Here’s a good idea if you encounter a bunch of wasps/bees/hornets/yellowjackets on the wall:
“Smoke ’em if you’ve got ’em. Beekeepers use smoke to dope up their livestock before harvesting honey. Tape a pack of butts and a lighter to your helmet, and light up if you encounter a nest. The smoke might buy you enough time to climb to safety.”
Or, do what I do – on a route with a lot of wasps, offer a belay to your climbing partner so s/he goes first. That way, the meanest ones are cleared out so you can climb more easily.