Ichneumonidae

Ichneumon wasps
Unidentified species, Rhône (France)
Scientific classification
Kingdom: Animalia Phylum: Arthropoda Subphylum: Hexapoda Class: Insecta Subclass: Pterygota Infraclass: Neoptera Superorder: Endopterygota Order: Hymenoptera Suborder: Apocrita Superfamily: Ichneumonoidea Family: Ichneumonidae
Subfamilies
Acaenitinae Agriotypinae Adelognathinae Anomaloninae (but see below) Banchinae Brachycyrtinae (disputed) Campopleginae (but see below) Collyriinae Cremastinae Cryptinae (but see below) Ctenopelmatinae (but see below) Cylloceriinae (disputed, and see below) Diacritinae (disputed) Diplazontinae Eucerotinae Ichneumoninae Labeninae (but see below) Lycorininae (disputed) Mesochorinae Metopiinae Microleptinae Neorhacodinae Ophioninae Orthocentrinae (disputed) Orthopelmatinae Oxytorinae Paxylommatinae (but see below) Pedunculinae Phrudinae Pimplinae (but see below) Poemeniinae (disputed) Rhyssinae (disputed) Stilbopinae (disputed) Tatogastrinae (disputed) Tersilochinae Tryphoninae Xoridinae and see below

Ichneumonidae is a diverse family of wasps, typically characterized by a parasitic component to the life cycle, antennae with 16 or more segments, an elongated abdomen, and females with long ovipositors that frequently are longer than their body. This family is within the Aporcrita suborder of the Hymenoptera order, a taxon that also includes ants, bees, and sawflies. Members of Ichneumonidae commonly are 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.

Ichneumonidae has a cosmopolitan distribution, with over 60,000 species worldwide. There are approximately 3,000 species of ichneumonids in North America. 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 (Sime and Brower 1998).

Ichneumon wasps are important parasitoids of other insects. Common hosts are larvae and pupae of Coleoptera, Hymenoptera, and Lepidoptera.

• for Charles Darwin ***

Overview

As members of the Hymenoptera suborder Apocrita, along with bees and ants, ichneumonids are characterized by a constriction between the first and second abdominal segments called a wasp-waist. This also involves the fusion of the first abdominal segment to the thorax. The larva of ichneumonids, like all Apocrita, do not have legs, prolegs, or ocelli.

The most familiar wasps belong to Aculeata, a division of Apocrita, whose ovipositors (an organ typically used for laying eggs) are adapted into a venomous stinger. Aculeata is one of two common groupings of the Aprocrita. The other is Parasitica, the term used for four superfamilies of Aprocrita—Ichneumonoidea, Chalcidoidea, Cynipoidea, and Proctotrupoidea (Grzimek et al. 2004). The Aculeata make up the remaining superfamilies. While the Parasitica tend to be parasites of other insects, and the Aculeata are stinging forms, in reality some Parasitca are phytophagous and many Aculeata (particularly wasps) are parasites (Grzimek et al. 2004). Aculeata also contains ants and bees.

Wasps are holometabolus insects, meaning they undergo complete metamorphosis in which the larvae differ markedly from the adults. Insects that undergo holometabolism pass through a larval stage, then enter an inactive state called pupa, and finally emerge as adults (imago).

In wasps, as in other Hymenoptera, sexes are significantly genetically different. Females have a diploid (2n) number of chromosomes and come about from fertilized eggs. Males, in contrast, have a haploid (n) number of chromosomes and develop from an unfertilized egg.

Description

Ichneumon wasps differ from the wasps that 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. Their 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.

Oviposition

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.

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 'listening' for wood boring larvae of the horntail wasps (hymenopteran family Siricidae) upon which to lay eggs, males are listening 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 process of oviposition in Dolichomitus imperator

1 Tapping with her antennae the wasp listens for the 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.

Taxonomy and systematics

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

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.

Subfamilies

The list presented here follows the suggestion of David Wahl of the American Entomological Institute. 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:

• Acaenitinae
• Agriotypinae
• Adelognathinae
• Anomaloninae (= Anomalinae)
• Banchinae
• Brachycyrtinae (sometimes included in Labiinae)
• Campopleginae (= Porizontinae)
• Collyriinae
• Cremastinae
• Cryptinae (= Gelinae, Hemitelinae, Phygadeuontinae)
• Ctenopelmatinae (= Scolobatinae)
• Cylloceriinae (= Oxytorinae, sometimes included in Microleptinae)
• Diacritinae (sometimes included in Pimplinae)
• Diplazontinae
• Eucerotinae (sometimes included in Tryphoninae)
• Ichneumoninae
• Labeninae (= Labiinae)
• Lycorininae (sometimes included in Banchinae)
• Mesochorinae
• Metopiinae
• Microleptinae
• Neorhacodinae (sometimes included in Banchinae)
• Ophioninae
• Orthocentrinae (sometimes included in Microleptinae)
• Orthopelmatinae
• Oxytorinae
• Paxylommatinae (sometimes not placed in Ichneumonidae at all)
• Pedunculinae
• Phrudinae
• Pimplinae (= Ephialtinae)
• Poemeniinae (sometimes included in Pimplinae)
• Rhyssinae (sometimes included in Pimplinae)
• Stilbopinae (sometimes included in Banchinae)
• Tatogastrinae (sometimes included in Microleptinae or Oxytorinae)
• Tersilochinae
• Tryphoninae
• Xoridinae

Gallery

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  Lissonota sp. (Banchinae)

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  Ichneumon suspiciosus (Ichneumoninae)

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  Ophion luteus (Ophioninae)

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  Unidentified South African species.

References

ISBN links support NWE through referral fees

• Aubert, J.F. (1969): Les Ichneumonides ouest-palearctiques et leurs hotes 1. Pimplinae, Xoridinae, Acaenitinae ["The Western Palearctic ichneumon wasps and their hosts. 1. Pimplinae, Xoridinae, Acaenitinae"]. Laboratoire d'Evolution des Etres Organises, Paris. [in French]
• Aubert, J.F. (1978): Les Ichneumonides ouest-palearctiques et leurs hotes 2. Banchinae et Suppl. aux Pimplinae ["The Western Palearctic ichneumon wasps and their hosts. 2. Banchinae and supplement to the Pimplinae"]. Laboratoire d'Evolution des Etres Organises, Paris & EDIFAT-OPIDA, Echauffour. [in French]
• Aubert, J.F. (2000): Les ichneumonides oeust-palearctiques et leurs hotes. 3. Scolobatinae (=Ctenopelmatinae) et suppl. aux volumes precedents [The West Palaearctic ichneumonids and their hosts. 3. Scolobatinae (= Ctenopelmatinae) and supplements to preceding volumes]. Litterae Zoologicae 5: 1-310. [French with English abstract]
• Fitton, M.G. & Gauld, I.D. (1976): The family-group names of the Ichneumonidae (excluding Ichneumoninae) (Hymenoptera). Systematic Entomology 1: 247-258.
• Fitton, M.G. & Gauld, I.D. (1978): Further notes on family-group names of Ichneumonidae (Hymenoptera). Systematic Entomology 3: 245-247.
• Gauld, I.D. (1976): The classification of the Anomaloninae (Hymenoptera: Ichneumonidae). Bulletin of the British Museum of Natural History (Entomology) 33: 1-135.
• Oehlke J. (1966): Die westpaläarktische Arte der Tribus Poemeniini (Hymenoptera, Ichneumonidae) ["The Western Palearctic species of the tribe Poemeniini"]. Beiträge zur Entomologie 15: 881-892.
• Oehlke J. (1967): Westpaläarktische Ichneumonidae 1, Ephialtinae. Hymenopterorum Catalogus (new edition) 2: 1-49.
• Perkins, J.F. (1959): Ichneumonidae, key to subfamilies and Ichneumoninae – 1. Handbk Ident. Br. Insects 7(part 2ai): 1–116.
• Perkins, J.F. (1960): Hymenoptera: Ichneumonoidea: Ichneumonidae, subfamilies Ichneumoninae 2, Alomyinae, Agriotypinae and Lycorininae. Handbk Ident. Br. Insects 7(part 2aii): 1–96.
• Sime, K., & Brower, A. (1998): Explaining the latitudinal gradient anomaly in ichneumonid species richness: evidence from butterflies. Journal of Animal Ecology 67: 387-399
• Townes, H.T. (1969a): Genera of Ichneumonidae, Part 1 (Ephialtinae, Tryphoninae, Labiinae, Adelognathinae, Xoridinae, Agriotypinae). Memoirs of the American Entomological Institute 11: 1-300.
• Townes, H.T. (1969b): Genera of Ichneumonidae, Part 2 (Gelinae). Memoirs of the American Entomological Institute 12: 1-537.
• Townes, H.T. (1969c): Genera of Ichneumonidae, Part 3 (Lycorininae, Banchinae, Scolobatinae, Porizontinae). Memoirs of the American Entomological Institute 13: 1-307.
• Townes, H.T. (1971): Genera of Ichneumonidae, Part 4 (Cremastinae, Phrudinae, Tersilochinae, Ophioninae, Mesochorinae, Metopiinae, Anomalinae, Acaenitinae, Microleptinae, Orthopelmatinae, Collyriinae, Orthocentrinae, Diplazontinae). Memoirs of the American Entomological Institute 17: 1-372.
• Townes, H.T.; Momoi, S.A. & Townes, M. (1965): Catalogue and Reclassification of Eastern Palearctic Ichneumonidae Memoirs of the American Entomological Institute 5: 1-661 pages.
• Wahl, David (1999): Classification and Systematics of the Ichneumonidae (Hymenoptera). Version of 1999-JUL-19. Retrieved 2008-JUN-18.

External links

Description

• Long Family Description Many illustrations from John Curtis British Entomology
• Short Family Description

Distribution

• Checklist of Japanese Ichneumonidae
• Fauna Europaea

Taxonomy and Systematics

• Ichneumonidae:Classification of afrotropical ichneumonid wasps. Extensive use of images.
• Key to Subfamilies found in Britain and Ireland Extensive use of images.

Other

• Important Systematic Literature
• Reference large-format photos of 15 different species of Ichneumonidae
• Photo Essay: Giant Ichneumon Wasps Ovipositing
• Reference Photos: Giant Ichneumon Wasps - Male Megarhyssa sp.
• Ichneumonidae as Biological Control Agents of Pests with Bibliography long download pdf
• Ichneumonid Types in Entomological Institute of Hokkaido UniversityIn Japanese but a pulldown menu of Subfamilies by clicking bottom box.
• Ichneumonidae Database In Korean but with images and type repositories in English.
• Diagnostic features of subfamilies
• Key to subfamilies in Spanish and not all the families, but good photos.
• Diadegma insulare on the UF / IFAS Featured Creatures Web site
• Taiwan Digital Insects 401 species imaged.
• Galerie Insecte French Images by subfamily and genus.
• Hymis De Images 47 on 6 pages of authority (expert) named Ichneumonidae.On going.

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