Where Do Fruit Flies Come From?

  • Written By Dan Edwards on February 2, 2021
    Last Updated: February 2, 2021

Fruit flies are a major indoor pest, especially during the warmer months. From holes in your window screens to pre-laid eggs in fruit, fruit flies always find a way inside your house. These pesky little creatures are attracted to everything from barely ripened fruit to scraps of rotting produce in your garbage can.

At first, the fruit flies can be considered a mere nuisance. Later on, however, when they begin reproducing indoors and the females begin to lay eggs, you’ll have a serious pest infestation problem. Understanding where they come from will encourage you to take proactive actions and keep those fruit flies out.


Common places for fruit fries to come from are:

  • Small cracks in infrastructure
  • Pre-laid eggs in produce
  • Surfaces with fermented juices

What Attracts Fruit Flies?

Fruit flies don’t have teeth and have gustatory receptors instead — they depend on liquids as their primary source of nutrition. They’re able to detect the scent of fermenting fruit from a good distance away. If you’ve left a bowl of fruit out and it’s summer, there’s a good chance a couple of fruit flies are trying to find a way inside.

Due to their tiny size — about 0.08–0.16 inches long — they can easily get in through window screens or tiny cracks in the walls.

Sometimes, fruit flies have already pre-laid eggs in the fruit you buy from the grocery store. Those strawberries you just brought home may already carry a new generation of fruit flies.

If you have a small garden, your house will be more susceptible to fruit flies. If you let some of your fruits and vegetables ripen before picking them, you might be harvesting fruit flies, as well.

Keep in mind; adult fruit flies also feed on the byproducts of the fermentation process not just the bacteria and yeast. This is why you may find fruit flies hovering around wine and soda as well.

Where Do Fruit Flies Lay Eggs?

Fruit flies thrive in moist areas filled with fermenting food products. Usually, it’s your fruits and vegetables that attract them. They can also be attracted to non-food items such as cleaning rags and mops. Trash bags and garbage disposals are also a fruit fly favorite.

The female fruit flies lay their eggs on the moist surfaces of these items. When the larvae hatch, they feed on the surface as well. They’re most commonly found embedded or burrowed in the surface of decaying organic matter. The juices concentrated in the food serve as the main energy source for the fruit flies.

Sometimes, fruit flies will lay their eggs in small, dark crevices in your walls. This is so that when the larvae hatch, they can enter the pupae stage undisturbed until they fully develop.

Fruit flies lay their eggs in food but usually only on the surface level where the fermented juices are. All female fruit flies have a sharp ovipositor, which is utilized to efficiently deposit eggs under the skin of the host fruit or vegetable. You can usually spot sting marks on light-colored produce, which is where they pierced a hole with their ovipositors.

Some types of fruit flies have weak ovipositors and can’t pierce the skin of fruits and vegetables. These fruit flies will look for a natural opening or bruise to lay their eggs into.

What Do Fruit Flies Look Like?

Fruit flies belong to the Drosophilidae family. They’re also known as vinegar or wine flies. This is because they’re attracted to fermented liquids often found in these products. They can be yellow, tan or red and usually have large red eyes. Their wings are translucent, and sometimes they may have dark, blotchy spots on their thorax.

Fully matured fruit flies have long, hairy antennae that stretch out well beyond their bodies. Many confuse their eggs with maggots because of their creamy white color and spindle-like shape. It can be difficult to differentiate between the two, which is why fruit fly infestations happen so often and inconspicuously.

Are Fruit Flies Harmful?

Apart from being an annoyance, fruit flies do have the potential to contaminate food with bacteria and other pathogens. They pick up and carry a wealth of contaminants from the rotten and fermented food they burrow in.

Can Fruit Flies Harm Humans?

Fruit flies are highly attracted to the aroma of decaying matter — especially fruit because of the fermented sugar. Due to their tiny size and them laying eggs in ripe food, you’ve probably eaten a fruit fly by accident before. Don’t worry, though, fruit flies aren’t disease vectors. This means they don’t directly transmit diseases to humans.

Keep in mind that these tiny nuisances have the potential to quickly multiply in number. They’re tough to get rid of once they’ve infested your home. They’ll usually hang around all summer and into early fall, spreading bacteria around your house.

Are Fruit Flies Harmful to Pets?

It makes sense to assume that fruit flies might harm our pets as parasitic pests do. Fruit flies do burrow into fruit, so why wouldn’t they burrow in your pet’s skin? Fruit flies and parasitic pests, like fleas, are more different than they are alike. Parasitic insects subsist on blood; fruit flies don’t. They don’t pose any harm to your pets since they don’t even have a mandible to bite with.

The Lifespan of a Fruit Fly

Fruit flies are short-lived insects that breed rapidly and are common household pests. A single fruit fly usually lives for about 50 days in optimal temperature conditions.

Fruit flies experience a four-stage life cycle. The life cycle of a fruit fly begins with an adult female laying eggs — up to 500 at a time. It only takes a fruit fly a couple of minutes to lay a batch of eggs into the host fruit.

The organisms that emerge from the eggs are called larvae. At this stage, these can be considered semi-developed immature fruit flies. The larvae will feed on organic matter — your rotting or fermenting fruit — to store enough energy to be able to enter the pupae stage. After about a week in this stage, the fruit flies will emerge as fully developed adults.

Fruit flies can be particularly difficult to get rid of because of the rapid conversion they undergo. In under a week, they go from gelatinous eggs to adult fruit flies with full motion and flight ability.

At this point, they’ll scavenge for a source of energy — fruits and vegetables — and begin to feed. When the females begin to lay eggs, the life cycle begins all over again. That’s how you end up with a fruit fly infestation. Fruit flies are very enduring pests and can survive on very little.

When Do They Appear?

Usually, fruit flies only appear in the warmer months. The fruit fly is known for its fondness for warm weather — especially your warm kitchen.

Fruit flies are poikilothermic ectotherms. This means that their internal body temperature is tied to the surrounding environment’s air temperature. Some insects can survive cold temperatures and be considered cold-adapted. Fruit flies, however, simply cannot bear the cold. They usually die quickly in relatively low mild temperatures, and their unhatched eggs are frozen until the next spring.

Fruit flies actually undergo a process similar to hibernation called diapause, which helps them preserve their species until the weather warms up again.

Early Signs of An Infestation

The first thing you’ll notice if you have an infestation is the active adult fruit flies hovering around. You’ll usually find them buzzing around in kitchens, trash cans and food disposals.

The next most visible sign of a fruit fly infestation is the pupae. You’ll see the mature larvae crawling out of their breeding material to pupate in a dry place. They’re incredibly tiny and can be easily mistaken for rodent droppings. The pupae, however, have a pair of horns on one end.

Prevention and Removal

The first thing you should do to address a fruit fly problem is to identify and destroy their feeding and breeding grounds. Throw out all damaged or rotting fruits and vegetables that have been left out in your kitchen or other eating areas.

To avoid a complete fruit fly infestation, be mindful of your buying habits. Buy only as much produce as you need. Any ripe or overripe fruits and vegetables should either be consumed as soon as possible or placed in the refrigerator. If you don’t want to place certain fruits and vegetables in the fridge, store your produce in air-tight containers instead.

Be sure to clean up all food scraps and take out the trash as frequently as possible. Fruit flies are opportunists! It only takes the smallest scrap of food to bring in a cluster of hungry fruit flies. Keep your kitchen free of all these sources, and they won’t have a reason to infiltrate your space.

This also includes any materials that may have come in contact with food products. Sponges and other dishwashing tools carry a lot of bacteria and food residue. It’s best to throw these out and purchase new, clean ones.

Using Bacterial Digesters 

There are also many bacterial digesters available that can be poured down infested drains. Sometimes, after you’ve thrown out all your food, you’ll still find fruit flies buzzing around your sink. This is because fruit flies are attracted to the accumulated slime inside the drain.

Bacterial digesters aren’t the most effective method of eliminating a fruit fly infestation. Quite like fruit fly traps, they merely provide temporary relief. If you don’t want to pay for an expensive exterminating service, the most effective solution is eradicating their sources of food. This stops them from being able to reproduce and eventually dying out.

Fruit Fly Trap

If you’re looking for a more immediate and aggressive solution, you can create a trap at home.

  1. Fill a container with about 2 inches of warm water, a small amount of sugar and a teaspoon of yeast.
  2. The warm water and the sugar will activate the yeast.
  3. Take a plastic storage bag and poke a tiny hole in one of its corners.
  4. Place the punctured corner inside the top of the container.
  5. Secure the bag around the container’s rim with a rubber band or hair tie.

The yeasty water will mimic that found in fermenting fruits and vegetables. The yeast formula will attract the fruit flies, which will make their way down the bag through the hole. They won’t be able to get back out!

If you don’t have yeast in your pantry, vinegar can also be used to attract them and works just as well.

Simply clean out the jar once a week until all the fruit flies in your house are gone. This has to be done while you’re making sure there aren’t any scraps of garbage or food lying around. It won’t be effective otherwise.

It can be kind of disgusting when you dump out the jar as the yeasty water will be filled with fruit flies. It’s best to throw the mess far away from your home or down the drain. If you opt for the drain option, run the water for at least a full minute to ensure that even the tiny eggs are completely gone.

Summary

It may seem that a fruit fly infestation comes out of nowhere. This is because of fruit flies’ incredible ability to breed and develop rapidly and in large quantities. Once they sense a source of food and energy, they won’t hesitate to move into your house. Fruit flies can thrive on very little. Even the smallest amount of food residue on your countertop gives them a reason to move in.

Fruit flies are indeed a nuisance, but they don’t pose any real harm to you or your family. Overripe and fermented produce is an open invitation for fruit flies to infest your house. Throwing out scraps of trash and refrigerating your fruits and vegetables can help keep those pesky fruit flies far away.