Balcha indica (Mani & Kaul)

Gibson, Gary A. P., 2005, The world species of Balcha Walker (Hymenoptera: Chalcidoidea: Eupelmidae), parasitoids of wood-boring beetles, Zootaxa 1033 (1), pp. 1-62 : 31-36

Balcha indica (Mani & Kaul) (Figs. 8, 12, 21, 33, 34, 48, 50, 51)

Thaumasura indica Mani & Kaul, 1973: 57–60 . Type data: [ INDIA], U.P. [Uttar Pradesh], Dehra Dun , 3.IV.1933, M. Bose, ex. Albizzia sp. (dead). Holotype female nec male, by original designation (USNM type no. 76264, examined; originally stated to be mounted on pin, now glued to card rectangle).

Thaumasura indica ; Bouček et al., 1979: 459 (stated as possibly belonging to Eupelmidae ); Farooqi & Subba Rao, 1986: 306 (unplaced species).

Balcha indica ; Gibson, 1989: 67. Change of combination.

Additional material examined. NEARCTIC. USA: Maryland: Montgomery Co., 4 mi. southwest Ashton , 39°06'30"N 77°01'30"W, on dead Prunus infested with scolytids/ cerambycids, 16.VIII.2003 (1♀ CNCI, 2♀ USNM), 24.VIII.2003 (4♀ CNCI, 4♀ USNM) ,

E. Grissell; 17.VIII.2003 (2♀ CNCI, 2♀ USNM), G.F. Hevel; 19.VIII.2003 (3♀ CNCI, 5♀ USNM), 24.VIII.03 (2♀ USNM) , Gates / Hevel; 10.VI.2004, G. Gibson (1♀ CNCI) . Michigan: Wayne Co., Livonia, 21.II.2003, from I­9­8, SELIS Lot # 0309518, H­P. Liu (1♀ MSUC) ; 27.II.2004, H­P. Liu (1♀ CNCI) ; 31.III.2003, from H­2, H.­P. Liu (1♀ USNM) ; 2.IV.2003, from II­21­7, ex. Ash logs infested with Agrilus planipennis , scolytids & cestodes, H­P. Liu (1♀ MSUC) ; 17.XI.2003, J. Gould, ectoparasitoid of Agrilus planipennis on Fraxinus, SELIS Lot 0400458, RN1 (1♀ USNM), RN2 (1♀ USNM) . Livonia, Bicentennial Park, 21.VII.2004, H­P. Liu (1♀ CNCI) ; 42°25.77N 83°23.71W, 237 m, 29.VI.04 (1♀ CNCI, 2♀ USNM), 30.VI.04 (5♀ CNCI, 2♀ USNM), on dying ash tree, M. Gates / G. Gibson. Novi, Maybury State Park , 21.VII.2004 H­P. Liu (1♀ MSUC) . Novi, Rotary City State Park , 20.VII.2004, H­P. Liu (1♀ MSUC) . Virginia: Clarke Co., Univ. Va. Blandy Exptl. Farm, 2 mi. S. Boyce, 4­15.IV.1994 (1♀ CNCI, 1♀ USNM), 19.VIII­2.IX.1994 (3♀ CNCI, 3♀ USNM), 3­21.IX.1994 (4♀ CNCI, 3♀ USNM), 22.IX­ 17.X.1994 (1♀ CNCI, 2♀ USNM), 3­19.IV.1995 (1♀ CNCI) , 25.VII­8.VIII.1995 (1♀ USNM) , D.R. Smith, Malaise trap. Warren Co., 1.5 mi. N. Linden, 1000 ft., 15.IV.95, L. Masner (1♀ CNCI) . ORIENTAL. BURMA: Maymyo, 17.III.1948, on wing, Chief Conservator of Forests (1♀ BMNH) . INDIA: [Nagaland], Nichugod [Nichugaurd], Naga Hills, 3.IV.1929, R.R.D. 215, B.C.R. Cage 10, S.N. Chatterjee (♀ nec ♂ paratype) . [Tamil Nadu], Yercaud nr. Salem, 4500', 12.IV.1962, G.J. Spencer (1♀ CNCI) . THAILAND: (NW), Chiangmai, Fang, 500 m., 15.IV.1958, dead tree (1♀ BPBM) . VIETNAM: Tonkin, Hoa­Binh, A. de. Cooman (11♀, 1♂ IZCAS) , 1929 (1♀ MNHN) , III.1937 (2♀ IZCAS) , VIII.39 (3♀ IZCAS) .

Description. FEMALE. Length, 3–9 mm. Antenna dark except scape, often pedicel and sometimes Fl 1 orange­brown to yellowish­orange, scape widened apically but spindlelike and with outer surface uniformly setose; Fl 1 quadrate to about 1.3 x as long as apical width and about 0.4–0.55 x as long as pedicel; Fl 2 about 0.8–1.5 x as long as clava. Head with punctures on parascrobal region green to blue or purple in contrast to dark, coppery or reddish interstices (cf. Fig. 2), the lower face usually more uniformly green under some angles of light, at least near oral margin, and parascrobal region dorsally usually with green spot on coriaceous region ( Fig. 12 ); ocellar region, vertex and occiput dark or with slight coppery to reddish luster, except usually with green to bluish spot or band in line with posterior ocellus, the two sometimes joined as V­ like mark behind ocelli, and outer orbits usually at least narrowly green to bluish under some angle of light. Face with setiferous punctures (Fig. 21), the punctures on lower face closely crowded, finely coriaceous, and with more distinct coriaceous to slightly reticulate interstices so as to appear somewhat rugulose toward oral margin, but parascrobal region with distinct punctures separated by flat, coriaceous interstices except about dorsal quarter quite abruptly coriaceous or with only very tiny, shallow setiferous punctures, flat, and uniformly setose with white to dark setae. Scrobal depression with scrobes dark or with purple luster under some angles of light and dorsally punctate­reticulate to transversely

strigose; channel smooth, shiny, setose dorsally, and under most angles of light with two bright violaceous to purple or blue bands, a transverse or V­ like band ventrally and a V­ like band or paramedial spot subdorsally, with the region between the bands and below anterior ocellus dark or with coppery or slight yellowish­green luster under some angles of light (cf. Fig. 2).

Pronotum dark or with coppery luster anteriorly, but posteriorly and laterally green or with purple or bluish luster under some angles of light; distinctly coriaceous. Tegula yellow to dark brown. Mesoscutum greenish at least anterolaterally and along parapsidal band, but usually darker or with purple or violaceous luster posterolaterally, and dark or purple posterodorsally, anterodorsally either with continuous broad dark region comprised of united parapsidal and notaular bands or with ­like pattern because of variably distinct greenish paranotaular band, but parapsidal band extending only about half length of mesoscutum and notaular band variably broad and extending partly or entirely to posterior margin ( Fig. 12 ). Mesoscutum almost uniformly alveolate laterally and dorsally posterior to anteromedial dark region ( Fig. 33 ), or dorsally with narrow medial band of much smaller, more reticulate­punctate sculpture extending to scutellum ( Fig. 34 ), the band posterior to parapsidal bands conspicuously narrower than dark region between paranotaular bands; without distinct impression anterior to level of inner margin of axilla; with slightly lanceolate white setae at least laterally anterior to tegula (Figs. 8, 12), dorsally with dark hairlike setae or with scattered white lanceolate setae interspersed with dark setae. Scutellum mostly dark or with slight coppery or violaceous to reddish luster under some angles of light ( Fig. 12 ); variably extensively reticulate posteriorly, but sculpture anteriorly usually more or less distinctly aligned into longitudinal, coriaceous, setiferous furrows and irregular ridgelike interstices, and usually with a higher, more distinct mediolongitudinal carina ( Figs. 33, 34 ). Metanotum dark or with green to bluish lusters under some angles of light; dorsellum thick, with crenulate dorsal surface and coriaceous posterior surface, the posterior surface often extensively setose ( Fig. 48 ) but at least with 2 setae on either side dorsally. Acropleuron with slender, minutely coriaceous subalar region separating punctate­alveolate prealar region from variably sculptured postalar region, the postalar region entirely coriaceous­aciculate or variably extensively and conspicuously punctate­reticulate with elongate, longitudinally aligned punctures; prealar region usually mostly green but often with some purple or violaceous luster (Fig. 8), subalar region often having slight coppery luster, and postalar region dark with green to purple or violaceous luster under some angles of light. Lower mesepimeron variably coriaceous to shallowly punctate­reticulate at least ventrally. Metapleuron distinctly coriaceous except for usually crenulate furrow along posterior margin and anterior margin ventrally. Propodeum mostly green except plical region dark and vertical surface of callus purple to violaceous; paraspiracular region bare, the setae anterior to spiracle extending mesally only to about level of inner margin of spiracle; callus smooth and shiny between setal pores or at most very finely coriaceous laterally near metapleuron; plical region bare, with carinate margin of foramen ­like recurved to anterior margin of propodeum as fine median carina similar in appearance to crenulae lateral to median carina ( Fig. 48 ). Forewing hyaline or rarely with slight brownish infusion on one or more of mediocubital fold, vannal fold, and membrane behind stigmal and postmarginal veins anterior to medial fold; vannal area with subcubital line of setae extending over about apical third to half. Front leg with tarsus yellowish but at least femur and tibia extensively brownish to dark brown with green luster; middle leg at least with trochantellus and tarsus yellowish and with brown region subapically on femur and subbasally on tibia so as to form dark band when tibia appressed to femur, but sometimes mesotrochanter, mesofemur and mesotibia more extensively brown, sometimes with only knee and about apical half of mesotibia yellowish to more orange apically; hind leg sometimes almost entirely yellowish beyond coxae, but usually with at least short subapical brownish region on femur and/or subbasal brownish region on tibia, and sometimes metafemur and metatibia more extensively dark brown similar to middle leg.

Petiole composed almost entirely of vertically raised, smooth and shiny rim ( Fig. 33 ). Gaster in dorsal view dark brown or with coppery luster, in lateral view terga usually with green to blue or purple lusters under different angles of light, except syntergum and often penultimate tergum more uniformly green or with coppery luster; about 1.1–1.5 x as long as head and mesosoma combined. Syntergum highly variable in length, about 0.15–0.35 x as long as remaining gaster and in lateral view only about as long as basal height to about 4 x as long as high; uniformly setose, sculptured and tapered posteriorly, with cercus at basal margin.

MALE. Similar to female except as follows: length, 6 mm; mesoscutum without a distinctly differentiated reticulate­punctate notaular band posterior to the parapsidal bands and with a few white lanceolate setae posteromedially, acropleuron with postalar region finely coriaceous­aciculate, and middle and hind legs mostly yellowish beyond coxae, but petiole and propodeal plical region longer; plical region without complete median carina, coriaceous with several irregular carinae radiating anteriorly from carina along foramen.

Biology. A solitary ectoparasitoid of Agrilus planipennis in Fraxinus spp. ( Bauer et al. 2004) and undoubtedly of at least one other wood­boring coleopteran host in North America. More than one host in North America is indicated by specimens being collected initially in Virginia prior to known establishment of the emerald ash borer in Michigan, the rearing of specimens from Prunus in Maryland, and probably by the conspicuous size difference among females, as discussed below.

Discussion. Of the five specimens listed originally as constituting the type series of B. indica , the holotype and one paratype, stated as males, are females. The other female (originally designated as allotype) and two males are correctly sexed but belong to B. elegans . The smaller size of the holotype and paratype female relative to the larger female designated as allotype likely contributed to the erroneous sex identification. All the associated plant­host data listed in the original description of B. indica refer to B. elegans . Although individuals of B. indica are superficially similar to B. elegans , they are readily distinguished by their bare paraspiracular region and by having at least a few setae dorsally on the posterior surface of the dorsellum ( Fig. 48 ). Individuals of B. indica are probably more likely to be misidentified as B. laciniosa if the dorsellar setae are abraded or not visible, but are distinguished by a combination of mesoscutal features, as discussed under the latter species. The similarity between B. indica and B. laciniosa could indicate a close relationship, even though they are assigned to different species groups based on setal pattern of the dorsellum.

Females in North America vary conspicuously in length from about 3–9 mm, but most comprise two largely discrete size classes rather than varying continuously in length. The conspicuously different body sizes may result from parasitism of different host species having two quite different­sized larvae or from parasitism of different­sized larval instars of the same species. Either instance would provide a different amount of host resource for parasitoid larval development. The specimens from Virginia collected by D. R. Smith are all quite small, perhaps indicating a host with comparatively small larval instars, whereas some specimens reared from Prunus and collected on dying ash in Michigan are large and others are very small, indicating two or more host species or a single host species with substantially different­sized larval instars. Correlated with the size difference is a different syntergal structure. Smaller females have a very short and stubby syntergum, whereas larger females have a conspicuously more elongate­tapered syntergum.

The single male from Vietnam is sufficient to demonstrate that males possess all the principal diagnostic features of females, but insufficient to assess the possible range of variation of propodeal sculpture or other features that are variable for females, as discussed below. The lack of any reared or collected males in North America, as well as the lack of any significant color or sculpture variation in females, suggests that a parthenogenetic form likely was introduced. Eriotremex formosanus (Matsumura) ( Hymenoptera : Siricidae ), an invasive wood­boring pest of deciduous trees in eastern North America, was also introduced from Asia and is parthenogenetic in North America ( Smith 1996). Parthenogenesis undoubtedly aids in the establishment and rate of dispersal of accidentally introduced alien species. Eriotremex formosanus is known from Japan, Laos, Taiwan and Vietnam in Asia, and Smith (1996) suggested that the species was introduced to North America with military traffic because some of the earliest records are from near military bases in Alabama and Georgia. The first collection records of B. indica in North America, although not from coastal localities, were from eastern Virginia near military and other shipping ports. The collection of the species in Michigan only eight years after its discovery in Virginia suggests that it may have been introduced quite some time prior to the 1995 earliest collection record. Although North American specimens differ conspicuously in leg color from specimens from Vietnam, they are more similar in sculpture and setal pattern to these than to the type specimens from India. Consequently, it is possible that the North American population of B. indica was established from a single female brought from Vietnam or another country in southeast Asia in military traffic during or after the Vietnam war.

The Nearctic specimens I identify as B. indica differ conspicuously from the holotype and paratype in color, sculpture and setal patterns. The two type specimens of B. indica , from northern India, have the mesofemur largely and the metafemur entirely yellowish, a narrow black longitudinal band medially on the mesoscutum that has comparatively minute punctate­reticulate sculpture ( Fig. 39 ), the scutellum anteriorly has aligned reticulations but not distinct longitudinal rugae ( Fig. 39 ), and there are no white lanceolate setae on the mesoscutum anterior to the base of the scutellum. The postalar region of the acropleuron is also partly reticulate, much more extensively so in the holotype ( Fig. 51 ) than in the paratype. Nearctic specimens have dark femora, the mesoscutum dorsally much more uniformly punctate­alveolate ( Fig. 33 ) even though there is a dark notaular band that extends to the scutellum ( Fig. 12 ), the scutellum usually has quite conspicuous rugae anteriorly ( Figs. 33 , 50 ), the mesoscutum sometimes has a few white lanceolate setae interspersed with the dark hairlike setae posteromedially, and the postalar region of the acropleuron is entirely coriaceous­aciculate ( Fig. 50 ). The female from Thailand is similar to the holotype in all described features. The female from southern India (Yercaud) has a small region of reticulate sculpture in the postalar region most similar to the paratype, but it is more similar to Nearctic specimens in leg color and mesoscutal and scutellar sculpture, and has scattered white lanceolate setae posteromedially on the mesoscutum. The females from Burma and the females and male from Vietnam have comparatively light­colored legs similar to all Old World specimens other than the Yercaud specimen, scattered white lanceolate setae posterodorsally on the mesoscutum similar to the Yercaud and some Nearctic specimens, and the mesoscutum, scutellum and acropleuron sculptured similar to Nearctic specimens. I interpret all observed differences as intraspecific variation, but molecular analyses of specimens from the different populations compared to those of similar but more definitely distinct species, such as B. laciniosa , B. cylindrica and B. reburra , might provide more definitive information.

Figures

FIGURES 9–18. Mesosoma dorsal: 9, Balcha laciniosa; 10, B. cylindrica; 11, B. elegans; 12, B. indica (N. Am.); 13, B. eximia; 14, B. eximiassita; 15, B. dictyota; 16, B. reticulata; 17, B. anemeta; 18, B. splendida (nob = notaular band, pnb = paranotaular band, ppb = parapsidal band).

FIGURES 31–38. Mesosoma dorsal: 31, Balcha anemeta; 32, B. punctiscutum; 33, B. indica (N. Am.); 34, B. indica (holotype); 35, B. elegans; 36, B. laciniosa (not = notaulus, pl = parapsidal line); 37, B. eximiassita; 38, B. reticulata.

FIGURES 47–54. 47. Metanotum and propodeum: Balcha eximia. 48. B. indica (N. Am.): dorsellum and propodeal plical region. 49 and 50. Mesosoma, lateral: 49, B. punctiscutum; 50, B. indica (N. Am.). 51–54. Posterior half of acropleuron: 51, B. indica (holotype); 52, B. eximiassita; 53, B. anemeta; 54, B. levicollis (sar = subalar region of acropleuron).

FIGURES 39–46. 39–42. Mesosoma, dorsal: 39, Balcha cylindrica; 40, B. splendida; 41, B. camptogastra; 42, B. enoptra. 43–46. Metanotum and propodeum: 43, B. levicollis; 44, B. punctiscutum; 45, B. enoptra (cal = callus, dor = dorsellum, pcr = precrenular region of metanotal panel, ppr = propodeal plical region, psr = paraspiracular region); 46, B. elegans.