A carpenter bee is a large black bee that doesn’t have wings. Like most bees, carpenter bees are opportunistic and will take advantage of any opening in wood.
Adult carpenter bees overwinter in tunnels. In spring, they emerge and mate. Once fertilized, females start a new tunnel or enlarge existing ones. To start a tunnel, the female chews a perfectly round hole about half an inch in diameter into the surface of the wood. The tunnel then begins at a right angle to the wood’s grain and may extend 6-12 inches. Once the tunnel is complete, the female stocks it with a dough-like mix of flower pollen and nectar she makes called bee bread, then lays her eggs in cells that are about an inch long. The eggs hatch during summer and the young bees eat bee bread. When the bees reach maturity, they leave their cells one by one and fly off to pollinate flowers.
Once the flowers are done blooming, the bees return to their tunnels and hibernate over winter. It’s important to repair and seal or fill all holes in decks or exterior parts of a home to prevent carpenter bees from using them for nests next year.
Carpenter bees are very effective pollinators. Their aggressive buzzing, however, can be frightening. The good news is that carpenter bees don’t sting unless threatened directly with a force equal to their own size. If you do happen to get stung, the pain will be similar to a bee sting from any other bee.