Following in the footsteps of his colleague Edward Lewis, whose work on the genetics of fly development earned him a Nobel Prize, Benzer created fly mutants by treating them with chemical agents and then studied their behavior. He established a fly lab to which many students came. They, like Benzer, were adventurous and, like Arrowsmith, contemptuous of a careerist path in science. They made tremendous progress and ignored criticism that flies could tell nothing about animal, let alone human, behavior. It was from this work that a gene controlling the flies' sense of time was discovered.
Flies have a daily rhythm.
But Benzer and his students found flies that woke up late and others that were insomniacs. They had discovered a clock gene. This same gene also turned out to control the rhythm of their love songs. Its mutant form caused male flies to ignore females and form long chains of similar males winding around their test tube hour after hour. They found that flies could learn to avoid an electric shock and located genes that improved a fly's memory.