attractants to incorporate into these baits.Moreover, leaf-cutting ants can avoid toxic baits by associating the attractant with the toxin.We evaluated attractiveness of heptyl butyrate, a volatile compound found in fresh applesand plums.We conducted field experiments with ten colonies ofAcromyrmex lobicornis. First, weevaluated the behaviour of ants exposed to heptyl butyrate at 1% by surrounding resources. Then, we compared the attractiveness of heptyl butyrate and orange pulp, the most commonly used attractant. Finally, we evaluated whether heptyl butyrate increases the attractiveness of a carbohydrate resource at varying doses. Heptyl butyrate at 1% attracted 92% more ants than the control and that it was as attractive as orange pulp. Heptyl butyrate paired with sucrose at concentrations of 0.001 and 0.1% was more attractive than sucrose alone, but greater concentrations did not increase sucrose's attractiveness. Therefore,heptyl butyrate could be added totoxic baits to manageA. lobicornisas it is as attractive as the most commonly used attractant and can be applied directly to the pellets.

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.

Species Composition, Abundance and Seasonal Phenology of Social Wasps (Hymenoptera: Vespidae) in Wisconsin Vineyards.

Social wasps can be serious pests in fruit growing plantings and are becoming increasingly problematic for grape growers. In this study, we conducted two experiments to assess the species composition and seasonal phenology of social wasps in Wisconsin vineyards in 2015 and 2017. In 2015, three attractants were used: (1) wine; (2) heptyl butyrate (HB); and (3) acetic acid and isobutanol (AAIB) and in 2017, two attractants were used: HB and AAIB. In both years, the same eight species were trapped from the genera Vespula, Dolichovespula, and Polistes. The predominant wasp species trapped were Vespula maculifrons, Vespula vidua, Vespula flavopilosa, and Vespula germanica in 2015 and V. maculifrons, V. flavopilosa, V. germanica, and Dolichovespula maculata in 2017, in order of total abundance. The populations of V. vidua decreased in 2017 compared to 2015, indicating large inter-annual variation. In both years, AAIB lures trapped significantly more V. flavopilosa, V. maculifrons, and V. germanica, the three most prevalent species during grape harvest, than HB, whereas HB lures trapped more V. vidua than AAIB. Wine was generally attractive to all species in 2015. This study identifies for the first time the wasp species present in Wisconsin commercial vineyards using chemical attractants. This knowledge, along with the seasonal phenology of these pest species, will help facilitate the development of management strategies for social wasps in commercial vineyards.

Heptyl butyrate, a putative pheromone involved in social communication of Vespula germanica wasps

Greater knowledge on the social communication of invasive Vespula germanica wasps is needed to fully understand their foraging behavior. This is particularly valuable considering that poison baiting is currently the only effective way of reducing wasp density. Heptyl butyrate is an attractant for many wasp species, but attempts to determine effects on V. germanica have yielded mixed results. We studied the behavior elicited by heptyl butyrate on V. germanica wasps in field experiments with foraging wasps. We also analyzed headspace volatiles of live V. germanica workers, to determine if heptyl butyrate is emitted. Heptyl butyrate was present in the headspace of live workers. Amounts of heptyl butyrate averaged 1.4 ± 0.2 ng per sample per hour, where each sample included six workers. Wasps approaching filter papers treated with different concentrations of heptyl butyrate hovered over it, but only a small percentage landed on it. Pure heptyl butyrate elicited the greatest response although all the concentrations tested were attractive. When heptyl butyrate was applied to protein baits, a greater number landed on the treated baits than on untreated ones, demonstrating this compound enhances attractiveness of baits. Results from our study suggest that heptyl butyrate is a pheromonal compound involved in attracting conspecifics to food resources, but other cues are needed to trigger landing.

Enhanced Trapping of Yellowjacket Wasps (Hymenoptera: Vespidae) via Spatial Partitioning of Attractants.

Several yellowjacket species are important pests in both their native habitat and in areas where they are invasive. Traps that contain one or more chemical attractants to lure insects inside are commonly used to combat these yellowjackets in urban environments. Usually, attractants are placed within the trap and combined indiscriminately, though little is known about how this design influences trap attractiveness or efficacy. Here, using the common attractant heptyl butyrate in combination with chicken extract, we demonstrate that spatial partitioning of attractants results in increased capture of the western yellowjacket Vespula pensylvanica—a widespread pestiferous species. Specifically, we show that partitioning of these attractants results in increased visitation of yellowjackets to a trap while also leading to more individuals entering the trap. Further, we provide evidence that this effect is driven by the ability of heptyl butyrate to function as an attractant to the general location of the trap while also blocking the effects of meat extract as a trap-entering stimulus. Thus, our data challenge the current paradigm of combining attractants inside yellowjacket traps, and suggest that these methods can be improved through the consideration of spatial variables and interactions. Our results not only provide novel insight into the mechanisms of yellowjacket attraction, but are also likely to be applicable to the control of other insects for which attractant-based traps are used.

Discovery and Development of Chemical Attractants Used to Trap Pestiferous Social Wasps (Hymenoptera: Vespidae).

Chemical attractants for trapping temperate social wasps have been discovered during the screening of chemicals as attractants for flies, the study of pentatomid bug pheromones, and the testing of volatiles of fermented sweet baits. Wasp attraction to these chemicals seems to be related to either food-finding or prey-finding behavior. Of these attractive chemicals, commercial lures marketed in North America for trapping wasps generally contain heptyl butyrate, or the combination of acetic acid and 2-methyl-1-butanol. Heptyl butyrate is a very good attractant for two major pest wasp species in North America and minor wasp pests in the Vespula rufa species group. The combination of acetic acid with isobutanol attracted nearly all North American pest species of social wasps, including yellowjackets (Vespula and Dolichovespula), a hornet (Vespa crabro), and several paper wasps (Polistes spp.). The testing of wasp chemical attractants in different geographic areas demonstrated responses of many wasp taxa and showed a broad potential scope for the marketing of trap lures. Comparisons of compounds structurally similar to isobutanol revealed similar activity with 2-methyl-1-butanol, which is now used commercially because of a vapor pressure that is more favorable than isobutanol for formulations and dispensers. Doses and concentrations needed for good wasp catches were determined for heptyl butyrate, acetic acid, isobutanol, and 2-methyl-1-butanol, either formulated in water or dispensed from a controlled release device. Trap designs were developed based on consumer considerations; visual appeal, ease and safety of use, and low environmental impact. The resultant lures and traps are marketed in numerous physical and on-line retail outlets throughout the United States and southern Canada.

Short‐ and long‐term control of Vespula pensylvanica in Hawaii by fipronil baiting

The invasive western yellowjacket wasp, Vespula pensylvanica (Saussure), has significantly impacted the ecological integrity and human welfare of Hawaii. The goals of the present study were (1) to evaluate the immediate and long-term efficacy of a 0.1% fipronil chicken bait on V. pensylvanica populations in Hawaii Volcanoes National Park, (2) to quantify gains in efficacy using the attractant heptyl butyrate in the bait stations and (3) to measure the benefits of this approach for minimizing non-target impacts to other arthropods. The 0.1% fipronil chicken bait reduced the abundance of V. pensylvanica by 95 ± 1.2% during the 3 months following treatment and maintained a population reduction of 60.9 ± 3.1% a year after treatment in the fipronil-treated sites when compared with chicken-only sites. The addition of heptyl butyrate to the bait stations significantly increased V. pensylvanica forager visitation and bait take and significantly reduced the non-target impacts of fipronil baiting. In this study, 0.1% fipronil chicken bait with the addition of heptyl butyrate was found to be an extremely effective large-scale management strategy and provided the first evidence of a wasp suppression program impacting Vepsula populations a year after treatment.

Attraction and antennal response of the common wasp, Vespula vulgaris (L.), to selected synthetic chemicals in New Zealand beech forests

The common wasp, Vespula vulgaris (L.), and the German wasp, Vespula germanica (F.), are significant problems in New Zealand beech forests (Nothofagus spp.), adversely affecting native birds and invertebrate biodiversity. This work was undertaken to develop synthetic attractants for these species to enable more efficient monitoring and management. Seven known wasp attractants (acetic acid, butyl butyrate, isobutanol, heptyl butyrate, octyl butyrate and 2,4-hexadienyl butyrate) were field tested, and only heptyl butyrate and octyl butyrate attracted significantly higher numbers of wasps than a non-baited trap. Accordingly, a series of straight-chain esters from methyl to decyl butyrate were prepared and field tested for attraction of social wasps. Peak biological activity occurred with hexyl butyrate, heptyl butyrate, octyl butyrate and nonyl butyrate. Polyethylene bags emitting approximately 18.4-22.6 mg day(-1) of heptyl butyrate were more attractive than polyethylene bags emitting approximately 14.7-16.8 mg day(-1) of heptyl butyrate in the field. Electroantennogram (EAG) studies indicated that queens and workers of V. vulgaris had olfactory receptor neurons responding to various aliphatic butyrates. These results are the first to be reported on the EAG response and the attraction of social wasps to synthetic chemicals in New Zealand beech forests and will enable monitoring of social wasp activity in beech forests.

TRAPPING YELLOWJACKETS (HYMENOPTERA: VESPIDAE) WITH HEPTYL BUTYRATE EMITTED FROM CONTROLLED-RELEASE DISPENSERS

Numbers of workers of Vespula pensylvanica (Saussure) (western yellowjacket) and V. atropilosa (Sladen) trapped with heptyl butyrate in Washington increased with greater release of the attractant from vial dispensers, up to an estimated 2.3 milligrams heptyl butyrate per hour. Vespula germanica (F.) (German yellowjacket) workers were also captured in significant numbers, and numbers of workers captured increased with increased release of heptyl butyrate, up to an estimated 1.4 milligrams per hour. Numbers of workers of Vespula squamosa (Drury) trapped with heptyl butyrate in Oklahoma increased with increased release of heptyl butyrate from dispensers, up to an estimated 3.3 milligrams per hour. Vial dispensers, with holes of 6, 12, 22, and 33 mm diameter in the vial lid, lost 0.42, 1.4, 2.3, and 3.3 milligrams of heptyl butyrate per hour in the laboratory and these rates changed little over a period of 4 weeks, indicating close to a zero order rate of release pattern. Rates of loss of 2 ml heptyl butyrate applied to a cotton ball decreased with exposure time, from an initial rate of 6.0 milligrams per hour to near zero at 16 days post-treatment. Captures of wasps in traps sold commercially might be improved with the use of a controlled-release dispenser.

Chemical Attractants for Trapping Yellowjackets Vespula germanica and Vespula pensylvanica (Hymenoptera: Vespidae)

Worker yellowjackets (Hymenoptera: Vespidae) were captured in traps baited with combinations of an aqueous solution of acetic acid and polyethylene caps loaded with either butyl butyrate, heptyl butyrate, or isobutanol. Vespula germanica (F.) were captured in large numbers in traps baited with acetic acid and isobutanol or acetic acid and butyl butyrate. Vespula pensylvanica (Saussure) were captured in large numbers in traps baited with heptyl butyrate, acetic acid and heptyl butyrate, acetic acid and butyl butyrate, and acetic acid and isobutanol. Acetic acid generally enhanced the attractiveness of these other compounds to V. pensylvanica and V. germanica . Vespula atropilosa (Sladen) were captured in large numbers in traps baited with heptyl butyrate or acetic acid and heptyl butyrate, with no apparent effect of the addition of acetic acid to the trap, and they were only weakly attracted to other baits. The importance of acetic acid to attraction of V. germanica and V. pensylvanica to these lures supports the hypothesis that this response is food-finding behavior. The chemical lure comprised of acetic acid and isobutanol can be used for trapping the worldwide pest V. germanica , with the added advantage of simultaneous attractiveness to V. pensylvanica .

Kinetic resolution of heptan-2-ol-enantiomers by lipase-catalysed esteri�ication in organic solvent

The lipase-catalysed esterification of racemic heptan-2-ol in organic solvent has been investigated. Porcine pancreas lipase, suspended in heptane, preferentially catalyses the synthesis of (R)-2heptyl butyrate starting from (R,S)-heptan-2-ol and butyric acid. The distribution of the reaction products and the stereochemical course of the esterification have been investigated by means of capillary gas chromatographic methods.

Meat Extracts Attractive to Scavenger Vespula in Eastern North America (Hymenoptera: Vespidae)

A horsemeat-based carnivore food, Nebraska Brands Feline Food (NBFF), was found to be much more attractive to workers of Vespula germanica (F.) and V. maculifrons (Buysson)than several meat-based pet foods currently used in toxic bait abatement programs. Solvent extracts made from NBFF were also strongly attractive, with the ethanol fraction being the most attractive. The combined extract fractions of NBFF were as attractive as whole NBFF. Performance of relatively unattractive meat products was enhanced after addition of various extract fractions made from NBFF. Possible applications of extract fractions as alternatives to chemical lures, i.e., heptyl butyrate, are discussed as they relate to yellow jacket abatement.

Color Preference of Vespula squamosa12

Translucent, white plastic wet traps containing a 1:1 volumetric mixture of heptyl butyrate and octyl butyrate and painted buttercup yellow captured significantly more Vespula squamosa (Drury) from Jan. to Sept., whereas traps painted saturn yellow captured significantly more yellowjackets from Oct. to Dec. than unpainted traps or traps painted other colors. The reflected light determined by regression analysis (r = 0.95) to be the most attractive to the yellowjackets during Jan.–Sept. was in the 590 nm region; it was 520 nm from Oct. to Dec. We therefore concluded that V. squamosa distinguish yellow-orange and green colors.

Trapping to Determine the Sympatry and Seasonal Abundance of Various Yellowjackets 1

The occurrence of various presumably sympatric species of Nearctic yellowjackets was determined in widely separated areas. Long-term trapping with n -heptyl butyrate in California, Maryland, and Minnesota disclosed the presence of up to 6 sympatric species of Vespula in some localities. The most responsive included Vespula pensylvanica (Saussure), Vespula sulphurea (Saussure), and Vespula atropilosa (Sladen). Male yellowjackets, Vespula germanica (F.), Vespula maculifrons (Buysson), and Dolichovespula species were nearly unresponsive to synthetic attractants but trapping combined with net collection indicated additional sympatry in some localities. Traps revealed the presence of various species of Vespula in specific localities and traps were used to determine the relative seasonal abundance only of responsive species. The detection sensitivity of trapping may be enhanced by the simultaneous use of protein, carbohydrate or various synthetic attractants.

Perimeter Traps Baited with Synthetic Lures for Suppression of Yellowjackets 1 in Fruit Orchards

Populations of wasps, Vespula spp., on a 22-acre peach orchard near The Dalles, Oregon, were successfully depressed during the summers of 1969 and 1971 with traps containing the highly potent specific lures, 2,4-hexadlenyl butyrate or heptyl butyrate placed around the orchard' periphery. Moreover, the yellowjackets, mostly Vespula pensylvanica (Saussure), were reduced below troublesome levels within four days after the traps were placed. In 1969 about 200,000 wasps were captured in 114 carton traps and four large Malaise traps; in 1971 about 65,000 wasps were taken in seventy 87-oz (2.5-liter) plastic-container traps.

Attraction of Yellowjackets (Vespulaspp.) to Heptyl Butyrate in Washington State (Hymenoptera: Vespidae)

During 2 years of trapping with artificial attractants in the Pullman, Washington, area, 6 species of Vespula were collected. Two species, V. atropilosa (Sladen) and V. pensylvanica (Saussure), were collected in large numbers. V. atropilosa was more strongly attracted to heptyl butyrate than was V. pensylvanica . Most queens and workers collected in attractant traps were V. atropilosa . Use of artificial attractant traps for controlling yellowjackets is discussed in relation to species composition. The importance of appropriate timing is emphasized and related to the seasonal buildup and decline of worker yellowjacket populations.

Synthetic Attractants Screened in the Field as Lures for Chloropidae1,

Most of 72 esters of organic acids tested as lures for eye gnats (Diptera: Chloropidae) in California were attractive to Conioscinella flavescens (Tucker) and Siphonella neglecta Becker, and 2,4-hexadienyl butyrate and propyl 2-heptynoate were particularly attractive. Octyl butyrate, though not especially attractive to C. flavescens, was the most attractive lure to S. neglecta. Hexyl crotonate was highly attractive (equal to 2,4-hexadienyl butyrate) to C. flavescens but not to S. neglecta. A positive correlation coefficient (0.618) was found for the numbers of specimens of the 2 species that responded to the various lures. Heptyl butyrate showed minor attraction to Hippelates collusor (Townsend).

Octyl Butyrate, an Effective Attractant for the Yellowjacket 1

Davis et al. (1969) determined that heptyl butyrate (HB) is a highly specific attractant for yellowjackets, especially for the common western species, Vespula pensylvanica (Saussure). This lure appears to be superior to 2,4-hexadienyl butyrate, the compound used as the standard of comparison in the several studies by Davis et al. (1967, 1968) and by McGovern et al. (1970). Therefore, for the past 3 years, we have conducted tests designed to compare heptyl butyrate with another promising lure, octyl butyrate (OB).