Deathwatch beetle (Anobiid) Various scientific names Class: Insecta Order: Coleoptera Families: Anobiidae

 

Size: Deathwatch beetle (anobiid) adults are 1/32-3/8 in (1.1-9 mm) long; those in structures are usually 1/8-1/4 in (3-7 mm) long. Mature larvae are up to about 1/2 in (11 mm) long.

Characteristics: Adult: hood-like prothorax usually encloses head, hiding it from top. Club on antenna is not symmetrical, the last 3 segments are usually lengthened, and sometimes also expanded. Larva is C-shaped with an enlarged thorax, short 2-segmented antennae, and hairy 4-segmented legs.

Color: The adult deathwatch beetle is reddish brown to nearly black, sometimes with areas of pale hairs. Larva is nearly white.

Droppings: Powdery frass containing pellets that are gritty and lemon-shaped in softwoods, but tightly packed in hardwoods. (Two anobiids do not produce pellets, but their frass is tightly packed.)

Where found: Deathwatch beetles (anobiids) are found around the world, with 310 species in the United States. 

Comparison with other species: Anobiids or deathwatch beetles are more common than Powderpost Beetles (lyctids) and False Powderpost Beetles (bostrichids). The name deathwatch, for some species, refers to the mating call, a tapping sound made by jaws hitting the wood walls of their tunnels. When heard while sitting through the night with a sick person, there was a superstition that the invalid would soon die. Bostrichids have heads that are not easy to see from the top, short antennae with compact clubs, and rasp-like teeth. Lyctids have flat bodies, with heads easy to see from the top. Bark and ambrosia beetles have elbowed antennae with symmetrical clubs. Dermestid beetles have antennae with symmetrical clubs.

Habitat: Sapwood of softwoods and hardwoods with a moisture content of 13-30%.

Food: Studies indicate that anobiids, unlike bostrichids and lyctids, can digest wood cellulose, due to yeast cells in their digestive tracts. 

Biology: Nocturnal. Female deathwatch beetles (anobiids) lay their 20-60 eggs in cracks, in old exit holes, and under surface splinters of wood. After hatching the larvae bore against the woodgrain a ways, then turn and go along the grain, packing their frass and fine wood fragments into the tunnel behind them. In a softwood (conifer) this mixture feels gritty due to the shape of the pellets; in a hardwood (broadleaf) the mixture is tightly packed and not gritty. With each larval molt and for pupation the tunnel is made wider. The adult bores straight to the surface of the wood to exit. (This differs from bostrichids, which bore almost to the surface first before pupating.) The adult does not feed, but looks for a mate. Development from egg to adult takes 1 year in good conditions, but often 2-3+ years indoors. 

Damage: Damage to structural timbers, lumber and lumber products, especially in the southeastern states and in moist coastal states. In structures, most species attack only older wood 9-10+ years old.

Invasion: Female deathwatch beetle usually lays eggs on the same wood from which she emerged. 

How to detect and control anobiids or deathwatch beetles:

Detection:
 

• Round exit holes, diameter 1/16-1/8 in (1.6-3.2 mm) with piles of gritty powder nearby.
• Spring: new exit holes.
• Summer: new holes, adults present.
• Fall: larvae still active inside wood. 

Control: If infestation is active, control by
 

• Localized treatment.
• Replacement of wood.
• Fumigation by a licensed technician.
• When using pesticide, be certain it is registered for target pest/location, read entire label first, and follow all directions, restrictions and precautions.