Encyrtidae is a large family of

parasitic wasp Parasitoid wasps are a large group of hymenopteran 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, sooner or later causi ...

s, with some 3710 described species in about 455

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

. 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. The ...

e of the majority are primary

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 on

Hemiptera Hemiptera (; ) is an order (biology), order of insects, commonly called true bugs, comprising over 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, Reduviidae, assassin bugs, Cimex, bed bugs, and shield bugs. ...

, though other hosts are attacked, and details of the life history can be variable (e.g., some attack eggs, some attack larvae, others are

hyperparasite A hyperparasite, also known as a metaparasite, is a parasite whose host, often an insect, is also a parasite, often specifically a parasitoid. Hyperparasites are found mainly among the wasp-waisted Apocrita within the Hymenoptera, and in two oth ...

s, and some Encyrtidae develop as parasitoids of

tick Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by ...

s). They are found throughout the world in virtually all habitats, and are extremely important as

biological control Biological control or biocontrol is a method of controlling pests, such as insects, mites, weeds, and plant diseases, using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also invo ...

agents. They may also present as an ecological threat to the population of some species. For example, the endangered ''

Papilio homerus ''Papilio homerus'', commonly known as the Homerus swallowtail or Jamaican swallowtail, is the largest butterfly species in the Western Hemisphere. The species is endangered and faces a potentially bleak future. Only two small populations of the ...

'' butterfly is parasitized at a rate of 77%, making them the main contributor to egg mortality in this (and other) butterfly species. Some species exhibit a remarkable developmental phenomenon called "

polyembryony Polyembryony is the phenomenon of two or more embryos developing from a single fertilized egg. Due to the embryos resulting from the same egg, the embryos are identical to one another, but are genetically diverse from the parents. The genetic differ ...

", in which a single egg multiplies clonally in the host and produces large numbers of identical adult wasps. Even more remarkably, some of the larvae are larger than the others and act in a similar way to the "soldiers" of

eusocial Eusociality (from Greek εὖ ''eu'' "good" and social), the highest level of organization of sociality, is defined by the following characteristics: cooperative brood care (including care of offspring from other individuals), overlapping generat ...

insects, attacking any other wasp larvae already in the body of the host, and dying without reproducing ("

altruism Altruism is the principle and moral practice of concern for the welfare and/or happiness of other human beings or animals, resulting in a quality of life both material and spiritual. It is a traditional virtue in many cultures and a core as ...

"). Wasps in this family are relatively easy to separate from other

Chalcidoidea Chalcid wasps (, , for their metallic colour) are insects within the superfamily Chalcidoidea, part of the order Hymenoptera. The superfamily contains some 22,500 known species, and an estimated total diversity of more than 500,000 species, me ...

by features of the wing venation, the migration of the cerci forwards on the

metasoma The metasoma is the posterior part of the body, or tagma, of arthropods whose body is composed of three parts, the other two being the prosoma and the mesosoma. In insects, it contains most of the digestive tract, respiratory system, and circula ...

(and accompanying distortion of the

tergite A ''tergum'' (Latin for "the back"; plural ''terga'', associated adjective tergal) is the dorsal ('upper') portion of an arthropod segment other than the head. The anterior edge is called the 'base' and posterior edge is called the 'apex' or 'mar ...

s), and a greatly enlarged

mesopleuron The mesothorax is the middle of the three segments of the thorax of hexapods, and bears the second pair of legs. Its principal sclerites (exoskeletal plates) are the mesonotum (dorsal), the mesosternum (ventral), and the mesopleuron (lateral) on ...

with anteriorly positioned mesocoxae. An extinct genus ''

Archencyrtus ''Archencyrtus'' is an extinct genus of wasp in the Chalcidoidea family Encyrtidae. The genus contains a single described species, ''Archencyrtus rasnitsyni'' known from a Middle Eocene fossil that was found in Eastern Asia. History and clas ...

'' has been described from the

Middle Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn ...

age Sakhalin amber in Eastern Russia.

References

External links

Universal Chalcidoidea Database

Image Database TOBIKOBACHI Based on the Encyrtid Wasp Collection of Dr. T. Tachikawa

on the UF / IFAS Featured Creatures Web site
''Diaphorencyrtus aligarhensis''
on the UF / IFAS Featured Creatures Web site {{Taxonbar, from=Q2266108 Apocrita families