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Insects and other arthropods

Pigeon tremex

English
Tremex columba
Photo: Insectarium de Montréal (André Payette)
Tremex columba
  • Tremex columba
  • Tremex columba

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Description

Pigeon tremex look like long, cylindrical wasps. The thorax is reddish-brown and the abdomen is marked with yellow and black bands. The wings vary from golden brown to black. The adults of both sexes have pointed appendages at the end of the abdomen. The females also have a long, slender egg-laying organ, called an ovipositor. The adults are from 2.5 to 5 cm long, with the females slightly larger than the males.

The white larvae, 5 cm long, have light brown heads and a black spine at the tip of the abdomen. Their legs are relatively undeveloped.

Life cycle

After mating, the females lay their eggs in weakened or dead trees, using their ovipositors to deposit eggs beneath the bark. This egg-laying organ can sometimes remain caught, and the trapped female will die.

A type of fungus is also introduced into the wood when the eggs are laid. The fungus, Cerrena unicolor, is necessary for the larvae’s complete development. The fungus and pigeon tremex are said to be symbiotic, since their association benefits both species.

The larvae bore long tunnels into the wood to feed. Since there are no holes for the sawdust they create to escape, it accumulates in the tunnels. Pigeon tremex spend about one year in the larval state, and then three to five weeks as pupae. When they emerge as adults they make a perfectly round 3 mm hole in the bark to escape.

All in all, the pigeon tremex life cycle generally lasts 2 years.

Geographic distribution

This species is found in most provinces across southern Canada, and in many American states.

French name
Tremex
Scientific name
Tremex columba
English name
Pigeon tremex (pigeon horntail, horntail wasp)
Class
Insecta
Order
Hymenoptera

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