The deathwatch beetle, a wood boring beetle species (Xestobium rufovillosum) appears from the wood in April and May. In heated buildings however, this period may start as early as in January and extend all the way to June. These beetles product a hard, ticking sound, from which they derive their name. The development from egg to beetle takes at least three years. The growth of the larvae depends on the presence of fungi in the wood. Wood that is humid and prone to rot, is especially affected by these insects. They can deteriorate the wood very deeply.
The eggs are white and have an approximate 0.6mm diameter. As they are this small, they are rarely noticed. The larva has a white-yellowish colour and can grow up to 11mm in length. The beetle itself is dark-brown and has a grey-yellow colour, is slightly spotted and has a 6 to 8mm length. The beetle leaves the wood through self-bored openings. A large amount of these openings are often found close to each other, which make the wood appear like being hit by a shotgun. The openings are round and have a 2.5 to 4mm diameter.