Deathwatch Beetle

The deathwatch beetle is a species of woodboring beetle that sometimes infests the structural timbers of old buildings. The adult beetle is brown and averages about seven millimeters in length. Eggs are laid in dark crevices in old wood, where the larvae bore in and feed for up to ten years before pupating and emerging as adults; timber that has been dampened and softened by fungal decay is what the larvae are able to chew through, using enzymes in their gut to digest the wood's cellulose and hemicellulose.