Female black fly taking a blood meal (Photo credit: Oklahoma State University)
What are Black flies?
While black flies are small (2-5 mm length), they can have a big impact on outdoor activities. Some black flies (Diptera: Simuliidae) can impact outdoor recreation and tourism cause serious by their persistent biting and swarming behavior. The black fly life cycle has four stages: egg, larva, pupa, and adult. All are aquatic except the adults, which leave the water to search for food and mates. Larval growth is very temperature dependent, with relatively slow growth during the cold winter months and very rapid growth during warm summer water temperatures.
The aquatic stages of black flies are often abundant organisms in river ecosystems, where the larvae filter and eat fine food particles from the water column. The immature stages of black flies are aquatic and exclusively inhabit flowing waters. However, black flies are not found in lakes, ponds, swamps, and other standing water habitats. Stream flow is essential for transporting food and oxygen to the immature stages. Black flies can play in important role in local food chains where they are preyed upon by many insect predators, fish, amphibians and birds.
Tips for Avoiding Black Fly Bites
- Avoid areas of high black fly infestation.
- Avoid unnecessary outdoor activities at dawn and dusk when black flies are most active.
- Wear long pants, long-sleeve shirt and hat when outdoors.
- Wear light-colored clothing because black flies are attracted to dark colors.
- Use black fly repellents containing DEET. Consult a physician before applying DEET to young children.
- Restrict the outdoor play of your children if black flies are present.
Additional personal protection tips