Will the Venus Flytrap Eat Fruit Flies?
Yes, they will, though rarely. Venus flytraps are amongst the worst of the carnivore plants when dealing with fruit flies. Fruit flies are often too light or small to trigger their senses to close their trap, and even then, it can allow enough time for them to escape.
Venus flytraps do not require fertilizers, as they don’t rely on soil nutrients for their diet. Instead, much like most carnivorous plants, they rely on the prey they trap to feed.
If you’re looking for a carnivore plant to deal with a fruit fly problem, the better option is the sundew, as it has several ways to deal with flies more efficiently than a Venus flytrap.
Keep in mind that these plants won’t get rid of an infestation or be a good answer to large amounts of flies. They can only eat and trap a limited amount of insects, rendering them useless for a while. Having multiple sundews can probably help out against a large number of fruit flies, though the underlying problem of the infestation has to be appropriately addressed in order to get rid of them completely.