About Hadrobregmus pertinax (Linnaeus, 1758)
Hadrobregmus pertinax is a species of woodboring beetle, belonging to the genus Hadrobregmus in the family Ptinidae. Adult Hadrobregmus pertinax are black, have yellow hairs at the back corners of the head, and measure 4–5 mm in length. Larvae of this species are white, around 5 mm long, and live inside decaying wood. The larval stage of this beetle can last for many years. In Finnish, this species is called "kuolemankello", which literally translates to "clock of death". This name comes from the ticking-clock-like sound males produce when striking their heads against wood surfaces to attract mates. In Finland, Hadrobregmus pertinax is the most destructive insect affecting buildings. It is able to survive Finland's long winters when temperatures drop below freezing. Since its larvae develop in decaying wood, the presence of this beetle indicates existing moisture damage to a structure. Fixing the moisture problem will cause the beetles to leave the area.
