A new trap and lure for Drosophila melanogaster (Diptera: Drosophilidae).

We conducted a series of nine laboratory experiments testing the response of "vinegar flies," Drosophila melanogaster Meigen (Diptera: Drosophilidae), released in bioassay chambers to experimental traps and lures. These experiments showed that an effective trap could be constructed from a clear 225-ml screw-cap jar fitted with a hollow 8-mm-diameter cylindrical cross bridge. Flies could enter the trap from either end of the cylindrical "gate" and in turn could enter the interior chamber of the trap through a cut out portion at mid-span of the cylinder. The experiments also showed that a natural-component lure could be made using a teabag containing freeze-dried banana powder, yeast, and carrageenan gum powder as a humectant. When dipped in water for 10-15 s and then placed in the bottom of a trap, the teabag provided effective attraction for at least 7 d. Captured flies were immobilized on a sticky card placed in the trap, allowing them to be easily seen. Unlike other traps that cannot be opened and have liquid lures, the cylindrical-gate trap can be reused repeatedly if the teabag and sticky card are replaced. A final two experiments showed that the prototype operational cylindrical-gate trap with a teabag lure captured 3.3 and 2.3 times more released flies, respectively, than the next best of three commercially available traps.

Synergistic blends of monoterpenes for aggregation pheromones of the mountain pine beetle (Coleoptera: Curculionidae).

The superiority of the host monoterpene myrcene as a synergist for trans-verbenol and exo-brevicomin, aggregation pheromone components of the mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae), suggests that the ancestral host of the mountain pine beetle is a pine rich in myrcene. A field trapping experiment in British Columbia testing reconstituted bole oleoresin of whitebark pine, Pinus albicaulis Engelmann, composed of mainly myrcene (20.7%), terpinolene (6.8%), and 3-carene (61.9%) showed it to be a better pheromone synergist than reconstituted bole oleoresin of lodgepole pine, Pinus contorta variety latifolia Engelmann, which contained only 2.7, 1.0, and 6.0%, respectively, of the above-mentioned three compounds. In the same experiment myrcene alone was the best synergist. In subsequent experiments, testing myrcene, terpinolene and 3-carene alone and in all possible binary and ternary combinations, a 50:50 blend of myrcene and terpinolene released at the same rate as either compound alone generally resulted in trap catches approximately 3 times higher than with myrcene as a synergist. This result held as long as the terpinolene was free of contaminants, and the traps were in the open, well away from potential interference of semiochemicals emitted by newly attacked trees. 3-Carene seemed to be inert or slightly inhibitory. No single monoterpene tested alone or in binary or ternary combination in the absence of pheromones was attractive. There was no effect of doubling or tripling the release rate of myrcene or terpinolene. In five of nine experiments, adding terpinolene to myrcene caused a significant increase in the percentage of female mountain pine beetles captured. Among host pines, the presence of highly synergistic monoterpenes at various levels in combination with other monoterpenes that are apparently either inert or inhibitory could account for different degrees of pheromone synergism, and thus host preference. The highly synergistic effect of combining myrcene plus terpinolene with the mountain pine beetle aggregation pheromone components opens up the potential for suppression of populations through semiochemical-based mass trapping.