Carpenter bees (Xylocopa) are large insects often considered a nuisance when they bore holes into wooden structures like decks, eaves, or fascia boards. Many people wonder about their ability to chew through wood. Carpenter bees do not possess teeth in the traditional sense, but they are equipped with highly specialized mouthparts that allow for their distinctive wood-boring behavior.
Mandibles, Not Teeth
The structures on a carpenter bee’s head often mistaken for teeth are actually mandibles. Mandibles are a pair of strong, hardened appendages common to most insects, functioning as powerful jaws for cutting and manipulating materials. Unlike vertebrate teeth, mandibles are extensions of the bee’s exoskeleton.
The female carpenter bee’s mandibles are notably robust and powerful. Their chitinous composition makes them durable enough to saw and rasp through wood fibers using a side-to-side motion, allowing the bee to excavate material efficiently.
The Mechanism of Wood Boring
Female carpenter bees use their specialized mandibles solely to create a nest cavity, not for food consumption. The process begins with the bee chewing a nearly perfect, circular entry hole, typically half an inch in diameter, through the wood’s outer surface. This initial hole is bored perpendicular to the wood grain for a short distance.
Once inside, the bee makes a sharp, 90-degree turn and excavates a tunnel, known as a gallery, that runs parallel to the wood grain. The chewed wood material is discarded from the tunnel entrance as coarse sawdust, sometimes called frass. The excavated gallery can extend several inches and is partitioned into individual cells. Each cell contains a single egg and a provision of pollen and nectar to sustain the hatching larva.
Biting Versus Stinging
Understanding the difference between a bite and a sting clarifies the actual threat carpenter bees pose to humans. Male carpenter bees are territorial defenders of the nesting site, often flying aggressively toward intruders. However, the male lacks a stinger entirely. Their aggressive dive-bombing is harmless, though they may attempt to pinch with their mandibles, causing no injury to human skin.
Conversely, the female carpenter bee possesses a stinger and has the capacity to sting. These bees are generally docile and non-aggressive, rarely stinging unless physically handled or severely provoked. Unlike honeybees, the female’s stinger is smooth, allowing her to sting multiple times without dying.