Do fruit flies bite?

Do fruit flies sting?

No. A sting is a modified egg-laying tube. The Amateur Entomologists' Society puts it plainly: the bees, ants and wasps that sting do it with a modified ovipositor, which is the tube a female lays her eggs through. A fruit fly is none of those. It's a fly, and no fly has one.

The NHS list of stings reads the same way: bees, wasps and hornets, and nothing else.

What happens if one lands on you

Nothing that can hurt you. Fruit flies taste with their feet as well as their mouths. A 2013 review of how they feed describes it: when the taste receptors on the mouthpart or the feet pick up something the fly likes, a hungry fly puts its mouthpart out to feed. On your arm, the most it can do is walk about and taste. That soft pad is all it has to work with.

It's also a sign of where they are and why. Fruit flies are sometimes called vinegar flies, because they go for vinegar and almost any rotting fruit. One on your hand in the kitchen means there's something they like more than you nearby, and it's worth finding. Whether they're harmful is a separate question, and the answer is about your food.

The other tiny flies in the house don't bite either

This clears out the usual suspects in one go. Fungus gnats, the small flies that come out of a houseplant pot, look like tiny mosquitoes, and Texas A&M notes that unlike mosquitoes they don't bite. Drain flies, the furry little moth-shaped ones on the bathroom wall, don't bite or sting either, according to Iowa State's extension service. And the ordinary house fly doesn't bite. If you're not sure which tiny fly you've got, fruit flies and fungus gnats side by side is the quickest way to tell.

A fruit fly is 2 to 4 mm long, stocky, and usually has reddish eyes. Some have black eyes, and those tend to breed in drains rather than the fruit bowl. What fruit flies look like covers the rest. None of those small flies is the thing that bit you.

The fly that looks like a house fly and does bite

If a fly bit you and it was the size of a house fly, the likely one is the stable fly. Florida's extension service says it's even called the biting house fly because the two look so alike. It's 5 to 7 mm long, against a fruit fly's 2 to 4 mm, so you won't mix the two up.

The difference is at the front. A stable fly has long, bayonet-like mouthparts for piercing skin and drinking blood, while a house fly has sponging mouthparts for liquids. It also has seven round spots in a checkerboard on its back end, where a house fly has none. Both males and females feed on blood, and people usually get bitten on the legs, behind the knees and on the elbows.

It mainly feeds on cattle and horses, and bites people and dogs when those aren't around. The same source calls the bites extremely painful. So a sharp bite on the leg from something house-fly sized points at a stable fly. It never points at a fruit fly.

So what is biting you?

I can't tell you what bit you, and nobody can from a description of the bump. What I can give you is how the NHS describes the usual ones, so you know what to look into:

Flea bites are usually found in groups below the knees. If you've got those and no pet, fleas in a house with no animal in it have their own explanation. Bed bug bites are often on skin that's uncovered while you sleep, like the face, neck and arms, and they're often in a line or grouped together. Mosquito bites are usually small, raised and itchy. Midge bites are usually small and raised in groups. Mite bites cause very itchy lumps on the skin.

If you suspect a spider, which house spiders actually bite has its own answer. A pharmacist can look at a bite that won't settle, and the NHS says to see one if it feels hot or looks red. Call 999 if your lips, mouth, throat or tongue suddenly swell, or you're struggling to breathe.

Getting rid of the ones that don't bite

The fruit flies are still worth sorting, because they're breeding in something. A trap catches the adults. Texas A&M is plain about the limit: traps alone rarely give you proper control, but they help you find the source while you deal with it. The source is the job, and getting rid of fruit flies begins there.

For the adults, the trap that works is the one that lets them in and makes the way out hard to find. The extension service describes the two parts that matter: a funnel or small entry ports that make escape difficult, and a drop of soap in the vinegar so landing flies drown. What makes a fruit fly trap work goes into the funnel and the exit properly.