How Long do Gnats Live: Factors That Affect the Longevity of Gnats

In general, the gnat is a mosquito-like fly, but much smaller. They also cause much inconvenience to humans as mosquitoes. Although gnats do not bite and make an annoying buzzing sound their rapid development does not bring anything good for us. To eliminate gnats from your home, you need to know about their characteristics, especially their fertility and longevity. In this article, we will discuss how long do gnats live, from which come up with a solution to get rid of them.

Factors that affect the longevity of gnats

Each species of fly live in different habitats. With distinctive characteristics, every gnat has different preferences for choosing food sources, appropriate temperatures, humidity, accessibility, and safety. As a result, depending on the different natural habitats that affect the longevity of gnats.


It can be said that climate and temperature play the most important role in the development of flies in particular and insects in general. More specifically, it greatly influences the early stages of their lifecycle. A housefly hatches eggs for 8 hours at 37 degrees Celsius. But if they live in a cold environment of about 4 degrees Celsius, the hatching time can last up to 2 days. Similarly, the transition to pupae stage also occurs faster in several days under high temperatures. However, it may last up to one month under low temperatures.


Image source: Arizona Daily Star


The best example of humidity is the living environment of fungus gnats. This species will live long, reproduce and thrive in high humidity and sufficient water environments.

The reason is that gnats like to eat fungus, while fungus only lives in places with high humidity.

So you will often find them living in plants in the house or the office. These are the areas where people are often over-watering plants, creating conditions for fungus gnats to thrive in.

In contrast, they rarely occur in areas where the soil is less watered or only slightly moist. Thus, it’s essential to keep your room balance humidity.

Food Source

When living in an environment that provides moderate food, an adult gnat can live between 1 month and two months. During the larval stage, if they get a large source of food, their lifespan and fertility will be significantly increased. The opposite would happen if they only received an average food source at this critical stage.

Four stages of lifecycle

Four stages of lifecycle

Image source: 420 Genetics

Gnats transform from an immature form to an adult form in 4 distinct stages. They are eggs, larvae, pupae, and adults.

The first stage in the life of gnats is the egg form. Depending on the species, after a certain period, the eggs will hatch into larvae. In the larval form, they usually eat organic food that is mainly leaf and mushroom. In this stage, the larval will build up enough nutrients to be ready to be transformed into pupae.

It can be said that pupa stage is the most important for them flies. At this time, they developed supporting organs for flight capabilities such as wings and limbs. At the end of the third stage, the fly comes out of the case and becomes an adult.

How long do gnats live

In general, there is no specific answer to the gnat’s lifespan because it depends on the specific species. However, it can be concluded that these flies do not live very long. They are only impressed by the amazing reproductive ability that always maintains a large population.

For fruit fly, it takes 1 to 2 months to complete the life cycle. In which the adult stage lasts only 2 to 4 weeks.

Phorid fly can live from 1 week to 1 month, and the adult ones live from 1 to 2 weeks.

Fungus gnats take from 1 month to 2 months to complete the life cycle. Their adult time lasts only about two weeks.

Drain fly completes the life cycle within 1 to 3 weeks while the adult can live for about two weeks.

Buffalo gnat, or so-called black fly, can live from 1 month to 7 months. However, its adult duration lasts only 1 to 2 weeks.

Sand gnat ages from 1 to 3 months with an adult period lasting from 4 days to 2 weeks.

Eye gnat can live from 1 to 2 months with an adult period of 1 to 3 weeks.

How to get rid of gnats in your home

As mentioned above, gnats are not good at living long but are masters in reproduction. A good example of this is the female fruit fly which is capable of delivering up to 600 eggs in the adult stage. Then how do we deal with the troubles of this great army?

Well, first of all, you have to identify where they are most likely to appear. As mentioned above, ornamental potted plants in the house or office are the heaven of these flies. Also, fruits such as potatoes, tomatoes, apples or bananas that are left long days are also fungus favorites. And where there is a fungus, there is a mass number of gnats. Also, if you are a gardener, you will probably find them flying around the compost bin in the house. In addition to being attracted to the humidity, gnats also love the light so you can easily see them flying near light bulbs, windows or mirrors.

Now that you have located the gnats, it is time to start working on them! Because what the point of knowing how long do gnats live if you do not know how to remove them?

Change the way you water your plants

Only water the right amount at the right time. Indoor plants do not require regular watering so you can do it for a week or by month. Do not water too much unless you want to keep attracting gnats and spoil your favorite plants. Moreover, do not forget to drain water from the pot after you water the plants for a while.

For some reasons such as the design of the pot or the texture of the soil, the drainage may be slower. As a consequence, the plant can rot, result in improving gnat and fungus growth.

Change the way you water your plants

Image source: Greatist

Not to store vegetables for too long

Many busy housewives have the habit of buying a lot of vegetables for a whole week. And potatoes kept in the kitchen for three to four days are enough to invite gnats to live in. If you have to do so, make sure you store them in the fridge. If you feel that you cannot eat them before they are rotten, then throw them away.

For the gardener, it is best to bring your compost out for more benefits than getting rid of gnats. Leaving it indoors not only give a chance for gnats to lay hundreds of eggs but also for other harmful mosquitoes.

Use an insect sprayer

The last method, if the above ones are not effective, is to use an insect sprayer. Spend some time to determine where gnats live and spray a few times on them once for good

Use an insect sprayer

Image source: The Domestic Curator

To sum up, gnats do not bite but do not bring anything but a nuisance. Knowing how long do gnats live will give you some information about these annoying friends and ways to eliminate them. These little flies can multiply to thousands in the summer so always be ready for that.

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