I am a mad scientist who has discovered a way of efficiently killing all sorts of annoying flies, from mosquitoes to fruit flies, and want to unleash my creation upon the unsuspecting buzzers. However, I want to do it in a way such that I don't destroy the entire ecosystem by removing an important food source for birds, bats, frogs, etc. or replace any sort of other potentially useful properties of the flies (including preventing aliens from destroying the earth).

How can I best accomplish this?