Note

The family Platygastridae has two subfamilies Platygastrinae and Sceliotrachelinae, the former being parasitoids of Cecidomyiidae (Diptera) while the latter are parasitoids of eggs of Flatidae, Pseudococcidae, Aleyrodidae, Curculionidae and Cerambycidae (Goulet & Huber 1993). Piestopleura belongs to the subfamily Platygastrinae. This genus is being reported for the first time from India.

While collecting Platygastroidea from their natural habitat, a specimen of the genus Piestopleura Forster was collected from a Malaise trap erected at the Institute of Wood Science and Technology (IWST), Malleswaram, Bengaluru. The specimen was imaged with a Leica M205A stereomicroscope, with 1x objective and Leica DFC-500 digital camera. Voucher specimen is deposited at the ICAR-National Bureau of Agricultural Insect Resources, Bengaluru, Karnataka, India.

Piestopleura Förster

(Images 1 & 2)

Material examined: ICAR/NBAIR/P1184, 28.vii.2012, India, Karnataka, Bengaluru, IWST, Malaise trap, forest land, coll. A. Rameshkumar.

Diagnosis: This genus can be easily distinguished from other genera of Platygastrinae by the presence of the following character states: head antero-posteriorly compressed; mesosoma extremely laterally compressed; mesoscutellum elongate, never semicircular; metasoma with flat ventral surface. The presence of a distinct T1 makes it more related to Leptacis than Synopeas (Ashmead 1893; Jackson 1969).

Biological information: Piestopleura parasitizes the eggs or larvae of gall midges (Cecidomyiidae). The wasp egg does not hatch until the fly larva is fully grown. The egg divides multiple times when the host is much larger than the wasp, resulting in identical clones that allow many wasps to develop from a single egg (polyembryony). Ossiannilsson (1937) recorded different parasitic Hymenoptera such as Macroglenes penetrans (Kirby), Leptacis tipulae (Kirby), Platygaster tuberosula Kieffer, Platygaster sp., Isostasius punctiger Nees, Piestopleura thomsoni Kieffer, Sactogaster pisi Förster, and Ectadius mamertes (Walker) as parasitizing the lucerne flower midge Contarinia medicaginis Kieffer. Barnes (1939) recorded eulophids [Aprostocetus annulatus (Förster) and Omphale aetius (Walker)] and platygastrids [Synopeas sp. and Piestopleura catillus (Walker)] as parasitoids of Dasyneura alpestris (Kieffer).

Distribution: Piestopleura is represented by 19 species worldwide (Johnson 2016). Of these, 14 are known from the Palaearctic region while one species each has been reported from the Nearctic, Neotropical, Afrotropical, Australasian and Oriental regions (Vlug 1995; Johnson 2016). The only Oriental species - Piestopleura milnei Buhl - was described from Philippines, and subsequently reported from Laos. This is the first report of the genus from India.

References

Ashmead, W.H. (1893). A monograph of the North American Proctotrypidae. Bulletin of the United States National Museum 45: 1–472.

Barnes, H.F. (1939). “Some Gall Midges and their Host Plant Range”. Annals of Applied Biology 26: 318–347.

Jackson, D.L. (1969). New characters for generic separation in the Synopeas-Leptacis complex. Proceedings of the Entomological Society of Washington 71: 400–404.

Johnson, N.F. (2016). Platygastroidea. Available from: http://osuc.biosci.ohio-state.edu/hymDB/eol_scelionidae.home (Accessed on 14 March 2016)

Masner, L. (1993). Superfamily Platygastroidea, pp. 558–563. In: Goulet, H. & J.T. Huber (eds.). Hymenoptera of The World: An Identification Guide to Families. Agriculture Canada Research Branch, Monograph No. 1894E, 668pp.

McKellar, R.C. & M.S. Engel (2012). Hymenoptera in Canadian Cretaceous amber (Insecta). Cretaceous Research 35: 258–279; http://doi.org/10.1016/j.cretres.2011.12.009

Ossiannilsson, F. (1937). “Lucerngallmyggan (Contarinia medicaginis Kieff.)”. Meddelanden Statens Vaxtskyddsanst 20: 1–43.

Vlug, H.J. (1995). Catalogue of the Platygastridae (Platygastroidea) of the world (Insecta: Hymenoptera). Hymenopterorum Catalogus 19: 1–168.