Jean Pierre Lafontaine

Synergistic Blends of Monoterpenes for Aggregation Pheromones of the Mountain Pine Beetle (Coleoptera: Curculionidae)

Abstract 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 ≈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.

New metabolites of α-pinene produced by the mountain pine beetle, Dendroctonus ponderosae (Coleoptera: Scolytidae)

Abstract Emergent females of the mountain pine beetle, Dendroctonus ponderosae , contained five previously undetected volatiles: toluene, 4-methylene-6,6-dimethylbicyclohept-2-ene (verbenene), p -mentha-1,5,8-triene, o - and p -cymene. Exposure of wild or axenically reared beetles to protio- and deuterio-α-pinene or protio- and deuterio- trans -verbenol indicated that all compounds except toluene were produced from α-pinene, with trans -verbenol as a probable intermediate. The ratio between these α-pinene metabolites was insensitive to the level of α-pinene to which the beetles were exposed, suggesting a tightly regulated enzymatic and/or acid-catalyzed conversion of α-pinene. Exposure of females to either enantiomer of α-pinene or to the same amount of (±)-α-pinene indicated that female mountain pine beetles possess two enantiospecific enzyme systems for processing α-pinene. Production of p -cymene constitutes the first record in an insect of an aromatic volatile produced from a monoterpene hydrocarbon.

A New Trap and Lure for Drosophila melanogaster (Diptera: Drosophilidae)

ABSTRACT 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.

Stabilized synthetic brood pheromone delivered in a slow-release device enhances foraging and population size of honey bee, Apis mellifera, colonies

Summary The 10-component honey bee brood pheromone has considerable potential for use in honey bee management now that durable stability has been obtained by adding a food-grade antioxidant. Practical applications require, however, that a long-term slow release device be developed and tested. After discarding 19 potential materials and devices for releasing synthetic brood pheromone, we found a suitable method using a small plastic pouch with a pheromone impermeable Mylar backing and a pheromone-permeable low-density polyethylene release surface. Heat-sealed pouches, 3.8 × 3.5 cm, containing 200 μl of synthetic brood pheromone released 0.30–0.35 mg of pheromone per day in the laboratory; pheromone had to be artificially removed from the polyethylene membrane daily (equivalent to being removed by contact with worker bees) in order for the flow to be maintained. Compared to untreated control colonies, colonies exposed from late summer to early fall in southeast Texas to pheromone-laden pouches mounted in 35 mm plastic slide frames demonstrated more frequent foraging trips by worker bees, heavier pollen loads, and a higher ratio of pollen to non-pollen foragers from days 8–36 of continuous exposure. Pheromone-treated colonies also had significant growth in brood comb area and adult population level at a time when untreated control colonies were naturally declining in size.