Gnats are restless two-winged flies commonly found in residential and commercial establishments. 
How long do gnats live?
The simple answer is: The average lifespan of Gnats is 7-21 days. This will depend on several factors like food sources, temperature, habitat, and available moisture.
Different Gnat species – How Long Do Gnats Live?
Examples of flies that fit the above description include fungus gnats, fruit flies, black flies, phorid flies, eye gnats, and biting midges. Read on and learn more!
1. Fruit flies
A fruit fly can live for 20-25 days and takes up to three weeks to complete the life cycle. This will depend on the environment and the available food. A female fruit fly is ready to mate 2 days after becoming an adult. Once the life cycle is complete, the new adults are ready to mate again after three days to begin a new generation.
2. Fungus gnats
These flies live in watered plants and have a lifespan of 14-17 days. The larvae stage feed on plants roots. About 3 days after the female lays eggs, they hatch and the larva emerges.
3. Eye gnats
These gnats like areas with organic matter and well-drained soils. They feed on perspiration, fluids associated with the eyes, and open wounds. Eye gnats can live for 11 days to three weeks.
4. Black flies
These flies are also known as Turkey or buffalo gnats. They bite livestock, wildlife, and humans. The female lays up to 450 eggs on running water. During the larvae stage, black flies feed on small organisms in the water. Finally, the pupae stage takes 2-6 days. When the flies mature, they will feed on blood and nectar. The whole life cycle can take up to 4 weeks.
4. Biting midges
Mature midges can live for 3-4 weeks. Unlike the other species, the females lay 25-100 eggs. The larvae stage takes two weeks while the pupa stage takes 2-3 days.
5. Phorid flies
These flies are common in sewer lines and leaky pipes. The larvae feed on the organic matter found in drains. Furthermore, the female lays up to 500 eggs in a lifetime. And depending on the habitat, an adult can live for 11-22 days.
Factors that contribute to the longevity of gnats
Gnats thrive in well-watered areas like residential potted plants and plants within commercial malls. However, these flies have to go through a complete metamorphosis – egg, larva, pupae, and adult.
Adults don’t eat unless they want to lay eggs. Since the most active stage of gnats is larva, they must have enough food or they will die. It’s worth mentioning that dragonflies are their main predator. Let’s look at the factors that contribute to the longevity of gnats.
1. Moisture
Gnats live in an environment with sufficient amount of water and humidity. Such places include garbage cans, over-watered plants, under the sink, leaky pipes, around window vents, etc. You’ll rarely find them in moist areas.
2. Food source
If you’re worried why gnats are always inside your house, you should check for organic materials. These flies like to feed on mold, moss, compost, and fungus. You can spot them in your potting soil where they feed on decaying leaves and roots.
Can cold temperatures kill gnats?
A cold environment won’t kill gnats but will stop them from breeding. Below 60 degrees F, these flies experience a sharp decline in lifespan. Generally, the ideal temperature for a healthy life cycle is 65-75 degrees Fahrenheit.
Ways to get rid of gnats from your home
Before you take any remedial measures, you should identify the gnats. These are tiny flies with long legs and thin wings. The eggs are hardly visible while the larvae are legless and about ¼-inch long. Here are the best methods to get rid of gnats.
1. Kill the larvae and adults
Dispose of infested fruits/vegetables and hang sticky fly traps. Alternatively, you can use apple cider vinegar as a homemade remedy. Just put undiluted ACV in a jar and wait for the gnats to come in.
When they crawl into the jar, close it and dump after 2-3 days. Repeat the process until you cannot see any more gnats.
2. Eliminate the potential breeding ground
Since gnats love watery indoor plants, you should remove the decayed parts. For phorid flies, fix the leaky pipes and fill the crevices where water can get trapped.
Don’t forget to take the trash out as often as possible. Finally, after you water the plants don’t forget to drain the excess water from the pot.
The bottom line
Gnats have a short life of 7-21 days depending on the species. While their longevity is not very impressive, they reproduce very fast.
A female can lay up to 450 eggs which take 4-30 days to hatch. This means that for every fly that dies, there will be hundreds waiting to replace it.
