[vanattab]

Maybe the bee dying is just the side effect of what it's really trying to do. Maybe if the the bees stingers did not have barbs they would just annoy a bear a little and he would happly suffer a few stings to get the honey. But with barbs the stinger stays in the mammal and irritates the skin for longer periods of time. If course this means the bee has its stinger ripped off and dies but his stinger still causes damage and has deterent affect. Also I imagine a bee that did not die when stinging still stood a good chance of dying due to slap from hand or paw anyway. Or if a bear is raiding hive thoese bees are died anyway if they don't stop him so you might as well inflict maximum damage

[slowhand09]

I can vouch for the veracity of bumblebees. I disturbed a nest and was chased by a couple of bees. I took 6 hits from one bee. 1st one felt like a rock hit me. Each after was similarly unpleasant. And after the 2nd each one was while I was in full sprint. I eventually escaped by jumping in a car.

[WalterBright]

Having been stung by bees, one really wants to get the stinger out. If one doesn't have fingers, that could be very annoying to the stingee, and certainly a further deterrent.

[hgsgm]

A stinger could, in principle, evolve to becomd separable and regenerable, like a lizard tail.