These gentle giants get their common name from their habit of using their strong mandibles to excavate precisely rounded tunnels inside wood. They prefer soft, weathered wood for this purpose, such as standing dead trees. If this is not readily available, some species (like our eastern Xylocopa virginica) may decide to take up residence in fence posts or structural timbers such as fascia,decks or porch railings, and become a minor nuisance. Small piles of sawdust or smears of frass (excrement) are a tell-tale sign that carpenter bees are at work! To deter them, simply apply a fresh coat of paint or stain to any exposed or weathered wood surfaces.
Inside the tunnel, the female deposits loaves of ‘bee bread’—balls of pollen and nectar-- upon which she lays her giant eggs (up to 15 mm long!). She forms partitions between each egg cell by mixing her saliva with sawdust, creating a substance very similar to particle board. Thus, each larva is supplied with ‘a room of its own’, along with all the food it will need to grow.
In spring, you’ll often see several of these large bees zooming about, buzzing loudly. They may seem threatening, but these are just territorial males who are out to impress the ladies. And rather than representing a threat to us, they’re all talk—male carpenter bees don’t even have stingers!
In our gardens, carpenter bees are generalists and may be found foraging and pollinating a wide variety of plants.
Photo: Amy Helser