Species Xestobium rufovillosum
Photomicrograph of the mouth of a death-watch beetle
The name ‘death-watch beetle’ comes from the tapping sound, which can be heard in warm weather between March and June, made by beetles banging their heads against the walls of the tunnels to attract mates. This insect is often found in churches hence the association with death reflected in its name.
In nature, the eggs are usually laid on dead branches of various deciduous trees. In buildings, eggs are confined to old timbers, almost always oak. Damage to old timber can be very severe and result in total failure of load bearing beams.
Larvae can only survive in timber that is damp enough for fungi to flourish. The fungi produces enzymes that help to break down the wood into digestible constituents, such as lignin and cellulose, to various sugars, which then can be absorbed as food.
Books stored on woodworm-infested wooden shelves can have eggs laid on them resulting in a complete life cycle being passed within the book. The frass that is produced by the larvae boring and eating their way through the wood is in the form of bun-shaped pellets and is very distinctive to this species which aids its identification.