Can a Venus flytrap survive on water alone or do I need to constantly feed it bugs?

Well, it can’t survive on water alone, but it CAN survive on just water and sunlight. All you really need to feed your flytrap is lots of sunlight and clean water. If you grow your flytrap outside, and you really should so it can get sufficient light, it will catch all the insects it needs on its own. Try to give your flytrap at least 4 hours of direct sunlight a day and it will be a happy and healthy plant!