A bug zapper is an electronic device that uses ultraviolet (UV) light to attract flying insects and eliminate them with a high-voltage electrical grid. While many people purchase these devices hoping to control common household nuisances like house flies, the direct answer is generally no. Bug zappers are highly effective for certain nocturnal insects, but the sensory biology of common flies means they rarely prioritize the UV light source, leading to user frustration.
The Specific Attraction Mechanism of Bug Zappers
Bug zappers exploit positive phototaxis, the instinct of many insects to move toward a light source. These devices use a fluorescent bulb emitting UV-A light, typically between 350 and 370 nanometers, which is highly visible to many insect species. This spectrum is particularly attractive to nocturnal insects that rely on visual cues for navigation and foraging. Examples include moths, certain beetles, and specific species of mosquitoes. When these insects are lured toward the light, they pass through the electrified grid.
The Sensory Biology of Common Flies
Common nuisance flies, such as the house fly (Musca domestica), rely heavily on chemoreception, or the sense of smell, rather than light. Their primary attractants are volatile organic compounds released by decaying matter, animal waste, and manure. Flies use specialized olfactory receptors to prioritize the search for food and oviposition sites over visual light sources. Although flies can see UV light, the UV-A light of a bug zapper does not function as a primary navigational cue. Field studies confirm that only a small fraction of insects killed by these devices are house flies, as they typically fly past the zapper toward a food source or breeding site.
Alternative Strategies for Fly Management
Since light-based devices are ineffective for house fly control, successful management must target the fly’s sensory biology and life cycle.
Sanitation and Exclusion
The most effective strategy is sanitation and source reduction. This involves removing organic materials that attract flies for feeding and breeding, such as uncovered garbage, pet waste, and standing water. Eliminating these attractants prevents the development of the next generation of flies. Exclusion is also a highly effective method for physically preventing flies from entering structures. This is achieved by ensuring all doors and windows have tight-fitting screens free of holes.
Chemical Trapping
When trapping is necessary, methods utilizing chemoreception are the most successful. Bait traps use chemical attractants that mimic the odors of decaying matter or pheromones, like (Z)-9-tricosene, to lure flies away from living spaces. Sticky traps or glue boards are also useful, especially when placed near windows or known fly activity areas, as they physically capture adult flies. These methods align with the fly’s natural behavior, offering a practical solution for managing the population.