Lixophaga punctata ( Townsend, 1927 )

Gudin, Filipe Macedo, 2023, Annotated Catalog of Vespid Hosts (Hymenoptera: Vespidae) of Tachinidae (Diptera), with Description of a New Species of Ophirion Townsend from Brazil, Zoological Studies 62 (6), pp. 1-25 : 13-20

Lixophaga punctata ( Townsend, 1927)

( Figs. 4 , 8 , 9 )

Paranetia punctata Townsend, 1927: 344 . Holotype male (USNM), examined ( Fig. 5 ). Type locality: Brazil, São Paulo, Itaquaquecetuba.

Polybiophila fitzgeraldi Curran, 1937: 3 . Holotype male (AMNH), examined ( Fig. 6 ). Type locality: Trinidad and Tobago, Mount Saint Benedict. syn. nov.

Santacruzia dubiosa Thompson, 1968: 125 . Holotype female (CNC), examined ( Fig. 7 ). Type locality: Trinidad and Tobago, Santa Cruz Valley . syn. nov.

Material examined: 10 ³ (one dissected), 3 $ (two dissected): same data as O. lenkoi (MZSP) .

Diagnosis: Lixophaga punctata can be distinguished from other Nearctic and Neotropical Lixophaga species by having: pale golden pruinosity on head and dorsal surface of thorax and abdomen; abdominal tergites 3 and 4 with pruinose bands on basal two-thirds and apical third dark brown; abdominal tergite 5 completely covered with pruinosity; palpi yellow; two katepisternal setae; anatergite bare; pair of apical scutellar setae subparallel or divergent; wings hyaline; one or two pairs of median discal setae on intermediate abdominal tergites; and males with terminalia bearing epiphallus very short, completely covered by postgonites, pregonites narrow and long, and surstyli and cerci arched in posterior view, with apical parts of cerci bent towards posterior region in lateral view. A comprehensive comparison of the main diagnostic characters of Lixophaga species similar to L. punctata is covered in the Remarks section below.

Redescription of males: Body length: 5.17–5.58 mm (mean = 5.44 mm). Wing length: 4.49–5.74 mm (mean = 5.25 mm).

Coloration: Head with pale golden pruinosity, including face, gena and postgena. Frontal vitta, lunule, antenna and arista dark brown. Clypeus black. Palpi and labella yellow. Occiput black, covered with silver pruinosity. Thorax with pale golden pruinosity, except lower region of pleural sclerites, with faint silvery pruinosity. Scutum with four marked, black vittae; outer vittae interrupted by transverse suture and extending to last postsutural dorsocentral seta, and inner vittae continuous and extending to median postsutural acrostichal seta. Lateral surface of thorax dark brown. Basal area of scutellum dark brown, with posterior half covered with pale golden pruinosity. Wing hyaline. Tegula and basicosta dark brown. Veins and halter light yellow. Calypteres yellowish, with yellow border. Legs dark brown, with silver pruinosity. Tarsal claws brown. Pulvilli light brown. Abdomen with pale golden pruinosity, except ventral surface of tergites, with silvery pruinosity; basal lateral surface of intermediate tergites yellowish in background. Syntergite 1+2 dark brown, becoming lighter towards ventral surface. Tergites 3 and 4 with pruinose bands on basal two-thirds, with apical third dark brown. Tergite 5 dark brown, completely covered with pruinosity.

Head ( Fig. 4E ): Ratio of head height/ head width in frontal view 0.86–0.89 (mean = 0.87). Ratio of frontal vitta width/ fronto-orbital plate width in dorsal view 0.58–0.82 (mean = 0.73). Ratio of vertex width/ head width in dorsal view 0.21–0.23 (mean = 0.22). Ratio of first flagellomere length/ pedicel length 2.93–3.16 (mean = 3.05). Ratio genal height/ head height in lateral view 0.21–0.23 (mean = 0.22). Dichoptic. Eye bare. Antenna inserted at middle level of eye, almost reaching lower facial margin. Scape short, about one-third length of pedicel. Pedicel setose dorsally, with one apical erect seta. First flagellomere subrectangular, with outer surface bearing one minute sensory pit closer to posterior margin. Arista long, pubescent and thickened at base, arising in basal dorsal surface of first flagellomere. Seven or eight subequal inclinate frontal setae from level of pedicel to level of upper quarter of eye. Proclinate orbital setae absent. Two or three reclinate orbital setae, with posterior setae about two-thirds length of anterior seta. Ocellar triangle densely setulose, with one pair of proclinate ocellar setae, about half length of anterior reclinate orbital seta; all ocelli with similar size. Two postocellar setae, about half length of ocellar setae. Inner vertical setae reclinate, subparallel. Outer vertical setae weak, about one-fifth length of inner vertical. Fronto-orbital plate setulose to second anterior frontal seta. Parafacial bare, about two-thirds width of fronto-orbital plate. Facial ridge bare, except on lowest quarter, with three or four weak supravibrissal setae. Vibrissa strong and crossed, arising at level of lower facial margin, with two or three subvibrissal setae. Face flat and not visible in lateral view, with slight facial carina on upper half. Gena with two or three setae on ventral margin. Genal dilation and postgena setulose, with patches of long, white setulae. Clypeus U-shaped. Palpi clavate and setose. Prementum short, setulose. Labella padlike.

T h o r a x ( Fig. 4A, C ): P r o s t e r n u m s e t o s e. Proepisternum bare. Two proepimeral setae, strong, upcurved, with setulae at base. Anterior spiracle with both lappets well-developed, covering almost entire opening. Posterior spiracle with posterior lappet shaped as an operculum. Three postpronotal setae, arranged as triangle. Scutum with 3+3 acrostichal setae; 2+2–3 dorsocentral setae; 2+3 intra-alar setae; 1+3 supra-alar setae, with first postsutural seta shorter than second, and second postsutural seta strong and subequal to median postalar seta. One weak intrapostalar seta. Two notopleural setae. Three postalar setae, with median seta stronger than other two. Two katepisternal setae. Anepisternum anterodorsal corner with one seta, about half length of notopleural setae; posterior margin with row of six setae. One anepimeral seta, with patch of setulae at base. Six or seven meral setae. Anatergite bare. Scutellum with one pair of basal setae, convergent and long, subequal to subapical setae; one pair of lateral setae, subparallel and about two-thirds length of basal setae; one pair of subapical setae, divergent; one pair of apical setae, subparallel or divergent, about one-fifth length of subapical setae; one pair of discal setae arising at level of subapical setae. Wing: Vein C ending right after R 4+5, just before wing apex, with short costal spine. Vein R 4+5 setose only at base. Bend of M obtuse, with distal part straight to wing margin. Cell r 4+5 open, with length shorter than crossvein r-m. Legs: Fore coxa with two longitudinal rows of setae on anterior surface. Fore femur with dorsal, posterodorsal and posteroventral rows of setae from base to apex. Fore tibia with one strong apical seta on dorsal surface, one strong median seta and one apical seta on posterior surface. Mid coxa with row of setae on anterior surface. Mid femur with two median setae on anterior surface and an incomplete row of setae on posteroventral surface. Mid tibia with one strong median seta on anterodorsal surface, one strong apical seta on anterior surface, two median setae on posterior surface, one median seta and one apical seta on posteroventral surface. Hind coxa with row of setae on apical and outer lateral margin. Hind femur with anterodorsal and anteroventral rows of setae from base to apex, and one incomplete row of posteroventral setae. Hind tibia with anterodorsal row of setae from base to apex, with median seta strong, one strong apical seta on dorsal surface, two strong median setae and one apical seta on anteroventral surface, two strong setae on posterodorsal surface. Basal tarsomeres long, but shorter than combined length of remaining tarsomeres; second and third tarsomeres long, about half length of basal tarsomeres. Tarsal claws long, almost as long as last tarsomeres.

Abdomen ( Fig. 4A, C ): Subtriangular, tapering towards posterior end. Syntergite 1+2 with mid-dorsal depression extending more than half way to hind margin, but not reaching hind margin. Syntergite 1+2 and tergite 3 with one pair of median marginal setae and one pair of lateral marginal setae. Tergite 4 with row of marginal setae. One or two pairs of median discal setae on intermediate tergites. Tergite 5 with row of discal and marginal setae. Sexual patches of setae absent. Sternites completely overlapped by tergites. Sternite 5 short, wider than long and subrectangular, with posterior margin with pair of lobes delimiting U-shaped notch; lobes covered with setulae and bearing single long seta on each one.

Terminalia ( Fig. 8 ): Tergite 6 divided into two hemitergites with pair of spiracles on membrane; left hemitergite well-developed and right hemitergite reduced to narrow strip. Sternite 6 asymmetrical, connected to left hemitergite of tergite 6 by wide area, tapering towards middle and ending right after connection to sternite 5, not reaching right hemitergite of tergite 6. Syntergite 7 + 8 with anterior half bearing pair of spiracles, and posterior half setulose. Anterior epandrial process well projected beyond ventral epandrial margin. Epandrium setulose, with dorsal surface about half length of ventral surface in lateral view; posterior margin forming pointed, projected lobe at middle and rounded, lower lobe in lateral view. Surstylus not fused with epandrium or bacilliform sclerite, same width as cercus in lateral view, with apex slightly curved towards anterior region; arched in posterior view, with apex clavate, with inner and outer surface covered with short, erect setulae. Bacilliform sclerite slender, connected to middle part of hypandrial arm. Hypandrium with hypandrial apodeme concave, with narrow and rounded apex in ventral view, almost as long as central plate of hypandrium; hypandrial plate concave, with posterior margin fused with pregonites; hypandrial arms not fused with each other. Phallapodeme flat, subequal to hypandrium length, with phallic guide long. Ejaculatory apodeme small, with upper part flattened and lower part broad. Phallus with epiphallus attached to base of distiphallus and very short, completely covered by postgonites; basiphallus without basal process, stout and about half length of distiphallus, with apex wider than base; dorsal sclerite of distiphallus fused with basiphallus, with long median process extending to apex of distiphallus; distiphallus slightly curved towards anterior region, forming an obtuse angle with basiphallus, with pair of lateroventral sclerites strongly sclerotized, without apparent granules and lobed apically; median groove short and sclerotized, located between lateroventral sclerites and distad on ventral surface of distiphallus. Pregonite with anterior base fused with central plate of hypandrium, narrow and long, with apex rounded and slightly curved towards anterior region; lower posterior margin bearing minute fine setae. Postgonite bare and bacilliform, same width as pregonite, with rounded apex. Cerci entirely setose, not fused with each other and with narrow median cleft on basal third; apex extending to level of apical part of surstyli, slightly arched in posterior view and with apical part bent towards posterior region in lateral view.

Redescription of females ( Fig. 4B, D, F ): Differ from male as follows: Body length: 5.21–5.36 mm (mean = 5.29 mm). Wing length: 5.07–5.14 mm (mean = 5.10 mm).

Coloration: Parafacial with silver pruinosity.

Head: Ratio of head height/ head width in frontal view 0.86–0.88 (mean = 0.87). Ratio of frontal vitta width/ fronto-orbital plate width in dorsal view 0.57–0.94 (mean = 0.75). Ratio of vertex width/ head width in dorsal view 0.25–0.25 (mean = 0.25). Ratio of first flagellomere length/ pedicel length 3.39–4.13 (mean = 3.76). Ratio genal height/ head height in lateral view 0.24–0.25 (mean = 0.24). Five or six inclinate frontal setae. Two proclinate orbital setae, with anterior seta arising at level of last posterior frontal seta and posterior seta arising between reclinate orbital setae. Basal tarsomeres almost as long as combined length of remaining tarsomeres.

Abdomen: Ellipsoidal, tapering towards posterior end.

Terminalia ( Fig. 9 ): Ovipositor long, with membranous area between segment 6 and 7 as long as tergite 6. Spermathecae lost during dissection. Tergites 6 and 7 divided into two hemitergites, with posterior margin with few fine setae; hemitergites of tergite 6 with posterior margin wider than anterior margin; hemitergites of tergite 7 subrectangular. Sixth pair of spiracles located in membrane, before hemitergites of tergite 6; seventh pair of spiracles on anterolateral margin of hemitergites of tergite 6. Sternite 6 subtriangular, with posterior margin setose and wider than anterior margin. Sternite 7 longer than wide, with narrow and setose posterior margin. Tergite 8 very small, reduced to pair of lateral narrow sclerites, close to hypoproct. Sternite 8 setose, short and convex in ventral view. Epiproct absent. Hypoproct evenly setose, wide and subrectangular in ventral view and compressed in lateral view, with pair of well-developed lateral arms arising on anterolateral margin and directed downwards. Cerci not fused, setose on posterior half.

Distribution: Trinidad and Tobago (San Juan- Laventille and Tunapuna-Piarco) and Brazil (São Paulo).

Remarks: The presence of median discal setae on abdominal tergites is also found in seven Lixophaga species, namely L. aristalis ( Townsend, 1927) , L. leucophaea (van der Wulp, 1890a) , L. neglecta (van der Wulp, 1890b) , L. solitaria ( Curran, 1926) , L. trichosoma (van der Wulp, 1890c) , L. umbripennis (van der Wulp, 1890a) and L. unicolor ( Smith, 1917) . Lixophaga leucophaea , L. solitaria and L. unicolor were described from Mexico, Jamaica and United States of America, respectively, showing silvery pruinosity covering the entire body; furthermore, L. leucophaea has palpi black and L. solitaria does not have apical scutellar setae. Lixophaga aristalis and L. neglecta were described based on a single specimen from Brazil and Mexico, respectively, showing pale golden pruinosity covering the entire body; they differ from L. punctata by having three katepisternal setae and wings infuscated along costal margin. The holotype female of L. trichosoma and the holotype male of L. umbripennis are from Mexico and both show pale golden pruinosity covering the entire body; L. trichosoma also has wings hyaline, differing from L. punctata by having three katepisternal setae and apical scutellar setae crossed; L. umbripennis also has two katepisternal setae and apical scutellar setae divergent, but differs from L. punctata in having wings infuscated along costal margin, especially around the veins R 1 and R 2+3. Other two Lixophaga species present only two katepisternal setae: L. charapensis ( Townsend, 1927) and L. parva Townsend, 1908 ( Townsend 1940 1941). Lixophaga charapensis was described based on one female from Peru with pale golden pruinosity covering the entire body, but has apical scutellar setae crossed and no discal setae on intermediate abdominal tergites. Lixophaga parva was described based on one male from United States of America with silvery pruinosity covering the entire body and no discal setae on intermediate abdominal tergites.

On examining the type material of Paranetia punctata , Polybiophila fitzgeraldi and Santacruzia dubiosa ( Figs. 5–7 ), I conclude that these species are synonyms, showing the same diagnostic characters provided above. Paranetia punctata was collected in the Atlantic Forest in Itaquaquecetuba, just a few kilometers away from the municipality of Nova Europa. Besides having a similar morphology with P. punctata , P. fitzgeraldi was also reared from Polybia , an additional evidence that both species are synonyms. Although the host of S. dubiosa is unknown, it was collected near the type locality of P. fitzgeraldi in Trinidad and Tobago, and shares the same characters; the abdomen color is lighter than usual due to the dissection made by Thompson. These synonyms expand the distribution of L. punctata in South America, which has a large gap between records. This fragmented distribution actually reflects the lack of specimen collection and taxonomic studies in Neotropical Tachinidae . As New World Polybia species are distributed from Mexico to Argentina ( Richards 1978a), L. punctata could have a wider distribution in the Neotropical Region.

Figures

Fig. 4. Record of Lixophaga punctata (Townsend) in Polybia (Myrapetra) scutellaris (White). A, C, E: Lateral habitus, dorsal habitus and head in frontal view of male (MZSP), respectively; B, D, F: Lateral habitus, dorsal habitus and head in frontal view of female (MZSP), respectively. Scale bars = 2 mm.

Fig. 8. Male terminalia of Lixophaga punctata (Townsend). A, Sternite five; B, Lateral view of postabdomen, showing sclerites of segments 5–8; C, Lateral view of genitalia and line drawing highlighting outer and inner structures (gray dashed lines) and membranous surfaces (dotted areas); D, Posterior view of genitalia. Scale bars = 0.5 mm. Abbreviations: bac scl = bacilliform sclerite, basph = basiphallus, epand = epandrium, cerc = cercus, d m proc = dorsal median process, distph = distiphallus, ej apod = ejaculatory apodeme, epiph = epiphallus, hemitg = hemitergite, hypd = hypandrium, lv scl = lateroventral sclerite, pgt = postgonite, phapod = phallapodeme, pregt = pregonite, st = sternite, sur = surstylus, syntg = syntergite.

Fig. 9. Female terminalia of Lixophaga punctata (Townsend). A, Dorsal, lateral, and ventral views, respectively; B, Line drawings of dorsal, lateral, and ventral views, respectively, highlighting outer and inner structures (gray dashed lines) and membranous surfaces (dotted areas). Scale bar = 0.5 mm. Abbreviations: cerc = cercus, hemitg = hemitergite, hyp = hypoproct, l arm = lateral arm; spr = spiracle, st = sternite, tg = tergite.

Fig. 5. Holotype male of Paranetia punctata Townsend (USNM). A, Habitus, lateral view; B, Head, frontal view; C, Habitus, dorsal view; D, Labels. Scale bars = 2 mm.

Fig. 6. Type material of Polybiophila fitzgeraldi Curran. A, C, E: Lateral habitus, dorsal habitus and head in frontal view of holotype male (AMNH), respectively; B, D, F: Lateral habitus, dorsal habitus and head in frontal view paratype female (AMNH), respectively. Scale bars = 2 mm.

Fig. 7. Holotype male of Santacruzia dubiosa Thompson (CNC). A, Habitus, lateral view; B, Habitus, dorsal view; C, Head, frontal view; D, Labels. Images originally lacking scales.