Scirtothrips dorsalis Hood

Masumoto, Masami & Okajima, Shûji, 2007, The genus Scirtothrips Shull (Insecta, Thysanoptera, Thripidae) and three related genera in Japan, Zootaxa 1552, pp. 1-33 : 22-26

Scirtothrips dorsalis Hood

( Figs. 9 B, 11C, 12E, 13E, 17B & 18B)

Scirtothrips dorsalis Hood, 1919: 90 .

Female. Distended body length 0.8–0.9 mm. Body yellow with brown markings on median fourth of abdominal terga III to VII median third ( Fig. 13 E), antecostal ridge of terga and sterna darker, head pale brown at apex of frons, pronotum slightly shaded partly at posterior half; antennal segment I pale, II shaded, III to V brown with extreme base barely pale, VI to VIII brown; fore wings almost uniformly strongly shaded; all legs yellow; prominent body setae shaded.

Head about twice as wide as long. Ocellar setae III situated between middle of hind ocelli ( Fig. 9 B). Two pairs of postocular setae mesad of compound eyes slightly longer than ocellar setae III. Compound eyes without pigmented ommatidia. Antennae 8-segmented, segment II with a mid-dorsal seta below CPS, III widest near apex and rapidly tapering forward to apex, VI the longest ( Fig. 11 C). Antennal segments I to VIII length/ width ratio as follows: 0.9–1.1, 1.2–1.4, 2.3–2.6, 2.3–2.7, 2.7–2.7, 3.1–3.3, 1.0–1.2, 2.3–3.3.

Pronotum 1.5–1.6 times as wide as long, space between lines of sculpture as wide as diameter of socket of discal setae, with about 20 discal setae (including anteromarginals and lateralmarginals); posteromarginal setae four pairs, B2 setae 0.3–0.4 times as long as pronotal median length and 1.6–2.0 times as long as B1 setae ( Fig. 9 B). Mesonotum without CPS anteromedially. Metascutum sculptured with transverse anastomosing striae near anterior margin and irregular longitudinal reticulations or anastomosing striae medially, smooth within reticulations; median pair of setae situated behind anterior margin ( Fig. 12 E). Fore wing first vein usually with six to seven basal and three distal setae; second vein usually with two (rarely three) setae; clavus with four veinal and one discal setae; posteromarginal fringe hair straight.

Abdominal terga with B1 setae slightly closer together than their length ( Fig. 13 E), especially on III to V, lateral microtrichial fields each with three discal setae ( Fig. 13 E); terga II to VII with posteromarginal microtrichia at out side of B2 setae ( Fig. 13 E); tergum VIII with microtrichia anteromedially; tergum IX with microtrichia at middle, B1 setae, B2 setae and B3 setae each 0.8–1.1, 1.1–1.4 and 1.0–1.1 times as long as the median length of the tergum; tergum X without microtrichia, B1 setae and B2 setae each 1.5–1.6 and 1.5–1.8 times as long as median length of the tergum; sterna with discal microtrichial rows extending across median area on posterior half ( Fig. 17 B); sternum VII with B1 setae at or slightly in front of posterior margin. Ovipositor 1.8 times as long as pronotal median length.

Measurements of females in microns. Distended body length 830–900. Head length 54–60, width across cheeks 115–120; compound eyes dorsal length 43–48, width 33–35. Pronotal median length 85–90, width 133–143; posteroangular setae I length 15–20, setae II length 30–33. Metascutal median length 55–63, median setae length 18–20. Fore wings length 500–570, width at middle 30–35. Abdominal tergum IX median length 48–53; B1 setae length 43–53, B2 setae length 58–65, B3 setae length 50–53, mid-dorsal setae length 33–38; tergum X median length 33–38; B1 setae length 50–58, B2 setae length 53–63. Ovipositor length 155–160. Antennal segments I to VIII length (width) as follows: 20–25 (21–23), 28–33 (23–24), 40–43 (16–18), 38–40 (15–16), 35–38 (14–15), 43–45 (14), 8 (6–8), 11–13 (4–5).

Male. Distended body length about 0.7 mm. Body colour paler than female. Abdominal tergum IX without drepanae and a pair of setae on near posterior margin ( Fig. 18 B).

Measurements of males in microns. Distended body length 670–730. Head length 54, width across cheeks 101–108; compound eyes dorsal length 43–45, width 30–31. Pronotal median length 73, width 115– 118; posteroangular setae I length 13–15, setae II length 25–28. Metascutal median length 48–50, median setae length 15. Fore wings length 420, width at middle 30. Antennal segments I to VIII length (width) as follows: 18–20 (18–20), 25 (23), 38–40 (15), 34–36 (15), 30–31 (14), 36–38 (14), 6 (6), 10 (4).

Specimen examined. Honshu, 1 female, Niigata Pref., Jouetsu City, Kuwadori-chiku, host unknown, 24- vii-2005, S. Okajima. 9 females, Tokyo, Hachioji City, Minamiasakawa-machi, on undermined tree leaves, 6- v-1993, T. Nonaka. 1 female, Kanagawa Pref., Kawasaki City, Tama-ku, Ikuta-ryokuchi, on leaves of Cocculus orbiculatus [ Menispermaceae ], 7-ix-1994, S. Okajima. 1 female, Kanagawa Pref., Yokohama City, Kanazawa-ku, Tomioka-sougoukouen park, on leaves of Morus bombycis [ Moraceae ], 21-viii-2005, M. Masumoto. 1 female, Kanagawa Pref., Yokohama City, Kanazawa-ku, Tomioka-sougoukouen Park, on leaves of Aucuba japonica [ Cornaceae ], 24-viii-2005, M. Masumoto. 34 females, 10 males, Kanagawa Pref., Yokohama City, Kanazawa-ku, Tomioka-sougoukouen park, on fern, 24-viii-2005, M. Masumoto. 11 females, Kanagawa Pref., Yokohama City, Kanazawa-ku, Tomioka-sougoukouen park, on fern, 25-viii-2005, M. Masumoto. 12 females, 1 male, Kanagawa Pref., Yokohama City, Kanazawa-ku, Tomioka-sougoukouen park, on fern, 10-ix-2005, M. Masumoto. 4 females, Kanagawa Pref., Yokohama City, Kanazawa-ku, Tomiokasougoukouen park, on fern, 11-ix-2005, M. Masumoto. 3 females, Kanagawa Pref., Yokohama City, Kanazawa-ku, Tomioka-sougoukouen park, on leaves of Hydrangea macrophylla [ Saxifragaceae ], 25-ix- 2005, M. Masumoto. 1 female, Kanagawa Pref., Yokohama City, Kanazawa-ku, Tomioka-sougoukouen park, on leaves of Piper kadtura [ Piperaceae ], 21-x-2005, M. Masumoto. 36 females, 2 males, Kanagawa Pref., Yokohama City, Kanazawa-ku, Kanazawa-shizenkouen park, on leaves of Hydrangea macrophylla , 27-vii- 2004, M. Masumoto. 5 females, Kanagawa Pref., Yokohama City, Kanazawa-ku, Kanazawa-shizenkouen park, on leaves of Arachnoides standisii [ Aspidiaceae ], 2-iv-2006, M. Masumoto. 1 female, Kanagawa Pref., Yokosuka City, Kannonzaki, on Carex kobomugi [ Cyperaceae ], 30-iii-2003, M. Masumoto. 1 female, Kanagawa Pref., Yokosuka City, Kannonzaki, on leaves of Aucuba japonica , 5-vi-2005, M. Masumoto. 2 females, Kanagawa Pref., Yokosuka City, Kannonzaki, on fern, 21-v-2006, M. Masumoto. 5 females, Kanagawa Pref., Hadano City, Kenritsu-togawakouen, on leaves of Salix serissaefolia [salicaceae], 13-viii-2005, M. Masumoto. 1 female, Kyoto-fu, Kyoto City, Sakyou-ku, Kitashirakawa, Kyoto University, on gall of Ponticulothrips diospyrosi [ Phlaeothripidae ]-leaves of Diospyros kaki [ Ebenaceae ], 1-vi-1987, T. Sota. 1 female, Kyoto-fu, Kyoto City, Sakyou-ku, Kitashirakawa, Kyoto University, on gall of Ponticulothrips diospyrosi , 16- vi-1987, T. Sota. 8 females, 1 male, Kyoto-fu, Kyoto City, Sakyou-ku, Kitashirakawa, Kyoto University, on gall of Ponticulothrips diospyrosi , 30-vi-1987, T. Sota. 1 female, Kyoto-fu, Kyoto City, Sakyou-ku, Kitashirakawa, Kyoto University, 17-vii-1987, host unknown, T. Sota. 2 females, Kyoto-fu, farm of Kyoto University, on Diospyros kaki , 30-vi-1987, T. Sota. 1 female, Kyoto-fu, Kyoto City, Sakyou-ku, Mt. Yoshida-yama, on gall of Ponticulothrips diospyrosi , 30-vi-1987, T. Sota. Izu-shotou Is. Miyake-jima Is., Tsubota, on leaves of Ligustrum ovalifolium var. pacificum [ Oleaceae ], 15-v-1999, S. Okajima. Kyushu 1 female, Kagoshima Pref., Yaku-shima Is., on flowers of Bidens pilosa [Compositae], 22-ii-2006. 2 females, Kagoshima Pref., Yaku-shima Is., on leaves of Eurya emarginata [Theacerae], 24-ii-2006. Ryukyu Is. 1female, 2 males, Okinawa Pref., Okinawa-hontou Is., Kunigami-son, nr. Oku, Oku-rindou, on grass, 27-viii-1988, S. Okajima. 1 female, Okinawa Pref., Ishigaki-jima Is., nr. Nagura, Takeda, on Ficus erecta [ Moraceae ], 11-i-1991, S. Okajima. 1 female, Okinawa Pref., Ishigaki-jima Is., Takeda-rindou, host unknown, 11-i-1991, S. Okajima. 2 females, Ishigaki-jima Is., Shiramizu, on host unknown (yellow pan trap), 5-x-2004, M. Sato & T. Ishizaki.

Comments. This species is polyphagous and is collected from a very wide range of plant species. It can easily be distinguished from other species in the genus by the body colour, chaetotaxy of head, and the distribution of microtrichia on the abdominal terga and sterna.

Figures

FIGURE 9. Scirtothrips species, head & pronotum (female). (A) S. albidus n. sp.; (B) S. dorsalis.

FIGURE 11. Scirtothrips species (female). (A) S. machili n. sp., Head & pronotum; B – C, Antenna: (B) S. albidus n. sp.; (C) S. dorsalis.

FIGURE 12. Scirtothrips species (female). A – C, Antenna: (A) S. flavus n. sp.; (B) S. katsura n. sp.; (C) S. machili n. sp., (D) S. albidus n. sp., mesonotum & metascutum. E – F, Metascutum: (E) S. dorsalis; (F) S. flavus n. sp.

FIGURE 13. Scirtothrips species (female). A – B, Metascutum: (A) S. katsura n. sp.; (B) S. machili n. sp. C – E, Abdominal terga: (C) S. albidus n. sp., tergum VI (microtrichial row omitted on left side); (D) S. albidus n. sp., tergum VII (microtrichial row omitted on left side); (E) S. dorsalis, left side of tergum VI (microtrichial row omitted.).

FIGURE 17. Scirtothrips species, abdominal sternum (female). (A) S. albidus n. sp., sternum VII; (B) S. dorsalis, sternum VI (microtrichial row omitted on left side.); (C) S. flavus n. sp., right side of sternum VI; (D) S. katsura n. sp., sternum VI (microtrichial row omitted on left side.); (E) S. machili n. sp. sternum V (microtrichial row omitted on left side.).

FIGURE 18. Scirtothrips species. (A) S. machili n. sp., Female (ventral aspect of thorax). B – D, Male abdominal terga: (B) S. dorsalis, tergum IX; (C) S. katsura n. sp., tergum IX (sculpture omitted.); (D) S. machili n. sp., terga IX – X (sculpture omitted.).