Norman Avelino

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.