| Ichneumon wasps | |
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| Metopius sp., Rhône (France) | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Hymenoptera |
| Suborder: | Apocrita |
| Superfamily: | Ichneumonoidea |
| Family: | Ichneumonidae |
| Subfamilies | |
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Acaenitinae |
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Ichneumonidae is a family within the insect order Hymenoptera. Insects in this family are commonly called ichneumon wasps. Less exact terms are ichneumon flies (they are not closely related to true flies), or scorpion wasps due to the extreme lengthening and curving of the abdomen (scorpions are not insects). Simply but ambiguously these insects are commonly called "ichneumons", which is also a term for the Egyptian Mongoose (Herpestes ichneumon); ichneumonids is often encountered as a less ambiguous alternative. Ichneumon wasps are important parasitoids of other insects. Common hosts are larvae and pupae of Coleoptera, Hymenoptera, and Lepidoptera.
There are over 60,000 species worldwide, and approximately 3,000 in North America - more than any other Hymenoptera family. The distribution of Ichneumonidae is one of the most notable exceptions to the common latitudinal gradient in species diversity because it shows greater speciation at high latitudes than at low latitudes[1].
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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.
 Lissonota sp. (Banchinae) |
 Ichneumon suspiciosus (Ichneumoninae) |
 Ophion luteus (Ophioninae) |
 Unidentified South African species. |
 Netelia producta |
 Male Netelia producta - note the lack of stinger/ovipostor |
 Grey spiderkiller |
Some species of ichneumon wasps lay their eggs in the ground, but most inject them directly into a host's body, typically into a larva or pupa. Host information has been notably summed up by J.F. Aubert, J.F. Perkins, and H.T. Townes and coworkers[2].
In some of the largest species, namely from the genera Megarhyssa and Rhyssa, both sexes will wander over the surface of logs, and tree trunks, tapping with their antennae. Each sex does so for a different reason; females are searching for the scent of wood boring larvae of the horntail wasps (hymenopteran family Siricidae) upon which to lay eggs, males are searching for emerging females with which to mate.
Upon sensing the vibrations emitted by a wood-boring host, the female wasp will drill her ovipositor into the substrate until it reaches the cavity wherein lies the host. She then injects an egg through the hollow tube into the body cavity. There the egg will hatch and the resulting larva will devour its host before emergence. How a female is able to drill with her ovipositor into solid wood is still somewhat of a mystery to science, though it has been found that there is metal (ionized manganese or zinc) in the extreme tip of some species' ovipositors. The adult insect, following pupation is faced with the problem of extricating itself from tunnels of its host. Fortunately, the high metal concentrations are not limited to the female's ovipositor as the mandibles of the adult are also hardened with metals and it uses these to chew itself out of the wood[3].
1 Tapping with her antennae, the wasp detects
and localizes scent and vibrations that indicate a host is
present.
2 With the longer ovipositor, the wasp drills a
hole through the bark.
3 The wasp inserts the ovipositor into the cavity
which contains the host larva.
4 Making corrections.
5 Depositing her eggs.
6 Depositing her eggs.
The Ichneumonidae have been and still are quite a taxonomic nightmare. About as diverse as the true weevils (Curculionidae), there are numerous small, inconspicuous and hard-to-identify ichneumon wasps. The sheer diversity means that DNA sequence data is only available for a tiny fraction of the species, and that detailed cladistic studies require major-scale computing capacity.
Consequently, the phylogeny and systematics of the ichneumon wasps are not definitely resolved. Several prominent authors - like H.T. Townes and J. Oehlke - have gone as far as to publish major reviews that defy the International Code of Zoological Nomenclature[4].
Regardless, there exist a number of seminal works, including the extensive study and the synonymic catalogue by Townes but also treatments by other entomologists, namely J.F. Aubert who has a fine collection of ichneumon wasps in Lausanne[5].
The list presented here follows the suggestion of David Wahl of the American Entomological Institute[6]. It will be updated as necessary, as new research resolves the interrelationships of the ichneumonm wasps better and better.
The subfamilies are not listed in a taxonomic or phylogenetic sequence, as the relationships between the groups are not yet resolved to a degree to render any such arrangement even marginally reliable[6]:
Main articles: Checklist of UK Recorded Ichneumonidae
Famous ichneumonologists include:
Main Page
Cladus: Eukaryota
Supergroup: Unikonta
Cladus: Opisthokonta
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Protostomia
Cladus: Ecdysozoa
Phylum: Arthropoda
Subphylum: Hexapoda
Classis: Insecta
Cladus: Dicondylia
Cladus: Pterygota
Cladus: Metapterygota
Cladus: Neoptera
Cladus: Eumetabola
Cladus: Endopterygota
Superordo: Hymenopterida
Ordo: Hymenoptera
Subordo: Apocrita
Superfamilia: Ichneumonoidea
Familia: Ichneumonidae
Subfamiliae:
Ichneumonidae Latreille, 1802
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For more multimedia, look at Category:Ichneumonidae on Wikimedia Commons. |
   | Reference Photos: Giant Ichneumon Wasps - Male ''Megarhyssa'' sp. - Giant Ichneumon Wasp - Megarhyssa macrurus |
| | Reference large-format photos of 15 different species of Ichneumonidae - Ichneumon Wasps - Hymenoptera Family Ichneumonidae |
| | Photo Essay: Giant Ichneumon Wasps Ovipositing - Giant Ichneumon Wasps Ovipositing |
| | Fauna Europaea - Fauna Europaea : Taxon Details |
| | Long Family Description - British Insects: Hymenoptera Families - Ichneumonidae |
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