{{Short description|Genus of wasps}} {{Italic title}} {{Automatic taxobox | image = Euplectrus sp. - lifecycle B - 09 - eclosion on a Noctuidae caterpillar (2010-05-23).jpg | image_caption = ''Euplectrus'' adults emerging from the caterpillar of a Noctuid moth | image2 = Euplectrus from Hong Kong.jpg | image2_caption = ''Euplectrus'' sp. from Hong Kong | taxon = Euplectrus | authority = Westwood, 1832 | type_species = ''Euplectrus maculiventris'' | type_species_authority = Westwood, 1832 | subdivision_ranks = Species | subdivision = 162 Species }}
'''''Euplectrus''''' is a cosmopolitan genus of parasitoid wasps of the family Eulophidae. The wasps parasitize various caterpillars from many families of moths. The genus is distinct from other genera in the family but species within the genus are difficult to distinguish. Species in this genus are all ectoparasitoids but vary in their strategies for host exploitation.
== Distribution and hosts == ''Euplectrus'' wasps have been found on every continent besides Antarctica and in every biogeographic realm, as their hosts also have a cosmopolitan distribution.<ref>{{Cite web |title=Universal Chalcidoidea Database, UCD at TaxonWorks |url=https://ucd.chalcid.org/#/taxon?taxonID=457142 |access-date=2026-04-17 |website=ucd.chalcid.org}}</ref>
''Euplectrus'' parasitize caterpillars of many different moth families, including Erebidae, Euteliidae, Geometridae, Lasiocampidae, Noctuidae, Nolidae, Notodontidae, Sphingidae and Tortricidae.<ref name="Zhu">{{cite journal | author1 = Chao-Dong Zhu | author2 = Da-Wei Huang | year = 2003 | title = A Study of the Genus ''Euplectrus'' Westwood (Hymenoptera: Eulophidae) in China | url = http://zoolstud.sinica.edu.tw/Journals/42.1/140.pdf | journal = Zoological Studies | volume = 42 | issue = 1 | pages = 140–164}}</ref><ref name="Hansson">{{cite journal | author1 = Christer Hansson | author2 = M. Alex Smith | author3 = Daniel H. Janzen | author4 = Winnie Hallwachs | year = 2015 | title = Integrative taxonomy of New World ''Euplectrus'' Westwood (Hymenoptera, Eulophidae), with focus on 55 new species from Area de Conservación Guanacaste, northwestern Costa Rica | doi = 10.3897/zookeys.485.9124 | pmid = 25829847 | journal = ZooKeys| issue = 485 | pages = 1–236| pmc = 4361813 | doi-access = free | bibcode = 2015ZooK..485....1H }}</ref> The larvae of all species of ''Euplectrus'' are greenish-yellow and are conspicuous on the host caterpillar's cuticle to which they are very firmly attached.{{Citation needed|date=April 2026}}
== Morphology and taxonomy == ''Euplectrus'' are easily distinguished from other members of the subfamily Eulophinae by three characteristics: long hind tibial spurs more than half as long as the hind tarsi, a scutellum without lateral grooves or rows of pits, and a propodeum with a single strong median carina. The genus is morphologically conservative, making species identification within the genus difficult.<ref name="Hansson" />
== Ecology and behaviour == thumb|''Euplectrus'' sp. on surface of host caterpillar
All species in the genus ''Euplectrus'' are caterpillar ectoparasitoids, attaching eggs to the surface of their hosts with a thin pedicel. During oviposition, the female wasps use their long tibial spurs to anchor themselves to the dorsum of the host caterpillar. Eggs are laid under the cuticle of the host, but above the hypodermis. Species are normally gregarious, laying between five and several hundred eggs per host caterpillar, although a few species lay a single egg on each host.{{Citation needed|date=April 2026}} Ovipositing females also inject venom in the host which prevents ecdysis (moulting), thus allowing the larvae and coccoons to remain attached to the host.<ref>{{Cite journal |last=Gelman |first=Dale B. |last2=Kelly |first2=Thomas J. |last3=Coudron |first3=Thomas A. |date=1997 |title=Mode of action of the venom of the ectoparasitic wasp,Euplectrus comstockii, in causing developmental arrest in the European corn borer,Ostrinia nubilalis |url=https://link.springer.com/10.1007/BF02480379 |journal=Invertebrate Neuroscience |language=en |volume=3 |issue=2-3 |pages=231–238 |doi=10.1007/BF02480379 |issn=1354-2516|url-access=subscription }}</ref> Additionally, some species are idiobionts, with ovipositing females injecting a paralytic venom, while other species are koinobionts, allowing host larvae to continue feeding during parasitoid development.<ref name="Hansson" />
After hatching, ''Euplectrus'' larvae remain attached to the host caterpillar, sucking on its haemolymph to feed. The larvae undergo 3-5 molts. Once larval growth is completed, larvae migrate from the dorsal side of the caterpillar to the ventral side of the caterpillar and spin coccoons to pupate.{{Citation needed|date=April 2026}} Some species spin communal cocoons around their host.{{Citation needed|date=April 2026}} The ability to spin cocoons is unique to this genus within the Eulophidae, with the larvae producing silk in modified malpighian tubules and exuding it from the anal opening.
Wasps in the genus normally take no longer than two weeks to go from oviposition to imago. [[File:Euplectrus sp. - lifecycle B - 06 - cocoons on a Noctuidae caterpillar (2010-05-05).jpg|thumb|''Euplectrus'' sp. cocoons on a Noctuidae caterpillar]]
==References== {{Reflist}} *[http://cache.ucr.edu/~heraty/Eulophidae/index.html Key to Nearctic eulophid genera] {{Webarchive|url=https://web.archive.org/web/20161201122149/http://cache.ucr.edu/~heraty/Eulophidae/index.html |date=2016-12-01 }} *[http://internt.nhm.ac.uk/jdsml/perth/chalcidoids/listChalcids.dsml?Superfamily=Chalcidoidea&Family=Eulophidae Universal Chalcidoidea Database] {{Webarchive|url=https://web.archive.org/web/20070310192605/http://internt.nhm.ac.uk/jdsml/perth/chalcidoids/listChalcids.dsml?Superfamily=Chalcidoidea&Family=Eulophidae |date=2007-03-10 }}
{{Taxonbar|from=Q5410829}} {{Authority control}}
Category:Eulophidae