How do fruit flies appear, seemingly, out of nowhere?

This week's Curiosity Desk investigation comes courtesy of Westborough resident and self-described “banana guy” Wayne Firstenberg, who reached out with a question that has long been bugging him.

"Monday through Fridays, [bananas are] my snack late in the day," said Firstenberg. "And then some days I don’t feel like having it or I don’t get to it and, you know, the bananas get older."

And when those bananas get older, some unwelcome guests tend to appear.

“Where do fruit flies come from ? It's an annoying miracle to me that they just suddenly appear on my aging fruit. I don't get how they're not there and then they're there. Please help."

WATCH: How do fruit flies appear, seemingly, out of nowhere?

Shakespeare may have asked “what’s in a name?” but in the case of fruit flies we’d be wise to spend a moment examining its moniker. Especially since the fruit flies messing with Wayne’s bananas are not actually fruit flies.

"The real fruit flies are another group of organisms in the group Tephritidae,” explained entomologist Tanya Latty, associate professor at the University of Sydney. ”If you're in Australia or warmer climates and you're talking about fruit flies in your garden or fruit flies attacking your crops — that's the fruit fly you're probably talking about.”

Here in the U.S., where what we call fruit flies are actually members of a completely different family of insects: Drosophilidae. It’s a big family that includes over 4,000 different species, about a handful of which we tend to see around the house. And despite their common name, these flies don’t really eat fruit.

“They’re not actually consuming much of the fruit,” said Latty. “They're actually more interested in the yeasts and bacteria and things that are growing on rotten fruit.”

This is why some scientists have advocated for calling them pomace or vinegar flies, rather than fruit flies.

“They are attracted to particular smells,” said Latty. “So things like vinegar, acetic acid, those odors are really attractive to females because that's an indicator of the kind of environment that they're looking for.”

They are looking for that “kind of environment” to lay their eggs. And a typical kitchen is a fruit fly dream home. Fruit bowls? Check. Garbage cans? Yup. Drains? Affirmative. All of them are prime spots for female fruit flies to lay eggs.

And laying eggs is something fruit flies are particularly good at. Indeed, they breed at a pace that would make rabbits blush.

“A female fruit fly can lay roughly 100 eggs a day, and she can live for around a month in some cases,” said Latty, “So over time, that's hundreds and hundreds of eggs per female if the conditions are just right.”

And those eggs mature incredibly quickly, too. It happens fastest in warmer temperatures, so we tend to see more of them in the summer. That’s also a time of year when we tend to have more fresh fruits and veggies lying around. And when the temperature is just right, flies can go from egg to reproducing adult in just over a week.

So, you can easily have a scenario where just two or three tiny little fruit flies make their way into your home, through a window or door, totally undetected. And a week later, there are literally hundreds of them being born and bred right there in your kitchen.

"It does feel like they come out of nowhere, but that's because the larva,” explained Latty. “The babies are really, really small. So small that most folks won't notice them if you're just kind of casually looking for where they come from.”

And, yes, that does mean that if a small colony takes flight when you pick up a ripe banana on, say, a Thursday morning, there’s a pretty good chance you might have gobbled up some of their siblings earlier in the week.

"I guarantee everybody has already eaten quite a lot of insect eggs and insect parts in their lives,” said Latty. “That's just protein. It's fine — it's not going to hurt you.”

And while their unique combination of size and speed make fruit flies a particularly pesky pest in the kitchen, it’s also enabled them thrive in another location, so to speak: The research lab.

“Even though they look really alien and different, fruit flies share a lot of their basic biochemistry, genetics, neurology, all of those things with humans,” said Latty. “And so they've become like the lab rat of science, except even more so than lab rats because they can breed quickly.”

We can thank the Drosophilids for a whole host of our recent discoveries in the fields of medicine, genetics and biochemistry. In fact, no fewer than six Nobel prizes have been awarded to scientists for breakthroughs they’ve made researching the humble fruit fly.

So, while this “annoying miracle” of an insect may be bothersome on your bananas, it’s also been a boon for biochemistry.

If there is something you've been itching to know more about, email The Curiosity Desk or send in your question below. Edgar might just dig up the answer in a future episode. For more from The Curiosity Desk, follow Edgar B. Herwick III on Twitter and subscribe to the GBH News YouTube Channel.