Pigeon tremex, Tremex columba Linnaeus (Hymenoptera: Siricidae). Photo by Drees.
Common Name: Pigeon tremex
Scientific Name: Tremex columba Linnaeus
Order: Hymenoptera
Description: The adult wasp is 1 to 1-1/2 inches long, with a straight-sided cylindrical reddish-brown body marked with a yellow banded and black pattern on the abdomen. Wings are tinted dark brown to black. Both sexes possess projections on the end of the abdomen (“horntails”). In addition, females have a longer projection that arises from the undersurface of the abdomen called an ovipositor, used to deposit eggs in tree trunks. Siricidae are also called wood wasps. Adults may be confused with sawflies.
Life Cycle: Females deposit eggs singly, into the wood of host trees. Larvae are grub-like, whitish, deeply segmented and have poorly-developed legs. They develop through several stages (instars) reaching a size of about 2 inches before pupating. Development is normally completed in 2 years.
Habitat, Food Source(s), Damage: Mouthparts are for chewing. Larvae develop in the trunks of dead and dying trees, including beech, elm, maple, oak and others. Larvae produce a round tunnel in the sapwood and heartwood.
Pest Status, Damage: Although larval stages develop in trunks of trees, host trees are usually stressed, dying or dead from other causes; damage caused by larvae seldom threatens tree health, although female wasps can infect the host tree with a tree-rotting fungus (Cerrina unicolor); adults do not sting; medically harmless.
For additional information, contact your local Texas A&M AgriLife Extension Service agent or search for other state Extension offices.
Literature: Borror et al. 1989; Johnson & Lyon 1988; Swan & Papp 1972.