Okay, perhaps “tummy” is too cheeky but honeybees do use magnetite in their abdomens.
One clue could lie in the fact that some of these organisms contain magnetite – a ferromagnetic oxide of iron that is also found in some types of rock. Indeed in 1997, Joe Kirschvink and colleagues at the California Institute of Technology showed that honey bees respond to local magnetic fields in a way that is consistent with magnetite-based magnetoreception.
The team then used a strong permanent magnet to expose live honey bees to a magnetic field of 2.2 kOe – several thousand times stronger than the Earth’s magnetic field – for about 5 s. Further measurements with the SQUID revealed that pellets made from the abdomen of these bees were more strongly magnetized than pellets made from bees that had not been exposed to a magnetic field.
Read more here: PhysicsWorld.com: Honey bees navigate using magnetic abdomens