The lesser mealworm, Alphitobius diaperinus Panzer 1797 (Coleoptera: Tenebrionidae), is a cosmopolitan insect pest affecting poultry production. Due to its cryptic behavior, insecticide control is usually not efficient. Thus, sustainable and effective methods would have an enormous and positive impact in poultry production. The aim of this study was to confirm the identity of the male-produced aggregation pheromone for a Brazilian population of A. diaperinus and to evaluate its biological activity in behavioral assays. Six male-specific compounds were identified: (R)-limonene (1), (E)-ocimene (2), 2-nonanone (3), (S)-linalool (4), (R)-daucene (5), all described before in an American population, and a sixth component, (E,E)-α-farnesene (6), which is apparently exclusive to a Brazilian population. Y-Tube bioassays confirmed the presence of a male-produced aggregation pheromone and showed that all components need to be present in a similar ratio and concentration as emitted by male A. diaperinus to produce a positive chemotactic response.

This study aimed to identify and quantify the compounds present in the abdominal glands of Alphitobius diaperinus Panzer, 1797 (Coleoptera: Tenebrionidae) and to evaluate the influence of these compounds on its behavior. The extraction of volatiles present in the abdominal glands was made by dissection (10 individuals per sex) and by air entrainment (200 insects per sex), and they were analyzed by gas chromatography-flame ionization detector, gas chromatograph-mass spectrometer, and gas chromatograph-electroantennography detector (GC-EAD). The influence of these volatiles on the behavior of conspecifics was evaluated in a four-arm olfactometer. Twenty-three compounds were identified from male and female abdominal gland extracts, of which six were quinones: the 2-methyl-1,4-benzoquinone and the 2-ethyl-1,4-benzoquinone were the major components, and 1,4 benzoquinone and three hydroquinones were registered for the first time for this species. The GC-EAD analysis using the crude extracts from abdominal glands showed that male and female antennae responded to the three major benzoquinones. For the olfactometer bioassays, both genders were repelled either by the abdominal gland extracts or by synthetic solutions containing the three benzoquinones. The results suggest that the 1,4-benzoquinones play a role as a repellent to A. diaperinus.

Bioassays using an olfactometer showed that Oebalus poecilus males produce the sexual pheromone, and the chemical analysis demonstrated that this compound is zingiberenol. Two groups of isomers, each containing four diastereoisomers, (1RS,4RS,1'S)- and (1RS,4RS,1'R)-zingiberenol, were prepared. These diastereoisomers were not separated on a chiral GC column. Therefore, to determine the absolute configuration of the carbon 1, 4, and 1' of zingiberenol produced by males, the following strategies were conducted. The extract containing males volatiles was submitted to dehydration microchemistry to produce zingiberene, in which the isomers are separated by chiral GC analysis, and by comparison with the natural zingiberene from ginger oil, the absolute stereochemistry of the carbons 4 and 1' was determined to be R and S, respectively, and the carbon 1 was determined as R from the (13)C NMR spectra of quercivorol. Finally, the bioassays showed that O. poecilus females responded to racemic mixture and to (1RS,4RS,1'S)-zingiberenol.

An attract-and-kill approach based on pellets from soybean or palm stearin fats blended with the entomopathogenic fungus Beauveria bassiana (Bals.) Vuill. sensu lato and the aggregation pheromone sordidin (Cosmolure â ) was tested against the banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae). The viability of B. bassiana conidia, blended with hydrogenated oil and exposed for up to 150 min to heating at 50°C, was not affected and the aggregation pheromone did not undergo any decomposition. Conidial viability in pellets decreased by 50% after an average of 15.1 and 9.1 days at 25 and 40°C, respectively, when packaged in polypropylene bags. Active packaging (hermetic bag + O 2 /moisture-absorbing sachet) increased the shelf lives almost 10 and 6 times at 25 and 40°C, respectively. In olfactometer bioassays, fat pellets amended with pheromone (sordidin, 1% wt/vol) were highly attractive to C. sordidus adults for up to 15 days, after which the pheromone release rate had decreased by about 90% and pellets were no longer attractive. Pellets with pheromone and conidia were as attractive to C. sordidus as banana rhizomes, and considerably more attractive than pieces of pseudostem. In no-choice experiments conducted in boxes, survival of insects exposed to fungus-impregnated pellets was affected by fat type (soybean fat vs. palm stearin) and bioassay temperature (25 vs. 30°C), with results favoring soybean fat pellets at the higher temperature (96.9% of mortality after 18 days and ST 50 of 7.7 days). However, mortality levels were low (21.7% for soybean fat pellets) or very low (1-5% for palm stearin pellets) in choice experiments carried out at 25°C when fungus-impregnated pellets were applied before or after exposure of pseudostem residues to insects, respectively. The potential of this delivery system to manage C. sordidus populations and other insect pests (including those with cryptic habits) is discussed.