Black Flies: Comprehensive guide to understanding them

Black Soldier Fly


You want to know more about black flies? These pesky insects can be a nuisance and cause discomfort during outdoor activities. In this article, we will delve into what they are, their habits, the problems they pose, and effective ways to deal with them. Whether you’re an outdoor enthusiast or someone living in an area where they are common, this guide will equip you with valuable information to tackle the issue.

What Are Black Flies?

Black flies, scientifically known as Simuliidae, are small flying insects belonging to the family Simuliidae. They are commonly found in various parts of the world, particularly in regions with clean, flowing water sources like rivers and streams. These tiny flies are known for their black coloration, hence the name “black flies.”

Black Flies
Diptera-Simuliidae-Simulium-Black Fly MALE

Identification and Characteristics

These insects are quite distinctive in appearance. They are usually black or dark gray and measure around 1 to 5 millimeters in length. One of their key identifying features is their humpbacked appearance when viewed from the side. Male black flies are often smaller than females and have larger eyes, while females have shorter antennae.

Life Cycle and Habitat of Black Flies

Understanding the life cycle of black flies is crucial in dealing with their presence effectively. These insects undergo a complete metamorphosis, consisting of four stages: egg, larva, pupa, and adult. Black fly larvae are aquatic and primarily found in clean, fast-flowing water bodies. They attach themselves to rocks and other substrates, where they filter-feed on organic debris.

The Problems Black Flies Pose

Biting Habits: Black flies are notorious for their painful bites. Female black flies require blood to develop their eggs, and they obtain it by biting animals, including humans. Their bites can cause itching, redness, swelling, and, in some cases, allergic reactions.

Health Concerns: While black fly bites are generally not dangerous, excessive scratching can lead to skin infections. Additionally, in rare cases, they can transmit certain diseases.

Impact on Outdoor Activities: They can be a major annoyance during outdoor activities like camping, hiking, fishing, or gardening, making the experience less enjoyable.

Prevention and Control of Black Flies

Use Repellents: Applying insect repellents containing DEET or picaridin on exposed skin can help repel black flies and reduce the risk of bites.

Cover Up: When venturing outdoors, wear long-sleeved shirts, pants, and hats to minimize exposed skin.

Avoid Peak Activity Hours: Black flies are most active during the early morning and late afternoon. If possible, plan outdoor activities during other times of the day.

Install Window Screens: To prevent them from entering your home, ensure that windows and doors have properly fitted screens.

DIY Traps to Reduce Black Fly Population

You can make a simple DIY black fly trap to help reduce their population in your vicinity. Here’s a step-by-step guide to creating an effective trap:

home made fly trap
Home-made Fly Trap

Materials Needed:

  • 2-liter plastic bottle
  • Scissors
  • Black paper or cloth
  • Sugar
  • Water
  • Yeast


  • Cut the top third of the plastic bottle and set it aside. Turn the remaining part upside down.
  • Wrap the inverted section with black paper or cloth, leaving the neck of the bottle exposed.
  • In a separate container, mix sugar and warm water to create a sweet solution.
  • Add a small amount of yeast to the sugar solution and stir. The yeast will create carbon dioxide, which attracts them.
  • Pour the sugar and yeast mixture into the bottom part of the bottle.
  • Invert the top section of the bottle and place it inside the bottom part, creating a funnel-like structure.
  • Secure the two parts with tape.
  • Place the trap in areas where they are commonly seen.


Black flies can be a nuisance, but with the right knowledge and preventive measures, you can minimize their impact on your outdoor activities and protect yourself from their bites. By following the tips and DIY trap guide provided in this article, you can effectively deal with them and enjoy your time outdoors without any worries.

Remember, a little preparation can go a long way in ensuring a pleasant and bite-free outdoor experience. Stay informed, take action, and make the most of your time in nature!