Scolothrips rhagebianus Priesner

Masumoto, Masami, Ohno, Suguru, Ganaha-Kikumura, Tomoko, Miyagi, Akiko & Okajima, Shûji, 2012, Review of the genus Scolothrips (Insecta, Thysanoptera, Thripidae) from Japan, Zootaxa 3183 (1), pp. 36-48 : 41-44

Scolothrips rhagebianus Priesner

( Figs. 3 A −E & 4A −E)

Scolothrips rhagebianus Priesner, 1950: 46 ; zur Strassen, 1993: 366; Bhatti, 1990: 251; Mound, 2011: 51 . Scolothrips indicus Priesner, 1950: 48 ; Wang, 2002: 256. [Synonymized by zur Strassen, 1993: 366.]

Female macroptera. Distended body length 1.0− 1.3 mm. Body almost uniformly white, pronotum ( Fig. 3 A) with two pairs of small greyish shadings at each side of posterior half, mesonotum and metascutum pale but slightly shaded laterally, abdominal tergites ( Fig. 4 B) II −VII with small greyish spots near anterior angle and transverse shadings between the spots; all antennal segments shaded in pale grey, I and II paler than remaining segments; fore wing ( Fig. 4 A) with three hyaline areas, brown bands small, clavus brown with distal half to third hyaline; all legs white; prominent body setae shaded, veinal setae of fore wing including clavus darker.

Head ( Fig. 3 A) 0.6−0.8 times as long as wide. Ocellar setae III on ocellar hump and in front of hind ocelli. Antennal segments ( Fig. 3 B) III and IV widest at middle, VI the longest, widest near base and tapering, V pedicelate, microtrichial row present on ventral surface of III and both dorsal and ventral surfaces of IV −VI. Antennal segments I −VIII length/width ratio as follows: 0.4−0.8, 0.9−1.2, 1.5−1.8, 1.3−1.8, 1.1−1.5, 1.9−2.5, 1.0−1.8, 2.3−3.0.

Pronotum ( Fig. 3 A) 0.7−0.8 times as long as wide, with indistinct groove-like transverse lines of sculpture, with a pair of discal setae posteromedially; anteromarginal setae 0.8−1.0 times as long as pronotal median length and usually slightly longer than anteroangulars; posteroangular setae I 0.7−0.8 times as long as pronotal median length and almost as long as setae II; posteromarginal setae 0.7−0.8 times as long as pronotal median length and usually slightly longer than ML setae. Mesonotum sculptured with wide spaced transverse anastomosing striae on posterior half; CPS absent anteromedially. Metascutum ( Fig. 3 C) sculptured with wide spaced transverse striae or irregularly reticulate medially; median pair of setae close to lateral setae, 0.6−0.8 times as long as metascutal median length; CPS absent. Prospinasternum ( Fig. 3 D) often triangle plate. Fore wing costal vein with 14−19 setae, first vein with 10−13 setae.

Abdominal tergites I −II or III ( Fig. 3 B) with transverse wide spaced anastomosing lines of sculpture, but smooth submedian areas, III or IV −VIII ( Fig. 4 B) laterally with similar sculpture slightly extending mesad of S2 setae, not reaching median CPS; tergite IX ( Fig. 4 C) with posterior pair of CPS only, only lateral minor setae (SS3) present and 0.4−0.7 times as long as median length of the tergite; sternite VII with S1 setae slightly in front of posterior margin. Ovipositor 1.8−2.1 times as long as pronotal median length.

Measurements (female in microns). S. indicus holotype in parentheses. Body length 1020−1290 (1020). Head length 56−90 (63), length including anterior prolongation 64−90 (75), width across cheeks 98−113 (103); compound eye dorsal length 43−63 (50), width 35−45 (38). Ocellar setae III length 58−85 (76−79), distance between their bases 18−23 (23) Pronotal median length 100−115 (113), width 130−158 (145); anteromarginal setae length 88−105 (98−100), anteroangular setae length 74−115 (80−115), posteroangular setae I length 75−89 (80−82), setae II length 67−93 (80−83); posteromarginal setae I length 58−98 (83−85), ML setae length 68−90 (68−90). Metascutal median length 53−65 (63); median setae length 33−50 (38−ca.48). Fore wing length 570−700 (570), width at middle 40−50 (50). Abdominal tergite IX median length 71−91 (75); S1 setae length 78−89 (83−85), S2 setae length 76−89 (83−84), S3 setae length 62−93 (88), MD setae length 43−60 (43−50), SS3 setae length 33−58 (50−53); tergite X median length 40−66 (63), S1 setae length 43−53 (48−50), S2 setae 39−55 (48−50). Ovipositor length 190−220 (200). Antennal segments I −VIII length/width ca.10−20 (ca.10)/23−28 (24), 22−30 (28)/24−26 (24), 30−36.3 (35)/18−21 (20), 24−35 (28)/18−20 (19), 20−25 (23)/15−18 (18), 35−38 (35)/15−19 (18), 8−11 (8)/ 6−8 (8), 12−15 (12)/5 (5).

Male macroptera. Body colour similar to female. Abdominal tergite IX ( Fig. 4 D) with MD setae, S1 setae much ahead of level of S2 setae and lateral to MD setae; sternal pore plates ( Fig. 4 E), 93-118 µm wide.

Measurements (male in microns). Body length 970. Head length 58 (length including anterior prolongation 67), width across cheeks 93; compound eye dorsal length 48, width 35. Ocellar setae III length 46−64, distance between their bases 18. Pronotal median length 90, width 130; anteromarginal setae length 76−81, anteroangular setae length 66−69, posteroangular setae I length 62−73, setae II length 70−72; posteromarginal setae I length 69−73, ML setae length 58−66. Metascutal median length 53; median setae length 33−38. Fore wing length 490, width at middle 40. Antennal segments I −VIII length (width) 15 (23), 28 (23), 25 (18), 22 (18), 22 (15), 33 (15), 10 (8), 15 (5).

Specimens examined. Holotype female of S. indicus , INDIA, Coimbatore, on pomegranate flowers, 1.ix.1923,A. G. R. (smf). Other specimens: JAPAN, Ryukyus:Okinawa-hontou Island, 59 females; Iheya-jima Island, 4 females; Irabu-jima Island, 1 female; Ishigaki-jima Island, 9 females; Iriomote-jima Island, 9 females; Yonaguni-jima Island, 1 female. TAIWAN, 1 female, 1 male (TARI); 13 females, 3 males.

Distribution. Japan: Ryukyus (Okinawa-hontou, Iheya-jima, Irabu-jima, Ishigaki-jima, Iriomote-jima, Yonaguni-jima); Taiwan; India; Egypt; Sudan; Transvaal; Mauritius; Cápe Vérde; Australia.

Possible prey species. The following spider mites species were identified with S. rhagebianus in the Ryukyus and Taiwan: Eutetranychus africanus , O. coffeae, Tetranychus evansi , T. kanzawai , T. ludeni , T. neocaledonicus , T. okinawanus , T. phaselus , T. piercei , T. urticae (green form).

Comments. This species is here newly recorded from the Ryukyu Islands. It is similar to the species of the sexmaculatus group by having posteromedian discal setae on the pronotum, but it can be distinguished from those species by the pattern of dark markings in mature adults. S. rhagebianus has abdominal tergites with isolated dark spots laterally, but species of the sexmaculatus group have abdominal tergites without such dark spots. However, the immature adults cannot be distinguished to species satisfactorily ( Mound, 2011).

Figures

FIGURE 3. Scolothrips rhagebianus, female. A, Head and pronotum; B, antenna, right; C, metascutum; D, prosternal ferna and prospinasternum; E, tergites I – II (right side omitted). Scales: 0.04 mm.

FIGURE 4. Scolothrips rhagebianus, female (A − C) and male (D − E). A, Fore wing, right, (marginal fringe hairs omitted), holotype of indicus; B, tergite V I (right side omitted); C, tergites VIII – XI, mid-dorsal seta (MD), seta 1 (S 1), seta 2 (S 2), seta 3 (S 3), small seta 3 (SS 3); D, tergite IX, mid-dorsal seta (MD); F, sternite VII (sculpture omitted). Scales: 0.04 mm.