Do they sting?

 

You don't have to worry about getting stung! Mason bees are extremely docile bees. All the females are fertile, which means there is no queen bee for the other bees to protect. They will happily go about their day visiting flowers and carrying mud to the nesting block and not be bothered or aggravated by your presence. You can easily stand in front of the bee house and watch them fly in and out without having to worry about getting stung. Recent experiments out of the Logan, Utah Bee Lab have shown that mason bee bodies do not contain any venom unlike honey bees or wasps. This means that even if they were to sting you (which might only happen if you were to pinch them or otherwise try to kill them) it would feel more like a mosquito bite than a sting.