Dendrothrips kinape, Noguchi & Masumoto, 2019

Noguchi, Soichiro & Masumoto, Masami, 2019, Description of a new species of the genus Dendrothrips Uzel (Thysanoptera: Thripidae) from Japan, Zootaxa 4695 (1), pp. 95-100 : 96-99

Dendrothrips kinape sp. n.

( Figs 1–7 )

Female macroptera. Distended body length about 1.0 mm. Body uniformly pale; antennal segments I to IV pale, segment V pale with extreme distal area light brown, segment VI brown with base pale, segments VII to IX brown; all femora and tibiae pale; all tarsi pale with distal area light brown; fore wing pale; prominent body setae pale.

Head ( Fig. 1 ) L/ W 0.4 –0.5 (holotype: 0.5); dorsal surface irregularly reticulate near posterior margin but almost smooth within ocellar triangle; cheeks slightly narrowed postward; ocellar setae pair I absent, pairs II and III minute, pair II in front of fore ocellus, pair III situated in front of posterior ocelli; dorsal length of compound eyes about 0.7–0.8 times head length (holotype: 0.7 times). Distance between posterior ocelli and posterior margin of head 0.5 times as long as distance between posterior ocelli. Antennae ( Fig. 2 ) 9-segmented; segments III and IV with forked sense-cones on outer and dorsal surfaces, respectively, segment VI with a long conspicuous simple sense-cone on inner side that extends practically to the apex of IX, and segment VIII with a thinner cone on outer side near base extending to beyond the tip of IX; segments III to VI each with two to four rows of microtrichia on dorsal and ventral surfaces. L/W of antennal segments I to IX (holotype) 1.9–2.3 (1.9), 1.0–1.2 (1.2), 0.5–0.8 (0.6), 0.6–0.8 (0.7), 0.6–0.8 (0.7), 0.5–0.6 (0.6), 1.0–1.4 (1.2), 0.7–1.0 (0.8), 0.3–0.5 (0.4), respectively. Maxillary palpi 2- segmented. Pronotum ( Fig. 1 ) L/ W 0.5 –0.6 (holotype: 0.5), weakly sculptured with transverse anastomosing striae, and with internal granules on anterior half, without elongate setae, with 13–17 discal setae (holotype: 14); 5 pairs of posteromarginal setae. Mesonotum ( Fig. 3 ) with transverse anastomosing striae and no wrinkles between striae, with campaniform sensilla. Metascutum without campaniform sensilla, sculptured with widely spaced longitudinal anastomosing striae. Fore wings ( Fig. 4 ) uniformly covered with microtrichia except a transverse narrow area on first vein at basal one–fifth, with costal margin down turned; costal vein with 25–30 minute setae (holotype: left wing 29, right wing 26); first vein with two to three basal and two distal setae; second vein without setae; scale with two to three (holotype: three) veinal setae and one discal seta. Tarsi 1-segmented.

Abdomen tergites II to VIII ( Fig. 5 ) sculptured with transverse striae, only partly anastomosing striae sparsely having microtrichia at outside of S2 setae and a few striae at middle, microtrichia distinct at each side and posterior segments, without wrinkles between the lines; tergites III to VIII with six pairs of setae: tergite VIII with posteromarginal comb complete; tergite IX 1.8–2.3 times as long as X (holotype: 2.0), with numerous microtrichia in posterior two–thirds, S1 setae longer than S2 setae; tergite X not divided, with paired campaniform sensilla and micritrichia; sternites II–VII sculptured with transverse striae; posteromarginal setae of sternum VII ( Fig. 6 ) situated ahead of posterior margin, S1 setae closer to S2 setae than each other. Ovipositor 1.7–1.9 times as long as pronotal median length (holotype: 1.7 times).

Male. Unknown.

Measurements (holotype female in microns). Distended body length 967. Head length 87, width across cheeks 174; compound eye dorsal length 63, width 45; distance between posterior ocelli 52; distance between posterior ocelli and posterior margin of head 25; antennal length 168. Pronotum length 104, width 213. Fore wing length 733. Abdominal tergite IX length 62; S1, S2 setae lengths 55, 40, respectively; tergite X length 31. Ovipositor length 181. Length of antenna 170; length (Width) of antennal segments I to IX 14 (25), 26 (30), 29 (18), 25 (16), 27 (18), 24 (14), 6 (8), 8 (6), 11 (4), respectively.

Type series. Holotype female: Japan, Hokkaidô, Sapporo City, Hokkaido University , on Oryza sativa , 28-VII- 2018, S. Nakazaki . Paratypes: 22 females, same data as for holotype. These types are deposited in the Hokkaido University Insect Collection, Sapporo, Japan .

Non-paratypic specimens: Hokkaidô, Sapporo City, Hokkaido University , 6-VI-2019, 1 female, 7-VI-2019, 1 female from Poa annua , by S. Noguchi .

Remarks. D. kinape ( Fig. 7 ) is very conspicuous by its entirely pale colored body and fore wing, whereas the species of Dendrothrips generally have the body and fore wing pigmented. This species shares several features with D. oleae from South Africa as follows: pale body including legs and fore wing, fore wing almost uniformly covered with microtrichia except basal area, and abdominal tergites with transverse sculpture lines bearing microtrichia ( Faure 1960, zur Strassen 1968). However, D. kinape can be distinguished clearly from D. oleae by the entirely pale body, antennal segments III–V pale, VI with long inner sense cone, and the fore wing second vein without setae, whereas in D. oleae , abdominal tergites laterally with grayish markings, antennal segments III–IX brown, VI with inner sense cone just reaching to base of segment IX, and the fore wing second vein with 3 setae. Moreover, in D. oleae , sculpture lines on the pronotum are more distinct, and the pronotal posteroangular setae are relatively long. Dendrothrips priesneri from Canary Islands is also similar to D. kinape by uniformly pale body color and the antennal segment VI with long inner sense cone, but it differs from the new species by having more slender head, 1.4–1.5 times as wide as long (1.9–2.3 times in D. kinape ), longer antenna, 208–221 μm (163–172 μm in D. kinape ), the fore wing first vein with 9–10 setae and second vein with 4–5 setae, and metascutum distinctly reticulate (zur Strassen 1965).

In many species of Dendrothrips , the abdominal tergites are more or less reticulate, and the striated condition appears to be exceptional. Tergite sculpture and relationships among Dendrothrips species were discussed by Wang et al. (2019), who suggested that similar sculpture on the abdominal tergites might indicate close relationships. On this basis there might be a relationship between D. oleae and D. kinape , both of which have transverse striae without inner markings and ridges on lines. However, their disjunct distribution and the difference in their host plants contradicts this view. Many Dendrothrips species, including D. oleae , are associated with trees and shrubs ( Marullo 2003). However, D. kinape was collected from a paddy field ( Oryza sativa with almost no other weeds) surrounded by Poaceae weeds. There were many poplar trees around this paddy field, but D. kinape has not been collected from the leaves of these or any other trees around the paddy field. However, larvae have not been collected from Oryza , and no feeding damage was observed. Moreover, in May and June many adults of this new species were collected from dead branches of poplar that had been cut in August and September and left through winter. The species thus possibly overwinters as pupa or adult. Further research is needed to establish the true host plant of this thrips, and confirm its relationship to Poaceae . All known host plants of Dendrothrips species are Dicotyledoneae ( Marullo 2003), and the adults recorded here represent the first example of a Dendrothrips species possibly associated with a monocotyledonous plant. In contrast, species of the Dendrothripinae genus Edissa Faure are known to be associated with grasses ( Mound 1999).

Etymology. The species epithet “kinape” means “dew” in the language of Ainu, the native Hokkaidô people (Hattori 1981).

Figures

FIGURE 7. Dendrothrips kinape, female.

FIGURES 1–6. Dendrothrips kinape, female. (1) Head and pronotum; (2) Antenna; (3) Meso and metanota; (4) Fore wing; (5) Tergites VII–X; (6) Sternite VII.