Eucoilinae


Eucoilinae is the largest subfamily within the wasp family Figitidae, comprising nearly 1000 described species in over 80 genera. They are small to minute parasitoid wasps that are endoparasitoids of cyclorrhaphous dipteran larvae. Eucoilines are recognized by the presence of a distinctive raised and often sculptured plate or cup on the dorsal surface of the scutellum.

Taxonomy and systematics

Eucoilinae has historically been treated as a separate family by some authors, but recent phylogenetic analyses have consistently placed it as a subfamily within an expanded concept of Figitidae. It is considered part of the "core figitids," a clade that also includes the subfamilies Pycnostigminae, Emargininae, Aspicerinae, and Figitinae, all of which are parasitoids of Diptera.
The most distinctive and diagnostic feature of the subfamily is the scutellar plate, a raised, distinctly margined structure on the dorsal surface of the scutellum, which contains a glandular pit. This feature is universally present in eucoilines and unique to them among parasitic wasps.
A comprehensive phylogenetic study in 2002 tested the monophyly of six informal genus groups proposed by Nordlander. The results supported the monophyly of the Eucoilinae and suggested a revised grouping of genera, with early divergences indicating an ancient split between primarily Afrotropical and Neotropical lineages.

Description

Adults are small, typically 1–5 mm in length, and most species are fully winged, though some are brachypterous. The body is usually shining black or brown and largely polished. The female antenna has 13 articles, often with a distally swollen club. The male antenna is 15-segmented, with the third or fourth segment modified to bear antennal sex glands. Many genera have a conspicuous ring of dense hairs anteriorly on the third abdominal tergite.
The key diagnostic character is the scutellar plate. The shape, size, sculpture, and position of the glandular pit on this plate vary considerably between genera and species.

Distribution

The subfamily has a worldwide distribution, with its highest diversity found in tropical regions, particularly the Neotropics.

Biology and ecology

All eucoilines are solitary koinobiont endoparasitoids. They attack first-instar larvae of cyclorrhaphous flies in various microhabitats. The wasp larva develops inside the host larva, which continues to feed and grow. The parasitoid emerges from the host pupa by chewing an irregular exit hole.
Hosts include a wide range of cyclorrhaphous flies whose larvae develop in diverse environments such as decaying vegetation, fungi, rotting wood, carrion, dung, bird nests, ant refuse deposits, and as leaf-miners or fruit-borers in plants. As such, some eucoiline species are important in biological control programs against pest flies and are also studied in the context of forensic entomology.

Genera

The following 73 genera are a partial list based on the 2025 update from WaspWeb:Acantheucoela Ashmead, 1900 Afrodontaspis Weld, 1961 Afrostilba Benoit, 1956 Aganaspis Lin, 1987 Angustacorpa Quinlan, 1988 Areaspis Lin, 1988 Aspidogyrus Yoshimoto, 1962 Banacuniculus Buffington, 2010 Bothrochacis Cameron, 1904 Caleucoela Kieffer, 1909 Chrestosema Förster, 1869 Coneucoela Kieffer, 1909 Cothonaspis Hartig, 1840 Delomeris Diaz & Gallardo, 1996 Dettmeria Borgmeier, 1935 Dicerataspis Ashmead, 1896 Didyctium Riley, 1879 Dieucoila Ashmead, 1903 Diglyphosema Förster, 1869 Discaspis Lin, 1988 Disorygma Förster, 1869 Ditanyomeria Yoshimoto, 1963 Ealata Quinlan, 1986 Endecameris Yoshimoto, 1963 Epicoela Borgmeier, 1935 Epochresta Lin, 1988 Eucoila Westwood, 1833 Eutrias Förster, 1869 Euxestophaga Gallardo, 2017 Fontaliella Pujade-Villar, 2013 Ganaspidium Weld, 1955 Ganaspis Förster, 1869 Garudella Buffington & Forshage, 2014 Gastraspis Lin, 1988 Glauraspidia Thomson, 1862 Gronotoma Förster, 1869 Hexacola Förster, 1869 Humboldteria Buffington Hydrelliaeucoila Díaz & Gallardo, 2009 Hypodiranchis Ashmead, 1901 Kleidotoma Westwood, 1833 Leptolamina Yoshimoto, 1962 Leptopilina Förster, 1869 Linaspis Lin, 1988 Linoeucoila Lin, 1988 Lispothyreus Yoshimoto, 1962 Lopheucoila Weld, 1951 Maacynips Yoshimoto, 1963 Marthiella Buffington, 2009 Micreriodes Yoshimoto, 1962 Microstilba Förster, 1869 Mirandicola Belizin, 1968 Moneucoela Kieffer, 1907 Moritiella Buffington, 2006 Muhaka Buffington & Copeland, 2015 Nanocthulhu Buffington, 2012 Nesodiranchis Perkins, 1910 Nordlanderia Quinlan, 1986 Nordlanderiana Kovalev, 1989 Nordlandiella Díaz, 1982 Odonteucoila Ashmead, 1903 Odontosema Kieffer, 1909 Paradettmeria Gallardo & Díaz, 2011 Paradiglyphosema Lin, 1988 Paraganaspis Díaz & Gallardo, 1996 Pentamerocera Ashmead, 1896 Penteucoila Weld, 1951 Perischus Weld, 1931 Pressia Belizin, 1968 Preseucoela Buffington, 2002 Promiomera Ashmead, 1903 Pseudodiranchis Yoshimoto, 1962 Quasimodoana Forshage, Nordlander & Ronquist, 2008 Rhabdeucoela Kieffer, 1907 Rhoptromeris Förster, 1869 Sinatra Buffington, 2011 Sinochresta Lin, 1988 Steleucoela Kieffer, 1908 Stentorceps Quinlan, 1984 Striatovertex Schick, Forshage & Nordlander, 2011 Tobiasiana Kovalev, 1979 Trichoplasta Benoit, 1956 Triplasta Kieffer, 1901 Tropideucoila Ashmead, 1903 Trissodontaspis Ashmead, 1903 Trybliographa Förster, 1869 Weldia Yoshimoto, 1962 Zaeucoila Ashmead, 1903 Zamischus Ashmead, 1903