Encyclopedia of Parasitology

2016 Edition
| Editors: Heinz Mehlhorn


  • Heinz Mehlhorn
Reference work entry
DOI: https://doi.org/10.1007/978-3-662-43978-4_3959

The name comes from Greek: ichneuein = to hunt out or hunt up.

The family of the so-called parasitic wasps (e.g., Ichneumon nigritarius) represents the biggest group among the Hymenoptera and among the so-called  parasitoids, which also include species from other insect groups. The European wood wasp Rhyssa persuasoria reaches a body length of up to 5 cm and has a similarly sized ovipositor, by the help of which it injects its eggs into larvae of butterflies (Lepidoptera), beetles (Coleoptera), or even eggs of spiders (Arachnida). Since these ichneumonids mostly kill their hosts, they are called  parasitoids, since the interest of “true parasites” must be to keep alive their hosts, since they have no more a free-living stage.

Ichneumonids have in nature an enormous impact on the control of pests reaching infestation rates of up to 80 % among their host species. Some of these species are now bred in industrial cultures and were used – especially in stores or in greenhouses – for pest control (e.g., against moths). Even Charles Darwin mentioned the ichneumonids in a letter to the American naturalist Asa Gray, when he expressed his doubts on the existence of a “good God” that should have created willingly also creatures that are cruel to others saying:

I own cannot see as plainly as others do, and as I should wish to do, evidence of design and beneficence on all side of us. There seems to me too much misery in the world. I cannot persuade myself that a beneficent and omnipotent God would have designedly created the Ichneumonidae with the express intention of their feeding within the living bodies of caterpillars, or that a cat should play with mice.

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  1. 1.Institut für Zoomorphologie, Zellbiologie und ParasitologieHeinrich-Heine-UniversitätDüsseldorfGermany