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).