From Wikipedia: "If a bee is sufficiently intoxicated, it will just lie on its back and wiggle its legs. Inebriated bees typically have many more flying accidents as well." Yup. Sounds like alcohol.
From Ricky the Meadmaker: "How do I keep coming up with these? I've done over 500 now."
If you wanted to be drunk from the hard work of drunk bees, anything in our mead section can help you out!