Conostigmus bipunctatus Kieffer, 1907

Trietsch, Carolyn, Mikó, István, Ezray, Briana & Deans, Andrew R., 2020, A Taxonomic Revision of Nearctic Conostigmus (Hymenoptera: Ceraphronoidea: Megaspilidae), Zootaxa 4792 (1), pp. 1-155 : 25-32

Conostigmus bipunctatus Kieffer, 1907

Figs. 13 , 14 , 15

Species Comments and History. Conostigmus bipunctatus Kieffer is a widespread and highly variable species. Kieffer (1907) described this species from a type series of 89 wingless male and female specimens collected across Italy. Dessart (1980a) later described a winged female and reported additional specimens from Greece, Austria, Germany, Switzerland and Belgium . Here, we increase the range of this species to include the Nearctic as well as the Palearctic, adding specimens collected across the United States and Canada.

Blue Ovoid Patches on the Syntergite. The defining character that Kieffer used to identify this species is the presence of paired, blue-iridescent ovoid patches on the syntergite ( Figure 14C ; Kieffer, 1907). Though the type series at the MCSN all bear these distinctive blue iridescent ovals, the majority of specimens we examined from the Nearctic and Palearctic did not have these structures. We found three specimens, two males ( PSUC _FEM 88137, PSUC _FEM 88167) and one female ( PSUC _FEM 88193) from the Palearctic with these patches. We found only one female specimen from the Nearctic ( PSUC _FEM 50192) that appeared to have the patches, but they were very faded and difficult to see .

Dessart (1980a) reported that while the blue patches were present on all of the specimens he observed from the Palearctic, the patches were variable between specimens and darker on some than others. Dessart (1980a) also reported one specimen of C. rugiceps that had paired blue iridescent ovoid patches present, though the patches were not present on any other C. rugiceps or other Conostigmus he observed. Likewise, we did not find any presence of these patches on any of the other Nearctic or Palearctic Conostigmus specimens we observed.

When we rubbed the patch on one specimen (PSUC_FEM 88167) with a piece of Blue-Tac on a pin, we found that we were able to rub some of it off. While the purpose of these patches is unknown ( Dessart, 1980a), we propose that these patches may be oil secretions produced by glands. It is possible that these patches are produced only under certain circumstances related to behavior (such as attracting mates, indicating mating status, etc.). Time of year does not appear to be a factor, as the specimens in Kieffer’s type series were collected from June to December ( Kieffer, 1907), and Dessart (1980a) adds specimens with the patches collected in March, April and May.

It is also possible that these patches were present in more specimens but were removed due to how they were collected or preserved (i.e. oils washing off with ethanol, cyanide, soapy pan trap water; rubbing between specimens in a net; etc.). Of the four specimens with patches present, only one had a collection method specified (PSUC_ FEM 88167, “screen sweeping”). Collection methods are not provided for Kieffer’s syntype series ( Kieffer 1907 a), though Dessart (1980a) lists specimens collected from prairie, moss, and in dead leaves or old branches of trees (beech, pine and chestnut).

Variability. Dessart (1980a) recognized a large degree of variation in the coloration and the morphology across both wingless and winged specimens, and even comments that this species may have caused Kieffer to reconsider how he described species. We consider Conostigmus bipunctatus as one widespread and highly variable species, but further work (molecular, morphological, behavioral) may reveal this to be a complex of cryptic species.

This species includes macropterous and bracypterous specimens from the Holarctic, with other morphological differences occurring as a consequence of their macropterous or brachypterous state. The sternaulus is always present, but it is elongate (exceeding 3/4 of mesopleuron length at the level of sternaulus) on all macropterous and some brachypterous specimens, and shorter (reaching less than 3/4 of mesopleuron length at level of sternaulus) on other brachypterous specimens. Because the sternaulus functions as an attachment point for the wing muscles, the length of the sternaulus likely correlates with wing development.

Coloration in this species can vary from yellow (PSUC_FEM 88137, PSUC_FEM 88167, PSUC_FEM 88193) to brown to black. Brachypterous specimens of C. bipunctatus tend to have yellow coloration and be lighter in color than macropterous specimens. All specimens have a median process on the intertorular carina, but it can be acute (PSUC_FEM 50138, PSUC_FEM 9733) or blunt (INHS Insect Collection 287559, PSUC_FEM 50271), and can sometimes extend across the intertorular area towards the dorsal margin of clypeus (PSUC_FEM 50271, PSUC_ FEM 34149). The species always has 2 mandibular points, though there is variation in the length of these mandibular points just as in other species of Conostigmus such as C. madagascariensis (see Mikó et al., 2016, Fig. 37 ).

In males, the curved or sickle-shaped harpe (distoventral margin of the harpe in lateral view concave) is one of the defining features of this species, but the harpe can be longer and more pointed in some specimens (IM 1628 from the Palearctic; PSUC_FEM 50060, PSUC_FEM 34268, PSUC_FEM 9733, INHS Insect Collection 287559 from the Nearctic) than in others. The gonocondyle is always acute, but it is more pointed in some specimens (PSUC_FEM 88167, PSUC_FEM 34065, IM 1799) than in others (IM 43397, PSUC_FEM 16777, IM 1823). Other variations in male genitalia include the presence and shape of the distodorsal notch of the gonostyle–volsella complex, and the dorsomedian conjunctiva of the gonostyle–volsella complex length relative to the length of the gonostyle–volsella complex (see next section for more details).

Differences between Nearctic and Palearctic Populations. Most of the variation observed in the species occurs across both Nearctic and Palearctic populations. The only consistent differences between Nearctic and Palearctic populations occur in the male genitalia, specifically in the presence of the distodorsal notch of the gonostylevolsella complex and the dorsomedian conjunctiva of the gonostyle–volsella complex length relative to length of gonostyle–volsella complex. Nearctic specimens tend to have the dorsomedian conjunctiva extending between 1/3 to 1/2 the length of the gonostyle–volsella complex in dorsal view, and the distodorsal notch of the gonostyle–vol-sella complex present. Palearctic specimens, on the other hand, tend to have the dorsomedian conjunctiva extending equal to or less than 1/3 the length of the gonostyle–volsella complex in dorsal view, and because it is so short, the distodorsal notch of the gonostyle–volsella complex is usually absent.

There are also slight differences in the shape of the proximodorsal notch of the cupula between Nearctic and Palearctic specimens. Though most Palearctic specimens do not have a proximodorsal notch of the cupula, in specimens where it is present, the proximodorsal notch of the cupula has an inverted U-shape (PSUC_FEM 148694, IM1568, IM1799). Most specimens from the Nearctic have a proximodorsal notch with an arched or inverted Ushape, though a few have a notch with an acute or inverted V-shape (PSUC_FEM 50060, PSUC_FEM 50278).

Differences Between Males and Females. Other than genitalia differences and sexual dimorphism in the antennae, there are no obvious differences between males and females.

Diagnosis. Males of this species can be distinguished from other Conostigmus by the curved, sickle-shaped harpe (distoventral margin of the harpe in lateral view concave), in combination with the fused parossiculi, the dense patch of setae on the distoventral edge of the harpe, and the distodorsal setae of the sensillar ring longer than the harpe width (sometimes 2× as long or greater). Males and females can be matched by the following characters: facial pit present, occipital carina complete, postocellar carina present, median process on the intertorular carina present and extending from the intertorular carina towards the dorsal margin of the clypeus, axillular carinae absent, and sternaulus present and elongate in winged specimens. This is also the only species known from the Nearctic to have paired blue iridescent ovoid patches on the syntergite in both males and females. However, the majority of specimens do not have these patches, and it is possible that they could be present in other species of Conostigmus (the patches were also reported on one specimen of Conostigmus rugiceps , a Palearctic species, by Dessart (1980)).

This species has similar male genitalia to the Palearctic species C. grangeri , which can easily be distinguished from C. bipunctatus by the lack of notauli and median mesonotal furrow. Other similar species from the Nearctic include C. minimus , C. musettiae , C. laeviceps , C. dessarti and C. franzinii , which all have elongated sternauli and the facial pit present, but C. bipunctatus can be distinguished by the curved or sickle-shaped harpe and the concave distoventral margin of the harpe in lateral view (convex or straight in others). These five species are also always macropterous and never have been reported with paired blue iridescent ovals on the syntergite.

Description. Body length: 1.275 –2.475 mm. Color hue pattern in male: cranium, mesosoma, metasoma ochre to brown to black, with lighter coloration more common on brachypterous specimens; metasoma sometimes with paired ovoid iridescent patches. Color intensity pattern in male: flagellomeres and pedicel darker than scape; cranium darker than mesosoma, flagellomeres darker than legs; mandible lighter on cranium on darker specimens; lighter specimens sometimes with a darker patch around the ocellar triangle (PSUC_FEM 88132, PSUC_FEM 88167); anterior half of metasoma lighter than the posterior half on the lighter specimens (PSUC_FEM 88132, PSUC_FEM 88167). Color hue pattern female: cranium, mesosoma, metasoma ochre to brown to black; metasoma sometimes with paired ovoid iridescent patches. Color intensity pattern female: mandible lighter on cranium on darker specimens; lighter specimens sometimes with a darker patch around the ocellar triangle (PSUC_FEM 88193); anterior half of metasoma lighter than the posterior half on the lighter specimens (PSUC_FEM 88193); flagellomeres darker than scape and pedicel; scape and pedicel lighter than flagellomeres. Color intensity dorsal and ventral to the site of the sternaulus: concolorous. Color intensity pattern of syntergite: petiole neck and anterior region of syntergite concolorus with the posterior region of the syntergite; petiole neck and anterior region of syntergite lighter in coloration than the posterior region of the syntergite. Foveolate sculpture on body count: absent. Rugose sculpturing count: absent. Rugose region on upper face count: absent.

Antennae: Male scape length vs. pedicel length: 3.5–6.8. Male scape length vs. F1 length: 1.0–1.8. Male F1 length vs. pedicel length: 2.5–4.3. Male F1 length vs. male F2 length: 1.0–1.5. Longest male flagellomere: F1. Female scape length vs. pedicel length: 3.2–4.2. Female scape length vs. F1 length: 3.2–4.2. Female F1 length vs. F2 length: 1.1–1.6. Female F1 length vs. pedicel length: 0.9–1.2. Longest female flagellomere: F1. Length of setae on male flagellomere vs. male flagellomere width: setae shorter than width of flagellomeres. Sensillar patch of the male flagellomere pattern: F6–F9.

Head: Head width, dorsal view: equal to or only slightly wider than mesosoma (less than 1.3× wider than mesosoma) in all macropterous and some brachypterous specimens; 1.3× wider than mesosoma in some brachypterous specimens. Head height (HH, lateral view) vs. eye height (EHf, anterior view): male HH:EHf=1.3–1.7; female HH: EHf=1.5–1.8. Head height (HH) vs. head length (HL): HH:HL=1.0–1.4. Head width (HW) vs. interorbital space (IOS): HW:IOS=1.6–2.0. Head width (HW) vs. head height (HH): HW:HH=1.1–1.4. Cephalic size (csb): Mean: 335–535 μm. Maximum eye diameter vs. minimum eye diameter: 1.1–1.4. POL:OOL: POL equal to or shorter than OOL and ocellar triangle with short base. Male ocular ocellar line (OOL) vs. lateral ocellar line (LOL): OOL: LOL=1.4–3.4. Male ocular ocellar line (OOL) vs. posterior ocellar line (POL): OOL:POL=1.1–2.0. Male ocular ocellar line (OOL): posterior ocellar line (POL): lateral ocellar line (LOL): 1.4–3.4:1.0–2.0:1.0. Female ocular ocellar line (OOL) vs. lateral ocellar line (LOL): OOL 1.8–3.0× as long as LOL. Female ocular ocellar line (OOL): posterior ocellar line (POL): lateral ocellar line (LOL): 1.8–3.0:1.2–2.3:1.0. Head shape (anterior view): circular or triangular. Preoccipital lunula count: present. Preoccipital carina count: absent. Occipital carina structure: occipital carina complete. Occipital carina sculpture: crenulate. Preoccipital furrow count: present. Preoccipital furrow anteri- or end: preoccipital furrow ends inside ocellar triangle, but ends posterior to the anterior ocellus. Preoccipital furrow sculpture: crenulate. Postocellar carina count: present. Dorsal margin of occipital carina vs. dorsal margin of lateral ocellus in lateral view: occipital carina ventral to lateral ocellus in lateral view. Transverse scutes on upper face count: absent. Transverse frontal carina count: absent. Randomly sized areolae around setal pits on upper face count: absent. Setal pit on vertex size: smaller than diameter of scutes. Ventromedian setiferous patch and ventrolateral setiferous patch count: absent. White, thick setae on upper face count: absent. Antennal scrobe count: absent. Facial structure count: facial pit present. Facial pit count: present. Facial sulcus count: absent. Median facial keel count: absent. Supraclypeal depression count: present. Supraclypeal depression structure: absent medially, represented by two grooves laterally of facial pit. Intertorular area count: present. Intertorular carina count: present. Median process on intertorular carina count: absent or present. Median process on intertorular carina shape: blunt; acute. Median process of intertorular carina structure: process extends across intertorular area towards dorsal margin of clypeus; process does not extend across intertorular area to dorsal margin of clypeus. Median region of intertorular area shape: convex. Ventral margin of antennal rim vs. dorsal margin of clypeus: not adjacent. Torulo–clypeal carina count: present. Subtorular carina count: absent. Mandibular tooth count: 2. Mandibular lancea count: absent.

Mesosoma: Weber length: WL=440–720 μm. Anterior mesoscutal width (AscW) vs. posterior mesoscutal width (PscW): AscW/PscW=0.5–0.9. Mesoscutal length (MscL) vs. anterior mesoscutal width (AscW): MscL/ AscW=1.2–2.2. Mesoscutal length (MscL) vs. mesoscutellar length (MscIL): MscL:MscIL= 0.6–1.3. Wing count: present; absent. Fore wing size: wings present and macropterous with apex extending past petiole; wings absent or reduced/brachypterous with apex never reaching past posterior margin of syntergite. Pronotum median length: less than longest median anatomical line of the mesoscutum. Notaulus count: present. Crenulae of notaulus width: width of the crenulae does not increase more than 2× anteriorly. Notaulus posterior end location: adjacent to transscutal articulation. Median mesoscutal sulcus count: present. Median mesoscutal sulcus posterior end: adjacent to transscutal articulation. Scutoscutellar sulcus vs. transscutal articulation location: adjacent. Axillular carinae count: present; absent. Axillular carinae shape: the left and right carinae are separated posteromedially. Speculum ventral limit: not extending ventrally of pleural pit line. Metapleural sulcus shape: straight. Mesometapleural sulcus count: present. Ventrolateral invagination of the pronotum count: present. Sternaulus count: present. Sternaulus length: elongate and exceeding 3/4 of mesopleuron length at level of sternaulus on macropterous and some brachypterous specimens but reaching less than 3/4 of mesopleuron length at level of sternaulus on some brachypterous specimens. Sternaulus sculpture: scalloped. Epicnemial carina count: complete. Epicnemium posterior margin shape: anterior discrimenal pit present; epicnemial carina curved. Transverse striations on the ventral metapleural area count: absent. Scutes on posterior region of mesoscutum and dorsal region of mesoscutellum convexity: flat. Ventral projection of the metapleural carina count: present; absent. Ventral projection of the metapleural carina length: less than 2× as long as wide. Lateral propodeal carina count: present. Lateral propodeal carina shape: inverted “Y” (left and right lateral propodeal are adjacent medially posterior to antecostal sulcus of the first abdominal tergum, and connected to the antecostal sulcus by a median carina representing the median branch of the inverted “Y”); straight (left and right lateral propodeal carinae compose a carina that is not broken medially). Mesopostscutellum count: absent (scutellum flat). Anteromedian projection of the metanoto–propodeo–metapecto–mesopectal complex count: present; absent. Posterior margin of nucha in dorsal view shape: concave.

Metasoma: Transverse carina on petiole shape: concave. Paired blue iridescent ovoid patches on the syntergite count: present; absent. Shortest width of petiole neck vs. syntergal translucent patch maximum width: 1.4–3.2. Shortest width of petiole neck vs. synsternal translucent patch maximum width: 1.6–2.5. Syntergal translucent patch maximum width vs. minimum width: 1.0–2.3. Synsternal translucent patch maximum width vs. minimum width: 1.6–3.0. Syntergal translucent patch maximum width orientation: anterolaterally. Synsternal translucent patch maximum width orientation: anterolaterally. Synsternal setiferous patch shape: linear, with a patch of setae lateral or posterior to the synsternal translucent patch. Synsternal setiferous patch structure: comprised of a single or double row of setae anterior to the synsternal translucent patch, with a patch of setae lateral or posterior to the synsternal translucent patch. Synsternal setiferous patch anterior end: synsternal setiferous patch begins anterior to the synsternal translucent patch anterior margin. Synsternal setiferous patch posterior end: synsternal setiferous patch ends posterior to the synsternal translucent patch posterior margin. Synsternal setiferous patch length vs. synsternal translucent patch maximum width: synsternal setiferous patch at least 2× as long as the maximum width of the synsternal translucent patch. S1 length vs. shortest width: S1 wider than long.

Male Genitalia: Distal margin of male S9 shape: straight; convex. Proximolateral corner of male S9 shape: acute. Male S9 distal setal line/setal patch count: distal setae composing setiferous patch or patches; distal setae composing transverse setiferous line or lines. Male S9 distal setal line / setal patch structure: single transverse row of distal setae occurring medially with less than 4 setae below it; patch of setae occurring medially; single transverse row of setae occurring medially with additional distal setae below it, sometimes organized in one or two additional transverse rows. Distomedian hairless area interrupting transverse row of setae or patch on male S9 count: absent with distal setiferous patch/line continuous medially. Submedial projections on proximal margin of S9 count: absent. Cupula length vs. gonostyle–volsella complex length: cupula less than 1/2 the length of gono-style–volsella complex in lateral view. Proximodorsal notch of cupula count: present; absent. Proximodorsal notch of cupula shape: arched (inverted U-shape); notched (inverted V-shape). Proximodorsal notch of cupula width vs length: wider than long; as long as wide. Proximolateral projection of the cupula shape: blunt. Gonocondyle count: present. Gonocondyle shape: acute. Distodorsal margin of cupula shape: concave. Distoventral submedian corner of the cupula count: absent. Dorsomedian projection of the gonostyle–volsella complex count: absent; present. Dorsomedian projection of the gonostyle–volsella complex shape: simple (not bilobed). Dorsomedian conjunctiva of the gonostyle–volsella complex count: present. Dorsomedian conjunctiva of the gonostyle–volsella complex length relative to length of gonostyle–volsella complex: dorsomedian conjunctiva extending equal to or less than 1/3 of length of gonostyle–volsella complex in dorsal view; dorsomedian conjunctiva extending equal to or less than 1/2 of length of gonostyle–volsella complex in dorsal view. Dorsomedial margin of gonostyle–volsella complex shape: straight without a median projection; straight with a median projection. Proximal end of dorsomedian conjunctiva of the gonostyle–volsella complex shape: blunt or straight. Parossiculus count or parossiculus and gonostipes fusion: present and parossiculi not fused with the gonostipes. Medioventral conjunctiva of the gonostyle–volsella complex count or fusion of parossiculi: medioventral conjunctiva absent and parossiculi fused. Medioventral ridge of the gonostyle–volsella complex count (only applicable if medioventral conjunctiva of the gonostyle–volsella complex absent): present. Medioventral ridge of the gonostyle–volsella complex length relative to length of gonostyle–vol-sella complex: ridge extending 2/3 of length of gonostyle–volsella complex in ventral view; ridge not extending 2/3 of length of gonostyle–volsella complex in ventral view. Apical parossicular setae count: one. Distal projection of the parossiculus count: present. Distal projection of the penisvalva count: absent. Gonossiculus spine count: 2, sometimes with an additional dorsal apodeme below the second spine. Gonossiculus spine length: one spine more than 2× as long as the other(s). Harpe length: harpe equal to or shorter than gonostipes in lateral view. Harpe shape: simple and not bilobed; curved or sickle-shaped. Harpe orientation: medial. Lateral margin of harpe shape: widest point of harpe is in its distal 1/3rd. Distal margin of harpe in lateral view: acute or pointed. Lateral setae of harpe count: present. Lateral setae of harpe orientation: oriented distally. Lateral setae on harpe density: setae sparse. Dense patch of setae on the distoventral edge of the harpe count: present. Distal setae on harpe length: setae not of equal length, longer setae present on distodorsal point of harpe. Distodorsal setae of sensillar ring of harpe length vs. harpe width in lateral view: setae longer than harpe width; setae two times as long as harpe width or greater. Distodorsal setae of sensillar ring of harpe orientation: distoventrally. Sensillar ring area of harpe orientation: distoventrally. Sensillar ring shape: elongate. Distoventral margin of harpe in lateral view: concave.

Distribution. Holarctic.

Material Examined. Non-type material (63 males, 9 females): CANADA: 1 male. PSUC _FEM 50060 ( PSUC). CANADA: British Columbia: 1 male. PSUC _FEM 34234 ( AMNH). CANADA: Ontario: 6 males. PSUC _FEM 15317, 15677 , 15846 , 16258 , 16317 , 16777 ( ROME). ITALY: 1 male. PSUC _FEM 88167 ( UCRC). NETHER- LANDS: 1 male, 1 female. PSUC _FEM 88137, 88193 ( CNC). RUSSIA: 1 male. UCRC _ ENT 00264026 ( UCRC). SWEDEN: 42 males. NCSU 0043327 , 0043347 , 0043390 , 0043398 ( NHRS); IM 1586 , 1587 ( NCSU); IM 1568 , 1583 , 1591 , 1620 , 1628 , 1688 , 1735–1740 , 1747 , 1751 , 1752 , 1754 , 1756 , 1762 , 1779 , 1798-1799, 1822–1824, 1762-1763, 1735-1740; NCSU 0043396 , 0043397 , 0055671 ; PSUC _ FEM 148439 , 148461 , 148604 , 148607 , 148652 , 148664 , 148694 ( PSUC). USA: Alaska: 3 males, 2 females. PSUC _FEM 34065, 50192 , 50271 , 50278 , 56133 ( AMNH). USA: California: 3 males. PSUC _FEM 34149, 34268 , 34270 ( TAMU). USA: Colorado: 1 male. INHS Insect Collection 287559 ( INHS). USA: Oregon: 1 male. PSUC _ FEM 9733 ( ROME). USA: Wisconsin: 2 males, 6 females. PSUC _FEM 50059, 50138 , 50140 , 50144 , 50176 , 50189 , 50338 , 91488 ( INHS) .

Figures

FIGURE 13. Conostigmus bipunctatus Kieffer, 1907 in lateral view. A. Macropterous male (PSUC_FEM 34149). B. Brachypterous male (PSUC_FEM 34065).

FIGURE 14. Conostigmus bipunctatus Kieffer, 1907. A. Reduced wing male, dorsal view (PSUC_FEM 34065). B. Reduced wing female, lateral view (PSUC_FEM 88193). C. Reduced wing female, dorsal view (PSUC_FEM 88193), with insert showing a close-up of the blue iridescent ovoid patch (Insert: reduced wing male; PSUC_FEM 88167).Abbreviations: median process on intertorular carina (mip; projection acute in this case); median mesoscutal sulcus (mms); pronotum (prn).

FIGURE 15. Conostigmus bipunctatus Kieffer, 1907 male genitalia.A. Ventral view (NCSU 0055671). B. Dorsal view (PSUC_ FEM 88193). C. Ventral view of a male with longer harpe (IM 1628). D. Lateral view (IM 1779). E. Lateral view (PSUC_FEM 148461). F. Lateral view of a male with longer harpe (IM 1628).

FIGURE 37. Conostigmus orcasensis (Brues, 1909) male holotype genitalia (UAM100257610). A. Ventral view. B. Lateral view. C. Dorsal view. Abbreviation: promixodorsal notch of cupula (pdn).