Why does the earth orbit the Sun and not go flying off hither and yon? Why did Shoemaker-Levy hit Jupiter? Hint: One has a stable orbit and the other does not wrt the major planets and the sun.
Plus your analogy with bugs surviving closer to the bulb will result in bugs fried on the light, glued on the light, etc with no other bugs elsewhere. You have provided no mechanism for the bugs to go elsewhere.
"A fly has, on average 350,000 neurons," he said. "Most of them dedicated to processing sensory information."Two-thirds to three-quarters of the brain are devoted to the eyes alone. It flies with great dexterity and precision, using only some of the remaining neurons. And yet, packed into this relatively small bunch of brain cells are all the instructions for flight maneuvers. Unlike mammals or birds, the fly doesn't have to learn anything.
"When a fly breaks out of its pupa, it can fly as well as it ever will," he said. Human beings seem to think that being constructed so that people learn complex behaviors is a superior life plan, Dr. Dickinson said. But it was an equally challenging evolutionary problem to make a brain about the size of a poppy seed, in the case of the fruit fly, "that can do everything in the behavioral repertory of a fly."