Chalcid wasps (, , for their metallic colour) are

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...

s within the superfamily Chalcidoidea, part of the order

Hymenoptera Hymenoptera is a large order (biology), order of insects, comprising the sawfly, 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 Par ...

. The superfamily contains some 22,500 known species, and an estimated total diversity of more than 500,000 species, meaning the vast majority have yet to be discovered and described. The name "chalcid" is often confused with the name "chalcidid", though the latter refers strictly to one constituent family, the Chalcididae, rather than the superfamily as a whole; accordingly, most recent publications (e.g.,) use the name "chalcidoid" when referring to members of the superfamily. Most chalcid wasps are

parasitoids In evolutionary ecology, a parasitoid is an organism that lives in close association with its host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionary strategies within parasi ...

of other insects, though other life styles are known, with the herbivorous fig wasps acting as pollinators. Various species are used as

biological pest 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 or in scientific research.

Description

Chalcidoids are generally small wasps, averaging 1.5 mm in length and usually being less than 3 mm. The body is often metallic in colour. The wings may be developed, reduced or absent. When the wings are developed, they have reduced venation or sometimes none at all. However, the group is morphologically very diverse. Chalcidoids range in size from up to 41.7 mm long (females of the pelecinellid '' Doddifoenus wallacei,'' this length includes the

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 typical ...

) to merely 0.13 mm long (males of the mymarid '' Dicopomorpha echmepterygis''). Various lineages have

convergently evolved Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...

features such as enlarged femora, enlarged acropleura, reduced numbers of antennal and tarsal segments, reduced wings or reduced wing venation. Some have significant

sexual dimorphism Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...

: male fig wasps are "turtle-like fighting machines" that are very different to the females, while males of the aforementioned ''D. echmepterygis'' lack eyes, ocelli, mouthparts, antennal flagella or wings.

Ecology

Most chalcidoids are parasitoids, their hosts including insects,

spiders Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species dive ...

, ticks and mites,

pseudoscorpions Pseudoscorpions, also known as false scorpions or book scorpions, are small, scorpion-like arachnids belonging to the order Pseudoscorpiones, also known as Pseudoscorpionida or Chelonethida. Pseudoscorpions are generally beneficial to humans sin ...

and even gall-forming nematodes. Some species parasitise a wide range of hosts, while others have a narrow host range. They attack host life stages ranging from eggs to adults. The superfamily includes primary, secondary and tertiary parasitoids, both ecto- and endoparasitoids, and both solitary and gregarious parasitoids. There are also herbivorous chalcidoids within the families of Agaonidae, Epichrysomallidae,

Eurytomidae The Eurytomidae are a family within the superfamily Chalcidoidea. Unlike most chalcidoids, the larvae of many are phytophagous (feeding in stems, seeds, or galls), while others are more typical parasitoids, though even then the hosts are usually ...

Eulophidae The Eulophidae are a large family of hymenopteran insects, with over 4,300 described species in some 300 genera. The family includes the genus ''Elasmus'', which used to be treated as a separate family, "Elasmidae", and is now treated as a subf ...

, Melanosomellidae, Ormyridae,

Pteromalidae The Pteromalidae are a very large family of mostly parasitoid wasps, with some 3,450 described species in about 640 genera (the number was greater, but many species and genera have been reduced by synonymy in recent years). The subfamily-level d ...

, Tanaostigmatidae and Torymidae. Agaonidae only develop within

figs The fig is the edible fruit of ''Ficus carica'', a species of small tree in the flowering plant family Moraceae. Native to the Mediterranean and western Asia, it has been cultivated since ancient times and is now widely grown throughout the world ...

. Predation is exhibited by larvae of some Encyrtidae (prey on coccid eggs) and some Eurytomidae (prey on

Cynipidae Gall wasps, also incorrectly called gallflies, are hymenopterans of the family Cynipidae in the wasp superfamily Cynipoidea. Their common name comes from the galls they induce on plants for larval development. About 1,300 species of this genera ...

larvae).

Importance

Chalcidoidea is one of the most important taxa of biological control agents. They are used to control pest insects in both natural and agricultural ecosystems. Some herbivorous species are also used in biological control, such as the melanosomellid '' Trichilogaster acaciaelongifoliae'' for control of the weed ''

Acacia longifolia ''Acacia longifolia'' is a species of ''Acacia'' native to southeastern Australia, from the extreme southeast of Queensland, eastern New South Wales, eastern and southern Victoria, and southeastern South Australia. Common names for it include lon ...

''. There are also chalcidoids that are agricultural pests themselves, mainly attacking plant seeds. ''

Bruchophagus ''Bruchophagus'' is a genus of wasps belonging to the family Eurytomidae. The genus has cosmopolitan distribution. Species Species: *''Bruchophagus abnormis'' *''Bruchophagus abscedus'' *''Bruchophagus acaciae ''Bruchophagus'' is a genus ...

'' attack seeds of legumes (e.g.

alfalfa Alfalfa () (''Medicago sativa''), also called lucerne, is a perennial flowering plant in the legume family Fabaceae. It is cultivated as an important forage crop in many countries around the world. It is used for grazing, hay, and silage, as w ...

), ''Systole'' attack seeds of Apiaceae used as spices (e.g.

coriander Coriander (;

) and '' Megastigmus'' attack seeds of Pinaceae grown in plantations. Females of family Agaonidae are important as pollinators of figs. Some chalcidoids, especially those in genera ''

Trichogramma ''Trichogramma'' is a genus of minute polyphagous wasps that are endoparasitoids of insect eggs. ''Trichogramma'' is one of around 80 genera from the family Trichogrammatidae, with over 200 species worldwide.Consoli FL, Parra JRP, Zucchi RA (2010 ...

'' (

Trichogrammatidae The Trichogrammatidae are a family of tiny wasps in the Chalcidoidea that include some of the smallest of all insects, with most species having adults less than 1 mm in length, with species of ''Megaphragma'' having an adult body length le ...

) and ''

Nasonia ''Nasonia'' are a genus of small Pteromalidae, pteromalid parasitoid wasps that sting and lay eggs in the pupae of various flies. The fly species that ''Nasonia'' usually parasitize are primarily Calliphoridae, blow flies and flesh flies, making ...

'' (

) are model organisms in scientific research. They have been used to study sex determination, the influence of bacterial

endosymbionts An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship. (The term endosymbiosis is from the Greek: ἔνδον ''endon'' "within" ...

and the genetics of speciation. The genome of moth parasitoid '' Copidosoma floridanum'' was sequenced as part of the i5K project.

Taxonomy

Chalcidoidea is a

superfamily SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...

, whose family constituency is in constant flux, as new hypotheses of relationships are constantly being proposed and rejected; with the advent of molecular systematics, it seems that the future will see further revisions of the classification in use today. There are fifty extant families recognized at present: * Agaonidae Walker, 1846 *

Aphelinidae The Aphelinidae are a moderate-sized family of tiny parasitic wasps, with about 1100 described species in some 28 genera. These minute insects are challenging to study, as they deteriorate rapidly after death unless extreme care is taken (e.g., p ...

Thomson Thomson may refer to: Names * Thomson (surname), a list of people with this name and a description of its origin * Thomson baronets, four baronetcies created for persons with the surname Thomson Businesses and organizations * SGS-Thomson Mic ...

, 1876 * Azotidae Nikolskaya & Yasnosh, 1966 * Baeomorphidae Yoshimoto, 1975 (formerly

Rotoitidae The Rotoitidae are a very small family of rare, relictual parasitic wasps in the superfamily Chalcidoidea, known primarily from fossils (14 extinct species in two genera, '' Baeomorpha'' and '' Taimyromorpha'').Huber JT, Shih C, Dong R (2019) A n ...

) * Boucekiidae Gibson, 2003 (formerly part of

) * Calesidae Mercet, 1929 (formerly part of

) *

Ceidae Ceidae is a small family of chalcid wasps, previously classified as subfamily Ceinae, in the Polyphyly, polyphyletic family Pteromalidae. These wasps are Parasitoid, parasitoids of other small insects. Hosts are known only for ''Cea pulicaris'' ( ...

Boucek, 1961 (formerly part of

) * Cerocephalidae Gahan, 1946 (formerly part of

) *

Chalcedectidae Chalcedectidae is a small family of chalcid wasps, previously classified as part of the subfamily Cleonyminae, in the Polyphyly, polyphyletic family Pteromalidae. Most species are parasitoids of wood-boring beetles. Astrid Cruaud and coworkers f ...

Ashmead, 1904 (formerly part of

) * Chalcididae Latreille, 1817 * Chrysolampidae Dalla Torre, 1898 (formerly part of Perilampidae) * Cleonymidae Walker, 1837 (formerly part of

) * Coelocybidae Boucek, 1988 (formerly part of

) * Cynipencyrtidae Trjapitzin, 1973 * Diparidae Thomson, 1876 (formerly part of

) * Encyrtidae Walker, 1837 *

Epichrysomallidae Epichrysomallidae is a family of gall-forming wasps associated with fig trees (genus ''Ficus'') - they make galls in figs, or on leaves or twigs. Once considered a subfamily of Pteromalidae (Epichrysomallinae), this group of genera has been elev ...

Hill & Riek, 1967 (formerly part of

) * Eucharitidae Latreille, 1809 *

Westwood, 1829 * Eunotidae Ashmead, 1904 (formerly part of

) * Eupelmidae Walker, 1833 *

Walker, 1832 * Eutrichosomatidae Peck, 1951 (formerly part of

) * Herbertiidae Boucek, 1988 (formerly part of

) * Hetreulophidae Girault, 1915 (formerly part of

) * Heydeniidae Hedqvist, 1961 (formerly part of

) * Idioporidae LaSalle, Polaszek & Noyes, 1997 (formerly part of

) * Leucospidae

Fabricius Fabricius ( la, smith, german: Schmied, Schmidt) is a surname. Notable people with the surname include: *people from the Ancient Roman gens Fabricia: **Gaius Fabricius Luscinus, the first of the Fabricii to move to Rome * Johann Goldsmid (1587� ...

, 1775 * Lyciscidae Boucek, 1958 (formerly part of

) * Macromesidae Graham, 1959 (formerly part of

) * Megastigmidae Thomson, 1876 * Melanosomellidae Girault, 1913 (formerly part of

) * Metapelmatidae Boucek, 1988 (formerly part of Eupelmidae) * Moranilidae Boucek, 1988 (formerly part of

) *

Mymaridae The Mymaridae, commonly known as fairyflies or fairy wasps, are a family (biology), family of chalcid wasp, chalcidoid wasps found in temperate and tropical regions throughout the world. The family contains around 100 genera with 1400 species. F ...

Haliday, 1833 * Neanastatidae Kalina, 1984 (formerly part of Eupelmidae) * Neodiparidae Boucek, 1961 (formerly part of

) * Ooderidae Boucek, 1958 (formerly part of

) * Ormyridae

Förster Förster or Foerster is a German surname meaning "forester". (It has often been Anglicised as Forster). Notable people of this name include: Förster * Arnold Förster (1810–1884), a German entomologist * August Förster (physician) (1822–18 ...

, 1856 * Pelecinellidae Ashmead, 1895 (formerly part of

) * Perilampidae Latreille, 1809 *

Pirenidae Pirenidae is a family of chalcidoid wasps. It was formerly treated as a subfamily within the family Pteromalidae but is now recognized as a distinct family. Genera The subfamilies and genera of Pirenidae include the following: *Subfamily Cecid ...

Haliday, 1844 ( including Eriaporidae) (formerly part of

) *

Dalman, 1820 * Signiphoridae Ashmead, 1880 * Spalangiidae Haliday, 1833 (formerly part of

) * Systasidae Boucek, 1988 (formerly part of

) * Tanaostigmatidae Howard, 1890 *

Tetracampidae The Tetracampidae are a small family of parasitic wasps in the superfamily Chalcidoidea. They are parasitoids of phytophagous insects, primarily flies. The 44 species in 15 genera are almost entirely absent from the New World The term ''N ...

, 1856 * Torymidae Walker, 1833 *

Haliday, 1851 There are also two extinct families: *

Khutelchalcididae ''Khutelchalcis'' is an extinct genus of chalcid wasp, it is the only member of the family Khutelchalcididae. It is only known from a single species, (''Khutelchalcis gobiensis'') described from the Early Cretaceous Tsagaantsav Formation The T ...

Rasnitsyn, Basibuyuk & Quicke, 2004 *

Diversinitidae Diversinitidae are an extinct family of Chalcid wasps. Three genera are known, all from the early Cenomanian aged Burmese amber. They are distinguished by the presence of multiporous plate sensilla on the first flagellomere Antennae ( antenna ...

Haas, Burks & Krogmann, 2018 Of these families, at least five are known to be artificial groups (

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 ...

), and are being - or will be - divided into several families, or perhaps fused with existing families. The most problematic, the Pteromalidae, has recently been split into 24 families, and Eupelmidae into three families.

Identification

* Key to families Grissell, E. E., and M. E. Schauff. 1990. ''A handbook of the families of Nearctic Chalcidoidea (Hymenoptera).''Entomological Society of Washington (Washington, D.C.) Handbook 1:1-85. Online a

* Gibson, G. A. P., Huber, J. T., and J. B. Woolley. 1997. ''Annotated keys to the genera of Nearctic Chalcidoidea (Hymenoptera).'' NRC Research Pres

References

External links

Universal Chalcidoid DatabaseImages of chalcidoids on MorphBank, a biological image database
Pictorial overview. {{Authority control Chalcidoidea, Biological pest control wasps