Paedarium subauratum (Blanchard) Toma & Takahashi, 2022

Toma, Ronaldo & Takahashi, Tamara Akemi, 2022, Paedarium subauratum (Blanchard, 1943) comb. nov. (Diptera, Tachinidae) parasitoid of the Southern armyworm Spodoptera eridania (Stoll): taxonomic redescription and biology, with notes on the genus Paedarium Aldrich, 1926, Papéis Avulsos de Zoologia (Pap. Avulsos Zool., S. Paulo) 62, pp. 1-8 : 3-6

Paedarium subauratum (Blanchard) comb. nov. ( Fig. 1 A-D)

Type material: According to Torres-Domínguez et al. (2020), two males syntypes, glued on card, labeled: “S noctuido de papa / Urundel / Salta [upperside] / 10-VIIII-1937 / Koehler lg [underside]” handwritten on white paper ; “ Cotipo ” handwritten on blue paper, black frame ; “ Neopaedarium / subauratum / Blnchd [handwritten] /det. E.E. Blanchard [printed]” on white paper, black frame ; “3329” handwritten on white paper; “ Museo La Plata ” printed on white paper. One syntype documented with one photo .

Diagnosis: This species differs from all others species of the genus by having the following combination of features: vertex, ocellar triangle, fronto-orbital plate, postocular plate and parafacial goldish-yellow pruinosity, the basal half of the parafacial sometimes varying from yellowish-gray to goldish-yellow; R₄₊₅ setose from the base up to the r-m crossvein or surpassing the latter by up to one time the r-m crossvein length; abdomen, in dorsal view, subshining black, tergites 3 and 4 with grayish-white pruinosity on basal half, and tergite 5 with gold pruinosity on basal half.

Paedarium subauratum differs from P. neotropicum by having vein R₄₊₅ setose from the base up to the r-m crossvein or surpassing the latter by up to one time the r-m crossvein length; differs from P. ica and P. parvum by having the following combination of features: vertex, ocellar triangle, fronto-orbital plate, postocular plate, parafacial with goldish-yellow pruinosity (the basal half of parafacial sometimes varying from yellowish-gray to goldish-yellow), and tergite 5 with gold pruinosity on basal half.

Description: Male: Body length: 6.37-6.66 mm, wing length: 5.00- 5.20 mm.

Coloration: Vertex, ocellar triangle, fronto-orbital plate, postocular plate, and parafacial with goldish-yellow pruinosity, the basal half of the latter sometimes varying from goldish-yellow to yellowish-gray; face, facial ridge, gena, and occiput with grayish-white pruinosity; frontal vitta brown; scape brown to reddish-brown; pedicel light reddish-orange; postpedicel black; palpus yellow; proboscis brown; thorax black in ground color with gray pruinosity; scutum with four black longitudinal stripes: two outside of the dorsocentral rows and two outside of acrostichal rows, the latter interrupted in halfway between transverse suture and scutoscutellar suture; a less intense black stripe between the acrostichal rows in the posterior half of the postsutural area more or less continuous on the scutellum from certain angle; legs black with gray pruinosity from certain angle, intense on the posterior portion of the anterior femur; wing subhyaline; tegula black; basicosta brown; upper and lower calypters subopaline white, with very short hairs of the same color on margin; abdomen, in dorsal view, subshining black, tergites 3 and 4 with grayish-white pruinosity on basal half, and tergite 5 with gold pruinosity on basal half.

Head: Eyes apparently bare, with short and sparse ommatrichia; vertex about 0.30x head width in dorsal view; inner vertical and outer vertical setae well developed, the first slight reclinate and subparallel, the later divergent and about two-thirds inner vertical setae length; ocellar setae well-developed and slightly proclinate and divergent; fronto-orbital plate with about five setae, upper and lower frontal setae reclinate, the intermediary setae convergent; the lower frontal seta situated just above the lower margin of the pedicel; upper part of the fronto-orbital plate with reclinate orbital seta arising outside of frontal row; fronto-orbital plate with two to three proclinate orbital setae,the middle one sometimes setula-like; parafacial usually with a row of three to five strong proclinate setae and scanty black hairs descending from fronto-orbital plate; fronto-orbital plate wider than parafacial; postpedicel about 1.65x length of pedicel; pedicel about 2.0x length of scape; facial ridge with hair-like setae on lower one-fourth, sometimes with one or two setulae smaller than half the length of the vibrissa; one or two genal setae on the posterior margin; a row of four to five setae shorter than or equal to half the length of the vibrissae extending from the subvibrissal ridge to the lower cranial margin of the postgena.

Thorax: Acrostichal setae 3 + 3, the posterior acrostichal presutural seta shorter and closer to the transverse suture; dorsocentral setae 3 + 3; intra-alar setae 2 + 3; supra-alar setae 2 + 3, the anterior presutural and postsutural setae shorter; three postalar setae, the second seta longer and stronger; three katepisternal setae, almost aligned and equidistant, the middle one being slightly lower than the other; scutellum with one pair of basal, one pair of lateral (the longest setae on scutellum), and one pair of apical setae crossed and horizontal; two pairs of preapical scutellar setae, one pair positioned between the apical scutellar setae and another pair more externally to the latter,both pairs are shorter, thinner,and slightly more erected than the apical scutellar seta; a group of six to eight discal setae, smaller and more erected than preapical setae.Wing with vein R₄₊₅ setose from the base up to the crossvein r-m or exceeding the latter by up to one time the crossvein r-m length.

Legs: Tarsal claws longer than tarsomere 5; mid tibia with six or seven anterodorsal setae, at least two longer setae interspersed among shorter setae, two or three short posterodorsal setae, and one or two short ventral setae; hind tibia with six to eight anterodorsal setae, of which two longer setae than the others, two or three posterodorsal setae.

Abdomen: Syntergite 1 + 2 with mid-dorsal depression extending back to its hind margin, without median marginal setae, and with one or two lateral marginal setae on each side; tergite 3 with a pair of median marginal setae and two to three lateral marginal setae on each side; tergite 4 with a pair of median marginal setae and two or more lateral marginal setae; tergite 5 with a row of discal setae and a row of smaller median marginal setae.

Terminalia ( Fig. 2 A-D): Segment 7 + 8 large and convex, wider at the sides than in the middle, with only one spiracle at the left side; tergite 6 is divided into two small hemitergites, connected to the tergites 5 and segment 7 by a broad membrane (as Tschorsnig’s (1985) fig. 9d); epandrium in profile with ventrolateral margin convex, expanding backwards covering the base of surstylus and portion of the base of cercus;cercus with stiff erect setulae decreasing in size from base to apex; cercus in profile gently narrowing from base to apex and slightly bent inward subapically; cercus in posterior view, narrow, elongated, and not fused; surstylus with short, stiff, and erect setulae on the outer and inner surfaces, the inner surface slightly excavated; surstylus in profile broad basally and tapered gradually to rounded apex; basiphallus lengthened by the epiphallus, extending behind the insertion of the distiphallus; distiphallus connected ventrally on the basiphallus;distiphallus long and ribbon-like; pregonites plate-like and fused along the length; postgonite narrowed from the base to apex, connected to the base of hypandrium.

Female: Like male, except for, vertex about 0.35 head width in dorsal view, tarsal claws shorter and abdomen slightly less elongated.

Female terminalia ( Fig. 4 ) with overlapping tergites and sternites; tergite 6 large, straight anteriorly and rounded posteriorly, with one spiracle on each lateral edge, posterior edge with a row of setae; presence of one spiracle on each side in the ventral membrane anterior to tergite 6; tergite 7 similar in shape to tergite 6, but narrower, with a row of smaller setae posteriorly; tergite 8 apparently divided into two small, irregular and poorly sclerotized hemitergites; sternite 5 trapezoid, posteriorly wider and with a row of setae; sternite 6 large, straight posteriorly and rounded anteriorly, with a row of setae posteriorly; sternite 7 similar in shape to sternite 6, about the same size, with a row of setae posteriorly; the setae become more widely spaced and smaller from sternite 5 to sternite 7; sternite 8 subquadrangular, poorly scler- sex ratio (female offspring/total offspring) is female biased (mean = 0.60 ± 0.09,N = 33), which favors biological control because it increases the chances of parasitism in the field and the establishment of the species.

Figures

Figure 1. Paedarium subauratum: (A-B) female in lateral and dorsal views,respectively.Paedarium subauratum: (C-D) male in lateral and dorsal view,respectively. Scale 1 mm.

Figure 2. Paedarium subauratum, male: (A-B) terminalia in lateral view. (C) sternite 5 in ventral view. (D) terminalia in posterior view. (Abbreviations: bac scl, bacilliform sclerite; bhp + epiph, basiphallus + epiphallus; cerc, cercus; distph, distiphallus; epand, epandrium; phapod, phallapodema; hypd, hypandrium; ptg, postgonite;pregt,pregonite;sur,surstylus).Scale:0.25 mm.

Figure 4. Paedarium subauratum, female:terminalia in posteroventral view. (Abbreviation: cerc, cercus; hyprct, hypoproct; st, sternite; tg, tergite). Scale: 0.25 mm.