Wood-Boring Beetles at Chambord

I did some reporting on news from the Château de Chambord this summer (see post on August 11, Changes Planned for the Château de Chambord?). Shortly after that, a beam in the château broke, causing a group of tourists to crash through the floor to a room below (see my post on August 19, Accident at Chambord). Further investigation has revealed the cause and suggests that other rooms may need to be closed from tourist traffic, as reported in the newspaper Libération (Chambord débarasse son plancher, November 15), of which I translate an excerpt here:

Two young people are hunting a wood-eating insect in the Château of Chambord. Since six visitors fell through a floor in the king's wing on August 17, the cracking of inlaid wooden floors is causing worry. Have gluttonous deathwatch beetles tucked in on other beams? The accident resulted in only light injuries: the tourists' fall was broken by a pile of statues, stored in the stone closet, 2.5 meters [8.2 feet] below. But the panic has been intense. A fall of 7.5 meters [24.6 feet], the normal ceiling height here, could be more harmful, and the Loire Valley castles don't need any bad publicity when its American clientele starts pouting.

Frédéric works at the Wood Rheology Laboratory at the University of Bordeaux; Stéphanie has started her own company, Xyloméca. "Our job is to evaluate the technical resistance of wood," she specifies. The monument is immense (440 rooms, 80 of which are open to 800,000 visitors annually), and for several days, they have been sounding the "support beams" identical to the one which gave way. [. . .]

The beam that broke is at ground level, victim of an attack by large deathwatch beetles. No suspicious sawdust indicated their presence. The insects died some years ago, when all that remained was wood too dry to gnaw. Why did the beam hold so long before giving way? The experts have no response. "For deathwatch beetles, there must be water and edible fungus present. It all depends on the history of each beam. The one that gave way may be the only one affected," says Frédéric.

After having inspected 18 rooms, or about 22 to 24 support beams, he remains cautious: "There are two or three we have doubts about." [. . .] Technology will certainly allow the installation of detectors able to indicate degradations as they happen. For walls, "fissurometers" measure the evolution of flaws. "Up to now, they have been stable," remarks Jean-Lucien Guenoun, government architect of buildings in the Loir-et-Cher. A water leak, a statue that comes unsoldered, a weathervane that dangles loose. Accidents are rare, but about twenty years ago, a little girl was killed in the neighboring Château of Blois, crushed by a block of stone.

If I had not been a music major, I probably would have studied entomology, and insects still fascinate me, so allow me this short digression from the arts. The grosse vrillette (Xestobium rufovillosum de Geer), or deathwatch beetle (see picture above), is a member of the order Coleoptera (you can see other pictures of the beastie here, which ranges in size from 5 to 12 mm, or between 3/16 and ½ inch). Coleopters are extraordinarily diverse, with over 350,000 identified species, the most of any type of organism on the planet. They are also often quite destructive, and in this case they have displayed excellent taste. (Take a look at the damage they can do to wood: no wonder the beam gave way at Chambord.) This beetle gets its name from the sound the male makes to attract females by tapping his armored head on a wood surface, usually at night. If it was heard by someone sitting up late at night with a sick person, the tapping was interpreted superstitiously as an omen of death.