Thanasimus formicarius (order Coleoptera: family Cleridae) feeding on a captured pine shoot bark beetle, Tomicus piniperda (Coleoptera: Scolytidae). The clerid predators are attracted to odors from damaged Scots pines (Pinus sylvestris). The attractive odors are comprised of monoterpenes such as alpha-pinene, 3-carene, terpinolene, and beta-pinene as well as odors from beetles. The clerid predators land on a pine and wait for Tomicus beetles to arrive. The Tomicus beetles are attracted by the monoterpenes and fly to the tree when the temperature is just above 12-13 degrees C (53-55 F). The Tomicus female beetles want to bore into the tree and lay eggs, while the males are looking to mate with females. The clerids walk about and simply bump into a Tomicus beetle whereupon they grab it and begin to tear off its legs. Then they insert their mandibles into the connecting areas between the head and thorax and between the thorax and abdomen and pry apart the beetle. In about 10-20 minutes the beetle is eaten and cast away. A clerid can eat several Tomicus beetles a day but usually get too full after about 10 to eat any more, then they ignore bark beetles. The female clerids search for bark beetle holes to lay eggs in (their larvae eat the larvae of bark beetles). The male clerids search for females which they bump into and grab but this time they mate for a few minutes before parting. This occurs for several days in the early spring (April) in southern Sweden.
image (C) 1995 by John A. Byers