Thrips spiranthicola, Masumoto & Tsutsumi & Okajima, 2023

Masumoto, Masami, Tsutsumi, Tadaaki & Okajima, Shûji, 2023, Two new species of the genus Thrips Linnaeus (Thysanoptera, Thripidae) in Japan with a revised key to Japanese species of Thrips, Zootaxa 5239 (3), pp. 358-372 : 366-371

Thrips spiranthicola sp. n.

( Figs 5–6, 10 , 20–27 )

Thrips sp. : Suetsugu et al., 2018: 2.

Female macroptera . Distended body length about 1.5 mm. Body uniformly yellow ( Fig. 5 ); antennal segment I yellow, II shaded, III pale brown with basal third pale, IV–VII brown; fore wings slightly shaded ( Fig. 10 ); all legs yellow; major body setae brown, abdominal tergites II–V with S2 setae as dark as lateral marginal setae. Head 0.8–0.9 times as long as broad, sculptured with transverse anastomosing striae dorsally, rounded at cheeks ( Fig. 20 ). Ocellar setae pair I absent, II much shorter than pair III, III situated posterolateral to fore ocellus and slightly longer than diameter of hind ocelli. Postocular setae arranged in a line, S1 setae slightly shorter than ocellar setae pair III, S2 and S4 setae much shorter than S1 and S3 setae. Antennae 7-segmented, segment II with microtrichia, III and IV with forked sense-cones, rounded at each side and with short apical neck, IV–V pedicelate, VI longest, gently tapered at distal half and not pedicelate ( Fig. 21a ), with 12 setae. Ratio length/broad of segments I–VII as follows: 0.8–1.0, 1.2–1.4, 2.1–2.4, 2.4–2.7, 2.1–2.3, 2.9–3.1, 2.3. Pronotum 0.7–0.8 times as long as broad, sculptured with transverse anastomosing striae, with 29–46 (mean 36, S.D. 3.7, n=40) discal setae, discal setae median length 13–20 microns (mean 16.3, S.D. 1.9, n=100) and 0.10–0.16 times as long as pronotal median length (15–18 microns, 0.13 times in holotype); posteroangular setae 2 pairs, pair I 0.5–0.6 times as long as median pronotal length, 1.1–1.3 times as long as pair II; posteromarginal setae 3 pairs, S1 setae longest. Mesonotum with paired CPS anteromedially, almost smooth around anteromedian CPS. Metascutum sculptured longitudinally sculptured except anteromedially, posteromedian sculpture indicates various pattern, usually anastomosing lines or irregular reticulations and not convergent to middle at posterior margin, often longitudinal parallel lines; median pair of setae slightly closer to each other than to submedian setae and much behind anterior margin, 0.5–0.6 times as long as metascutal median length; paired or single CPS present or absent ( Fig. 22 ). Fore wing costal vein with 21–24 setae, first vein with 7 basal (rarely 8) and 3 distal setae, second vein with 10–15 setae; clavus with 5 veinal and 1 discal setae. Hind coxa apparently without microtrichia on inner dorsal surface ( Fig. 23 ). Abdominal tergites V–VIII with paired ctenidia, ctenidia situated mesad of spiracles on VIII ( Fig. 24 ); tergite II with 4 lateral marginal setae; tergites II–VII with a line of sculpture across tergites anterior to S1 setae, but smooth between S1 setae; tergite VIII with posteromarginal comb complete, S1 setae usually much shorter than S2 setae; tergite IX with 1 or 2 pairs of or 3 CPS, or only single CPS; tergite X with median split almost complete; sternites without discal setae; sternite I with 2 or 3 microsetae anteromedially; sternites III–VII with 3 pairs posteromarginal setae, II with 2 pairs; sternite VII with S1 setae much in front of posterior margin; pleurotergites with dentate microtrichia and no discal setae ( Fig. 25 ). Ovipositor 1.7–1.8 times as long as pronotal median length.

Measurements (holotype female in microns). Distended body length 1450. Head median length 118, width across cheeks 135, compound eye dorsal length 70, width 43. Pronotum median length 125, width 170: posteroangular setae pair I length 60–68, pair II length 53–64, posteromarginal S1 setae length 28–30. Metascutal median length 75: median pair of setae length 38–43. Fore wing length 600, width at middle 50. Abdominal tergite IX length 68, tergite X length 50. Ovipositor length 220. Antennal segments I–VII length (width) as follows: 25 (30), 30 (25), 48 (23), 48 (18), 40 (18), 50 (16), 18 (8).

Male macroptera . Body colour and structure very similar to female but smaller ( Fig. 6 ). Antennal segment VI with 14 setae. Abdominal tergite IX with S1 setae usually slightly shorter than, sometimes subequal in length to, S2 setae, almost equidistance to S2 setae and arranged transversely, usually 1 pair of (rarely 3) CPS ( Fig. 26 ); sternites III–VII with large transverse pore plates constricted medially and smaller at posterior sternites, each side reaching at S2 setae ( Fig. 27 ).

Measurements (male paratypes in microns). Distended body length 1090–1180. Head median length 100– 108, width across cheeks 115–125, compound eye dorsal length 58–65, width 35–38. Pronotum median length 100–108, width 143–150: posteroangular setae pair I length 47–59, pair II length 44–50, posteromarginal S1 setae length 21–25. Metascutal median length 58–65: median pair of setae length 28–33. Fore wing length 490–540, width at middle 40–45. Abdominal sternites III–VII pore plates width as follows: 90–120, 93–120, 98–115, 85–108, 78–100. Antennal segments I–VII length (width) as follows: 20–25 (25–28), 28–30 (23–24), 40–43 (16–18), 38–43 (18), 33 (15–16), 45–48 (15–16), 15 (8).

Type series. Holotype female, Japan, Honshu, Kanagawa-ken, Yokohama-shi, Kanazawa-ku , Tomiokahigashi , on flower of Spiranthes sinensis var. amoena [ Orchidaceae ], 13.vi.2021, M.Masumoto . Paratypes: Honshu: 23 females & 1 male collected together with holotype. 57 females & 9 males on flower of S. sinensis var. amoena at same place with holotype, 26.iv.2021. Kanagawa-ken, Yokohama-shi, Kanazawa-ku: Tomioka-sogo-koen park, 3 femlaes on flower of S. sinensis var. amoena , 23.vi.2019. Nagahama-koen park, 10 females on flower of S. sinensis var. amoena , 13.vi.2021. Chiba-ken, Inba-gun, Sakae-machi: 5 females on flower of S. sinensis var. amoena , 27.vi.2020. (all collected by M.Masumoto). Osaka-fu, Sakai-shi, Minami-ku: 22 females & 12 males on flower of S. sinensis var. amoena , 30.vi.2013, Y.Kojima. Nara-ken, Nara-shi, Sahodai: 9 females on flower of S. sinensis var. amoena , 22.vi.2014, K.Suetsugu. Hyogo-ken, Sanda-shi: Shimoaino, 5 females on flower of S. sinensis var. amoena , 23.vi.2014, K.Suetsugu. Sumada, 2 females on flower of Epipactis thunbergii [ Orchidaceae ], 24.vi.2014, K.Suetsugu. Kyoto-fu, Kyoto-shi, Sakyo-ku: 5 females & 3 males on flower of S. sinensis var. amoena , 29.vi.2014, K.Suetsugu. Kyushu: Kagoshima-ken, Kanoya-shi, Chuo-koen park, 55 females & 11 males on flower of S. sinensis var. amoena , 30.vi.2018, T.Tsutsumi. The holotype is deposited in TUA. Most paratypes are deposited in FU and TUA.

Non-paratypic specimens. Japan, Honshu: Hiroshima-ken, Mihara-shi, Hongou-cho , 11 females on flower of S. sinensis var. amoena , 11.vii.2008, Y. Nakamoto ( TUA) .

Comments. T. spiranthicola and T. palmi are difficult to distinguish in the female as they often share metascutal sculpture curved to middle near posterior margin ( Fig. 31 ), but in T. palmi the pronotal median discal setae tend to be longer than in T. spiranthicola ( Fig. 29 ), 18-23 microns (mean 19.8, S.D. 1.0, n=54) and 0.15–0.21 times as long as pronotal median length, and the discal setae are almost as stout as posteromarginal S2 or S3 setae in T. palmi whereas slender in T. spiranthicola . In contrast, they are relatively distinct in the male as in above key and Table 4 . The sternal pore plates are larger on anterior sternites in both species but much wider on all sternites of T. spiranthicola than at T. palmi . Moreover, the new species is associated with flowers of Spiranthes , whereas T. palmi is extremely polyphagous. Two of the paratype females were collected from flower of Epipactis thunbergii and recorded by Suetsugu et al. (2018) as Thrips sp. In their research, 102 individuals of more than nine species of three insect orders were carrying pollen grains of E. thunbergii , but 66 individuals within 102 are Thysanoptera with three genera and four species. In these thrips species, Frankliniella intonsa was abundant (56 individuals), whereas of T. sp. only two females were found. In contrast, Thrips spiranthicola may be abundant on Spiranthes sinensis , although the following thrips species were also collected from that plant: F. intonsa , F. occidentalis , Taeniothrips eucharii , Haplothrips spp. and several Thrips species such as T. coloratus and T. hawaiiensis . Thus, T. spiranthicola may be the pollinator of Spiranthes .

Figures

FIGURES 1–10. Thrips species. (1) T. alni, female. T. coxalis sp. n. 2–3: (2) female; (3) male. (4) T. palmi, female. T. spiranthicola sp. n. 5–6: (5) female; (6) male. Fore wing, female 7–10: (7) T. alni; (8) T. coxalis sp. n.; (9) T. palmi; (10) T. spiranthicola sp. n.

FIGURES 20–27. Thrips spiranthicola sp. n. (20) head & pronotum, female. Antenna 21a–b: (21a) segments I–VII, female; (21b) segments VI-VII, male. (22) mesonotum & metascutum, female; (23) hind coxa to femur, female; (24) tergites VIII–X, female; (25) pleurotergite IV (right), female. Male 26–27: (26) tergites VIII–IX; (27) sternites V–VI.

FIGURES 28–33. Thrips species, female. Head 28– 29: (28) T. alni; (29) T. palmi. Mesonotum & metascutum 30–31: (30) T. alni; (31) T. palmi. Hind coxa to femur 32–33: (32) T. alni; (33) T. palmi.