The humble fruit fly, Drosophila melanogaster, can actually be quite a pesky pest. Come spring and early summer (and a little bit of rain), and the banana that was resting peacefully in your fruit basket is invaded by swarms of flies. All they need are some fruit, or a trashcan and some moist corners, to breed in and soon you have a horde of them. The Pacific Northwest, like many other places, has swarms of fruit flies in early summer (when there's a bit of rain, but also plenty of warm weather), and we are under seige. No trashcan is safe, and no fruit outside can hide. In addition, though these flies are primarily just a nuisance, they can also be disease vectors.
This is the time when people waste their hard (or otherwise) earned money on toxic bug sprays (Even some bug sprays that are "100% natural" can be harmful. Everything natural need not be toxin free). Or else they make multiple trips to the store (because they keep forgetting to buy fly paper). But that needn’t be so.
My friends have patiently waited for me to discover something spectacular, and patent some new drugs (or have some such similar delusions), so that they can buy stock in my imaginary company and become rich. Thus far, I have been singularly useless for them. But today I shall change all of that (and redeem myself) by revealing the flytrap I have made and effectively used to get rid of the pesky flies.
Fruit flies like “fruity”, fermenting smells. They practically live by smell (having 36 classes of olfactory receptor neurons, just to smell!), hunting down their food by sniffing around. So, to make the perfect flytrap, just take a glass (or a beaker, or small cup or any small container), pour a little bit of something fruity and fermenting into it (apple cider is fantastic, so too is vinegar, or some spoilt wine), and add a few drops of dishwashing soap to it. Then seal the opening with plastic wrap, and pierce a few small holes in the seal (with a fork or something small), to create openings a little larger than the fly. Now, keep this on the table (or near the trash can, or fruit basket or wherever) and go take a walk. Or, if you are sadistic, sit and watch. You'll see flies slowly being drawn to it, like iron to a magnet. They'll first alight on the glass, then make their way into the little holes, all the way down to the liquid. And then they'll drown, and….die like flies! The decreased surface tension (due to the drops of soap) is enough to ensure that they cannot escape.
Die fly, die!
So much more efficient and smarter than bug spray and flypaper, don't you think? Works for houseflies also, but less efficiently.