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

Ichneumonidae The Ichneumonidae, also known as the ichneumon wasps, Darwin wasps, or ichneumonids, are a family of parasitoid wasps of the insect order Hymenoptera. They are one of the most diverse groups within the Hymenoptera with roughly 25,000 species cu ...

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 analy ...

. The group is thought to contain as many as 100,000 species, many of which have not yet been described. Like other parasitoid wasps, they were long placed in the "Parasitica", variously considered as an

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

or an unranked clade, now known to be

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

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''.

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 Antennae ( antenna), sometimes referred to as "feelers", are paired appendages used for sensing in arthropods. Antennae are connected to the first one or two segments of the arthropod head. They vary widely in form but are always made of one o ...

segments. Both included families have a cosmopolitan distribution. Ichneumonoids have morphological similarities with relatives within the order Hymenoptera, including ants and

bee Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyly, monophyletic lineage within the ...

s. 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 () is the scientific study of insects, a branch of zoology. In the past the term "insect" was less specific, and historically the definition of entomology would also include the study of animals in other arthropod groups, such as arach ...

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. Fore wings lack vein 2m-cu.

Ichneumonidae

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

Evolution

Parasitoidism evolved only once in the Hymenoptera during the

Permian The Permian ( ) is a geologic period and 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 251.9 Mya. It is the last period of the Pale ...

, leading to a single clade 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) forme ...

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 Mya. The J ...

Parasitic life cycle

Ichneumonoids are solitary insects, and the vast majority are parasitoids; the

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. Th ...

e feed on or in another insect until it finally dies. Most hosts are holometabolus 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 ( la, pupa, "doll"; plural: ''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 ...

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 ''Ichneumon eumerus'' is a species of parasitic wasp belonging to the family Ichneumonidae, subfamily Ichneumoninae. It is a specialist parasite of the larva of the mountain Alcon blue butterfly (''Phengaris rebeli''). Life cycle The life cycle ...

'' 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 and high mountains in Southeast Asia. The genus consists of around 200 known species and additional subspecies, ...

'' 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