Culicoides peregrinus Kieffer 1910

Harsha, Rupa, Paul, Nilotpol, Mazumdar, Abhijit, Online, Published & Version, Final, 2017, Description of immature stages of Culicoides peregrinus (Diptera: Ceratopogonidae), a potent vector of bluetongue virus, Turkish Journal of Zoology 41 (5), pp. 812-820 : 813-819

Culicoides peregrinus Kieffer 1910

Kieffer, 1910: 191 (female, figure wing); Mayer, 1934: 187 (figure pupa); Howarth, 1985: 60 ( Laos records); Wirth and Hubert, 1989: 228 (diagnosis of male and female, figures male genitalia and female body parts, distribution); Narladkar et al., 1991: (life stages); Nandi and Mazumdar, 2013: 50–51 (diagnosis of male and female); Borkent, 2015: 98 (catalog).

Egg (SEM, n = 6; bright field microscopy, n = 20; as shown in Figures 1–6 ):

External morphology as shown in Figures 1–4 : laterally compressed, dorsally curved, beginning at the posterior of the egg midline and ventrally flattened. Mean length 489.36 (456–520) µm and mean width 51.28 (47–53) µm. Matured egg dark gray in color. Micropyle with adhesive coating as shown in Figure 3 , aeropyles numerous.

Chorion: Surfaces with pillar-shaped tubercle (strut) as shown in Figures 5 and 6 . Tubercles arranged randomly in two broad longitudinal rows dorsally and ventrally, laterally connected at the posterior end. Each dorsal and ventral row 42.30 (41–44) µm in width, with each large circular tubercle pillar 3.23 (3–4) µm. Small tubercles placed poorly in lateral side, and almost bare chorion seen in these areas. Posterior end 32.05 (30–34) µm long and snout-like.

Larva:

First, second, and third instar larvae: Total length I, II, and III instar larvae 0.68–0.72 mm, 1.05–1.44 mm, and 1.70–2.73 mm, respectively, as shown in Figures 7 and 8 . Length (µm) and ratios of head capsule are given in the Table.

Fourth instar larva (n = 19, except otherwise stated; as shown in Figures 9–16 ): Live specimen creamy white in color, head capsule deep yellow, first 3–5 segments somewhat reddish-brown pigmented as shown in Figure 9 . Exuviae pale yellow with brownish marginal shade. Total length 3.198 (2.964 –3.914) mm as shown in Figure 10 .

Chaetotaxy as shown in Figures 11 and 12 .

Head capsule oval, HL 216.5 (205–228) µm, HW 165 (156–182) µm, HR 1.30 (1.18–1.42), SGW 98.5 (92–110, n = 6) µm, SGR 1.70 (1.55–1.84, n = 6).

Labrum as shown in Figure 13 , 52.5 (50–57) µm long, somewhat extending beyond hypostoma. One small sensilla campaniformia on labrum immediate after antennal pore, antenna protruded. Palatum as shown in

Figures 13 and 14 , 30 (28–32) µm wide with large sensilla styloconica, minute campaniformia and trichodeum 6 (5–6.5) µm long; palatal bar triangular and long posterior to messors and bent inwardly. Maxilla large, and as shown in Figures 13 and 14 , 19 (17.5–22) µm long with 3 unequal projections of papillae, a 4–5.5 µm sensilla basiconica on maxillary palpus. Galeolacinia as shown in Figures 13 and 14 , roughly two parts, upper papilla lobed, lacinial sclerite (LC 1) and (LC 2) flat. Hypostomal opening semicircular with an uplift middle area as shown in Figure 13 ; 39 (37– 44) µm long, with 3–4 small teeth. Mandible as shown in Figures 14 and 15 , straight, hooked anteriorly with strong tooth; MDL 49.69 (47.5–51, n = 13) µm, MDW 14 (12–15.5) µm, mandibular fossa absent. Epipharynx as shown in Figure 15 , moderately massive and well developed, lateral arm stout and heavily sclerotized; comb 4 with 16–18 lancelet teeth, lateral teeth present on lateral curtain with 13–14 teeth. Dorsal comb large with 22–24 teeth; combs 2 and 3 absent. LAW 51 (48–53, n = 6) µm, DCW 27.5 (25–30, n = 6) µm; hypopharynx as shown in Figures 13 and 15 , somewhat triangular mesal, thin, roughly folded elevation and striated lateral margin with 4–6 lateromarginal teeth. Thoracic coloration uniformly smoky white to pale yellowish with brown shade on middle part of each segment. Caudal segment as shown in Figure 16 (n = 6): CSL 353 (337–375) µm, CSW 169 (162–177) µm, CSR 2.08 (1.98–2.27); OL 82 (75–85) µm, OD 81 (79–83) µm, OL/OD 1.00 (0.90–1.06); d 45–48 µm, I 1 60–62 µm, I 2 49–52 µm, and i 55–57 µm.

Instar differentiation: The developmental period of first instar: approximately 24 h, second instar: 2 to 3 days, third instar: 6 to 8 days, and fourth instar: 3 to 4 days. Larval period lasts for about 12–16 days at 26 °C.

Pupa:

Female pupa (n = 20) as shown in Figures 17–30.

Total length 2.415 (2.355 –2.475) mm. General body pattern: coloration deep brown, exuviae yellow with brown shade as shown in Figure 17. Respiratory organ as shown in Figures 18 and 19, dark yellow to pale brown, apically blackish, 189.6 (182–197) µm long and 28 (28–30) µm wide; respiratory horn 5.35 (6.06–7.03) times longer than broad, middle portion of outer surface covered with spine, apex with 10–11 spiracles; pedicel stout, 40–43 µm long. Dorsal apotome as shown in Figure 19 (n = 3): ventral margin rounded and ∩-shaped, small dorsomedial tubercle present, whole surface covered with short wrinkles, lateral-marginal area bare; each side of mesal portion with raised area. DAL 141 (130–152) µm, DAW 182.3 (177–190) µm, and DAW/ DAL 1.29 (1.24–1.37). Dorsal apotomal sensilla as follows: DA–1–H spine 81 (76–87) µm, on large rounder tubercle, DA–2–H large pore. Cephalothorax length 1073 (975–1260) µm, cephalothorax tubercles: 2 dorsolateral cephalic sclerite sensilla as shown in Figure 19: DL–1–H and DL–2–H equal in size, 90.6 (85–96) µm, arising from single large tubercle on each side; 2 anterolateral sensilla as shown in Figure 20: AL–1– T 50.7 (45–55) µm and AL–2– T 26 (25–28) µm on a small tubercle placed on each side; anteromedial sensilla as shown in Figure 21, AM –1– T minute and short, placed close to the base of the respiratory organ on each side .

Ventral ocular sensilla as shown in Figure 22: O–1–H and O–3–H both 47–53 µm and O–2–H absent on each side. Palpus with terminal and basolateral small tubercle. Clypeal/labral sensilla present as shown in Figure 22, CL– 1–H large 45 (44–47) µm and CL–2–H thin 22 (20–24) µm on each side.

Six dorsal sensilla as shown in Figures 23 and 24, as follows: D–1–T 21.6 (20–24) µm spine on large tubercle, D–2–T 29 (27–32) µm on tubercle, D–3–T pore, D–4–T 39 (38–44) µm on tubercle, D–5–T 10 (8–11) µm on tubercle and SA–2–T pore more posterolaterally placed.

Metathoraxes as shown in Figure 25, 1 seta and 2 campaniform sensilla; M–1–T 30 µm, M–3–T near middle of metathorax.

First abdominal segment as shown in Figure 26, with setae as follows: dorsal sensilla D–2–I spine 15 (14–16) µm, D–3–I 37 (36–39) µm, pore D–4–I posteromarginally placed to D–2–I and D–3–I, and other pore D–7–I more mesally placed, very fine 26–30 µm long D–8–9–I on a small tubercle. Lateral 3 setae separately placed; L–1–I seta thin, 14 (12–15) µm; L–2–I 46 (44–49) µm on tubercle, and another seta L–3–I minute. Fourth abdominal segment with setae as shown in Figures 27–29, as follows:D–2–IV 18 (17–20) µm long, tiniated and stout seta on small tubercle; D–3–IV 30 (28–32) µm thin seta on small tubercle; D–5– IV short on small tubercle, D–4–IV pore, D–7–IV cmp. sen.; D–8–IV 17 (16–19) µm and D–9–IV 18 (17–21) µm, thin seta on separate tubercle. All lateral sensilla on separate tubercle, L–1–IV stout on medium tubercle 17–19 µm; L–2–IV small spine 20–22 µm, dorsolaterally placed; L–3–IV 35 (32–37) µm on large tubercle; L–4–IV more ventrally placed, 16–18 µm; V–5–IV 11–13 µm, V–6–IV 34 (32–36) µm on tubercle, and V–7–IV 19 (17–21) µm on tubercle. All abdominal segments generally smooth. Segment nine as shown in Figure 30, 1.0–1.2 times longer than wide. Dorsally an inverted V-shaped stripe composed of spicules downwardly arranged extending to the terminal process; terminal processes downwardly placed 68.3 (65– 75) µm, deep depression of D–6–IX base present.

Male pupa (n = 12) as shown in Figures 31–35 .

Similar to female with usual sexual differences. Total length 2.332 (2.235 –2.400) mm, shorter than female. General coloration light brown, exuviae yellow with brown shade. Cephalothorax length 997.5 (945–1059) µm. Respiratory organ as shown in Figure 31 ; 175–190 µm long, more brown than female. Prothoracic extension as shown in Figure 32 ; 149–165 µm long; antennal sheath with a middle pale band as shown in Figure 32 . Dorsal apotome as shown in Figure 33 with moderate dorsomedial tubercle, DAW 173–182 µm, DAL 158–163 µm, DAW/ DAL 1.08–1.12. Palpus as shown in Figure 34 with more prominent terminal and basolateral tubercle.

Segment 9 as shown in Figure 35 , length (excluding TP) 172–183 µm, TP 76–82 µm; genital lobe almost as long

Figures 17–30. Culicoides peregrinus Kieffer , female pupa. 17: Pupa, 18: respiratory organ and anterolaterals, 19: cephalothorax (ventral view), 20: anterolaterals, 21: anteromedial, 22: clypeal/labral and ocular sensilla, 23: dorsal sensilla, 24: cephalothorax (dorsal view) with dorsal sensilla, 25: metathoracic chaetotaxy, 26: first abdominal segment, 27: fourth abdominal segment (dorsal view), 28: fourth abdominal segment (ventral view), 29: fourth abdominal segment (dorsolateral view), 30: segment 9. Anterolaterals sensilla (AL–1–T, AL–2–T); anteromedial (AM–1–T); clypeal/labral sensilla (CL–1–H, CL–2–H); dorsal apotomal sensilla (DA–1–H); dorsolateral cephalic sclerites sensilla (DL-1-H, DL-2-H); dorsal sensilla of first abdominal segment (D–2–I, D–3–I, D–4–I, D–7–I, D–8–I, D–9–I); dorsal sensilla (D–1–T, D–2–T, D–3–T, D–4–T, D–5–T); dorsal sensilla of segment four (D–2–IV, D–3–IV, D–4–IV, D–5–IV, D–7–IV, D–8–IV, D–9–IV); lateral sensilla of first abdominal segment (L–1–I, L–2–I, L–3–I); lateral sensilla of segment four (L–1–IV, L–2–IV, L–3–IV, L–4–IV); metathoracic sensilla (M–1–T, M–2–T, M–3–T); ocular sensilla (O–1–H, O–3–H); supraalar (SA– 2–T); RO, respiratory organ; TP, terminal process. Ventral sensilla of fourth abdominal segment (V–5–IV, V–6–IV, V–7–IV). Scale bar 50 µm except when otherwise stated.

as segment 9 or extending just beyond posterior margin of segment 9; dorsal surface of segment 9 with an inverted V-shaped band of spicules on ventral side; a circular base of D–6–IX at latero-basal TP.

Figures

Figures 1–6. Culicoides peregrinus Kieffer, egg. 1: Dorsolateral view, 2: dorsal view, 3: micropylar end, 4: posterior end, 5: dorsal papillae of chorion, 6: lateral papillae (left side) and dorsal papillae (right side).

Figures 7–16. Culicoides peregrinus Kieffer, larva. 7: Second instar, 8: head capsule of third instar, 9: body pigmentation of fourth instar, 10: fourth instar, 11: head capsule with cephalic setae and sensory pore (ventrolateral view), 12: head capsule with cephalic setae and sensory pore (dorsolateral view), 13: mouthparts, 14: mouthparts (close view), 15: epipharynx and hypopharynx, 16: setae of caudal segment. AN, antenna; GL, genital lobe; HY, hypostoma; LB, labrum; LC1, lacinial sclerite 1; LC2, lacinial sclerite 2; MD, mandible; MP, maxillary palp; MS, messors; MX, maxilla; PL, palatum; SC, scopae; ss, sensilla styloconica; st, sensilla trichoidea. Caudal segment chaetotaxy: d, dorsal setae; i, inner setae; I 1, first lateral setae; I 2, second lateral setae; o, outer setae. Head capsule chaetotaxy: o, parahypostomal setae; p, posterior perifrontal; q, post frontal; s, anterior perifrontal setae; t, prefrontal setae; u, mesolateral setae; v, posterolateral setae; w, anterolateral setae; y, ventral setae. Scale bar 50 µm except when otherwise stated.

Figures 31–35. Culicoides peregrinus Kieffer, male pupa. 31: Respiratory organ, 32: antennal sheath with pale spot and prothoracic extension, 33: close view of dorsal apotome, 34: palpus-clypeal/labral sensilla and ocular area, 35: segment 9. Abbreviations same as before. Scale bar 50 µm.