I know plenty of bee keepers who have had hives decimated by bears. One friend only keeps hives on rooftops. Another has two electric fences around his.. I've been told that the critter gitter will not deter a bear. One friend tried scaring a bear off first by honking the horn, then by chasing him in his van then by shotgun blasts and eventually shot the bear(not with the shotgun)but only after losing 5 hives. Once they find your apiary, nothing will stop them from tearing it apart. They love honey, but even more, bears love brood. Stings seem to have no effect. Fall is probably the worst. that's when there's lots of honey wafting on the breeze and bears are looking for lots of calories to carry them thru the winter.