Insects and Windshield Impact

By Christine Sellers

It’s a common problem. You’re driving somewhere, when splat, a bug flies right into your windshield and sprays its guts everywhere. How does this happen? And why?

We caught up with Academy Entomology Collection Manager Jason Weintraub who gave us the low down.

Jason Weintraub holds an insect friend.
Jason Weintraub holds an insect friend.

Tell us why so many insects hit our windshields. Are there any factors that influence this?

Yes. The amount of insects hitting a windshield at a given time depends on where someone is driving, what time of year it is, what type of vehicle they’re driving, and how fast they’re going. Insect behavior and location of different habitat types near roads are also factors.

Is this more of a problem in an urban area or a rural area? If so, why?

It really goes back to the type of vehicle, and the speed at which it’s traveling as well as the time of year. These factors, combined with the precise route the vehicle travels relative to habitats of various types of flying insects play a more important role than “urban,” ”suburban,” or “rural.”

This photo of a horse fly splat indicates the presence of animal blood.
This photo of a horse fly splat indicates the presence of animal blood.

Why does the vehicle make such an impact?

Insects are less likely to hit the windshield when a vehicle is traveling slower. This is due to the “physics of airflow” around the vehicle. They either wind up getting trapped in the airflow or flying above the car.

In addition, the insects’ flight patterns and behavior also influence how many of them will hit the windshield. And where the vehicle is traveling in relation to insect habitats. The type of vehicle and shape of the front of the vehicle also influence the percentage of flying insects that impact the front grill or windshield rather than get trapped in airflow over the top of the vehicle.

Horse flies are just one of the many insects that can collide with your car windshield.
Horse flies are just one of the many insects that can collide with your car windshield.

And what about time of year?

The amount of insects likely to hit your windshield decreases in the winter, but increases in the summer, early fall, and late spring. This is because most insects “hibernate,” or overwinter in a dormant pupal stage during the winter.

Besides this, the time of day can influence the probability of insects hitting your windshield. Insects that are nocturnal use moonlight to direct their flight path. If you’re driving with your headlights on, they’ll be more likely to fly into the path of your car. In the same way that insects are attracted to porch lights, they are also attracted to car headlights.

 

Let’s say an insect does splatter on your windshield. Can you determine what type of insect it is by its innards?

Yes. Mark Hostetler, an entomologist at the University of Florida actually wrote a book about this, called, That Gunk on Your Car. It’s based on research he conducted.

 

Illustrations courtesy of: That Gunk on Your Car by Mark Hostetler/Rebekah McClean

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