Ips typographus (Coleoptera: Scolytidae) and Thanasimus formicarius (Coleoptera: Cleridae) The bark beetle on the left of photo is beginning to bore into the thin bark of Norway spruce. In a few hours the beetle will be under the bark and safe from the reach of the predator (T. formicarius) on the right of the photo. This predator, although having 400 ommatidia (facets) in their eye still do not usually find bark beetles by vision since in many instances (including this one) the clerid walked right by the beetle. This beetle was hungary since I later placed a bark beetle in front of its antennae and elicited an attack and feeding response. Most of the time the clerid seems to only bump into walking or exposed bark beetles and then using chemical cues decides to make an attack. All species of bark beetle (and even small weevils) are preyed upon. The clerid lifts the bark beetle off the bark and then proceeds to bite off almost all the legs presumably so the beetle can not crawl away. Then the clerid bites into the soft tissue between the thorax and the abdomen and between the thorax and head. All the soft insides are eaten out leaving a hull of the insect carcass (usually in about 10 minutes at room temperature). Several bark beetles can be eaten per day, but I have not had any feed on more than about 8 bark beetles (when kept in the refrigerator and taken out for feeding periods). Click to see T. formicarius eating a bark beetle Tomicus piniperda.

Images © 1996 by John A. Byers, Chemical Ecology.