This is a tricky lens to use. Best to use a tripod and a macro flash for smaller apertures and a larger DOF. At f/3.5 on 180mm the DOF is too small for bug work.
Lucked out here though, this was handheld without flash. there were a few missed foucus out takes though.
Great timing, and also good use of the long focal length to be able to get this without spooking the bee. It takes a lot of shots to get one this nice of a bee. The focus on the eyes is perfect, not an easy thing at 180 and 3.5.