Wasps are attracted to wood fibers, but not as a food source. This behavior is exclusive to specific social wasp species that utilize the wood’s cellulose to manufacture the distinct paper-like substance forming their nests. These insects seek raw building materials, which is a significant distinction from other wood-destroying pests. The attraction is strictly utilitarian, focused on harvesting the fibrous content to create the lightweight, protective covering for an expanding wasp colony.
The Difference Between Attraction and Harvesting
Wasps that construct paper nests engage in harvesting, actively removing the outermost layers of wood to obtain cellulose. This process turns wood fibers into a pulp that is shaped into the nest structure. The insect uses its powerful mandibles to scrape off minute fragments, which are chewed and mixed with saliva. This mixture creates a pliable, quick-drying paste, often called carton, which functions similarly to paper-mâché.
The preference is generally for soft, weathered, or unpainted wood because the fibers are easier to tear away and process. Untreated surfaces like decking, fencing, or weathered siding offer readily available, softened fibers that require less energy to harvest. Unlike pests such as termites or carpenter bees, the wasp’s interaction with the wood is superficial. The damage is purely cosmetic and material-gathering, focused only on extracting necessary fibers rather than compromising the lumber’s structural integrity.
Species That Harvest Wood for Nesting Material
The primary culprits responsible for harvesting wood belong to the family Vespidae, including social wasps and hornets. Species within the Polistes genus, known as paper wasps, frequently harvest wood fibers from residential structures. These wasps typically build umbrella-shaped, open-comb nests suspended beneath eaves or sheltered overhangs. Their constant foraging results in visible, long, scraped grooves or a fuzzy appearance on wood surfaces as they follow the grain.
Another prominent species is the Bald-faced Hornet (Dolichovespula maculata), which is actually a type of yellowjacket. This species constructs large, enclosed, football-shaped nests requiring a significant volume of wood pulp for the protective outer envelope. Even some Vespula yellowjacket species, like the German Yellowjacket (Vespula germanica), collect wood fibers, particularly when the queen establishes the initial nest structure. Identifying the damage—a surface-level scraping—helps distinguish it from the perfectly round bore holes created by carpenter bees.
Protecting Wooden Structures from Wasp Damage
Preventing wasps from harvesting wood centers on making the cellulose fibers inaccessible. The most effective strategy is applying a protective finish to all exposed wooden surfaces, which hardens the outer layer and locks down the fibers. Using high-quality paint, stain, or a clear polyurethane sealant creates a barrier that wasps cannot easily penetrate to scrape off material. This application denies the insects the loose fibers they seek for manufacturing their paper nests.
Routine inspection of weathered or untreated areas, such as railings or fence posts, helps identify early scraping activity. Treating affected areas with a fresh coat of sealant or tung-oil deters further harvesting by making the surface too hard or slick. Sealing potential nesting locations with physical barriers prevents the colony from establishing nearby, reducing the localized demand for building material. Vulnerable spots, such as vents, soffits, and openings around eaves, should be sealed with caulk or covered with fine-mesh screening.