Spalangia drosophilae Ashmead, 1887

Gibson, Gary A. P., 2009, 2259, Zootaxa 2259, pp. 1-159 : 50-56

7. Spalangia drosophilae Ashmead, 1887

(Figs 114–129)

Spalangia drosophilae Ashmead, 1887: 199 ; holotype ♀ (USNM, examined). Type data: Jacksonville , Fla. [Florida].

Description. Female. Length = 1.0– 2.1 mm. Legs dark except sometimes knees and usually basal 3 or 4 tarsal segments yellow. Head in anterior view about 1.2–1.3x as high as wide; in dorsal view about 2.0–2.5x as wide as long; in lateral view (Fig. 115) with malar space about 0.8–1.0x as long as eye height and about 1.2–1.6x as eye width. Head capsule (Figs 114, 115) smooth and shiny except for setiferous punctures as follows: with complete median sulcus extending ventrally to level of lower orbit, usually within elongate-triangular to slightly transverse-oval scrobal depression, otherwise upper face and parascrobal region usually with widely scattered, minute pinprick-like punctures, though sometimes punctures quite deep and distinct even though only slightly larger than base of seta; scrobal depression (Fig. 114) delineated by coriaceous to coriaceousgranular scrobes on either side of smooth and shiny interantennal region, the coriaceous sculpture variably conspicuously extending laterally onto inner half of parascrobal region above torulus and with setae often extending partly over coriaceous sculpture from parascrobal region, but scrobal depression without distinctly inclined or convex lateral surface; gena (Fig. 115) rugulose-roughened near oral margin and with linear malar sulcus, but otherwise smooth with setae originating from at most pinprick-like punctures or tiny bumps; temple smooth with setae originating from pinprick-like punctures. Antenna (Fig. 124) with scape about 4.6–6.4x as long as wide, the inner (Fig. 127) and outer (Fig. 128) surfaces coriaceous-alutaceous to quite strongly rugose and uniformly setose; pedicel about 2.0–2.1x as long as apical width and about 1.8–3.0x as long as fu 1; funicle with fu 1 transverse to obviously (about 0.8–1.2x) longer than wide, fu 2 sometimes only about 1.3x as wide as long but usually more conspicuously transverse (at least 1.5x as wide as long), and subsequent segments usually at least slightly and often obviously transverse with fu 7 about 1.0–2.0x as wide as long; clava about 1.9–2.7x as long as wide.

Figs 114–121. Spalangia drosophilae Ashmead. 114–116, ♀ head: 114, frontolateral view, 115, lateral view, 116, posterior view; 117, ♁ head, lateral view; 118 &119, ♀ mesosoma: 118, dorsal view, 119, posterodorsal view; 120, ♁ scutellum–petiole, posterodorsal view; 121, ♀ gaster.

Figs 122–128. Spalangia drosophilae Ashmead. 122 & 123, mesopleuron: 122, ♀, 123, ♁; 124 & 125, antenna: 124, ♀, 125, ♁; 126, ♁ pedicel and fu 1; 127 & 128, ♀ scape: 127: inner view, 128: outer view.

Pronotal collar in lateral view (Fig. 115) only very low convex behind neck and with circumpronotal band anterolaterally, but anteriorly smoothly rounded to neck (Figs 118, 119); smooth and shiny to extensively coriaceous, but without cross-line posteriorly and variably densely and conspicuously setose except mediolongitudinally (Figs 118, 119). Mesoscutal median lobe (Figs 118, 119) with transverse band of coriaceousalutaceous sculpture near midlength and usually with at least a couple of irregular punctures forming more coarsely sculptured region posterior to coriaceous band, but otherwise smooth and shiny except for setae near notauli. Axillae (Figs 118, 119) shiny except for setae. Scutellum (Figs 118, 119) flat and shiny, variably extensively but sparsely setose with setae originating from at most pinprick-like setiferous punctures; frenum with frenal line usually interrupted over at least medial third (Fig. 118) or punctate-crenulate line at least tapered medially if sometimes virtually complete (Figs 119, 120). Mesopleuron (Figs 122, 123) at least partly distinctly sculptured as follows: pectal region smooth and shiny, mirror-like, and bare except for 1 posteroventral seta; acropleuron longitudinally striate-carinate and with stronger or at least obliquely angled or curved carina directed toward base of tegula abruptly differentiating acropleuron from pectal region; subalar and episternal scrobes variably shallow depressions connected by a linear furrow; upper mesepimeron longitudinally to obliquely striate or strongly alutaceous, with lower mesepimeron more coriaceous-alutaceous; upper and lower mesepisternum sometimes differentiated anteriorly by transepisternal line, but mostly smoothly merged except for partial or rarely complete line of setae, the upper mesepisternum smooth and shiny to coriaceous. Fore wing hyaline to slightly embrowned; sometimes bare behind submarginal vein but often mediocubital fold with 1–5 setae and sometimes with setae in basal cell and/or on basal fold near parastigma. Propodeum (Figs 118–120) with distinct postspiracular sulcus; callus punctate-reticulate to rugulose or sometimes more finely sculptured or with small smooth and shiny region posterior to spiracle adjacent to postspiracular sulcus; plical region with more or less Y- shaped paramedian crenulate furrows sometimes essentially delineating a median carina, but usually with a variably broad and distinct median lanceolate band, the band usually smooth and shiny though rarely finely punctate, and furrows united into single crenulate line over at least posterior half; supracoxal bands usually separated from paramedian crenulate furrow, sometimes connected by region of minute punctures; panels smooth and shiny.

Petiole about 1.9–2.3x as long as medial width; punctate-reticulate to partly longitudinally carinate; bare. Gaster (Fig. 121) sometimes smooth and shiny but usually at least Gt 2 and Gt 3 variably distinctly coriaceous.

Male. Length = 0.9–1.8 mm. Antenna (Fig. 125) with scape about 4.9–6.2x as long as wide; pedicel subglobular (Fig. 126), only about as long or slightly longer than wide; flagellum with conspicuous, semierect setae about as long as width of segment; funicle with fu 1 (Fig. 126) about 3.5–5.6x as long as wide and about 2.0–4.3x as long as pedicel, and subsequent segments all obviously longer than wide, with fu 7 about 1.3–2.2x as long as wide. Otherwise similar to female except as follows. Head in anterior view as wide as or slightly wider than long; in lateral view (Fig. 117) with malar space about 0.8–0.9x eye height and 1.0–1.2x eye width; scrobal depression sometimes with quite narrow coriaceous scrobes and smooth, convex, sparsely setose surface lateral to scrobes. Fore wing sometimes more extensively setose behind submarginal vein. Petiole (Fig. 120) about 2.0–2.5x as long as wide.

Material examined. Nearctic and Neotropical (998 specimens in AEIC, AMNH, BMNH, CNC, CSCA, CUAC, CUIC, DEBU, DENH, EMEC, FSCA, INBIO, INHS, LACM, MCZH, MLPA, MZCR, NCSU, ROME, TAMU, UATV, UCDC, UCFO, UCRC, USNM). Complete collection records are not provided; those with host data: Nearctic. CANADA: Alberta, Lethbridge, 10, 30.VIII.61, R. Depner, H. irritans (L.). Ontario, Belleville, VII.42, VIII.42, F.J. Simmonds, Oscinella frit (INHS, USNM) . Kars, First Line Road, Acres farm, 45º12.155'N 75º41.642'N, 26.VII.01, G. Gibson & L. Bartels, M. domestica . Yorks Corners Road, S Kenmore, Donevelyn farm, 45º11.758'N 75º23.547'W, 22.VIII.00, 26.VII.01, G. Gibson & L. Bartels, M. domestica . USA: Arizona, Oak Creek Canyon, coll. 3.IX.69, em. 16.X.69, Rhagoletis juglandis puparum - possibly not natural host and from Portal, Ariz. ( USNM). Arkansas, Scott Co., nr Ione, Hyw. 23 & US71, 25.VI.75, H.N. Greenbaum, Chloropidae pupa, 21.VII.75, in 2 nd year cone Pinus taeda (FSCA) . California, IX.62, T. Finlayson, Hippelates collusor . Mariposa Co., Lake Tenaya, 22.VII.49, Dom. Par. Lab., Recurvaria milleri . Riverside Co., Riverside, 7.IX.62, E.C. Bay, Hippelates collusor . Florida, Dade Co., Homestead, 24.II.87, H. Glenn, lonchaeid in Euglenia fruit ( USNM). Maryland, [?], 7, 10, 20, 24, 30.III.1898, Oscinis longipes Loew (USNM) . Bell, 18.XI.26, W.L. McAtte ( USNM). North Carolina, Wade Co., Raleigh, L.M. Rueda, M. domestica in chicken manure ( NCSU). North Dakota, Beach, 10.XII, C.N. Ainslie, house fly infested wheat ( USNM). Fargo, 21.VII.22, R.L. Webster, Oscinid puparium ( USNM). Ohio, Kent, 28.XI.66, Pseudocalliope flaviceps (Loew) (USNM) . South Dakota, Elk Point, 13.VIII.14, C.N. Ainslie, Webster no. 11867, Oscinids ( USNM). Texas, Laredo, 1.V.43, I.A. Lane, Otitid pupa ( USNM). Uvalde, 27.X.33, A.W. Lindquist, Bishopp no.20042 ( USNM). Virginia, Montgomery Co., 18.VI.70, W.A. Allen, O. frit pupa ( USNM).

Neotropical. PANAMA: Canal Zone, Balboa Heights, VI-VII.28, J. Zetek, Anastrepha fraterculus . Taboga Island, 29.IX.26, J. Zetek,? Drosophila ampelophila (USNM) . PUERTO RICO: Lake Guanica, 22.IX.36, K.A. Bartlett, H. irritans puparium ( USNM). Punta Arenas, IV.63, Hippelates pusio, E.F. Legner (USNM) . TRINIDAD: VII.27, S.C. Bruner, Theresia claripalpis pupa in Diatraea (USNM) .

Fig. 129. Distribution of Spalangia drosophilae Ashmead.

Distribution. Spalangia drosophilae is a widespread native New World species (Fig. 129). I have seen specimens from North America ( Canada, USA, Mexico), Central America ( Costa Rica, Guatemala, Panama), West Indies ( Barbados, Cuba, Dominica, Dominican Republic, Jamaica, Puerto Rico, St. Vincent, Trinidad, Virgin Islands), and South America ( Argentina, Brazil, Colombia, Ecuador, French Guiana, Peru, Venezuela). Additional unconfirmed records based on Noyes (2003) include Bermuda and British Virgin Islands. De Santis (1967, 1979) and De Santis and Fidalgo (1994) also reported S. drosophilae from various localities in Central and South America, but males and females in AEIC from Nova Teutonia (Santa Catarina) that De Santis identified as S. drosophilae are a mixture of S. drosophilae and S. plaumanni , indicating his records for S. drosophilae likely reflect more than one species.

Spalangia drosophilae was also introduced into Russia and Latvia from Canada for biological control of the frit fly, Oscinella frit (L.) ( Chloropidae ) ( Marshakov 1983). Vago (2002) reported the species from Morocco, but I cannot confirm this record.

Biology. Noyes (2003) lists S. drosophilae as a primary parasitoid of about 20 species in 6 different families of Diptera and also as a primary or hyperparasitoid of species in 3 families of Hymenoptera and 2 families of Lepidoptera . The species was described originally by Ashmead (1887) from a specimen reared from Drosophila sp. (Drosophilidae) and Simmonds (1944) stated that he reared it for six generations on the common fruit fly, D. melanogaster Meigen. I did not see voucher specimens for the latter, but did see specimens reared in Panama from two other drosophilids, the South American fruit fly, Anastrepha fraterculus (Wiedemann) , and what was questionably identified as Drosophila ampelophila Loew. Based on rearing records, S. drosophilae may more commonly parasitize species of Chloropidae than Drosophilidae . Chloropid hosts indicated through label data include the frit fly as well as Liohippelates collusor (Townsend) , Leohippelates pusio Loew , and Stenoscinis longipes (Loew) . Noyes (2003) additionally lists Incertella minor (Adams) , Meromyza americana Fitch , Rhopalopterum carbonaria (Loew) and Rhopalopterum soror (Macquart) , all based on Simmonds (1952). Simmonds studied the life history of S. drosophilae as a parasitoid of the frit fly in several papers (see Noyes 2003), including describing and illustrating the immature stages and reporting rearing it once as a hyperparasitoid through a Hexacola sp. ( Hymenoptera : Figitidae ) pupa and twice through two other unidentified primary parasitoids ( Simmonds 1952). Simmonds (1954) also stated that it develops rarely as a hyperparasitoid through Losotropa sp. ( Hymenoptera : Diapriidae ), but in the laboratory he could not induce it to parasitize either Hexacola or Spaniopus ( Hymenoptera : Pteromalidae ), all larval parasitoids of the frit fly ( Simmonds 1944). Lindquist (1936) also reported S. drosophilae as a parasitoid and a hyperparasitoid of H. irritans through Gnathopleura ridibunda (Say) ( Hymenoptera : Ichneumonidae ) and Eucoila rufocincta (Kieffer) ( Hymenoptera : Figitidae ), but it is possible that these records may be associated with S. leiopleura because voucher specimens show that both species were reared (see further under with S. leiopleura ). A female was reared as a hyperparasitoid of Diatraea ( Lepidoptera : Pyralidae ) through Paratheresia claripalpis (van der Wulp) (Tachinidae) in Trinidad and De Santis (1967) reported the sugarcane borer, Diatraea saccharalis (Fabricius) , as a host in Brazil. The latter record and the female labelled as reared from the lodgepole needle miner, Recurvaria milleri Busck. ( Lepidoptera : Gelechiidae ), likely also result from hyperparasitism through a tachinid primary parasitoid. According to Simmonds (1952), S. drosophilae is not normally a hyperparasitoid and is so only when unparasitized hosts are very few. Other indicated Diptera hosts based on label data are M. domestica , Pseudocalliope flaviceps (Loew) (Lauxaniidae) , possibly Rhagoletis juglandis Cresson (Tephritidae) , and unidentified species of Lonchaeidae and Otitidae . Marchiori (2001, 2002) also reported Sarcophagula occidua (Fabricius) (Sarcophagidae) and Archisepsis scabra (Loew) and Palaeosepsis sp. (Sepsidae) as hosts in Brazil. Legner (1967) studied three “strains” of S. drosophilae from California, Jamaica and Puerto Rico and showed developmental differences between them. I did not find voucher material to determine whether more than one species may have been involved, but a single female in the USNM that was reared by Legner from cow dung in Puerto Rico is S. impunctata , a morphologically very similar species.

Recognition. I include S. drosophilae along with S. bethyloides , S. flavicrus , S. impunctata , S. innuba , S. leiopleura and S. plaumanni in the drosophilae species group. These seven species are united by a combination of pronotal, propodeal and mesopleural sculpture patterns, though not all of the diagnostic features are exhibited by all of the species or necessarily by all individuals of a species. Most drosophilae -group species have quite a smooth pronotal collar that at least lacks distinct setiferous punctures and, except for S. innuba , a distinctly crenulate cross-line as compared to cameroni - and nigra -group species (see further under S. plaumanni ). Most species are also characterized by a propodeum with a variably broadly lanceolate, smooth and shiny or sculptured (Figs 53, 118–120, 243, 244, 263–265) median band rather than a carina. However, width of the median propodeal band varies in most of the species, particularly in males, and sometimes is very narrow or essentially a carina (Figs 180, 245, 258, 391, 394). The key is constructed to first segregate those drosophilae -group individuals with an obviously lanceolate median propodeal band (couplet 31), and then those with only a very slender band or median carina from subpunctata -group species (couplet 44). Most importantly of the secondary features used to differentiate those drosophilae -group species with a median carina is mesopleural sculpture. Except for S. impunctata (Fig. 242), drosophilae -group species have at least the upper and lower mesepimeron (Figs 122, 123), and often also the upper mesepisternum (e.g. Figs 54, 55), more strongly sculptured than subpunctata -group species (e.g. Figs 160, 212, 225, 440), which also have a smooth pronotal collar and always a median propodeal carina. Some drosophilae -group species males are further characterized by not only having elongate-slender funicular segments but also conspicuously long, semierect setae (Figs 60, 126).

Individuals of S. drosophilae are morphologically most similar to those of S. impunctata and S. leiopleura , as discussed under the later species. Its comparatively finely sculptured upper mesepisternum differentiates S. drosophilae from S. bethyloides , S. plaumanni and S. flavicrus , which have an obliquely striatestrigose upper mesepisternum. Individuals of S. drosophilae could be mistaken for S. bethyloides if sculpture of the upper mesepisternum is not visible because both species lack setiferous punctures from the gena. However, S. bethyloides is not known north of the isthmus of Tehunatepec, Mexico, and individuals have at least 6 setae on the mediocubital fold and additional setae within the basal cell. Neotropical specimens of S. drosophilae typically have the fore wings bare behind the submarginal vein. I saw a single UCFC female labelled “Florida: Orange Co., Orlando, MacKay Tract, 2.VI.99, R. Russell & S. Fullerton” that would key to S. drosophilae except that it has about 40 setae behind the marginal vein. It also has a complete crenulate frenal line and a petiole that is more distinctly longitudinally carinate than for females of S. drosophilae . In other respects this female is similar to S. drosophilae , though its lanceolate median propodeal band is distinctly, irregularly punctate, and it has unusually long, quadrate funicular segments. This specimen almost certainly represents a distinct species from any I include within the drosophilae -group, but additional specimens are required to better assess variation before description.