Ichneumon Wasps

Description:

Ichneumon wasps differ from typical wasps, which sting in defense (Aculeata: Vespoidea and Apoidea), in that the antennae have more segments; typically 16 or more, whereas the others have 13 or fewer. An ichneumon wasp's abdomen is characteristically very elongated, unlike in their relatives the braconids. This lengthened section may also be segmented. Female ichneumon wasps frequently exhibit an ovipositor longer than their body. Ovipositors and stingers are homologous structures; some Ichneumons inject venom along with the egg, but they do not use the ovipositor as a stinger, per se, except in the subfamily Ophioninae. Stingers in aculeate Hymenoptera - which like Ichneumonidae belong to the Apocrita - are used exclusively for defense; they cannot be used as egg-laying equipment. Males do not possess stingers or ovipositors in either lineage.

Habitat:

species are found in a wide range of habitats, but tend to occur in woodlands and farmland

Notes:

Ichneumon wasps are parasitoids; females lay their eggs on a caterpillar and the wasp larva burrows into and develops inside this host, eating its internal tissues and eventually killing it after it pupates. The adult ichneumon flies emerge from the remains of the dead host and are active at night (1) (2). Two generations are produced each year; the adults of the first generation are present from May to June, those of the second generation from November to December (1).