Dead Bugs on Your Windshield? The Science Behind Bug Splatter

Ever wonder how that big yellow splat in the middle of your windshield started its life? So did Mark Hostetler, an urban wildlife ecologist at the University of Florida. This self-described “splatologist” drove his Honda Accord around the country for an entire summer to research birds and cities and thought it was a good opportunity to also explore the bugs that hit our windshields and why. Then he wrote That Gunk on Your Car: A Unique Guide to Insects of North America (Ten Speed Press), a book which chronicles the most common bug splats nationwide. That big splat? Probably a moth.

“The whole idea was to write something so people would be interested in insects,” says Hostetler, who wrote his master’s thesis on the cockroach. “People forget the role they play. Every fruit and nut you eat has been pollinated by an insect.”

Some frequent splatterers, like the lovebug (Plecia nearctica), so-called because they fly together, ahem, while in the throes of passion, are daytime fliers. Sunlight hitting car exhaust mimics the scent of decaying organic matter—normally the perfect location for laying eggs—but in the case of cars, it’s a fatal fake-out.

When do bug splats occur?

Overall, most bug splats occur at night. Like the moth, as well as some flies, mosquitoes, and beetles, they’re attracted to light—and mistake the headlights for moonlight. Flying a mere 4 to 5 feet off the ground, windshields are the perfect height to catch these misguided insects, which unknowingly meet their demise.

What do the colors mean?

To the untrained eye, a splat is a splat, but there are a few clues. A splat with a bit of red in it is most likely a female, because they’re the biters. The red? Somebody’s blood, which the female needs for her eggs to develop. A yellow or cream-colored splat that’s strung out is likely a moth or a butterfly.

How do you clean them off?

Cleaning off the remains isn’t always easy. Some bug remains combined with bacteria that eat it the gunk are acidic and can damage a car’s paint, but a good wax job can help remove the gunk. The sooner the splats are removed, the better. Soap and water will work, but Hostetler’s favorite bug-off? “I hate to say it, but cola* is good.”

*While it does remove bug guts from your windshield, avoid any painted areas of the vehicle, so the cola’s acid doesn’t eat away at the finish and the paint itself.