Ormyridae

Ormyrus orientalis, copyright ICAR-National Bureau of Agricultural Insect Resources.

Belongs within: Chalcidoidea.

The Ormyridae are a group of chalcidoid wasps that parasitise plant galls of other insects (Bouček 1988). The majority of species are included in a single genus Ormyrus; attempts to divide this morphologically diverse genus into finer subgroups have generally not been successful.

Ormyrids: attacking the gall
Published 28 December 2011
Female of Ormyrus nitidulus, photographed by Penny Metal.

Everyone knows about God’s supposed inordinate fondness for beetles, but it is my opinion that the true poster children for insect diversity should be the wasps. Wasps, admittedly, do not have as many described species as beetles (there are some who suspect that the actual number of species of wasp may eventually be higher, but that remains in the realm of the hypothetical). However, many species of beetle are very difficult to distinguish except by skilled specialists, being otherwise small, brown, and conservative. Wasps, on the other hand, come in a kaleidoscopic array of colours and shapes, such that even a novice may look at an array of wasps and be immediately struck by the disparity.

An unnamed species of Ormyrus, photographed by Simon van Noort.

The Chalcidoidea, commonly referred to as chalcids, are one of the largest subgroups of wasps, a clade of mostly small (often minute), mostly parasitoid wasps (some have larvae that feed on plants). Members of the Ormyridae, one of the commonly recognised families of chalcids, are generally about two to three millimetres long. Ormyrids are distinguished from other chalcids by their robust body form, with a strongly sclerotised gaster* (ormyrids and perilampids tend to look like steroid-abusing pteromalids). The segments of the gaster are usually ornamented by rows of coarse foveae (pits) that give it a distinctive rough appearance, though in some species these foveae are less obvious or are replaced by longitudinal ribs (Bouček 1988). Ormyrids are often recorded in association with plant galls, but are not gall-formers themselves: rather, they are parasites of the insect larvae that formed the galls (usually flies or other wasps). Some ormyrids are associated with figs and parasites of fig wasps.

*Wasp researchers generally refer to the sections of the body behind the head by terms such as ‘mesosoma’ and ‘gaster’ (or metasoma), rather than ‘thorax’ and ‘abdomen’. This is because the section of the body that is the first segment of the abdomen in other insects has become the last segment of the mesosoma in Hymenoptera.

A female of Ormyrus on a knopper gall (a type of gall that develops when a developing acorn of the pedunculate oak Quercus robur is parasitised by the cynipid wasp Andricus quercuscalicis), photographed by Tristram Brelstaff.

There are about 125 known species of ormyrid (making this a quite small family by chalcid standards) according to the Universal Chalcidoidea Database (an absolutely wonderful resource). However, there isn’t yet a really good classification system within the family. Ormyrids vary to a fair degree, particularly in the form of the antennae or the ornamentation of the gaster, but most authors have placed almost all species within the single genus Ormyrus. Attempts to subdivide this diverse group (for instance, that of Doğanlar, 1991, who recognised four genera of ormyrids with three subgenera within Cyrtosoma) have suffered from not considering the full range of ormyrid diversity. Some of the Australian forms referred to by Bouček (1988), for instance, may not be placeable in Doğanlar’s system. Until an appropriately large-scale review is conducted, most authors will probably continue to recognise an all-purpose Ormyrus.

Systematics of Ormyridae

Characters (from Bouček 1988): Antenna thirteen-segmented; gena posteriorly rounded; occipital carina present, horseshoe-shaped; pronotum relatively short; notauli complete, posteriorly subparallel; forewing with marginal vein at least five times as long as narrow pedunculate part of stigmal vein, without linea calva; tarsi five-segmented; gaster always strongly sclerotised, often with coarse sculpture, sometimes sculpture reduced to small longitudinal ridges bearing a bristle at apex; male gaster broader than high, with at least a blunt edge on sides; cerci reduced to low plates, placed on undivided sclerotised epipygium which is subconical in female, or in form of transverse plate in male; ovipositor not exserted.

<==Ormyridae [Ormyrinae]HB13
    |--*Ormyrulus gibbusB88, HB13, B88
    `--Ormyrus Westwood 1832 (see below for synonymy)B88
         |--*O. punctigerB88
         |--O. australiensis Girault 1915B88
         |--O. bicarinatus Girault 1915B88
         |--O. bicoloripes Girault 1915B88
         |--O. brevicaudisMS01
         |--O. carinativentris Girault 1915B88
         |--‘Torymus (*Chrysoideus)’ chrysidiformisB88
         |--O. langlandi Girault 1920 [incl. Tribaeus decaryi Risbec 1955]B88
         |--O. longicornis Bouček 1970B88
         |--O. orientalisB88
         |--O. rosaeHB13
         |--O. silvae Girault 1925B88
         |--O. variolosusMS01
         `--O. watshamiB88

Ormyrus Westwood 1832 [incl. Chrysoideus De Stefani 1898, Cyrtosoma Perris 1840 non Perty 1830, Monobaeus Förster 1860, Periglyphus Boheman 1833, Siphonura Nees 1834, Tribaeus Förster 1860, Wania Risbec 1951]B88

*Type species of generic name indicated

References

[B88] Bouček, Z. 1988. Australasian Chalcidoidea (Hymenoptera): A biosystematic revision of genera of fourteen families, with a reclassification of species. CAB International: Wallingford (UK).

Doğanlar, M. 1991. Systematic positions of some taxa in Ormyridae and descriptions of a new species of Ormyrus from Turkey and a new genus in the family (Hymenoptera, Chalcidoidea). Türkiye Entomoloji Dergisi 15 (1): 1–13.

[HB13] Heraty, J. M., R. A. Burks, A. Cruaud, G. A. P. Gibson, J. Liljeblad, J. Munro, J.-Y. Rasplus, G. Delvare, P. Janšta, A. Gumovsky, J. Huber, J. B. Woolley, L. Krogmann, S. Heydon, A. Polaszek, S. Schmidt, D. C. Darling, M. W. Gates, J. Mottern, E. Murray, A. D. Molin, S. Triapitsyn, H. Baur, J. D. Pinto, S. van Noort, J. George & M. Yoder. 2013. A phylogenetic analysis of the megadiverse Chalcidoidea (Hymenoptera). Cladistics 29: 466–542.

[MS01] Mocsáry, A., & V. Szépligeti. 1901. Hymenopterák [Hymenopteren]. In: Horváth, G. (ed.) Zichy Jenő Gróf Harmadik Ázsiai Utazása [Dritte Asiatische Forschungsreise des Grafen Eugen Zichy] vol. 2. Zichy Jenő Gróf Harmadik Ázsiai Utazásának Állattani Eredményei [Zoologische Ergebnisse der Dritten Asiatischen Forschungsreise des Grafen Eugen Zichy] pp. 121–169. Victor Hornyánszky: Budapest, and Karl W. Hierseman: Leipzig.

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