Parasitoids of Fruit-Infesting Tephritidae

This species attacks leaf-mining tephritids, as does Eurytenes macrocerus, while Eurytenes maya Wharton attacks fruit-infesting tephritids. Despite the difference in host habitat, all three species share many morphological features, and readily fit the characterization of Eurytenes (Stigmatopoea).

This species is named after the collector, Allen Norrbom, who has provided many valuable host records for tephritid parasitoids.

Eurytenes (Stigmatopoea) norrbomi Wharton, 2012. In: Wharton et al. (2012): 58-62.

Female. Head in dorsal view 1.2-1.3 x broader than mesoscutum, 1.75-1.85 x broader than face; eye in dorsal view 1.2-1.5 x longer than temple, temples weakly receding behind eyes. Frons and vertex as in E. maya except vertex and outer part of occiput densely covered with long, decumbent setae; width of ocellar field 1.20-1.35 x distance from ocellar field to eye. Face 1.75-1.85 x wider than high; slightly less polished than frons; uniformly setose (as in Figs 51, 53), distinctly punctate, the punctures separated by about 1 x their diameter. Frons and face delimited by a slightly more distinct change in sculpture in area between torulus and eye. Malar space about 0.6 x basal width of mandible, 0.25 x eye height. Clypeus 3.0-3.4 x wider than high; protruding in profile. Occipital carina distinctly curved medially at dorsal end, absent mid-dorsally, the space where the carina is absent approximating width of ocellar field. Antenna 1.15-1.30 x longer than fore wing, with 31-33 flagellomeres; first flagellomere 1.05-1.10 x longer than second, 1.05-1.20 x longer than third; flagellomeres 3.1-4.1 x longer than wide basally, 2.3-2.7 longer than wide apically. Head otherwise as described for Eurytenes maya Wharton.

Mesosoma 1.35-1.45 x longer than high; 1.8-1.9 x longer than wide; 1.3-1.4 x higher than wide. Pronotum dorsally as in E. maya but with slightly enlarged pit in middle of crenulate groove consistently present; crenulae extending in shallow groove onto pronotum laterally, covering dorsal 0.2-0.6; groove margined anteriorly as in E. maya. Anterior declivity of mesoscutum completely vertical, densely covered with white, decumbent setae except for bare median band extending posteriorly to midpit; anterior-lateral corners of mesoscutum at upper edge of declivity elevated, rounded, densely setose, the setal pattern extending in broad bands all along notauli and laterally from anterior declivity to tegula; notauli complete, extending from anterior margin to scuto-scutellar sulcus, weakly converging posteriorly alongside but not into tear-drop shaped midpit; crenulate throughout, with sculpture extending laterally around margin to tegula, sculpture largely obscured by dense setae; lateral lobes of mesoscutum bare posterior-medially. Scuto-scutellar sulcus 4-5 x wider than midlength, lateral margins difficult to discern due to setal density; with low midridge and indistinct crenulae on either side; otherwise as in E. maya. Scutellum as in E. maya except with long marginal setae extending medially to cover most of posterior 0.5. Propodeum extensively rugulose, obscuring nearly all traces of carinae; pleural carina weak, often indistinct, very short median carina often present basally; transverse carina rarely weakly indicated across middle; propodeum uniformly setose anteriorly, with a few scattered setae posteriorly. Mesopleuron as in E. maya except subalar region densely setose and groove below subalar ridge varying from nearly smooth to weakly rugulose. Precoxal sulcus distinctly impressed, unsculptured. Metapleuron a little more extensively setose but otherwise as in E. maya.

Wings. Fore wing stigma parallel-sided, discrete posteriorly, 6.3-6.6 x longer than wide; r1 arising from basal 0.35; 1RS (excluding parastigma) 0.25-0.35 x length of 1M; RS+M weakly sinuate; 3RSa 1.05-1.30 x longer than 2RS; 2RS 2.6-3.1 x longer than r; 2RS and 3RSb straight; 3M variable, but often pigmented and sclerotized for most of its length; 2CUa 0.8-0.9 x length of 2cu-a, 2CUb arising slightly above middle of first subdiscal cell; position of m-cu, 1cu-a, and 1-1A, shape of second submarginal cell, and angle between r1 and 2RS as in E. maya. Hind wing as in E. maya.

Metasoma distinctly petiolate; head 3.75-4.10 x wider than apex of T1. T1 2.2-2.5 x longer than apical width; nearly parallel-sided, with apex 1.20-1.35 x wider than base; surface granular coriaceous throughout; completely without subapical depressions dorsally; dorsope, laterope, dorsal carinae, dorsal surface of T1 in profile, as in E. maya; lateral carina at least partially present but difficult to distinguish from surrounding sculpture. S1 extending about 0.25-0.30 x length of T1; T2 and following without sharp lateral margins; spiracle of second metasomal terga laterally displaced, only partially visible in dorsal view. Ovipositor shorter than mesosoma, base not visible in type series, but total length approximately 0.6-0.7 x length of mesosoma; ovipositor sheath 0.30-0.35 x length of mesosoma, with setal pattern as in E. maya.

Color: Mesosoma, T1, S1, ovipositor sheath, and most of head dark brown to black; antenna yellow basally, apical 0.3 brown; mandibles yellow; palps white; lower gena adjacent malar sulcus brown to brownish red; ventral 0.3-0.4 of clypeus yellow to brownish red. Tegula reddish brown with yellow margin. Legs yellow to pale yellow except most of hind coxa, apical 0.6-0.7 of hind femur, and fifth tarsomere of all legs brown; hind tibia vaerying from weakly infumate to light brown, basal 0.2 nearly always pale yellow. T2 mostly brownish red with median yellow blotch posteriorly; T3 yellow with anterior and lateral margins brownish red; T4-T&6 yellow with anterior and lateral margins dark brown; visible parts of remaining terga yellow.

Male. As in female except antenna with 37 flagellomeres; eye in dorsal view 1.55-1.75 x longer than temple; width of ocellar field 1.05-1.10 x distance from ocellar field to eye. Color same except visible parts of apical terga dark brown.

Body length 2.8-3.5 mm; wing length 3.2-3.6 mm.

This species shares with Eurytenes maya and Eurytenes macrocerus the diagnostic features of Stigmatopoea, most notably: Mandible without basal tooth or lobe ventrally (Figs 2, 3); labrum broadly exposed (Fig. 2); notauli deep, well developed anteriorly (Fig. 4); midpit present (Figs 4, 5); fore wing (Fig. 1) stigma long, narrow, parallel-sided, discrete posteriorly, r1 arising distinctly basad its midpoint; second submarginal cell with 2RS shorter than 3RSb; 2CUb arising above middle of hind margin of first subdiscal cell; dorsope present. Eurytenes norrbomi is most readily differentiated from Eurytenes maya Wharton on the basis of the more densely setose head and body (Figs 3-5), particularly the vertex, occiput, and mesoscutum, and the more extensively rugose propodeum. It also has a shorter ovipositor than Eurytenes maya. The setal pattern on the mesoscutum also differentiates Eurytenes norrbomi from Eurytenes macrocerus. The latter has shorter setae that are more sparsely distributed laterally.

Type locality: Mexico, Morelos, Km. 9-10 between Huitzilac and Lago Zempoala. The species is thus far known from the type locality and nearby sites in D.F. and the state of Mexico.

Four of the specimens from the type series were reared from puparia of Trypeta concolor (Wulp) (Tephritidae) mining leaves of Barkleyanthus salicifolius (H.B.K.) H. Robins & Brett (Asteraceae). The remaining specimens were collected from flowers of this same plant together with Trypeta concolor and Trypeta reducta Han and Norrbom. See Han and Norrbom (2005) for details on the hosts and the collecting localities.