Bug zappers seem logical: bugs fly toward light, so why not hang up a light that kills the bugs and enjoy a bug-free evening? Unfortunately, the bugs you’re targeting aren’t actually on board with your plan. The ones that get zapped are almost all harmless; the ones that want to suck your blood are going to do so anyway.
I was reminded of this by a tweet from Alex Wild, who is the curator of entomology at the University of Texas at Austin:
As summer approaches, please do not buy or use Bug Zappers.
Zappers do not kill significant amounts of biting flies (mosquitoes aren’t attracted to light), but they do kill beneficial and neutral insects, including ones used by birds and bats for food.
Just pointless killing.
— Dr. Alex Wild (@Myrmecos) April 6, 2021
Mosquitoes and other biting insects find us by scent and by the carbon dioxide that we breathe out. They don’t care very much about light. Meanwhile, horseflies and other insects that bite during the day aren’t going to see a light hanging off your porch as anything special.
Instead, Wild says, bug zappers mostly capture night-flying insects that use moonlight to navigate. These include moths, midges, beetles, and the types of wasps that prey on other insects. In other words, they kill beneficial insects. Many of these are pollinators or help with insect control in your garden, or they provide food for bats and birds.
Many of those insects may look like mosquitoes, but it turns out there are a lot of little harmless insects that look like mosquitoes. Entomologists once ran an experiment by setting up a bug zapper in a Delaware suburb and counting up the bodies over the course of the summer. Of 13,789 little bug corpses, only 31 were of female (biting) mosquitoes or biting gnats.
“That satisfying ‘pop’ of an insect [in the zapper] is hardly ever going to be a biting insect that bothers people,” Wild says. “It’s much more likely to have been some random fungus gnat just on its way from one mushroom to the next.”
What to do instead
If you’re concerned about mosquitoes, the best ways to keep them away in the short term are some of the simplest: setting up a fan (mosquitoes can’t fly in a breeze) and using an effective repellent spray on your skin.
People hate mosquitoes, and so companies make a lot of anti-mosquito things: candles, wristbands, chemical and herbal sprays, even electronic devices. But if you want to keep mosquitoes off your bare skin, you really just need two things: bug spray and a fan.Read more
Wearing long sleeves and long pants can help; so can going indoors if the bugs really get to be too much. Wild also notes that carbon dioxide traps like these can work, but since they have to attract mosquitoes to kill them, you may just end up inviting more bugs to the party. If you use them, make sure to place them far away from your house.
But nothing compares to stopping the mosquitoes from breeding at all. “If you’re serious about mosquitoes, clean your gutters, clean your bird baths regularly, and don’t let water sit in containers,” Wild says. If you have a pond, add mosquitofish, which eat mosquito larvae.