Average Lifespan of a Fly: How Long Do Flies Live in Hawaii?
You swat one fly, and by lunchtime there are three more. It can seem like they never die, but they do. The average adult house fly lives about 15 to 25 days, and some make it close to two months when conditions are right. The problem is that a fly spends most of that short life making more flies. On Oahu, the weather never slows them down.
This guide answers how long a fly lives, how fly lifespan changes from one species to the next, and how fast flies grow from egg to adult. It also covers why Hawaii's climate keeps them going all year and what to do when they keep coming back.
What Is the Lifespan of a Fly?
The lifespan of a fly depends on the species, the temperature and how easy it is to find food. Most common household flies live from about two weeks to two months as adults. The University of Florida's house fly fact sheet says adult house flies usually live 15 to 25 days but may live up to two months.
Here is the average life of a fly for the kinds you're most likely to see around an Oahu home or business:
- House fly: usually 15 to 25 days as an adult, up to about two months
- Fruit fly: about 40 to 50 days as an adult
- Drain fly: about two weeks as an adult
- Blow fly: about two and a half weeks from egg to adult, with adult life varying by species
So if you're wondering how many days a fly can live, the honest answer is anywhere from about two weeks to two months. That life span of a fly covers only the adult stage. Before it can fly, it has already spent days as an egg, a maggot and a pupa, usually hidden somewhere you don't look.
What Affects Fly Longevity?
Fly life expectancy isn't fixed. How long adult flies live comes down to a few things:
- Temperature: warmth speeds up every stage of the life cycle. Heat means faster breeding, and cold slows development way down.
- Humidity and moisture: eggs and larvae need damp material to survive. Wet garbage, drain slime and moist soil keep them going.
- Food: adult flies need a steady supply of food and liquids. Open trash, pet food, spills and food waste all help them live longer.
- Shelter: indoors, flies are safe from wind, rain, birds, geckos and spiders, so they often live longer than flies outside.
- Species: a tiny drain fly and a large blow fly live very different lives and breed in very different places.
Flies Life Span by Species
Knowing which fly you have tells you where it is breeding. That is the key to getting rid of it.
House Fly Lifespan and Life Expectancy
The house fly is the gray, quarter-inch fly you see around kitchens, lanais and dumpsters. The average house fly lives 15 to 25 days as an adult, and some live up to about two months. That's the typical life expectancy of a house fly in warm weather with plenty to eat.
In that time, one female can lay up to 500 eggs in batches of 75 to 150. In warm weather, a house fly can go from egg to adult in as little as seven to ten days. That's why a small fly problem can turn into a big one in a couple of weeks.
How Long Do Fruit Flies Live?
Fruit flies are the tiny tan flies with red eyes that circle the fruit bowl, the recycling bin and the sink. Adult fruit flies live about 40 to 50 days, much longer than most people expect. A female can lay up to 500 eggs in her lifetime, and each one can grow from egg to adult in about 8 to 10 days.
Fruit flies breed in overripe or fermenting produce, like a forgotten mango or banana peel, and in the gunk around drains and drink dispensers. In restaurants and bars, they show up around soda and beer lines.
Drain Fly Lifespan
Drain flies, also called moth flies, are small, fuzzy and gray. You'll usually find them sitting on bathroom walls near the shower or sink. Adults live about two weeks, and as the old ones die, new ones keep coming up out of the drain. The whole life cycle can take one to three weeks. Their eggs and larvae live in the slimy film inside drains and overflow pipes, so spraying the adults does very little.
Blow Fly Lifespan
Blow flies are the big, shiny green or blue flies. Females lay hundreds of eggs on dead animals. The eggs hatch in about a day, and the maggots feed for about a week. New adults come out about eight days after that. Large numbers of blow flies indoors often come from a dead animal in a wall, crawlspace or attic. On Oahu, that is usually a rat or mouse, and rodent control for Oahu homes and businesses is often the real fix.
The Life of a Fly: How Long Each Stage Lasts
Every fly goes through four stages. Here is how it works for the house fly, the one most people deal with:
When it's warm, a house fly can go from egg to egg-laying adult in about a week and a half. When it's cold, the same cycle can stretch to two months.
How Long Do Flies Live Without Food?
Not long. Adult house flies without food survive only about two to three days. That is why food matters so much. Take away open trash, spills, pet food and rotting produce, and a fly's lifetime drops from weeks to days.
Female flies also need protein-rich food before they can produce eggs. Cutting off food sources shortens the life of the flies you already have and also stops them from breeding.
How Long Do Flies Live in the House?
How long a fly lives in a house depends mostly on what it can find to eat. Indoors, flies usually live longer than outside. They have steady temperatures, easy food, water from sinks and pet bowls, and far fewer predators. A house fly that gets into an air-conditioned office or a kitchen with crumbs and trash can live its full 15 to 25 days or longer.
In a clean house with no food left out, flies don't last long. A fly trapped in a room with nothing to eat will usually die within a few days.
Outdoors, flies face rain, wind, birds, geckos and spiders, so many die early. But most breeding also happens outdoors, in dumpsters, green waste, compost, pet waste and anything rotting in the yard.
Flies inside your house are usually adults that found a way in. Most of the population is often outside, or in a drain, a trash can or a hidden food source.
When Do Flies Go Away?
On the mainland, flies drop off when winter comes. On Oahu, there's no cold season to do that job. Flies go away when two things happen: the adults already flying around reach the end of their lifespan, and no new flies are hatching to replace them.
In practice, once you remove the breeding source, most house flies and drain flies will be gone within a few weeks. Fruit flies can take longer because the adults live longer. If flies are still showing up after that, something nearby is still breeding them.
Why Flies Thrive Year-Round on Oahu
House flies lay the most eggs at about 77°F to 86°F, and Oahu is in or near that range for much of the year. Add island humidity, and flies can breed in every season.
- No cold season: flies breed all year instead of dying off each winter.
- Humidity: moist garbage, green waste and drains keep eggs and maggots alive.
- Older homes and buildings: worn screens, gaps around doors and older plumbing let flies in and give them damp places to breed.
- Busy commercial areas: restaurant dumpsters, grease areas and loading docks can feed flies for a whole block.
The same warm, humid climate keeps roaches, ants and Formosan termites active all year here too.
Why Killing Adult Flies Isn't Enough
Swatters, sticky traps and bug spray only get the adults you can see. Meanwhile, eggs, maggots and pupae keep developing in the trash, the drain or the compost pile. A fly can go from egg to adult in about a week in warm weather, so new flies keep replacing the ones you kill.
This is where the average lifespan of a fly matters. If you remove the breeding source, the adults already flying around will die off on their own within weeks. If the source stays, new flies keep coming.
How to Cut Flies Off at the Source
Get Rid of Breeding Spots
- Take trash out often and keep lids tight on every can, inside and out.
- Rinse garbage and recycling bins so no film or residue builds up.
- Pick up pet waste and fallen fruit in the yard.
- Store ripe fruit in the refrigerator, and don't leave produce out for days.
Deal With Moisture and Drains
- Scrub drains with a stiff brush to remove the slime where drain flies breed.
- Fix leaky pipes, dripping faucets and standing water.
- Clean under appliances and around floor drains in kitchens and bathrooms.
Keep Them Out
- Repair torn window and door screens.
- Seal gaps around doors, windows, vents and utility lines.
- Keep doors closed near dumpsters and loading areas.
Many of these steps also keep out roaches and rodents. Our homeowner pest prevention checklist covers the rest.
For Restaurants, Hotels and Other Businesses
In a restaurant, warehouse, hotel or school, flies are a sign that something is feeding pests. The dumpsters, drains, grease areas and loading docks that breed flies also attract roaches and rodents. Pests breed quickly in Oahu's heat, so commercial sites do best with regular service, not a one-time fix. Learn how ongoing prevention plans are set up for different properties.
When Flies Point to a Bigger Pest Problem
Flies are often a warning sign. The conditions that feed them also feed other pests:
- Garbage and food waste attract roaches as well as flies. If you're seeing both, look into professional roach treatment.
- A sudden swarm of large flies indoors can mean a dead rodent in a wall, attic or crawlspace.
- Moist, damaged wood and leaky plumbing that attract drain flies can also attract termites.
If you're seeing flies along with roaches, rodents or other pests, a trained technician can find the source you're missing. Xtermco has been solving pest problems on Oahu since 1961. You can see our complete lineup of residential and commercial pest services.
Frequently Asked Questions About Fly Lifespan
How long does a fly live?
Most adult flies live from about two weeks to two months. House flies usually live 15 to 25 days, drain flies about two weeks, and fruit flies about 40 to 50 days.
What is a fly's life span from egg to death?
For a house fly in warm weather, the egg, maggot and pupa stages together take about seven to ten days. The adult then lives about 15 to 25 days. That adds up to roughly three to five weeks in all, and longer in cool conditions.
How long does the average housefly live?
The average housefly lives 15 to 25 days as an adult. With warmth, food and shelter, some live up to about two months.
How long does a fruit fly live?
An adult fruit fly lives about 40 to 50 days. Because it can go from egg to adult in 8 to 10 days, a few fruit flies can become many very quickly.
Do flies only have a 24-hour lifespan?
No, the idea that flies only live 24 hours is a common myth. House flies live for weeks as adults, drain flies live about two weeks, and fruit flies can live more than a month.
How long can flies live for without food?
Adult house flies without food survive only about two to three days.
How long do house flies live indoors?
If they can find food and water, house flies indoors can live their full 15 to 25 days or longer. Without food, they usually die within a few days.
How fast do flies multiply?
Very fast. One female house fly can lay up to 500 eggs in batches of 75 to 150. In warm weather, those eggs can become egg-laying adults in about seven to ten days.
Why do I keep seeing flies after I kill them?
New flies keep hatching from a breeding source nearby, like trash, a drain, rotting fruit or pet waste, and they replace the ones you kill. Find and remove the source and the flies will die out.
Do flies live longer in Hawaii?
Each fly doesn't live much longer, but flies breed all year because Oahu never gets cold enough to slow them down. That means more generations and more flies overall.
Need Help With Pests on Oahu? Call Xtermco
Flies, roaches, ants, rodents and termites all thrive in Hawaii's warm, humid weather. Xtermco is a locally owned Oahu company that has been handling pest problems for more than 60 years. We're licensed (Lic # PC-201), and our employees go through pre-employment and quarterly drug testing. We offer same-day service and free estimates. Here's why Oahu families choose a local exterminator.
Call (808) 591-2922 or request your free estimate online, and we'll tell you exactly what happens next.