Fruit flies are a pesky little insect. The saying that if you've seen one, there are probably a hundred, is true for the fruit fly. Once you start to capture them you will be amazed at how many you see in the trap and how many were really in your house!
As its name implies, fruit flies like to feed on fruit. There can be many reasons fruit flies are in your house. They could be attracted to your fruit in the fruit bowl display, the row of freshly picked tomatoes waiting for processing, or even a dirty garbage disposal with its mixture of old foods. No matter the reason, fruit flies are an unwelcome guest but can be easily removed with the following homemade device.
Why does this work? You would think that if the fruit fly could find its way in, it could also find its way out. But the fruit fly hones in on the fruit to get in. When it's time to get out of an object with sides, its instinct is to travel straight up. So the fruit flies will be trying to escape by flying up to where the container meets the paper. This is why you have to make sure your seal between the container and paper is air tight. Because you have a funnel shape that goes below the walls, the opening is too hard to for the fruit flies to find.
Good luck, and good riddance!