The next is an insect we call a wood-worm,
That lies in old wood like a hare in her form;
With teeth or with claws it will bite or will scratch,
And chambermaids christen this worm a death-watch;
Because like a watch it always cries click;
Then woe be to those in the house who are sick:
For, as sure as a gun, they will give up the ghost,
If the maggot cries click when it scratches the post
"Wood An Insect"
Jonathan Swift, 1725
The deathwatch beetle (Family: Anobiidae; numerous species, particularly Xestobium rufovillosum) is a somewhat common insect outdoors and found in both North America and Europe, particularly England. It is a wood boring beetle that helps the natural process of breaking down dead or decaying wood that has been subjected to fungal rot (itself part of the process). The insects burrow beneath the surface of the wood as part of their life cycle, further hastening its return to the soil.
But it is not its helpful nature in its out-of-doors habitat that gives this coleopteran its colorful (dreadful?) name. It is itsnoticablebehavior in-doors.
Deathwatch and the Tell-Tale Beetle
In the modern age, the concept of the deathwatch seems a part of the past, an almost nostalgic (in a romantic literary sort of way) part of eras long gone. There was a time when a significant number of people died at home, surrounded by friends and family. When someone became critically ill, someone(s) would sit up with the person through the long night, waiting and watching for either the dawning of another day or all too common inevitable passing. The closest thing today might occur in a hospital room or waiting room or a hospice. Despite the proximity, there is something sterile and detached in a well-lit room surrounded by medical equipment and personnel.
The term "deathwatch" is also derived from the idea of a ticking watch that ticks away toward the last moments of one's life. This is where the little beetle comes into the picture. One of its habits is that the adult taps its head or jaws against the walls of its tunnels or the surface of the wood that results in a clicking or ticking sound. That sound, heard inside the quiet and lonely room of the patient, came to be viewed as a foreshadowing of death for the sick person. The irony is that the sound is actually a mating call. Circle of life.
Meet the Beetle
With a name like "deathwatch beetle" one might expect a large, mean-looking insect with large grasping jaws or, perhaps, some sinister marking like a death's head moth (which has a pattern resembling a skull on its back). But the deathwatch beetle is fairly small and nondescript like one of many thousands of species of beetles.
The deathwatch beetle is dark red or greyish brown in color. Rather dull aside from small pale or yellowish hairs on the body. The head is difficult to see from above because of a prothorax that almost obscures it like a hood or helmet. The head is nearly under the segment, the whole situation described by some as "hunchbacked." Certainly no mammoth insect, the adult ranges from around 3 mm to 7 mm (though as small as just over 1 mm and as large as nearly 10 mm). In fact, the larvae are bigger11 mm to 15 mm. But hardly Them.
Lifestyles of the Xylophagous
Deathwatch beetles are rarely ever seen flying as they stick close to the food source, which being sedentary woodwhether outside or in a buildingis not difficult to do. Rather than arguing chicken or egg, we'll arbitrarily start with the egg. Deathwatch beetle eggs are laid in cracks, joints, crevices, or the small (slightly larger than the tip of a ball point pen) flight holes from which many of the beetles emerge as adults to mate and begin the cycle all over again. This is done on unfinished wood or wood that has already been compromised by fungal rot. The beetles need wood with a moisture content of around 13%-14% (and the larvae will probably die if it is drier than that). Generally the number of eggs laid are 40 to 60 (though numbers nearly four times that have been recorded) in clutches of three or four.
The eggs will hatch between two and five weeks after being laid depending on the environmental conditions. Warmer and more humid weather is preferred. Once hatched, the hook-shaped white larvae burrow into the surface of the wood, then turn 90° and continue burrowing along the grain. A single larva or even several larvae are not overly harmful but an infestation, especially working alongside other environmental factors, can become a serious problem, especially in old buildings.
An interesting thing about the larval stage is the variability in its length. Under "ideal" conditions (temperature, moisture content, et cetera) it can be as short as one year but it typically lasts much longer, as many as twelve years (even longer periods have been reported). It is the larval stage during which most of the damage to wood occurs. Signs of infestation include the small exit holes and "frass." Frass is...insect droppings. The frass from the deathwatch beetle is made up of "bore dust" and small fecal pellets. This makes it easier to determine it is a deathwatch wood borer as opposed to one of the other two main types, the powderpost beetle and the false powderpost beetle. As one source nicely puts its, deathwatch frass feels "gritty" while the others (which do not include pellets) feel either like talc or are simply hard to dislodge from the hole. They are pelletless. The source helpfully footnotes that the way to examine it is to "rub the frass between your fingers." "All employees must wash hands before returning to work."
When the larva has gotten large enough to pupate, it burrows near the surface and creates gallery where it pupates. Little happens externally during this period, though inside the adult insect is forming. The adult remains in the chamber until April to June (probably dependent on temperature). In most cases, the adult exits through the surface of the wood where it mates and the life cycle begins again. During that time, the insect does not eat; reproduction being its sole purpose. "Most cases" because it has been found that when conditions aren't conducive, adults have been found to mate within the chamber and even lay the eggs deeper into the wood. There is some speculation that it have been an adaptation to the use of surface chemicals but it isn't clear.
Eating house and home
What the beetle is known for beyond its moniker is the damage that an infestation can cause in (usually) old buildings or even furniture. Over time, it can threaten structural integrity of a building, making the building unsafe. That said, there is also reason to believe that the beetle should not be as feared as it might seem evident.
Becuase of the length of the lifecycle, the progress of an infestation can take many years or decades. The fact that the insect rarely moves far from the original ground zero of infestation also suggests that any building that has a clear problem is one that has had it for many years (which is why it has been of concern in England where there are many old buildings). Because of the environmental conditions required, newer structures are less likely to suffer an infestation because of drier interior conditions and chemically treated wood. Older buildings are more prone to draft and subject to humidity. They are more often unheated or poorly heated, more likely to have suffered minor rot during the past, and have untreated wood. This combines with the fact that most indoor attacks likely stem from a beetle presence in the wood during the original construction.
So, it's unlikely that one will see many "new" infestations if wood is kept in good condition, humidity low, and care is taken when choosing the original lumber. It is possible that they could be brought into a home if firewood containing eggs is stored near timber that has already has some decay, though this scenario is probably rare.
An inordinate fondness for left out trivia
If an adult insect is disturbed, it has a habit of drawing up its legs and playing dead.
Superstitions about the ticking of the beetle presaging death date back medieval Europe.
They are less likely to attack the heartwood, preferring the softer sapwood. But, as with most things involving this beetle, conditions can dictate behavior. If the moisture content of the wood is high enough, it will burrow into the heartwood, as well.
Unlike the other two types of wood boring beetles mentioned, the deathwatch beetle can digest wood cellulose due to yeast in its digestive system.
The deathwatch beetle is xylophagouswood-eating. Which is far more palatable (to continue punning) than some of the other common beetle diets such as adephagous (predators, they eat living things), necrophagous (carrion-eating), and coprophagous (dung-eating).
So popular its evocation, the beetle has becomes part of popular culture. There is (or was at one time) and one-man musical project out of Toronto, Canada called Deathwatch Beetle Repairman (put out on, you guessed it: Deathwatch Beetle Music). It has also been appropriated (in giant form, of course) as a monster in the MMORPG (Massive Multiplayer Online Roleplaying Game) Ultima Online. This beetle can spit poison and eats fruits and vegetables. Its "hatchling" cannot spit poison but still seems to like the same tier of the Food Pyramid.
Holy Trinity Church in Stratford-upon-Avon, the church where William Shakespeare was baptised and where he was buried is facing serious repair problems because of dry rot and deathwatch beetle infestation.
They are nocturnal. As if something called a "deathwatch beetle" could be anything else.
"Death watch Beetle" http://app-ltd.com/beetle.html
"Death Watch beetle" http://www.ri-research.com/otherservices/propertycare/PDFs/pcil2.pdf
"Deathwatch beetle" http://www.alltimepc.com/deathwatch_beetle.htm
"deathwatch beetle" http://www.britannica.com/eb/article-9029655
"Precision Treatment of Death Watch Beetle Attack" http://www.buildingconservation.com/articles/beetle/beetle.html
'"DEATHWATCH BEETLE"' http://www.ssproul.com/deathwatch.html
"Hydrex Pest Control - The Deathwatch Beetle" http://www.hydrexheat.com/pests/deathwatch.html
"Wood-Boring Beetles in Homes" http://www.ipm.ucdavis.edu/PDF/PESTNOTES/pnwoodboringbeetles.pdf