The Wharton Lab

Biosteres Foerster, 1862: 259. Type species: Bracon carbonarius Nees, 1834 (monobasic and original designation).

Type locality of type species: Germany; original type specimen lost, neotype male in Institut Royal des Sciences Naturelles de Belgique, Brussels, designated by Wharton (1987).

Used as a subgenus of Opius by Fischer starting about 1957 (e. g. Fischer 1957), with more formal redescription in Fischer (1959). Re-established as a genus in Fischer (1967). Accepted as genus by most subsequent authors, though with some disagreement about status (Tobias 1977, Tobias and Jakimavicius 1986).
Valid genus.

None of the species currently included in the genus Biosteres attack fruit-infesting Tephritidae. However, most of the species now included in genera such as Fopius and Diachasmimorpha were formerly placed in Biosteres. See the Opiinae page for additional information on the current status of names of tephritid parasitoids formerly placed in Biosteres.

In the late 1800s, with works such as Marshall in Andre (1891), Biosteres was redefined largely on the basis of the short second submarginal cell, concealed clypeus, and incomplete occipital carina. Fischer (1972) revived this concept for his classification of Opiinae. Wharton (1988) noted that many of the species fitting this description did not appear to be closely related and included additional features that more narrowly restricted the definition of Biosteres. This resulted in the removal of species now placed in genera such as Fopius and Diachasmimorpha.

Biosteres has long been characterized on the basis of the small second submarginal cell of the fore wing (Figs 9, 11), concealed labrum (Figs 1, 4), and occipital carina that is present laterally and ventrally but widely absent dorsally. Additionally, the thick mandibles have a basal tooth or lobe ventrally (Figs 1, 2), both a dorsope (Fig. 8) and a large pronope are present, and the hind wing has distinct though weak m-cu and RS (Fig. 10). Tobias (1977) and Wharton (1988) discussed the overall resemblance of Biosteres with Opius s. s. while Li et al. (2013) emphasized differences how the basal tooth or lobe is formed in defining Opius s. s. relative to other opiines (without specifically comparing Opius to Biosteres). Essentially, the base of the mandible ventrally has a narrow, sharp tooth or carinate projection in Biosteres (Figs 1, 2), with the mandible more gradually narrowing distally. In the type species of Opius and its close relatives, the basal-ventral expansion is wider (Fig. 3), with a more abrupt demarcation between the broad basal and narrow, parallel-sided apical portions of the mandible.

Biosteres is a large genus with many valid species. Fischer (1972) divided Biosteres largely on the basis of sculptural characteristics, with Biosteres s.s. characterized by reduced sculpture, as represented by the loss of sculpture in the precoxal sulcus. Fischer (1972) used the name Chilotrichia for species that were more heavily sculptured, but Chilotrichia has also been treated as a separate genus on the basis of mandibular and clypeal characteristics. The type species of both Stenospilus Foerster, 1862 and Zetetes Foerster, 1862 also have sculptured precoxal sulci, and since Zetetes is a junior homonym, Stenospilus would be the oldest available name for those species with a sculptured precoxal sulcus. The scutellum is also heavily sculptured in some species of Biosteres, but sculpture on the scutellum is not always correlated with sculpture on the precoxal sulcus.

Various biological information has been published on various species of Biosteres as parasitoids of flies in the family Anthomyiidae (especially vegetable pests in the genus Pegomyia such as the beetfly). Among the publications I have seen are those by Kemner (1925) (Swedish data), Bengtsson (1926) (mostly host lists), Bremer and Kaufmann (1928) (summary of known parasitoids, but most of focus on Utetes fulvicollis), Blunck et al., 1929 (as in Bremer and Kaufmann, with similar reports extending into the 1950’s: e. g. Kaufmann 1937), Cory (1916) (North American rearing records), Decoux and Roland (1934) (records from Belgium), Frost (1919) (North American record from dock), Gersdorf (1960), (1962), (1965) (data on parasitoids from Germany), Hawley (1925: 26) (parasitism on sugar-beet pests in Utah, USA), Kohlmeyer and Kohlmeyer (1960) (attacking Phorbia feeding in fungi), and Hille RisLambers (1932) (data from The Netherlands).

This page was assembled by Bob Wharton and Danielle Restuccia. It is part of a review of the genera of World Opiinae, conducted at Texas A&M University. We are particularly grateful to Xanthe Shirley, Andrew Ly, Patricia Mullins, Trent Hawkins, Lauren Ward, Cheryl Hyde, Karl Roeder, and Andrea Walker, who did nearly all of the imaging (together with Danielle) for this project. Matt Yoder and Istvan Miko provided guidance on databasing issues associated with our use of mx and HAO respectively. This project would not have been possible without the kindness of many curators at museums throughout the world who gave generously of their time to Bob Wharton and his students. In particular, I thank Henry Townes (deceased) and David Wahl (American Entomological Institute, Gainesville), Gordon Nishida (Bernice P. Bishop Museum, Honolulu), Norm Penny, and Bob Zuparko (California Academy of Sciences, San Francisco), Bill Mason (deceased), Mike Sharkey, Andrew Bennett, and Henri Goulet (Canadian National Collection, Ottawa), Paul Dessart (deceased) (Institut Royal des Sciences Naturelles de Belgique, Brussels), Marc De Meyer (Koninklijk Museum voor Midden-Afrika, Tervuren), Axel Bachmann (Museo Argentino de Ciencias Natureles, Buenos Aires), Eberhard Koenigsmann (deceased) and Frank Koch (Museum fuer Naturkunde der Humboldt-Universitaet, Berlin), J. Casevitz Weulersse and Claire Villemant (Museum National d’Historie Naturelle, Paris), James O’Connor (National Museum of Ireland, Dublin), Jenö Papp (National Museum of Natural History, Budapest), Kees van Achterberg (National Museum of Natural History, Leiden), Max Fischer, Herb Zettel, and Dominique Zimmermann (Naturhistorisches Museum, Wien), Per Persson and Lars-Åke Janzon (Naturhistoriska Riksmuseet, Stockholm), Ermenegildo Tremblay (Silvestri Collection, Portici), Erasmus Haeselbarth (Staatliche Naturwissenschaftliche Sammlungen Bayerns, Munich), Tom Huddleston and Gavin Broad (The Natural History Museum, London), Paul Marsh and Robert Kula (USDA Systematic Research Laboratory and US National Museum of Natural History, Washington, D. C.), Vladimir Tobias (deceased) and Sergey Belokobylskij (Zoological Institute, Academy of Sciences, St. Petersburg), and Roy Danielsson (Zoological Institute, Department of Systematics, Lund) for facilitating loans and general assistance associated with examination of holotypes and other material in their care. This work was supported largely by NSF/PEET DEB 0328922 and 0949027, with REU supplements 0723663, 1026618, 1213790, and 1313933 (to Wharton). Page last updated July, 2015. The material on this page is freely available, but should be acknowledged if used elsewhere.

This material is based upon work supported by the National Science Foundation under Grant Numbers DEB 9300517, DEB (PEET) 9712543, DEB (PEET) 0328922 with REU supplements 0723663 and 1026618 and DEB 0949027 with REU supplements 1213790 and 1313933. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.