Semiochemicals produced by fungal bark beetle symbiont Endoconidiophora rufipennis and the discovery of an anti-attractant for Ips typographus.

Bark beetles vector symbiotic fungal species into their host trees during mass attacks. The symbiotic relationship with blue stain fungi of the Ascomycetes, including genera of Endoconidiophora (syn. = Ceratocystis), promotes successful establishment whereby the microbes help to overcome the host trees' defence and degrade toxic resins.

Linoleic Acid Promotes Emission of Bark Beetle Semiochemicals by Fungal Symbionts.

Tree-killing bark beetles in conifer forests vector symbiotic fungi that are thought to help the beetles kill trees. Fungal symbionts emit diverse volatile blends that include bark beetle semiochemicals involved in mating and host localization. In this study, all 12 tested fungal isolates emitted beetle semiochemicals when growing in medium amended with linoleic acid.

Anti-attractant activity of (+)-trans-4-thujanol for Eurasian spruce bark beetle Ips typographus: Novel potency for females.

Background: Eurasian spruce bark beetles (Ips typographus) use both attractant and anti-attractant semiochemicals to find suitable mature host trees. Trans-4-thujanol is abundant in young, unsuitable spruce trees. Electrophysiological studies have demonstrated its high activity levels, but field data are lacking.

Climate change risk to pheromone application in pest management.

Since of the first sex pheromone and the adoption of pheromone in pest management, the global pheromone market size has grown to reach USD 2.4 billion per year in 2019. This has enabled the development of environmentally friendly approaches that significantly reduce the application of pesticides.

Feeding Volatiles of Larval Sparganothis pilleriana (Lepidoptera: Tortricidae) Attract Heterospecific Adults of the European Grapevine Moth.

Plants release volatiles in response to caterpillar feeding. These herbivore-induced plant volatiles (HIPVs) attract natural enemies of the herbivores and repel or attract conspecific adult herbivores in a tri-trophic interaction which has been considered to be an indirect plant defense against herbivores. Recently, we demonstrated the attraction of male and female European grapevine moth, Lobesia botrana (Denis & Schiffermüller) (Lepidoptera: Tortricidae) to a blend of phenylacetonitrile and acetic acid, two compounds identified as HIPVs in heterospecific apple-leafroller interactions.

Effects of Methyl Salicylate on Host Plant Acceptance and Feeding by the Aphid .

Methyl salicylate (MeSA) is a volatile shown to act as an inducer of plant defense against pathogens and certain herbivores, particularly aphids. It has been shown to have potential for aphid pest management, but knowledge on its mode of action is lacking, particularly induced plant-mediated effects. This study investigated the effects of exposing plants to MeSA on the host searching, host acceptance and feeding behavior of the bird cherry-oat aphid .

Chemoenzymatic Dynamic Kinetic Asymmetric Transformations of β-Hydroxyketones.

Herein we report on the development and application of chemoenzymatic Dynamic Kinetic Asymmetric Transformation (DYKAT) of α-substituted β-hydroxyketones (β-HKs), using Candida antartica lipase B (CALB) as transesterification catalyst and a ruthenium complex as epimerization catalyst. An operationally simple protocol allows for an efficient preparation of highly enantiomerically enriched α-substituted β-oxoacetates. The products were obtained in yields up to 95 % with good diastereomeric ratios.

Diffusible signal factor signaling controls bioleaching activity and niche protection in the acidophilic, mineral-oxidizing leptospirilli.

Bioleaching of metal sulfide ores involves acidophilic microbes that catalyze the chemical dissolution of the metal sulfide bond that is enhanced by attached and planktonic cell mediated oxidation of iron(II)-ions and inorganic sulfur compounds. Leptospirillum spp. often predominate in sulfide mineral-containing environments, including bioheaps for copper recovery from chalcopyrite, as they are effective primary mineral colonizers and oxidize iron(II)-ions efficiently.

Functional Evolution of a Bark Beetle Odorant Receptor Clade Detecting Monoterpenoids of Different Ecological Origins.

Insects detect odors using an array of odorant receptors (ORs), which may expand through gene duplication. How and which new functions may evolve among related ORs within a species remain poorly investigated. We addressed this question by functionally characterizing ORs from the Eurasian spruce bark beetle Ips typographus, in which physiological and behavioral responses to pheromones, volatiles from host and nonhost trees, and fungal symbionts are well described.

Asymmetric Synthesis of Oxygenated Monoterpenoids of Importance for Bark Beetle Ecology.

Herein we report the asymmetric syntheses of a number of oxygenated terpenoids that are of importance in the chemical ecology of bark beetles. These are pinocamphones, isopinocamphones, pinocarvones, and 4-thujanols (= sabinene hydrates). The camphones were synthesized from isopinocampheol, the pinocarvones from β-pinene, and the thujanols from sabinene.

Odorant receptor phylogeny confirms conserved channels for sex pheromone and host plant signals in tortricid moths.

The search for mates and food is mediated by volatile chemicals. Insects sense food odorants and sex pheromones through odorant receptors (ORs) and pheromone receptors (PRs), which are expressed in olfactory sensory neurons. Molecular phylogenetics of ORs, informed by behavioral and functional data, generates sound hypotheses for the identification of semiochemicals driving olfactory behavior.

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.

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.

Styrene, (+)-trans-(1R,4S,5S)-4-Thujanol and Oxygenated Monoterpenes Related to Host Stress Elicit Strong Electrophysiological Responses in the Bark Beetle Ips typographus.

Bark beetles kill apparently vigorous conifers during epidemics by means of pheromone-mediated aggregation. During non-endemic conditions the beetles are limited to use trees with poor defense, like wind-thrown. To find olfactory cues that help beetles to distinguish between trees with strong or weak defense, we collected volatiles from the bark surface of healthy felled or standing Picea abies trees.

Convergent evolution of semiochemicals across Kingdoms: bark beetles and their fungal symbionts.

Convergent evolution of semiochemical use in organisms from different Kingdoms is a rarely described phenomenon. Tree-killing bark beetles vector numerous symbiotic blue-stain fungi that help the beetles colonize healthy trees. Here we show for the first time that some of these fungi are able to biosynthesize bicyclic ketals that are pheromones and other semiochemicals of bark beetles.

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.

Reverse chemical ecology-based approach leading to the accidental discovery of repellents for Rhodnius prolixus, a vector of Chagas diseases refractory to DEET.

Rhodnius prolixus is one of the most important vectors of Chagas disease in Central and South America for which repellents and attractants are sorely needed. Repellents like DEET, picaridin, and IR3535 are widely used as the first line of defense against mosquitoes and other vectors, but they are ineffective against R. prolixus.

Comparison of Phenylacetates with Benzoates and Phenylpropanoates as Antifeedants for the Pine Weevil, Hylobius abietis.

This study concludes an extensive investigation of antifeedants for the pine weevil, Hylobius abietis (Coleoptera: Curculionidae), an economically important pest of planted conifer seedlings. Building on the previously reported antifeedant effects of benzoates and phenylpropanoids (aromatic compounds with one- or three-carbon-atom substituents on the benzene ring), we here report the antifeedant effects of compounds with two-carbon-atom side chains (i.e.

Attraction of Rhodnius prolixus males to a synthetic female-pheromone blend.

Background: The triatomine bug Rhodnius prolixus Stål, 1859 (Heteroptera: Reduviidae) is the primary vector of Chagas disease in Colombia and Venezuela. An important step in controlling Chagas disease is monitoring the growth and spread of bug populations to inform effective management. Such monitoring could be carried out using pheromone traps.

Dose reduction and alternatives to the phenol pheromone in monitoring and management of the grass grub Costelytra zealandica.

Background: Endemic New Zealand grass grub Costelytra zealandica is a pest of introduced pasture that uses phenol as a sex pheromone. The pheromone could be used to monitor and manage grass grub populations, but the irritating properties and toxicity of phenol for human handlers, as well as the possible ecotoxicological effects, pose obstacles to the deployment of the pheromone. This study aimed to limit the use of phenol by dose-response studies and investigation into alternative attractants and synergists to phenol.

Morganella morganii bacteria produces phenol as the sex pheromone of the New Zealand grass grub from tyrosine in the colleterial gland.

Costelytra zealandica (Coleoptera: Scarabeidae) is a univoltine endemic species that has colonised and become a major pest of introduced clover and ryegrass pastures that form about half of the land area of New Zealand. Female beetles were previously shown to use phenol as their sex pheromone produced by symbiotic bacteria in the accessory or colleterial gland. In this study, production of phenol was confirmed from the female beetles, while bacteria were isolated from the gland and tested for attractiveness towards grass grub males in traps in the field.

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.

Combining odours isolated from phylogenetically diverse sources yields a better lure for yellow jackets.

Background: Invasive wasps have major impacts on bird populations and other biodiversity in New Zealand beech forests, and new solutions are needed for their management. Baits were combined from four phylogenetically diverse sources (protein and carbohydrate) to improve attraction to a level that could be used as the basis for more powerful attract-and-kill systems. Many compounds from honey, scale insect honeydew, fermenting brown sugar and green-lipped mussels were highly attractive and, when combined, outcompeted known attractants.

Attractiveness of fermentation and related products to spotted wing Drosophila (Diptera: drosophilidae).

Laboratory screening bioassays and field trapping experiments of spotted wing drosophila flies, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), were conducted to determine the attractiveness of 17 compounds as well as to compare attractant efficiency during peak fruit ripeness and postharvest captures late in the season. Compounds structurally related to each of the fermentation products acetic acid, ethanol, ethyl acetate, and 2-phenethyl alcohol were screened for attractiveness compared with a soap water control in greenhouse cage bioassays. The compounds determined to be attractive in the greenhouse bioassay (methanol, ethanol, propanol, formic acid, acetic acid, ethyl acetate, propyl acetate, phenethyl acetate, phenethyl propionate, and phenethyl butyrate) were individually tested in the field added to apple cider vinegar (ACV).