Ultraviolet Light Traps: Design Affects Attraction and Capture

Traps that use ultraviolet light as an attractant for flies are widely used in urban situations. To determine the differences in trap efficacy from design and lighting, pairs of traps were compared under laboratory conditions. Comparisons were made between traps with open fronts and with traps with restricted open fronts, black light bulbs, and black light blue bulbs, and glue boards with and without z-9-tricosene pheromone. In a windowless laboratory, pairs of traps were placed approximately 90 cm above the floor and 3 m apart. Fifty mixed-sex, 3to 5-day-old house flies (Musca domestica) were released and counts of captured flies were made after 1, 4, 24 hrs. Traps with black light bulbs attracted and captured significantly more flies that those with black light blue bulbs. Black light bulbs increased the catch significantly in traps with open fronts but black light blue bulbsdid not. Glue boards with pheromone did not influence fly catch in either housing type when black light blue bulbs were used. In traps with closed fronts and black light bulbs, the fly catch was numerically higher with glue boards with pheromone. The type of trap housing plus the type of light can affect fly catch and the use of pheromones on glue boards can decrease fly catch.