Carpenter bees do not eat wood. Despite their name and their habit of drilling perfectly round holes into wooden structures, they never consume the wood itself. They are nectar and pollen feeders, just like honeybees and bumblebees. The wood shavings they produce during excavation are either discarded or repurposed as construction material for their nests.
What Carpenter Bees Actually Eat
Carpenter bees are generalist foragers that visit a wide variety of flowering plants in gardens, farms, and wild areas. Adults feed on nectar for energy and collect pollen as a protein source. They’re especially effective at a technique called buzz pollination, where they vibrate their powerful thoracic muscles to shake pollen loose from flowers that other bees can’t easily access.
They also provision food for their young. Inside their wood tunnels, female carpenter bees create individual cells, each stocked with a small loaf made from pollen and nectar. A single egg is laid on each loaf, and the developing larva feeds on that pollen supply over several weeks until it matures into an adult. Wood plays no role in the diet at any life stage.
Why They Drill Into Wood
If they don’t eat it, why bore into it? Carpenter bees excavate wood to build nests. A fertilized female uses her strong mandibles to chew a perfectly round entrance hole, roughly the diameter of your little finger. After boring straight in for a short distance, she makes a right-angle turn and tunnels parallel to the wood surface, creating a gallery where she constructs five or six individual egg chambers.
The sawdust produced during drilling doesn’t go to waste. The female mixes wood pulp with her saliva to build partitions between each egg cell, sealing them off one by one as she works from back to front. The rest of the sawdust is pushed out of the entrance hole, which is why you’ll often see a small pile of fine wood shavings on the ground below an active nest.
Wood Types They Prefer
Carpenter bees are picky about their nesting sites. They strongly prefer bare, unpainted, or weathered softwoods like redwood, cedar, cypress, and pine. Fascia boards, deck railings, porch ceilings, and exposed eaves are common targets.
Painted or pressure-treated wood is somewhat less attractive, but it’s not a guarantee. Several coats of oil-based or polyurethane paint may discourage drilling, though experienced homeowners report that paint alone doesn’t make wood completely bee-proof. A quality exterior stain or varnish on all exposed wood surfaces remains one of the most effective long-term deterrents.
The Real Damage Problem
A single carpenter bee tunnel may not cause serious harm, but these bees tend to reuse and expand the same galleries year after year. Over time, a well-established nesting site can develop an extensive network of branching tunnels that weakens the structural integrity of the wood. Railings, support beams, and trim boards are all vulnerable to this cumulative damage.
The bees themselves aren’t the only concern. Woodpeckers are major predators of carpenter bees and their larvae. They’re drawn to the sound of active boring and will tear into wooden structures to reach the insects inside. The holes woodpeckers leave behind are far larger and more destructive than the neat, round openings the bees create. A carpenter bee infestation that attracts woodpeckers can lead to significant cosmetic and structural damage.
How to Protect Your Wood
Prevention works better than treatment. Painting or staining all bare wood surfaces is the simplest first step and one of the most effective over the long run. Carpenter bees are far less likely to drill into a finished surface than raw wood. Multiple coats provide better protection than a single layer.
If you already have active holes, don’t seal them right away. Plugging an entrance hole while bees are still inside just forces them to chew a new exit. If you’ve treated the tunnels, leave the holes open for seven to ten days so returning bees contact the treated surfaces. Seal in early fall, once you’re confident the galleries are empty, using wood putty, cork, or caulk.
Non-chemical options include carpenter bee traps, which are designed to mimic the look of a nest entrance and catch bees as they investigate. Hanging traps directly over existing holes, or at the peaks and sunniest corners of your home if you’re trying to prevent new activity, gives you the best results. Citrus-based sprays are another natural option, as carpenter bees tend to avoid citrus oils.
Their Value as Pollinators
For all the frustration they cause homeowners, carpenter bees are important native pollinators. Roughly 15% of agricultural crops in the United States are pollinated by native bees, and carpenter bees are among the most effective in that group. Their buzz pollination technique makes them especially valuable for crops like tomatoes, blueberries, and eggplants, where pollen is tightly held inside the flower.
They do have one less helpful habit: nectar robbing. Some carpenter bees use their mouthparts to cut a slit at the base of a flower and steal nectar without touching the pollen, bypassing pollination entirely. Still, their overall contribution to pollination far outweighs the occasional shortcut, and many gardeners consider them a net positive despite the occasional hole in a fence post.