Spalangia nigripes Curtis, 1839

Gibson, Gary A. P., 2009, 2259, Zootaxa 2259, pp. 1-159 : 116-121

21. Spalangia nigripes Curtis, 1839

(Figs 327–345)

Spalangia nigripes Curtis, 1839 : folio 740; type ♀ lost ( Bouček 1963: 461). Type data: [ England], taken by Mr. Shuckard .

Spalangia hyaloptera Förster, 1850: 509–511 ; lectotype ♀ (NHMW, not examined) designated by ( Bouček 1963: 461). Type data: [ Germany], Aachen [lectotype: Or. Ex.]. Synonymy by Bouček (1963: 461).

Spalangia formicaria Kieffer, 1905: 1–2 ; holotype ♀ (NHME, not examined). Type data: Luxembourg, May, E. Wasmann, in nest of Lasius fuliginosus . Synonymy by Bouček (1963: 461).

Spalangia muscarum Girault, 1920: 213–214 ; holotype ♀ (USNM, examined). Type data: 39589 [Urbana, Illinois, reared from muscid puparia, Illinois State Laboratory of Natural History]. Synonymy by Bouček (1963: 461).

Description. Female. Length = 2.6–3.1 mm. Legs dark with tarsi at least not bright yellow, usually with only basal segment of fore tarsus yellowish but sometimes both fore and middle tarsi with basal segments yellowish and hind tarsus with middle three segments somewhat lighter than basal and apical segments. Head in anterior view (Fig. 327) about 0.9–1.0x as high as wide; in dorsal view about 1.7–1.8x as wide as long; in lateral view (Fig. 329) with malar space about 0.7x eye height and about 0.9–1.0x eye width. Head capsule (Figs 327–331) smooth and shiny except for setiferous punctures as follows: with complete median sulcus extending to elongate-triangular scrobal depression, otherwise upper face and parascrobal region with crowded circular punctures mostly separated by about own diameter or less; scrobal depression with dorsally tapered, coriaceous-granular scrobes on either side of smooth and shiny interantennal region, and inclined lateral surface punctate similar to parascrobal region (Figs 327, 328); gena with scattered, often shallower punctures than on face but with linear malar sulcus; temple with slightly larger and often somewhat more multisided punctures than on face, at least posteriorly near occipital carina and dorsally toward upper orbit. Antenna (Fig. 338) with scape about 5.5–6.9x as long as greatest width, the inner (Fig. 339) and outer (Fig. 340) surfaces setose and similarly coriaceous-granular to strongly alutaceous or somewhat longitudinally strigose; pedicel about 2.1–2.4x as long as apical width and about 1.7–1.9x as long as fu 1; funicle with fu 1 about 1.1–1.4x as long as wide, fu 2 subquadrate and subsequent segments increasingly transverse apically with fu 7 about 1.4– 1.7x as wide as long; clava about 1.8–2.0x as long as wide.

Figs 327–335. Spalangia nigripes Förster (Palaearctic) . 327–331, head: 327, anterior view ♀, 328, frontolateral view ♀, 329, lateral view ♀, 330, lateral view ♁, 331, frontolateral view ♁; 332 & 333, ♁ pronotum and mesoscutum, dorsolateral view; 334, ♀ thorax, dorsal view; 335, ♀ mesopleuron.

Figs 336–344. Spalangia nigripes Förster. 336, P ♀ propodeum and petiole, dorsal view; 337, P♁ frenum–petiole, posterodorsal view; 338, P ♀ antenna; 339 & 340, P ♀ scape: 339, inner view, 340, outer view; 341, N♁ scape, outer view, and fu 1 (insert: median portion of scape, inner view); 342, P♁ antenna; 343 & 344, P♁ scape: 343, inner view; 344, outer view. Abbreviations, N = Nearctic, P = Palaearctic.

Pronotal collar in lateral view convexly arched behind neck and anterolaterally with vertical ridge interrupting circumpronotal furrow, but anteriorly smoothly rounded to neck; more or less uniformly covered by setiferous punctures without distinctly differentiated cross-line posteriorly, the punctures often sparser medially but circular even if separated by shiny interstices of less than own diameter anteriorly and laterally (Figs 332, 334). Mesoscutal median lobe (Figs 332, 334) with anterior convex region smooth and shiny or only very narrowly coriaceous posteriorly; internotaular region with distinct circular setiferous punctures lateral to more punctate-rugose medial region having punctures of different sizes and shapes and often slender median smooth line (Fig. 334). Axillae (Fig. 334) shiny but with scattered setiferous punctures. Scutellum (Fig. 334) smooth and shiny mediolongitudinally but with distinct circular setiferous punctures in region behind axillae; frenum (Figs 334, 337) differentiated by complete crenulate frenal line. Mesopleuron (Fig. 335) smooth and shiny as follows: pectal region bare except for 1 posteroventral seta; acropleuron longitudinally carinate, the carinae extending posteriorly onto alar shelf and ventrally, often as weaker striae, over at least dorsal half of upper mesepimeron; subalar scrobe longitudinally to obliquely carinate dorsally, but much more finely roughened-wrinkled to rugose-wrinkled ventrally where at least obscurely extending posteriorly along transepisternal line; episternal scrobe a vertically oval to somewhat lunate, usually longitudinally carinate depression connected to subalar scrobe by punctate-crenulate line; precoxal scrobe tapered dorsally but not extending as distinct line to episternal scrobe; lower mesepimeron often with a few fine longitudinal striae dorsal to and sometimes ventral to episternal scrobe; upper and lower mesepisternum differentiated by carinate transepisternal line over about anterior half and by complete line of adjacent setae (Fig. 335). Fore wing hyaline; mediocubital fold with line of several setae and basal cell variably extensively setose distally. Propodeum (Fig. 336) with distinct postspiracular sulcus; callus reticulate-rugose; plical region with only slightly widened paramedian crenulate furrows delineating median carina, the carina highest near anterior third so in lateral view obviously angulate, and with anterior-most cell often longer but at least of similar width as other cells (Fig. 336); supracoxal bands contiguous with paramedian crenulate furrows; propodeal panels smooth and shiny.

Fig. 345. Distribution of Spalangia nigripes Curtis , S. nigroides Gibson , S. stictocephala Gibson and S. stictocyla Gibson.

Petiole (Fig. 336) about 1.6–1.8x as long as medial width; transversely carinate to reticulate between longitudinal carinae; bare. Gaster smooth and shiny or Gt 2 and/or Gt 3 very finely and obscurely coriaceous.

Male. Length = 2.1–2.8 mm. Antenna with scape about 5.5–5.9x as long as wide, the inner and outer surfaces similarly sculptured as female but ventrally with long, apically curved setae at least as long as greatest width of scape (Fig. 341); pedicel about 1.8–1.9x as long as wide; flagellum (Fig. 342) with setae much shorter than width of respective segment; funicle with fu 1 about 3.5–3.8x as long as wide (Fig. 341) and about 2.1–2.2x as long as pedicel, and subsequent funicular segments quadrate or slightly longer than wide, with fu 7 about 1.0–1.2x as long as wide. Otherwise similar to female except as follows. Tarsi dark. Head (Fig. 331) in anterior view as wide as high; in lateral view with malar space subequal in length to eye height and about 1.3x eye width; upper face and parascrobal region more sparsely punctate, the punctures separated by interstices distinctly greater than own diameter; scrobal depression with scrobes and inclined lateral surface of depression distinctly coriaceous to coriaceous-granular (Fig. 331). Pronotal collar somewhat longitudinally punctate-strigose and/or coriaceous posterolaterally, with setae arising from small bumps within variably distinct and crowded punctures varying from very shallow depressions only slightly larger than setal origin (Fig. 333) to distinct and closely crowded depressions (cf. Fig. 332), but with for smooth, bare median band. Mesoscutal median lobe (Fig. 333) with anterior convex region more extensively coriaceous posteriorly, the coriaceous sculpture sometimes extending more finely over internotaular region; internotaular region with narrower median punctate-rugulose region but with separate, circular setiferous punctures laterally similar to female. Fore wing with brownish tinge along mediocubital fold. Propodeum (Fig. 337) with median carina in lateral view low angulate, projecting less distinctly in anterior third than for female. Petiole (Fig. 337) about 2.7–2.9x as long as medial width; with 1–3 setae laterally.

Material examined. Nearctic (20♀, 2♁). USA: California, Stanislaus Co., Turlock, 12.II.55. R.R. Snelling (1♁ EMEC). Illinois, 16117, 39573 (2♀ INHS), 39589 (holotype, USNM). Algonquin, 8.VII.1894, 29.IV.1895, 5.III.1896, 15, 16, 24.IV.1896, 8.V (3♀ INHS, 6♀ USNM). Urbana, 23.XI.13 (1♀ INHS). New Hampshire, Durham, 20.V.55, R.L. Blickle (1♀ DENH). New York, Schuyler Co., Huston 6, 8.VII.86, L. Smith, pupa M. domestica in dairy manure (2♀ USNM); Huston 2, 19.IX.85 (3♀ CUIC). Oregon, Jackson Co., Murphy Gulch, 42º32.183'N 123º04.044'W, 2,600 ft, 29.III.07, E.F. Drake (1♁). South Dakota, Elk Point, 1915, C.N. Ainslie, reared from H. unipunctata hyper on Apanteles (Webster no. 8856) (1♀, USNM).

Distribution. Spalangia nigripes is a native Palaearctic species ( Noyes 2003) that I only tentatively record as present in the Nearctic region (Fig. 345) as discussed below. Burks (1979) recorded S. nigripes from Arkansas and Colorado, presumably based on specimens in the USNM, but I did not see any to confirm these state records.

Biology. In addition to M. domestica, Noyes (2003) lists S. calcitrans and species of Fannia Robineau-Desvoidy (Muscidae) as well as Lucilia sp. (Calliphoridae) as hosts, but the type specimen of the junior synonym S. formicaria was taken from an ant nest of Lasius fuliginosus (Latreille) (Formicidae) . The host record of H. unipunctata from South Dakota undoubtedly refers to Hypagyrtis unipunctata (Haworth) ( Lepidoptera : Geometridae ) and the label implies that it was reared as a hyperparasitoid through Apanteles Förster ( Hymenoptera : Braconidae ).

Recognition. I include S. nigripes and S. endius in the endius species group as discussed under S. endius . However, presence of S. nigripes in the New World and synonymy of S. muscarum Girault under S. nigripes Curtis are both questionable. Males and females of what I tentatively identify as S. nigripes in North America are either incorrectly associated or they represent a morphologically very similar but separate species from true European S. nigripes . There does appear to more than one species in Europe that keys to S. nigripes using Bouček (1963). A CNC female labelled “ Italy: Sicily, PA, near Piana degli Athanesi, 7.VI.92, J.D. Pinto” and a USNM male labelled “ Cyprus: Argaki, 22.XII.64, H.G. Walker ” almost certainly represent a similar but different species. The two individuals have pronotal and mesopleural sculpture patterns similar to typical S. nigripes , plus a linear malar sulcus, coriaceous scrobes, completely dark tarsi and a basally setose fore wing, but there are 5 or 6 long white setae on either side of the petiole in about its anterior third similar to nigra - group species. The pronotal collar is also less distinctly transverse (width only about 1.4–1.5x medial length compared to about 1.8x medial length in typical S. nigripes ), the mesoscutal median anterior convexity is completely, strongly coriaceous, the median propodeal carina is almost flat rather than distinctly angulate, the head in anterior view is longer with less strongly convergent genae, and the scape is quite smooth and shiny in both sexes. The female also has quadrate apical funicular segments and a more elongate-slender clava (about 2.7x as long as wide) as well as a more elongate-lanceolate gaster. The gaster is about 2.4x as long as wide and has the ovipositor sheaths projecting for a distance slightly greater than length of the basal segment of the hind tarsus, but with Gt 3 only about 1.5x as long as Gt 2. A fully inflated gaster of a typical S. nigripes female is only about 1.7x as long as wide and the ovipositor sheaths project only slightly. As noted by Bouček (1963), S. nigripes females also have Gt 3 conspicuously (at least 2.5x) longer than Gt 2. The male of the unidentified species has oblong funicular segments about 1.4x as long as wide. However, both the Cyprus male and typical European males of S. nigripes have undifferentiated setae on the scape (Figs 343, 344) and fu 1 at most about 2.5x as long as wide (Fig. 342).

I only have two males that I tentatively identify as S. nigripes from North America and one lacks its head though one of its antennae is glued to the point. The scape is distinctly coriaceous-granular or, particularly the outer surface (Fig. 341), more longitudinally strongly alutaceous so as to be somewhat strigose. Although this sculpture pattern is similar to European S. nigripes males (Figs 343, 344), the North American male has long, distally curved setae ventrally on the scape and fu 1 is at least 3.5x as long as wide (Fig. 341). Furthermore, the North American male with a head has smaller eyes than European S. nigripes males (cf. Figs 330, 331). Because of this, both the malar space (Fig. 331) and fu 1 (Fig. 341) are subequal in length to the height of the eye and the malar space is obviously longer than the width of the eye (about 1.3x) in the North American male, whereas European males of S. nigripes have the malar space only about 0.6x the height and about 0.7– 0.8x the width of the eye (Fig. 330) and the height of the eye is about twice the length of fu 1 (Fig. 342). Both North American males also have the pronotal collar partly coriaceous posterolaterally and the Oregon male has atypically shallow setiferous punctures, the setae arising from tiny bumps within only very slight depressions (Fig. 333). The California male has much more distinct and crowded punctures, which posteriorly are aligned so as to be somewhat longitudinally punctate-strigose posterolaterally. This sculpture pattern is intermediate between that of typical European S. nigripes males and those S. erythromera males with a strongly sculptured pronotum (Figs 154, 155). Bouček (1963: 462) correctly observed that S. nigripes “belongs morphologically in the neighborhood of S. erythromera ”. Individuals of the two species are very similar except that the pronotum of S. erythromera lacks circular setiferous depressions, varying from completely smooth and shiny to more or less longitudinally strigose or strigose-rugulose anterior to a smooth band along the posterior margin (Figs 153–155). Spalangia erythromera males also have a much smoother, only finely alutaceous scape and shorter fu 1 (Fig. 163), and a comparatively smooth and shiny head (Figs 147–152) compared to European or the two North American males (Fig. 331) that I tentatively identify as S. nigripes . In particular, S. erythromera males have at most only very finely coriaceous scrobes whereas the North American S. nigripes male with a head not only has the scrobes but also the inclined lateral surface of the scrobal depression distinctly coriaceous (Fig. 331). The latter sculpture pattern is very similar to at least females of the European species S. crassicornis , though pronotal sculpture of S. crassicornis is more similar to those S. erythromera having a distinctly sculptured pronotum than to typical S. nigripes (see further under S. erythromera ).

I am quite confident that the males I identify as S. nigripes in North America and Europe represent different species. However, I am much less confident that the two males from western USA and the females from South Dakota and northeastern USA (Fig. 345) are correctly associated. I could not find any features to differentiate European and North American females that I identify as S. nigripes . Consequently, either S. nigripes is parthenogenetic in North America and the males from California and Oregon belong to some other species or what I interpret as S. nigripes in North America is very similar to but a different species than European S. nigripes . The latter hypothesis might be supported by the apparent rarity of “ S. nigripes ” in North America.