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The plum curculio Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae) is a major pest of pome and stone fruit, but will also attack other fruits. Males produce the aggregation pheromone grandisoic acid; emitting only the (+)-enantiomer which is attractive to both sexes of the univoltine and multivoltine strains, while the synthetic racemic mixture contains optical isomers with equal amounts of (+)- and (−)-enantiomers. Synergy between odours can increase trap captures and improve monitoring techniques, therefore tests were performed in a dual-choice olfactometer with odours attractive to plum curculios according to literature to determine 1) under what physiological conditions (mating status, age, starvation period) these odours are attractive or repulsive, 2) if the (+)-enantiomer or the odour of live males synergizes with host plant volatiles, and 3) if there is a difference in response between plum curculio strains. Females were exposed to: benzaldehyde; trans-2-hexenal; apples; extracts of: plums, apples, blueberries; grandisoic acid; and live males. Plum essence was found to be the most attractive host-plant odour for both immature and mature virgin females, and immature whole apples were attractive to starved females, while trans-2-hexenal, McIntosh apple essence, benzaldehyde along with the combination of benzaldehyde and plume essence was found to be repulsive. Starvation, age, and mated status all influence response to odours. No synergistic or additive affects were observed between any of the odour combinations tested, including the combination of both the natural and synthetic pheromone and plum essence or apples. [ABSTRACT FROM AUTHOR]

Chemical substances excreted from individuals are regarded as chemo-sensory signals that induce aggregation in Collembola. However, chemical or physiological evidence is required to identify the chemical composition of signals responsible for aggregation behavior. Present study applied solvent extraction and gas chromatograph-mass spectrometer-computer technology to separate and identify the chemical compounds in cuticle extracts from the model Collembola species, Folsomia candida. The occurrence of aggregation behavior was confirmed by conspecific attractiveness using a trap bioassay. Eight chemical compounds were obtained from F. candida's cuticle solvent. The trap assay detected fatty acid combinations from the body extracts of F. candida that induced attractiveness behavior among conspecific individuals and small molecules with higher concentration induced repellent. However, single sensillum recordings of two thin-wall chemical receptors at the second segment of the distal position of the antenna did not receive any positive responses to fatty acids, either single or in combination. The way F. candida used fatty acid combinations as chemical signal for conspecific aggregating was discussed. [ABSTRACT FROM AUTHOR]

The lesser mealworm beetle (LMW), Alphitobius diaperinus (Panzer), is a serious pest in poultry production facilities world-wide and is difficult to control by conventional means. Pheromone-based tools might become useful in the management of this species. Male LMW emit a five-component pheromone consisting of, ( R)-(+)-limonene, ( E)-β-ocimene, ( S)-(+)-linalool, ( R)-(+)-daucene, and 2-nonanone. Three of the five components (( E)-β-ocimene, ( R)-(+)-daucene, and 2-nonanone) had shown behavioral activity, but it was not yet known if different blend combinations of the five components could modulate the beetle behavioral response. We developed a dual choice wind tunnel walking bioassay to test the attraction of male and female adult beetles to individual pheromone components and their blends. We tested hundreds of male and female adults at the same time to create a high throughput bioassay, which confirmed that only three compounds, ( E)-β-ocimene, ( R)-(+)-daucene, and 2-nonanone, are necessary to exhibit the pheromone behavioral activity of the naturally emitted blend. Randomly roaming males and females responded by forming lines while walking up to a source of attractive odor. [ABSTRACT FROM AUTHOR]