The superfamily Ichneumonoidea contains one extinct and three extant families, including the two largest families within

Hymenoptera Hymenoptera is a large order of insects, comprising the sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are parasitic. Females typi ...

Ichneumonidae The Ichneumonidae, also known as ichneumon wasps, ichneumonid wasps, ichneumonids, or Darwin wasps, are a family of parasitoid wasps of the insect order Hymenoptera. They are one of the most diverse groups within the Hymenoptera with roughly 25 ...

and

Braconidae The Braconidae are a family of parasitoid wasps. After the closely related Ichneumonidae, braconids make up the second-largest family in the order Hymenoptera, with about 17,000 recognized species and many thousands more undescribed. One analysis ...

. The group is thought to contain as many as 100,000 species, many of which have not yet been described. Like other

parasitoid wasp Parasitoid wasps are a large group of hymenopteran Superfamily (zoology), superfamilies, with all but the wood wasps (Orussoidea) being in the wasp-waisted Apocrita. As parasitoids, they lay their eggs on or in the bodies of other arthropods, ...

s, they were long placed in the "Parasitica", variously considered as an

infraorder Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between Family_(biology), family and Class_(biology), class. In biological classification, the order is a taxonomic rank used in the classific ...

or an unranked

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

, now known to be

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

Etymology

The name is derived from Latin 'ichneumon', from Ancient Greek ἰχνεύμων (ikhneúmōn, "tracker"), from ἴχνος (íkhnos, "track, footstep"). The name is shared with the Egyptian mongoose, ''

Herpestes ichneumon The Egyptian mongoose (''Herpestes ichneumon''), also known as ichneumon (), is a mongoose species native to the tropical and subtropical grasslands, savannas, and shrublands of Africa and around the Mediterranean Basin in North Africa, the Mi ...

''.

Description

The superfamily is defined by fusion of the costal and radial veins of the fore wing, and almost all species have more than 11 antennal segments. Both included families have a

cosmopolitan distribution In biogeography, a cosmopolitan distribution is the range of a taxon that extends across most or all of the surface of the Earth, in appropriate habitats; most cosmopolitan species are known to be highly adaptable to a range of climatic and en ...

. Ichneumonoids have morphological similarities with relatives within the order Hymenoptera, including

ant Ants are Eusociality, eusocial insects of the Family (biology), family Formicidae and, along with the related wasps and bees, belong to the Taxonomy (biology), order Hymenoptera. Ants evolved from Vespoidea, vespoid wasp ancestors in the Cre ...

s and bees. Ichneumonoidea contains a great deal of morphological diversity, with species ranging in size from long. Most are slender, and the females of many species (particularly in the genus '' Megarhyssa'') have extremely long

ovipositor The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typica ...

s for laying eggs. The ichneumonid wasps may be more familiar to non-

entomologist Entomology (from Ancient Greek ἔντομον (''éntomon''), meaning "insect", and -logy from λόγος (''lógos''), meaning "study") is the branch of zoology that focuses on insects. Those who study entomology are known as entomologists. In ...

s than braconids, as they are generally larger. The two families are distinguished from each other primarily by details of wing venation.

Braconidae

Most are brownish or black, not brightly colored. Forewings lack vein 2m-cu.

Ichneumonidae

Ichneumonids vary greatly in size and their color varies from brightly colored to uniform black. Forewings with vein 2m-cu present and tubular.

Evolution

Parasitoidism evolved only once in the

during the

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the s ...

, leading to a single

which contains the

Apocrita Apocrita is a suborder of insects in the order Hymenoptera. It includes wasps, bees, and ants, and consists of many families. It contains the most advanced hymenopterans and is distinguished from Symphyta by the narrow "waist" ( petiole) formed ...

and the Orussoidea, but has been secondarily lost multiple times. The Apocrita emerged from that clade during the

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

Parasitic life cycle

Ichneumonoids are solitary insects, and the vast majority are

parasitoid In evolutionary ecology, a parasitoid is an organism that lives in close association with its host (biology), host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionarily stable str ...

s; the

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e feed on or in another insect until it finally dies. Most hosts are holometabolous insect larvae, but there are many exceptions. In general, ichneumonoids are host specific, and only attack one or a few closely related host species. Many species use polydnaviruses to suppress the immune systems of their host insects. Due to the wide variety in hosts and lifestyles, see subfamily pages for more detail. The female ichneumonoid finds a host and lays an egg on, near, or inside the host's body. The

of ichneumonoids generally cannot deliver a sting as many wasps or bees do. It can be used to bore wood and lay eggs on hosts deep inside, or reach hosts hidden inside leaf shelters. Upon hatching, the larva feeds either externally or internally, killing the host when it is ready to

pupa A pupa (; : pupae) is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their life cycle, the stages th ...

te. Various ichneumonoids are used as biological control agents in controlling horticultural or forest pests. An example is the relationship between the species '' Ichneumon eumerus'' and its host butterfly '' Phengaris rebeli''. The butterfly larva is a parasite within ''

Myrmica ''Myrmica'' is a genus of ants within the subfamily Myrmicinae. It is widespread throughout the temperate regions of the Holarctic realm, Holarctic and high mountains in Southeast Asia. The genus consists of around 200 known species and additio ...

'' ant nests. The adult ''I. eumerus'' searches for ant nests and only enters when they contain ''P. rebeli'' caterpillars. Once inside, they oviposit within the caterpillars and escape the nest by releasing a chemical which causes the worker ants to fight each other rather than the intruding wasp. The wasp eggs then hatch inside the caterpillar and eventually consume and kill the host. ;Life cycle of '' Hercus fontinalis'' File:Hercus fontinalis early instar larvae.jpg, Early instar larvae on caterpillar File:Hercus fontinalis later instar larvae.jpg, Later instar larvae File:Hercus_fontinalis_final_instar_larva.jpg, Final instar larvae building cocoon File:Hercus fontinalis pupa.jpg, Pupa inside cocoon File:Hercus fontinalis eclosion.jpg, Adults emerging from cocoons File:Hercus fontinalis female.jpg, Adult female

References

External links

* *
Reference large-format photos of 15 different species of Ichneumonidae
* A
interesting account
of an observer's encounter with Ichneumons.

* ttp://bugguide.net/node/view/14971 Bugguide.net. Superfamily Ichneumonoidea - Braconids and Ichneumons {{Taxonbar, from=Q957016 Apocrita superfamilies Biological pest control wasps Insects in culture de:Schlupfwespen