And the black flies, the little black flies Always the black fly no matter where you go I'll die with the black fly a-pickin' on my bones In North Ontario, io, in North Ontario. -Chorus from "The Blackfly Song" by Wade Hemsworth blackfly song.

The first bothersome bug to hatch in early spring is the blackfly. Unlike the mosquito which lays its eggs on the smooth surface of a pond, marsh or stagnant puddle, the blackfly lays its eggs in a running brook or river.

After hatching, the baby blackfly (larvae) drifts downstream, holding on to a strand of silk like a spider to its web on a windy day. Once it finds a place to feed, the blackfly then spins a disk-shaped pad of silk on a rock or log; holds itself in place with its hooked rear end; and begins to snack on tiny bacteria, protozoa, diatoms, and even the odd brother and sister blackfly that drifts by.

When the blackfly grows into an adult, the bug pulls itself out of its skin, stretches out its wings, rises quickly to the surface in a tiny gas bubble, and "pops" itself free. The males fly off to munch on plant nectar. The females, however, search out a victim for a meal of protein-rich blood, which it needs to produce its eggs.

All blood feeding insects find their prey by body temperature, activated by lactic acid produced by muscle movement and the carbon dioxide emitted when you exhale. They absolutely love warm sweaty skin on a cool day. Warm days, however, seem to confuse them. All species also dislike pouring rain, cold days when temperatures reach below 30 F (10 C), and blowing winds; the blackfly in particular is not a strong flyer and can only reach a top speed of half-a-mile (one kilometer) per hour.

Dark colors attract much more than shiny bright colors. Wearing blue jeans is just asking for it; lime green neither attracts them nor keeps them at bay; and hot pink works great.

Come Exploring with us
Off the beaten path locations, tips and tricks, interviews with interpid explorers and more.
Plan your next great adventure
Off the beaten path locations, tips and tricks, interviews with interpid explorers and more.
Get Updates from Explore
  • Top Secret Outdoor Adventure Locations
  • How-to Videos & Articles
  • Interviews with Known Explorers