Perilampus hyalinus, Say, 1829

Yoo, Jeong Jae & Darling, D. Christopher, 2024, Integrative taxonomic revision of the Nearctic Perilampus hyalinus species complex (Hymenoptera, Chalcidoidea, Perilampidae) resolves 100 years of confusion about the host associations of P. hyalinus Say, Journal of Hymenoptera Research 97, pp. 1301-1383 : 1301-1383

P. hyalinus species group sensu Smulyan (1936) and Darling (1996)

Description.

Female. Color: head and body entirely or at least partially brightly iridescent (Fig. 2 A, H ).

Head: in anterior view weakly transverse, slightly wider than high, HW / HH 1.2–1.3; slightly wider than pronotum, HW / PW 1.1–1.2. Frontal carina: distinct, extended from posterior margin of median ocellus (Fig. 2 B ) to near lower eye margin (Fig. 2 A ); in dorsal view narrow near median ocellus. Ocelli: median ocellus in line with lateral ocelli or only slightly advanced (Figs 2 B , 12 G ). Eye: slightly shorter than head height, EH / HH 0.6–0.7. Vertex: rounded behind. Occiput: with vertical groove below vertex, with subparallel costulae; occipital carina absent. Malar space (Fig. 2 A ): with oblique striae obliterating malar sulcus (Fig. 2 D ). Clypeus (Fig. 3 A ): weakly transverse to strongly transverse, CW / CH 1.3–1.6; lateral sulci straight or weakly curved, strongly divergent; with small and indistinct tentorial pits; epistomal sulcus concave, deeper and more distinct than lateral sulci; ventral margin concave or nearly flat. Supraclypeal area (Fig. 3 A ): subquadrate; shorter and narrower than clypeus, SCH / CH 0.5–0.6. Scape (Figs 3 C – E ): length about 0.6 × EH; narrow throughout; pits absent or if present distad covering no more than 0.2 × scape length (Figs 3 D, E ). Flagellum (Fig. 3 I ): anellus transverse, AL / PL about 0.3; Fu 1 subquadrate, Fu 1 L / Fu 1 W 1.0–1.1; subequal to or slightly longer in length than pedicel, Fu 1 L / PL 1.0–1.3; Fu 2 subquadrate or transverse, Fu 3 – Fu 7 transverse; clava 4 - segmented, C 1–3 as long dorsad as ventrad, with distinct terminal button (C 4).

Mesosoma: slightly longer than wide, ML / MW 1.2–1.3. Pronotum: carinulate (Fig. 2 H ); short, PN / MSC about 0.2; shorter along midline, 0.5–0.7 length laterad; anterior margin sharp, all rows of punctures on same plane. Lateral panel of pronotum: without flange (Fig. 4 D ) or with flange below level of mesothoracic spiracle in posterior oblique view (Fig. 16 D : arrow); anterior margin sharp, all rows of punctures on same plane. Prepectus: wide and triangular; differentiated from pronotum with distinct suture; ventral strap short, without row of alveolae; central area of lateral panel smooth, with foveae along dorsal and posterior margins. Mesoscutum (Fig. 2 H ): midlobe without tubercle; notaulus distinct and continuous, uninterrupted by sculpture of mesoscutum. Mesoscutellum: without tubercle; slightly longer than mesoscutum, SC / MSC 1.2–1.3; strongly vaulted, frenum ventrad and not visible in the dorsal view. Axilla: with axillar shelf (Fig. 2 F ). Axillula: elongate and finger-like, AxL / AxH usually 2.0 or greater (Fig. 2 F ). Metanotum: short, length 0.4–0.5 × length of propodeum along midline. Propodeum: width about 3 × length along midline; submedian area smooth to weakly imbricate, with foveae or groove laterad median carina, delimited laterad and ventrad by complete plicae, dorsad by transverse band of foveae; callus with angulate process below spiracle, and alveolate-rugose, with alveolae sometimes obliterated below spiracle; nucha with transverse to arcuate rugae. Fore wing: elongate, WL / WW 2.3–2.4; hyaline, with yellow or brown venation; parastigma swollen with weak equilateral triangular process; postmarginal vein 0.7–0.8 × as long as marginal vein; stigmal vein 0.3–0.4 × as long as marginal vein; stigma with weak uncus.

Metasoma: petiole short and straplike, with weak transverse wrinkles; petiolar flange short with ventral margin of upper area with shallow emargination mesad; antecostal sulcus transverse, with weak vertical carinae laterad and smoothened mesad; Mt 2 with trapezoidal demarcation and shallow median groove, imbricate and wrinkled anteriad, and smooth posterad without lateral protruberances along midline, posterior margin straight and sparsely setose; Gt 3 smooth.

Male. As in female, except: Color: mesonotum sometimes nearly entirely black or with cupreous iridescence (Fig. 3 L cf. Fig. 3 K ). Eye: in dorsal view often more bulbous (Fig. 3 H cf. Fig. 3 G ). Ocellus: often larger (Fig. 3 H cf. Fig. 3 G ). Ocellar ratios LOD: POL: OOL: LOL: often shorter. Frontal carina: distance from lateral ocellus usually shorter. Malar space: MSL / EH often shorter. Flagellum: slightly wider (Fig. 3 J cf. Fig. 3 I ). Scape (Fig. 3 F ): in anterior view weakly expanded distad, 1.3–1.4 × width above radicle; with distinct pits on anterior surface (Fig. 3 F cf. Fig. 3 D, E ); pitted surface not swollen in lateral view. Aedeagus: without a pair of lateral spines.

Diagnosis.

The P. hyalinus species group is characterized by: brightly iridescent coloration (Fig. 2 A, H ), distinct frontal carina extended from posterior margin of median ocellus (Fig. 2 B cf. Fig. 2 C ) to near lower eye margin (Fig. 2 A ), oblique costae obliterating malar sulcus (Fig. 2 D cf. Fig. 2 E ), carinulate pronotum (Fig. 2 H cf. Fig. 2 I ), distinct and uninterrupted notaulus (Fig. 2 H ), axilla with axillar shelf (Fig. 2 F cf. Fig. 2 G ), and elongate and finger-like axillula (Fig. 2 F cf. Fig. 2 G ). The P. platigaster species group has a similar structure of the frontal carina, axilla, and axillula, but is distinguished by having a malar sulcus (Fig. 2 E cf. Fig. 2 D ) and the general body color black with or without weak iridescent reflections (Fig. 2 I cf. Fig. 2 H ).

Distribution.

The P. hyalinus species group occurs exclusively in the Western Hemisphere, from the southern Canada to Argentina.

Host association.

The previously published host records indicate that species are mostly hyperparasitoids, parasitizing dipteran ( Tachinidae and Sarcophagidae ) and hymenopteran parasitoids (Ichneumonoidea) of Lepidoptera , Orthoptera , and rarely, Phasmatoidea and Coleoptera (e. g. Smith 1912; Smith 1958; Pitts et al. 2002; Janzen and Hallwachs 2009). Smith (1912) gave a detailed description of the biology of P. hyalinus Say as an indirect hyperparasitoid — the planidia actively searches and burrows into the host of the primary parasitoid (e. g. caterpillars), but can only feed and develop on the dipteran or hymenopteran parasitoids. There are relatively fewer cases of primary parasitoids in the P. hyalinus species group, and the best documented are the parasitoids of Neodiprion sawflies ( Hymenoptera : Diprionidae ) ( Tripp 1962).

Remarks.

This species group was hypothesized as a monophyletic group based on morphological characters ( Darling 1996) and was well corroborated in our combined analysis of COI and ITS 2 (Fig. 1 ). The oblique costae obliterating the malar sulcus (Fig. 2 D ) is the only shared and putatively derived character exclusive to this species group. Other character states (e. g. frontal carina) are widely distributed across Perilampidae in varying combinations, and a comprehensive phylogenetic analysis of this family is required to understand their evolution. Yoo (2023) recognized two clades in the P. hyalinus species group supported by COI + ITS 2 and morphology: the P. carolinensis species complex, which has a parascrobal area abruptly narrowed in lateral view and the lateral panel of pronotum without a flange (Fig. 1 Clade II), and the P. hyalinus species complex which has a parascrobal area usually gradually narrowed in lateral view and the lateral panel of pronotum with or without a flange (Fig. 1 Clade III). The P. hyalinus species complex is further divided into three major clades which are congruent in genetic and morphological characters, for example the density of pits on the male scape, the shape of the lateral panel of the pronotum, and color of the mesonotum in females ( Yoo 2023). The species in the P. hyalinus clade 3 (IIIc, Fig. 1 ), including P. arcus , P. seneca , and P. ute , are distinguished by a usually densely pitted male scape (Figs 17 G , 17 H , 19 H , 19 I , 21 G , 21 H ) and the lateral panel of pronotum with a triangular flange (Figs 16 D , 18 D , 20 D ). The species in the P. hyalinus clade 1 (IIIa, Fig. 1 ), including P. sonora , can be recognized by the cupreous mesonotum in females (Fig. 22 B ), in addition to the usually sparse pits on the male scape (Fig. 23 G, H ) and the lateral panel of the pronotum that lacks a triangular flange (Fig. 22 D ). The P. hyalinus clade 2 species (IIIb, Fig. 1 ), including P. crassus , P. neodiprioni , P. hyalinus , P. monocteni , P. pilosus , and P. sirsiris , also has a sparsely pitted male scape (Figs 5 G, H , 7 F, G , 9 G, H , 11 G, H , 13 G, H , 15 F, G ) and the lateral panel of pronotum without a triangular flange (Figs 4 D , 6 D , 8 D , 10 D , 12 D , 14 D ). But the P. hyalinus clade 2 species do not have the strong cupreous mesonotum in females (e. g. Fig. 4 B ), except in P. pilosus (Fig. 15 A ).

Figures

Figure 1. Maximum likelihood tree of Perilampus hyalinus species group retrieved from the combined analysis of COI and ITS 2 (modified from Yoo 2023). Bootstrap support values are shown on the left side of the nodes. The roman numerals and black dots adjacent to the nodes indicate the major morphological clades recovered as monophyletic (I = P. hyalinus species group; II = P. carolinensis species complex; IIa = “ pseudocarolinensis ” clade; IIb = P. carolinensis clade; III = P. hyalinus species complex; IIIa = P. hyalinus clade 1; IIIb = P. hyalinus clade 2; IIIc = P. hyalinus clade 3; IIId = “ regalishyalinus ” clade. The morphospecies designation for the sequences is marked by vertical bars, colored according to their placements within their respective morphological subgroups. The names of the species described herein are indicated in white boxes.

Figure 2. The morphological characters of Perilampus hyalinus species group (A B D H F) and other Perilampus species groups (C E G I) A head, anterior-oblique view, P. seneca B vertex, dorsal view, P. neodiprioni C vertex, dorsal view, P. auratus D malar space, P. seneca E malar space, P. platigaster F axilla and axillula, P. hyalinus G axilla and axillula, Perilampus sp. H pronotum and mesoscutum, posterior oblique view, P. neodiprioni I pronotum and mesoscutum, posterior oblique view, P. platigaster. Abbreviations: ax, axilla; axl, axillula; axsh, axillular shelf; ca, carina; fc, frontal carina; ms, malar space; msl, malar sulcus; not, notaulus; psa, parascrobal area. [A ROME 182769; B, H ROME 162273; C ROME 162320; D ROME 199563; E ROME 141508; F ROME 162229; G ROME 182831; I DHJPAR 0038540]. Scale bars: 250 μm (A – C, H, I); 100 μm (D – G).

Figure 3. Sexual dimorphism in the Perilampus hyalinus species group A female head, anterior view, P. seneca B male head, anterior view, P. seneca C female scape anterior margin, P. seneca D female scape inner margin, P. seneca E female scape inner margin, P. neodiprioni F male scape anterior margin, P. neodiprioni G female head, dorsal view, P. seneca H male head, dorsal view, P. seneca I female flagellum, P. seneca J male flagellum, P. seneca K female habitus, dorsal view, P. neodiprioni L male habitus, dorsal view, P. neodiprioni. Abbreviation: scp, scape. [A ROME 199563; B ROME 183976; C, D ROME 199531; E ROME 198219; F ROME 198147]. Scale bars: 250 μm (A, B, G – J); 100 μm (C – F); 500 μm (K, L).

Figure 4. Perilampus hyalinus Female A habitus, lateral view B habitus dorsal view C lateral lobe of mesoscutum along notaulus D lateral panel of pronotum, posterior oblique view E axillula F axilla G head, dorsal view H head, anterior view I lower face J parascutal carina K mesoscutellum apex L, M mesofemoral depression. [A ROME 185913; B, K ROME 189058; C, M ROME 185947; D, F ROME 189056; E, G ROME 162229; H ROME 167636; I ROME 189060; L ROME 162246]. Scale bar: 1 mm (A).

Figure 5. Perilampus hyalinus Male A habitus, lateral view B lateral panel of pronotum and parascutal carina, posterior oblique view C head, anterior view D head, dorsal view E lower face F lateral lobe of mesoscutum along notaulus G, H scape. [A Neotype, ROME 204130; B – D, F, G ROME 182798; E ROME 167638; H ROME 189059]. Scale bars: 1 mm (A); 100 μm (G, H).

Figure 6. Perilampus sirsiris Female A habitus, lateral view B habitus, dorsal view C lateral lobe of mesoscutum along notaulus D, E lateral panel of pronotum, posterior oblique view F parascutal carina G head, dorsal view H head, anterior view I lower face J head, lateral view K mesoscutellum apex L mesofemoral depression. [A, B, D, F, H, J, K ROME 182764; E, G, L ROME 189054; I ROME 182766]. Scale bar: 1 mm (A).

Figure 7. Perilampus sirsiris Male A habitus, lateral view B lateral panel of pronotum, parascutal carina, and axilla, posterior oblique view C head, dorsal view D head, anterior view E lateral lobe of mesoscutum along notaulus F, G scape. [A ROME 162278; B ROME 204099; C ROME 199527; D ROME 162281; F ROME 152680; E ROME 162281; G ROME 185910]. Scale bars: 1 mm (A); 100 μm (F, G).

Figure 8. Perilampus neodiprioni Female A habitus, lateral view B habitus, dorsal view C lateral lobe of mesoscutum along notaulus D lateral panel of pronotum, posterior oblique view E axillula F axilla G head, dorsal view H head, anterior view I clypeus J parascutal carina K mesoscutellum apex L, M mesofemoral depression. [A – E, G, H, J, L Paratype, ROME 162273; F, M Paratype, ROME 198146; I ROME 181757; K ROME 189061]. Scale bar: 1 mm (A).

Figure 9. Perilampus neodiprioni Male A habitus, lateral view B lateral panel of pronotum, parascutal carina, and axilla C head, anterior view D head, dorsal view E lower face F lateral lobe of mesoscutum along notaulus G, H scape. [A – D, F Paratype, ROME 162274; E ROME 185922; G ROME 152634; H Paratype, ROME 97556]. Scale bars: 1 mm (A); 100 μm (G, H).

Figure 10. Perilampus monocteni Female A habitus, lateral view B habitus, dorsal view C lateral lobe of mesosucutm along notaulus D lateral panel of pronotum, posterior oblique view E parascutal carina F axilla G head, dorsal view H head, anterior view I, J c lypeus K mesoscutellum apex L mesofemoral depression. [A, B, D, K Paratype, ROME 201078; C Paratype, ROME 207336; E, J, L Holotype, ROME 201079; F Paratype, ROME 207331; G – I Paratype, ROME 207334]. Scale bar: 1 mm (A).

Figure 11. Perilampus monocteni Male A habitus, lateral view B lateral panel of pronotum, parascutal carina C head, anterior view D head, dorsal view E, F clypeus G, H scape. [A – C, E, G Paratype, ROME 207328 D, F, H Paratype, ROME 207329]. Scale bars: 1 mm (A); 100 μm (G, H).

Figure 12. Perilampus crassus Female A habitus, lateral view B habitus, dorsal view C lateral lobe of mesoscutum along notaulus D lateral panel of pronotum, posterior oblique view E parascutal carina F axilla G head, dorsal view H head, anterior view I lower face J head, lateral view K mesoscutellum apex L mesofemoral depression. [A – H, J, L Holotype, ROME 182771 I Paratype, ROME 189085 K Paratype, ROME 189115]. Scale bar: 1 mm (A).

Figure 13. Perilampus crassus Male A habitus, lateral view B lateral panel of pronotum, parascutal carina, and axilla, posterior oblique view C head, anterior view D head, dorsal view E lower face F lateral lobe of mesoscutum along notaulus G, H scape. [A, B, G Paratype, ROME 189063; C, E, F Paratype, ROME 189062; H Paratype, ROME 189117]. Scale bars: 1 mm (A); 100 μm (G, H).

Figure 14. Perilampus pilosus Female A habitus, lateral view B habitus, dorsal view C lateral lobe of mesoscutum along notaulus D lateral panel of pronotum, posterior oblique view E parascutal carina F axilla G head, dorsal view H head, anterior view I lower face J head, lateral view K mesoscutellum apex L mesofemoral depression. [A, H Holotype, ROME 182765; B, C, E – G, L Paratype, ROME 182819; I, J Paratype, ROME 189067; K ROME 189129; L Paratype, ROME 152679]. Scale bar: 1 mm (A).

Figure 15. Perilampus pilosus Female A habitus, dorsal view. Male B habitus, lateral view C head, anterior view D head, dorsal view E lower face F, G scape. [A Paratype, ROME 189067; B Paratype, ROME 152727; C, D, F Paratype, ROME 182757; E Paratype, ROME 152714; G Paratype, ROME 152725]. Scale bars: 1 mm (B); 100 μm (F, G).

Figure 16. Perilampus seneca Female A habitus, lateral view B habitus, dorsal view C lateral lobe of mesoscutum along notaulus D lateral panel of pronotum, posterior oblique view E parascutal carina F axilla G head, dorsal view H head, anterior view I lower face J head, lateral view K mesoscutellum apex L mesofemoral depression. [A, H, I, J, L Paratype, ROME 199563; B, F, G Paratype, ROME 182769; C Paratype, ROME 158541; D Paratype, ROME 199544; E Holotype, ROME 183977; K Paratype, ROME 198142]. Scale bar: 1 mm (A).

Figure 17. Perilampus seneca Male A habitus, lateral view B lateral panel of pronotum, parascutal carina, and axilla, posterior oblique view C head, anterior view D head, dorsal view E habitus, dorsal view F lateral lobe of mesoscutum along notaulus G, H scape. [A – C, F, G Paratype, ROME 183976; D Paratype, ROME 199551; E Paratype, ROME 162263; H Paratype, ROME 199552]. Scale bars: 1 mm (A); 100 μm (G, H).

Figure 18. Perilampus ute Female A habitus, lateral view B habitus, dorsal view C lateral lobe of mesoscutum along notaulus D, E lateral panel of pronotum, posterior oblique view F axilla G head, dorsal view H head, anterior view I lower face J head, lateral view K mesoscutellum apex L mesofemoral depression. [A, C, D, F, G, H Holotype, ROME 182768; B, E, I – L Paratype, ROME 182763]. Scale bar: 1 mm (A).

Figure 19. Perilampus ute Male A habitus, lateral view B, C lateral panel of pronotum, posterior oblique view D head, anterior view E head, dorsal view F habitus, dorsal view G lateral lobe of mesoscutum along notaulus H, I Scape. [A, B, D – F, H Paratype, ROME 182781; C, G, I Paratype, ROME 198139]. Scale bars: 1 mm (A); 100 μm (H, I).

Figure 20. Perilampus arcus Female A habitus, lateral view B habitus, dorsal view C lateral lobe of mesoscutum along notaulus D lateral panel of pronotum, posterior oblique view E parascutal carina F axilla G head, dorsal view H head, anterior view I lower face J head, lateral view K mesoscutellum apex L mesofemoral depression. [A, D, E Holotype, ROME 189051; B, C, H, J, L Paratype, ROME 185944; F Paratype, ROME 189050; G Paratype, ROME 158551; I, K Paratype, ROME 189131]. Scale bar: 1 mm (A).

Figure 21. Perilampus arcus Male A habitus, lateral view B lateral panel of pronotum, parascutal carina, and axilla C head, anterior view D head, dorsal view E lower face F lateral lobe of mesoscutum along notaulus G, H scape. [A – E, G Paratype, ROME 185954; F, H Paratype, ROME 198214]. Scale bars: 1 mm (A); 100 μm (G, H).

Figure 22. Perilampus sonora Female A habitus, lateral view B habitus, dorsal view C lateral lobe of mesoscutum along notaulus D lateral panel of pronotum, posterior oblique view E parascutal carina F axilla G head, dorsal view H head, anterior view I lower face J head, lateral view K mesoscutellum apex L mesofemoral depression. [A, B, D, G, H, J, K Holotype, ROME 152670; C, E, I Paratype, ROME 186060; L Paratype, ROME 189110]. Scale bar: 1 mm (A).

Figure 23. Perilampus sonora Male A habitus, lateral view B lateral panel of pronotum, parascutal carina, and axilla, posterior oblique view C head, anterior view D head, dorsal view E lower face F lateral lobe of mesoscutum along notaulus G, H scape. [A – F, G Paratype, ROME 182754; H Paratype, ROME 198215]. Scale bars: 1 mm (A); 100 μm (G, H).