The Carpenter Bee: A Pretty Cool Pest

For a few years we've been lucky(?) to have carpenter bees around our house. For some reason despite knowing that they are probably ruining the railings on our front porch, I just think they are cool and haven't done anything to get rid of them. I'm sure I wouldn't say the same thing about termites, but I just find carpenter bees fascinating. 

If you have carpenter bees around the house, you probably know it either from the tell-tale signs they leave behind or from a big black and yellow bee that flies right up to you. The signs of carpenter bees are unmistakable. They chew perfectly round smooth half-inch holes into wood and leave sawdust on the ground beneath the holes. There is often a yellowish stain beneath or around the hole that is fecal matter exuded by the female. These holes serve as overwintering hibernation spots for the bees and as the brood chambers where the females lay eggs and the young bees develop. If you take a flashlight and look up into one of the holes, you maybe be able to see that they start out straight but then begin to branch off at right angles. These tunnels are lengthened into one or more T-shaped chambers where the female lays eggs and where they hatch and develop into adult carpenter bees. The female creates the tunnels by chewing the wood and then divides them into separate chambers using the chewed wood fibers. An egg is laid in each chamber and provisioned with pollen and nectar that she gathered. This will serve as food for the bee larva once the eggs hatch. After an appropriate amount of time, the larva pupate and then in time hatch into adult bees.  

Carpenter bees are ecologically important as pollinators and as a food source for other animals like woodpeckers that drill into wood looking for them. They are often mistaken for bumblebees but can be easily told apart. Bumblebees have a hairy abdomen which is often yellow and carpenter bees have a shiny black one. Male carpenter bees are also very easy to separate from females by their light yellow face.

We are lucky that our carpenter bees are nesting in the porch railing right by the front door because that allows us to easily watch the cool behaviors of the male bees. The big male bees are constantly hovering around the porch keeping an eye out for anything that enters their territory around the nest. When something (or someone) enters his territory, he rapidly flies right up to the intruder to investigate, often coming within inches of our heads. While this is a bit startling and there is a natural human panic reaction to quickly move way, the males are totally harmless. They do not sting and don't even possess a stinger. By sitting quietly near the nest it is easy to watch their interesting behavior. When the females leave the nest, they don't hover like the males, but apparently head off in search of nectar and pollen for their own food and to provision the egg chambers. They must not leave too often because I don't ever recall seeing a bee exit the nest hole. But I'm not too sure about this and will try to spend some more time watching to see what happens. 

If you are lucky enough to have carpenter bees nesting around your house, take a few minutes and observe the really interesting behavior of the males. While they might do a bit of minor damage, their importance as pollinators and their cool behavior and interesting life history, is worth it.