Culicoides paraensis (Goeldi)

Ayala, Mahia M., Díaz, Florentina, Spinelli, Gustavo R., Micieli, María V. & Ronderos, María M., 2022, Redescription of immature stages of Culicoides paraensis (Goeldi) (Diptera: Ceratopogonidae), vector of the Oropouche virus, Zootaxa 5205 (3), pp. 249-264 : 252-253

Culicoides paraensis (Goeldi)

( Figs. 2–31 )

Fourth instar larva ( Figs. 2–8 ; 16–19 ). Coloration yellowish in life. Larva small 0.27 mm. ( Fig. 16 ). Head capsule ( Figs. 2–3 , 17 ) yellowish, moderately elongate, apex slightly bent ventrally, all setae simple, except seta “x”, “o”, “p”; moderately thin, medium-sized to elongate; chaetotaxy as in Figs. 2–5, 7 ; HL 0.12–0.160 (0.15, n=4) mm, HW 0.08–0.11 (0.10, n=4) mm, HR 1.47–1.62 (1.53, n=4). Antenna short ( Figs. 2, 4 ). Labrum ( Figs. 2–4 ) shorter than greatest width, with three pairs of anterolateral sensilla styloconica ( Fig. 4–5, 7 ); palatum ( Figs. 3, 5–6 ) with three pairs of sensilla trichoidea closely spaced, two anterior pairs medium-sized, posterior pair short; messors ( Fig. 4 ) well developed, stout, with four-five prominent teeth; scopae well developed, formed by three brushes, each with three–four short, stout teeth ( Fig. 4–5 ). Maxilla well developed, heavily sclerotized ( Fig. 3 ); galeolacinia with two–three papillae, with long seta; maxillary palpus ( Figs. 5–6 ) medium-sized, cylindrical, with three apical papillae, two of them medium-sized, other short; lacinial sclerite 1 ( Fig. 7 ) without seta, lacinial sclerite 2 ( Figs. 5–7 ) with medium-sized, thin seta and two papillae. Mandible ( Figs. 2–5, 7 , 17 ) small, heavily sclerotized, hooked, curved, with broad base, basal articulations blunt, one sensory pit and one medium-sized seta near hypocondyle; MDL 0.02–0.03 (0.025, n=3) mm, MDW 0.008 –0.011 (0.009, n=3) mm. Hypostoma ( Figs. 3, 5–6 ) with curved mesal elevation, smooth, lateral margin with five–six truncate, strong teeth. Labium elongate, not extending beyond hypostoma. Epipharynx ( Figs. 17 ) massive, strongly sclerotized; with three comb present, dorsal comb very narrow, with two–four teeth/sclerite, unequal and angular; ventral comb 4 with 10–12 teeth; ventral comb 2 with numerous finely, pointed teeth, lateral arms stout, elongate, with lateral curtains with finely pointed teeth of moderate length LAW 0.045 –0.055 (0.052, n=4) mm; DCW 0.010 –0.015 (0.013, n=4) mm. Hypopharynx ( Figs. 17 ) elongate, thin, moderately sclerotized, without fringe. Thoracic pigmentation uniformly pale. Abdominal segment whitish. Caudal segment ( Fig. 8 , 19 ) with six pairs of setae: ‘o’ long, stout seta, ‘i’, l1, l2, v, d, long, thin setae; CSL 0.25–0.38 (0.32, n=4) mm, CSW 0.10–0.15 (0.12, n=4); OL 0.16–0.22 (0.19, n=3) mm; OD 0.035 –0.042 (0.038, n=3) mm.

Female pupa ( Figs. 9–15 , 20–21 ). Exuviae general coloration light brown. Total length 1.52 mm. Head: Dorsal apotome ( Fig. 9–10 , 22 ) 1.20X broader than long, pale brown, apex apparently truncated, distal margin truncate; surface smooth, except for three rows of spicules on distal margin, raised areas present; dorsal apotome sensilla: DA-1-H, long, stout seta, DA-2-H campaniform sensillum at tubercle base; DAL 0.11 mm; DAW 0.14 mm; DAW/ DAL 1.27. Mouthparts as in Fig. 13 , with mandible, lacinia well developed; palpus extending to posterolateral margin of labium; labium separated medially by labrum, apex of labrum concave. Sensilla: two dorsolateral cephalic sclerite: DL-1-H long, stout seta, DL-2-H short, stout seta; clypeal/ labrals ( Fig. 13 ): CL-1-H long, thin seta, CL-2-H medium-sized, thin seta; oculars ( Fig. 13 ): O-1-H medium-sized, thin seta, O-3-H long, thin seta, O-2-H campaniform sensillum. Thorax: prothoracic extension absent; respiratory organ ( Figs. 10–12 , 20–21 ) pale brown; nearly straight, with scale-like spines, with 6–9 apical, 2–3 lateral pores; RO length 0.170 mm, RO wide 0.020 mm; pedicel ( Figs. 10, 12 ) medium-sized, stout, P length 0.03 mm; P/RO length 0.17. Sensilla: one anteromedial AM-1-T medium-sized, hyaline seta; three anterolaterals: AL-1-T long, stout seta, AL-2-T medium-sized, hyaline, stout seta, AL-3-T campaniform sensillum; dorsals ( Fig. 21 ): D-1-T, D-4-T medium–sized, stout seta, D-1-T stouter than D-4-T, D-2-T long, thin seta, D-3-T campaniform sensillum, D-5-T short, stout seta, SA-2-T campaniform sensillum. Metathoracics: M-2-T long, thin seta, M-3-T campaniform sensillum. Cephalothorax ( Fig. 21 ) rectangular, smooth, except for a few small spinules, length 0.72 mm; width 0.475 mm. Abdomen: segments with smooth integument, pale yellow, with scarce, scattered spicules; without pigmentation pattern. Sensilla: Tergite 1 ( Figs. 21 ) with setae as flows: D-2-I short, stout seta; D-3-I long, thin seta; D-7-I campaniform sensillum; D-4-I medium-sized, thin seta; D-8-I short, thin seta; D-9-I long, thin seta; L-1-I long, thin, seta, L-2-I, L-3-I campaniform sensilla. Second abdominal segment similar to the first one; segment 4 with sensillar pattern as follows: D-1-IV minute setae, D-2-IV short, stout seta; D-3-IV long, thin seta; D-4-IV, D-5-IV, D-8-IV minute setae; D-7-IV campaniform sensillum; D-9-IV long, thin seta; V-1-IV, V-2-IV campaniform sensilla; V-5-IV medium-sized, stout seta, V-6-IV short, thin seta; V-7-IV medium-sized, thin seta; L-I-IV, L-2-IV, L-3-IV short, stout setae, L-2-IV longer than L-1-IV and L-3-IV. Segment 9 ( Figs. 14-15 ) 1.36 X longer than wide; ventral surface with many spicules; anterior band continuous with spines; length 0.16 mm, width 0.12 mm. Terminal process ( Fig. 14-15 ) triangular, elongate, divergent, tip pointed; ventral surface spiculate, with D-5-IX, D-6-IX campaniform sensilla; length 0.07 mm.

Male Pupa ( Figs. 22–31 ). Similar to female with usual sexual differences. Total length 1.45–1.60 (1.53, n=2) mm. Exuviae pale brown. Dorsal apotome and sensilla ( Fig. 22, 25–26 ) DAL 0.11 mm; DAW 0.14 mm; DAW/DAL 1.27. Mouthparts as in Fig. 23 . Clypeal/ labrals and oculars as in Fig. 23 . Sensilla anteromedial and anterolaterals as in Figs. 24–25 . Dorsals as in Fig. 26 . Respiratory organ ( Figs. 25–25 ): length 0.15–0.16 (0.155, n=2) mm, RO wide 0.02 (n=2) mm; pedicel ( Figs. 24–25 ) P length 0.03–0.04 (0.035, n=2) mm; P/RO length 0.27 (n=2). Cephalothorax rectangular: length 0.72–0.75 (0.73, n=2) mm; width 0.47–0.48 (0.475, n=2) mm. Metathoracics and tergite 1 as in Fig. 27 . Segment 9 ( Fig. 31 ) 1.36x longer than wide, ventral surface with several stout spicules on anterior margin, length 0.15 (n=2) mm, width 0.11–0.13 (0.12, n=2) mm. Terminal process ( Fig. 31 ) moderately triangular, elongate, divergent, pointed; length 0.11 mm; genital lob ( Fig. 31 ) produced beyond posterior margin of segment.

Examined Material. Argentina, Misiones, Estancia “Santa Inés”, Ruta Nacional Nº 105, Km 8.5, Garupá , Departamento Capital , 27°31′40.9′′S, 55°51′59.4′′W, altitude 177 m; X-2014; M. Ayala; 2 males (with pupal exuviae), 1 female (with pupal exuvium); 4 larval exuviae ( MPLA) .

Material examined by SEM. Argentina, Misiones, Estancia “Santa Inés”, Ruta Nacional Nº 105, Km 8.5, Garupá , Departamento Capital , 27°31′40.9′′S, 55°51′59.4′′W, altitude 177 m; X-2014; M. Ayala; 2 larvae, 1 pupa ( MPLA) .

Distribution. USA (Colorado, Nebraska, Pennsylvania, Wisconsin to Louisiana and Florida) to Argentina (Jujuy, Salta, Tucumán, Mendoza, Chaco, Misiones, Corrientes).

Bionomics. The immatures here described were collected in mud in the southwestern province of Misiones, Argentina. The entomological survey was carried out in spring, on a sunny day between 12:00 and 12:30 pm, the air temperature was 24ºC, the water temperature was 20ºC, the conductivity was 37.5 µS, the dissolved oxygen was 4.3 ppm (59%) and the pH of 6.4. In the laboratory, the larvae were kept in a mixture of mud from the natural environment and demineralized water; they exhibited a typical serpentine motion when moving across the substrate. At 25–27ºC, the stage IV larva took 4 days to reach the pupal stage. The pupae exhibited slow abdominal circular movements, completing the stage development within 3 days when individually placed in cotton-stoppered vials at room temperature. All emerging adults were C. paraensis .

Figures

FIGURES 2–8. Scanning electron micrographs of larva Culicoides paraensis (Goeldi) (Diptera: Ceratopogonidae) collected in Argentina: 2. head capsule, dorsal view; 3. head capsule, ventral view; 4. Detail of head capsule, ventral view; 5. Palatum and maxillary palpus; 6. Mandible; 7. Caudal segment. Antennae (AN); frontoclypeus (FC); galeolacinia (GL); hypostoma (HY); labrum (LB); mandible (MD); maxillary palpus (MP); messors (MS); maxilla (MX); lacinial sclerite 2 (LC2); palatum (PL); scopae (SC); sensilla styloconica (ss); sensilla trichodea (st). Head capsule chaetotaxy are indicated by single letters: o, parahypostomal setae; s, anterior perifrontal setae; t, prefrontal setae; posterolateral setae; w, anterolateral setae y, ventral setae;“p”, posterior perifrontal seta; “q”, postfrontal setae. 8. Caudal segment chaetotaxy: “i”, inner seta; “l1”, first lateral seta; “o”, outer seta, “j”, collar pits.

FIGURES 9–15. Scanning electron micrographs of female pupa Culicoides paraensis (Goledi) (Diptera: Ceratopogonidae) collected in Argentina: 9. Cephalothorax; 10. Respiratory organ; 11. Detail of apical portion of respiratory organ; 12. Detail of basal portion of respiratory organ; 13. Mouthparts; 14. Segment 9, dorsal view; 15. Segment 9, ventral view. Anntena (AN); clypeal/labral sensilla (CL-1-H, CL-2-H); dorsal apotome (DA); ocular sensilla (O-1-H, O-3-H); pedicel (P); respiratory organ (RO); terminal processes (TP).

FIGURES 16–19. Photographs of Culicoides paraensis (Goeldi) (Diptera: Ceratopogonidae) collected in Argentina: 16. Entire larva; 17. Head capsule, ventral view; 18. Mandible; 19. Caudal segment. Head capsule (HC); caudal segment (CS); dorsal comb (DC); epipharynx (epy); hypopharynx (hyp); mandible (MD); fossa mandibularis (MF); ventral comb (VC).

FIGURES 20–26. Phothographs of pupa Culicoides paraensis (Goeldi) (Diptera: Ceratopogonidae) collected in Argentina: 20–21. Female pupa; 22–26. Male pupa; 20. Entire pupa; 21. Cephalothorax; 22. Dorsal apotome; 23. Mouthparts; 24. Respiratory organ; 25. Cephalothoracic sensilla; 26. Dorsals. Antennae (AN). Anterolateral sensilla (AL-1-T, AL-2-T, AL-3-T); anteromedial sensilla (AM-1-T); clypeal/labral sensilla (CL-1-H, CL-2-H); cephalothorax (CL), dorsal apotome sensilla (DA-1-H, DA-2-H); dorsolateral cephalic sclerite sensilla (DL-1-H); dorsal seta (D-1-T, D-2-T, D-3-T, D-4-T); metathorax (MT); ocular sensilla (O-1-H, O-3-H); pedicel (P); respiratory organ (RO).

FIGURES 27–31. Photographs of male pupa Culicoides paraensis (Goeldi) (Diptera: Ceratopogonidae) collected inArgentina: 27. Metathorax and tergite 1; 28. Segment 4, dorsal view; 29. Segment 4, lateral view; 30. Segment 4, ventral view; 31. Segment 9, ventral view. Genital lobe (GL), methatoracic sensilla (M-1-T, M-2-T), Segment 4 sensilla (D-2-IV, D-3-IV, D-4-IV, D-5-IV, D-7-IV,, L-1-IV, L-2-IV, L-3-IV, L-4-IV, V-IV, V-6-IV, V7-IV); supraalar sensillum (SA-2-T); tergite 1 sensilla (D-2-I, D-3-1, D-4-I, D-78-I, D-9-I, L-1-I, L-2-I, L-3-I); terminal processes (TP).