Wood boring beetles, often referred to as woodworms during their larval stage, are insects whose larvae cause significant damage by tunneling through timber. The vast majority of these species, which include common household pests, possess wings and are capable of flight in their mature form. The adult beetle stage is relatively brief, lasting from a few days to a few weeks. Flight is a fundamental biological action during this period, responsible for establishing new infestations and the continued spread of the pest.
The Purpose and Timing of Adult Flight
Flight is a behavior serving the two main goals of the adult beetle’s short life: dispersal and reproduction. Once the larva has completed its development inside the wood, it pupates and emerges as a winged adult, chewing an exit hole to leave the material. The adult must immediately fly away from the original wood source to find a mate and locate new, suitable timber in which to lay eggs, ensuring the next generation.
This emergence is highly dependent on environmental conditions, typically occurring during the warmer months of spring and summer, often between April and September. Many species are attracted to light, meaning newly emerged adults often fly toward windows and doors as they try to leave. The adult’s life is solely dedicated to this brief reproductive cycle, which is why flying beetles found in a home are often the first visible sign of a long-standing, mature infestation.
Common Wood Borers That Take to the Air
Several families of wood borers commonly encountered in structures use flight as their primary means of movement. The Powderpost beetles, encompassing Lyctid and Anobiid species, are small, destructive fliers that are frequently the source of household infestations.
Lyctid Powderpost Beetles
Lyctid Powderpost beetles are slender, ranging from 1/8 to 1/4 inch long, with colors from reddish-brown to black. They exclusively target hardwoods like oak and ash. Their flight allows them to locate suitable wood with large pores for egg-laying.
Anobiid Powderpost Beetles
Anobiid Powderpost beetles, which include the Common Furniture Beetle and Deathwatch Beetle, are similar in size but can attack both softwoods and hardwoods. The Common Furniture Beetle is small, around 1/8 inch long, and has a cowl-like hump that covers its head. The Deathwatch Beetle is slightly larger, up to 7 millimeters long, dark reddish-brown, and favors older, damp hardwoods.
Long-horned Beetles
Another significant group of fliers is the Long-horned beetles, such as the Old House Borer. These are larger, measuring 5/8 to 1 inch long, and are brownish-black with a distinct pair of gray spots on the thorax. This species primarily infests softwoods, such as pine, and the adults are strong fliers that actively search for new wood surfaces.
How Flight Impacts Infestation and Spread
The flight capability of adult wood boring beetles has implications for how an infestation begins and spreads. Flying adults are the vector that transports the infestation from the original piece of wood to new, uninfected timber within a structure or to neighboring buildings. They can enter a home through open doors, windows, vents, or other small openings, attracted by the light.
Once inside, the female beetle seeks out exposed or unfinished wood surfaces, such as floor joists or the backs of furniture, to deposit her eggs in cracks and crevices. This ability to fly means that an infestation is rarely localized to the initial piece of infested material. Infestations can rapidly spread throughout a home’s structural components or even across a neighborhood.
Finding a dead beetle near a window or on a windowsill is a consequence of the flight stage, indicating a successful emergence from the wood. This visible sign confirms that the hidden larval damage is mature and that new adults are actively mating and seeking fresh wood. Controlling the spread requires preventing these adult beetles from flying to new locations and laying eggs.