Ovipositor

female ichneumon wasp

The morphology of the ovipositor is extremely varied among insects - they may be short or long, thin or thick, blunt or sharp. The most diverse ovipositor morphology is probably found in the Hymenoptera (bees, wasps and ants). Some females of Ichneumon wasps (photo above) have a very long, thin ovipositor which may be up to 7cm in length, allowing the female to inject her eggs into hidden hosts such as leaf-rolling or stem-boring caterpillars. Other species of parasitoid wasp have large teeth on the ovipositor in order to 'drill' through wood to reach their host.

One of the most interesting modifications of the ovipositor is found in stinging Hymenoptera, where the ovipositor is not used to lay eggs at all but is instead modified into a stinger. The venom is ejected at the tip of the stinger and the eggs are laid from a genital chamber which is located at the base of the ovipositor.

Photo courtesy of Keith Power, Toowoomba, Qld.