Once its summer, fruit flies appear magically inside the house and begin to socialize with ripen fruits and vegetables. We never see them coming and we never witness their parturition either. Just boom, nature’s wiggle of the magic wand and they’re inside the apartment like someone summoned them up.

I once heard that fruit flies were products of spontaneous generations that originated from rotting fruits and vegetables. Thank goodness i’ve come to realize that’s nothing short of a pre 21st century scientific fallacy.

In this article, we discuss the real origin of our pesky little buddies, how they get into the house in the first place, and the first thing they do when they sneak into the apartment.


Where do fruit flies come from?

Fruit flies come from outside the house in order to infest inside. They are not products of spontaneous generations emerging out from rotten and fermented food items like the century old theory suggest. They are rather, wild animals that are attracted into the house by the smell of fermenting fruits and vegetables as well as the strong stench produced by trash cans and drains.


Where do fruit flies live?

Fruit fly (Scientifically identified as Drosophila melanogaster) is a free living wild animal that is found everywhere on earth with the exception of Antarctica; because of the extremely chilly climate which inhibits its reproduction and survival.

The natural range of fruit fly constitutes the tropical regions of Africa, Asia and Europe, collectively known as the Old World Tropics. Its preferred habitat within this range is only controlled by availability of water and temperature, though scientific evidence suggests that they are mostly concentrated in moist humid regions.

Fruit flies dislike any climate characterized by extremities (too hot or too cold). So in the vast continents that they inhabit, they usually avoid mountain ranges, deserts, and high latitude areas.

Within these habitats, adult fruit flies primarily live on plant materials i.e. rotting plants and fruits, while their eggs are laid on unripe/ripen fruits, so that by the time the larva emerges out from their eggs, the fruits must have started going bad. Eggs can also be laid on decaying mushrooms and sap fluxes of trees and plants.

If you’ve comprehended the above paragraph really well, you’ll understand fully by now that fruit flies don’t employ invisible dimensions to magically appear inside your house.

They are rather, attracted by source materials which are basically food items that have gone bad or are at the brink of turning bad. And because the summer temperature around the house is one that nearly matches the optimal requirement for breeding and growth in fruit flies, these critters without any hesitation, take up residence to feed, breed and chill at the expense of someone’s happiness.


How do fruit flies get into the house?

At the head of every fruit fly are short antenna hairs that are sensitive and finely tuned to detect stenches from more than one kilometers away. Not just any stench, but that of fermentation and rot to be specific. So because these critters are virtually everywhere and anywhere, they just happen to never miss out on opportunities when present with one.

So an overripe banana fruit lying underneath the refrigerator would easily command the attention of a passer by fruit fly and so will the murky sludge lying at the base of the recycle bin at the basement.

When the fruit fly is locked in on the smell, it’s only a matter of hours before it locates the tasty dinner and seep through holes, cracks, gaps and plumbing openings like water does into the soil. In other words, fruit flies are very tiny — the equivalent of the sesame seed, and therefore getting into the house would be as easy as water flows into cervices.

Another way that fruit flies can get into the house is if you by yourself brought them in. How the heck is this even possible you might ask?

It’s through fruits and vegetables that are already harboring fruit fly eggs which you have brought from grocery shopping or retrieved from the garden or fruit cellar. The next section discusses how long it takes fruit fly eggs to develop from eggs into adults.


What do fruit flies do when they get into the house?

Once in the house, the next thing on any fruit fly’s mind is how to infest the area with generation as quickly as possible. And this is best done through mating.

So fruit flies, after feeding their bellies to the brim with the ferment remains, rot and microorganisms on the source material that invited them in, they mate indiscriminately with individuals of the opposite sex and the females lay eggs directly on or near the surface of nearby rot source or potential rot source i.e. on top of overripe fruits, on or near rotten or soon to rot vegetables, or on the sludge present in rot filled recycle bins. Basically anywhere with a moist film of fermenting or rotting stuff including the drain in your kitchen and in the garbage disposal sinks.

It’s actually useful to note at this point that the scientific name “Drosophila” constituting the first name of the fruit fly actually means “lover of dew”, stemming from the fact that fruit flies primarily thrive in moist environments.

Female fruit flies can lay as much 5 eggs at a time and more than one hundred per season. Now you see how an infestation occurs easily right? When the eggs are laid, it only takes around a week or so for them to hatch given the optimal condition of your apartment in summer.

Around 12 to 15 hours after the eggs are laid, they hatch into larvae that begins feeding on the rotting material instantly. In under 48 hours, the larvae completes its first, second and third larvae stages and continues to grow in steadily size and length for about 4 days. After that, the larvae turns into pupae and stays like that for the next 4 days after which it develops into an adult. That’s approximately one week at optimal condition.

Once these babies emerge, the next thing on their minds, just like their determined adults counterparts, is to find a willing partner to mate with, lay eggs and thereafter, give birth to their own generations too.

That’s basically how two fruit flies can give rise to several thousand others in less than a month if no precautions are taken to eliminate them.


Why are fruit flies notoriously difficult to swat?

Fruit flies have 270 degrees compound eyes that are sensitive to difference in light intensity, and also pointy hairs on their backs that are super sensitive to air currents.

The 270 degrees vision essentially means that they can detect approaching humans from almost any angel be it front, back or from the sides.

So when fruit flies are approached for a swat, the sudden changes in air current and brightness alongside the 270 degrees vision signals to them the possibility of potential danger. Then, they quickly calculate the angle of attack and plan for the perfect escape in as little as a 100 milliseconds.

Once in air, killing them becomes next to impossible give their excellent ability to accelerate fast by flapping their wings 200 times per second and changing directions in as little as one, one hundredth of a second.


Are fruit flies harmful?

Fruit flies are not harmful by themselves in that they do not transmit any diseases that cause sickness or illness. They neither bite nor bruise human skin too, only that their company is extremely irritating. They swarm across the kitchen like they contributed a dime to furnish it and scream to the next door neighbor how dirty your entire life is. I swear if i ever catch one, i’d smack it silly!


How to get rid of fruit flies?

We have written a comprehensive guide on the causes of fruit flies and measures you can take to get rid of them, you can read that here:

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