Urban Pest News

Electric Insect Traps Get Good Bugs, Miss Mosquitoes

Homeowners often buy fancy electric insect traps to keep the mosquitoes and other biting flies at bay. The snap, crackle and pop of fried arthropods seems to confirm their effectiveness, but are these traps really doing much good? The traps in question use ultraviolet light to lure in flying insects, but many species of mosquitoes are not attracted to light. However, many other nontarget insects are attracted to lights and are inadvertently destroyed. Researchers in Delaware tracked the insects caught in the electric traps of six homeowners in suburban Newark on a weekly basis throughout the summer. All the homes were in or near lowland, wooded sites rich in aquatic breeding habitats, so they were close to lots of mosquitoes and no-see-ums.

Of the 13,789 insects counted, only 31 were biting flies (a mere 0.22%!). Nearly half of the insects collected were nonbiting aquatic insects such as caddisflies and midges. More importantly, 1,868 predators and parasites (13.5%) were destroyed within 27 families of predators and nine families of parasitoids. Ground beetles, rove beetles, and braconid wasps were particularly common vicitms.

By their calculations, 71 to 350 billion nontarget insects are needlessly destroyed in the U.S. each year by misinformed homeowners, without any real control of nuisance insects. The heavy toll on nontarget insects, including beneficial insects, suggests that electrified traps may actually be counterproductive for insect control.


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