Fly traps control flying pest populations by disrupting the insect’s natural search for food, mates, or breeding sites. These devices employ sophisticated science, ranging from specialized polymer chemistry to the exploitation of insect phototaxis and chemoreception, to lure and immobilize their targets. Understanding the specific mechanisms of these technologies—whether adhesive, containment, or electrocution—allows for the selection and deployment of the most effective pest management strategy.
Adhesion Traps and Sticky Surfaces
The mechanism behind sticky fly traps, such as fly paper and glue boards, relies on a pressure-sensitive adhesive (PSA). This adhesive material is a viscoelastic polymer that maintains a permanent tack at room temperature. The two main components of the glue are an elastomer, which provides the strength to hold the insect, and a tackifier, which gives the initial “grabbing power” upon contact.
The tackifiers are often low-viscosity resins that allow the material to quickly bond to the fly’s exoskeleton or wings. This combination creates a physical bond strong enough to immobilize the insect, which is unable to exert the necessary force to overcome the adhesion. The fly’s small body mass means that any attempt to escape results in a larger portion of its body or wings becoming further entangled in the viscous glue. These traps rely on the fly’s random flight path, though some manufacturers incorporate mild attractants, such as visual patterns or trace amounts of chemicals, directly into the adhesive or the backing material to increase the odds of contact.
Lure and Containment Traps
Lure and containment traps utilize a dual-component system: a potent attractant draws the fly in, and a physical mechanism prevents its escape. The attractants are formulated to mimic odors associated with the flies’ preferred food sources or breeding grounds, which often involve decay. Chemicals like indole, a naturally occurring compound in fecal matter, or putrified proteins are common ingredients designed to appeal to the fly’s highly tuned chemoreceptors.
Once the insect is drawn to the source, the containment mechanism, frequently a one-way funnel, forces the fly to enter a collection chamber. The funnel is designed with a narrow opening at the bottom, which is easy for the fly to enter but difficult to locate for exit. After passing into the larger collection vessel, the fly instinctively flies upward toward the light or the container walls, away from the narrow entry point. This disorientation prevents the fly from finding the small exit, trapping it inside the chamber where it often drowns in a liquid solution or succumbs to dehydration.
Electric Zappers and Light Attraction
Electric fly zappers, more formally known as electrical discharge insect control systems, combine insect phototaxis—the instinctual movement toward a light source—with a lethal high-voltage grid. These devices typically use a fluorescent or LED lamp that emits light in the ultraviolet (UV) A spectrum, often peaking around the 365 nanometer wavelength. This specific wavelength is highly attractive to many flying insects, including house flies and mosquitoes, guiding them directly toward the trap.
The light source is surrounded by a pair of interleaved, bare wire grids separated by a small gap, typically about 2 millimeters. A power supply generates a high-voltage electrical charge, often 2 kilovolts or more, across these two grids. When a fly attempts to land, it completes the electrical circuit by simultaneously touching two wires of opposite polarity, resulting in electrocution. The protective outer cage prevents accidental contact with the high-voltage grid by humans or larger animals. Indoor units usually feature a collection tray, while outdoor models are designed for greater area coverage and durability.
Maximizing Trap Effectiveness Through Placement
Effective fly control requires strategic placement of traps, leveraging knowledge of fly behavior and environmental factors.
Lure and Containment Traps
Lure traps emit strong odors and should be placed near fly breeding sites, such as compost piles or garbage bins. They must be positioned far away from areas where people gather. Placing a lure trap too close to a patio, for example, will draw flies toward the living space instead of away from it. Wind aids in scent dispersal for these traps.
Electric Zappers and UV Traps
Electric fly zappers and UV light traps should be mounted between 3 and 5 feet high for maximum effectiveness, as this height targets the typical flight path of many insect species. It is important to place UV traps away from competing light sources, especially direct sunlight, which diminishes the attractiveness of the UV emission. Strong air currents can disrupt the flight paths of incoming insects.
Sticky Traps
Sticky traps benefit from placement near windows or entry points, as flies naturally congregate at these transition zones. They should be kept out of direct sunlight to prevent the adhesive from drying out or dripping.