Why do horsefly bites hurt so much more than mosquito bites?

Horseflies have serrated mandibles that slice through your skin rather than piercing it like a mosquito does. You're essentially being cut, not punctured, which is why it hurts considerably more.

Do horseflies only bite certain people?

It depends on how detectable you are. People who run warmer, sweat more, or wear dark clothing are easier targets because horseflies track using CO2, heat, moisture, and visual cues. If you feel like you're being targeted more than others, you probably are—you're just easier to find.

Does insect repellent actually work on horseflies?

Yes, repellents containing DEET or Icaridin do offer some protection, though horseflies are notoriously persistent. Use them according to the product label for best results.

Creepy-Crawlies: A Field Report

How Horseflies Find You: The Science Behind the Bite

Only the females bite, needing blood protein for egg development, and they deploy serrated mandibles to get it. There's evidence they locate their hosts partly by detecting exhaled carbon dioxide, which is mildly unsettling.

26 August 20266 min read