Eli5 How do fruit flies appear even when there’s no fruit?


Every now and then I’ll be having a glass of wine and one single fruit fly will show up and be gone by the next day. I have no fruit in my house. There’s a few vegetables in the fridge. Everything’s clean and there are none in the trash. I’m so confused. It’s happened a few times.

I know fruit flies appearing has been asked 1000 times but I’ve gone through them and can’t find a question without fruit.

In: 2

Contrary to their name, fruit flies will infest any rotting material (not just fruit). They’ll find any source of moisture or decaying material, including sponges, mops, or even puddles of water. This type of material is where adult fruit flies lay eggs. Kitchen sink drains commonly foster fruit fly infestations.

The eggs are really, really tiny and easily overlooked. They can travel on many different surfaces, and can be transfered to different surfaces pretty easily. If you buy groceries from a store with fruit, you could bring eggs home, even without the fruit.

It could also be a different insect and not a fruit fly. You would need to research flying insects native to your area. Many state universities have some sort of annex or other community information program that might be able to help you.

They’re probably drain flies, not fruit flies. As the name implies, they come up out of your drains. They look similar.