Several studies suggest that the fruit fly Drosophila melanogaster can use magnetic fields for orientation1-4; however, the responses to magnetic fields are not consistent across studies and experiments investigating the mechanism of magnetoreception rely on magnetic fields that are at least 10 times stronger than the magnetic field of the Earth5-6. We are attempting to determine whether Drosophila have the ability to detect Earth-strength magnetic fields by running flies through a progressive Y-maze and then selectively breeding the flies based on their choices in the maze. There are two main hypotheses about the mechanism of magnetoreception in animals. The first is based on the use of magnetite, which forms long chains and serves as a magnetic dipole and has been found in organisms such as bats7. The other hypothesis is based on a light-dependent magnetic response utilizing the cryptochromephotoreceptor8. While the predominant hypothesis is that fruit flies use cryptochrome to detect magnetic fields1-6, experimental results have shown that most invertebrates use magnetite or both magnetite and cryptochrome
