Ethirothrips rubeus Wang

Okajima, Shûji & Masumoto, Masami, 2023, Six genera of the subtribe Macrothripina from Southeast Asia to Taiwan (Thysanoptera, Phlaeothripidae, Idolothripinae), Zootaxa 5291 (1), pp. 1-74 : 45-47

Ethirothrips rubeus Wang

( Figs 121–126 , 231–232 )

Ethirothrips rubeus Wang , in Wang et al. 2019: 96–98.

This species was described based on nine females and four males from Taiwan, in which four females and two males are macropterae and the remaining five females and two males are apterae. Through the courtesy of Dr. Chin-Ling Wang, we examined macropterous one female and one male paratypes collected from Fenggu (the labels on slides are written by Taiwanese letter, and we extracted this locality name from the original description) at 23.vii.1993. According to the original description, however, only three females, no male, were designated as paratypes under this data. E. rubeus has characteristic short antennal segment III which is shorter than segment IV, with unusually long and curved sense-cones. These features also found in some other genera in the Macrothripina , such as Aesthesiothrips , Dichaetothrips , Peltariothrips and Tarassothrips . Moreover, even in the genus Ethirothrips , E. indicus (Bagnall) from India also has similar short antennal segment III and long and curved sense-cones. According to the literature, including the original description of E. indicus ( Bagnall 1921b; Mound 1968; Ananthakrishnan & Jagadish 1970), rubeus can be distinguished from indicus by the longer head, shorter postocellar setae which are usually less than 30μm, and fewer fore wing duplicated cilia. This species was compared in the original description with E. boninensis Okajima from the Ogasawara Islands, Japan, but these two are presumably not closely related.

There are a long series of females and males collected from Southeast Asia ( Indonesia, Singapore, Thailand and Vietnam) in the collection of TUA, which could well be identified as this species. All of them are macropterae, while the type series from Taiwan includes both macropterae and apterae. In the original description, however, differences between these two wing forms were not mentioned. The full description of this species is given below based on the macropterous females and males from Southeast Asia, because the original description is somewhat insufficient for the present study.

Female (macroptera). Distended body length: 2.7–4.0mm. Colour dark brown. Antennal segments I–II and IV–VIII dark brown, segment IV scarcely paler; segment III yellowish brown to brown, usually paler than segment IV, but sometimes darker. Fore tibiae brown to dark brown, somewhat paler than femora, but often concolourous with femora; all tarsi brown. Fore wings almost clear. Prominent setae yellowish. Head ( Fig. 121 ) longer than broad, about 1.3 times as long as broad or a little shorter, broadest across eyes; dorsal surface almost smooth, sculptured with transverse row of reticles or striae sub-basally. Cheeks sub-parallel, almost straight, but distinctly constricted at base; each with some setae. Postocular setae situated behind eyes, much longer than eyes, nearly pointed, at least not sharply pointed; postocellar setae almost as long as diameter of a posterior ocellus, or a little shorter, usually shorter than 30μm, situated behind posterior ocelli. Eyes comparatively small, about 0.3 times as long as head, relatively wider apart from each other; posterior ocelli close to eyes. Antennae ( Fig. 122 ) about 2.0 times as long as head; segment VIII relatively slender, very weakly constricted at base; segment III short, about 2.0 times as long as broad, shorter than segment IV; segments IV and V subequal in length; sense-cones long and curved, setiform, longer than 2/3 length of the segment; segment IV with four sense-cones. Maxillary stylets retracted to near postocular setae, but usually not reaching postocular setae, V-shaped. Pronotum ( Fig. 121 ) longer than half the length of head, about twice as broad as long; dorsal surface almost smooth, weakly sculptured laterally and posteriorly. Prominent setae blunt, epim the longest. Mesopresternum ( Fig. 123 ) narrowly boat-shaped. Metanotum ( Fig. 124 ) without CPS, sculptured with concentric reticulation. Fore femora moderately enlarged, with short setae; fore tarsus ( Fig. 126 ) with a wide-based stout tooth. Fore wings each with 17–26 duplicated cilia; sub-basal setae arising in a triangle, blunt. Pelta ( Fig. 124 ) trilobed, distinctly reticulated. Abdominal tergite II slightly eroded laterally in anterior 2/3. Posteromarginal setae on abdominal tergite IX sharply pointed, shorter than tube, S1 and S2 subequal in length. Tube ( Fig. 125 ) comparatively large, much longer than head, more than 1.25 times as long as head, about 3.2 times as long as broad, sides very weakly rounded, weakly constricted at apex.

Measurements (a female from Bangkhen, Thailand, in μm). Body length about 3520 (distended). Head length 345, from anterior margin of eyes 325, width across eyes 270, maximum width across cheeks 264; eyes length 98, width 80; postocular setae 140–145, postocular cheek setae 30–33. Antenna total length 690, segments I–VIII length (width) as follows: 79 (50), 70 (40), 98 (49), 113 (48), 111 (41), 90 (34), 70 (28), 50 (16). Pronotum length 195, width 385. Setae on prothorax: am 35–45, aa about 40, ml 50–60, pa 90, epim 135–140. Fore wing length 1300. Sub-basal wing setae: S1 45 –50, S2 60 –65, S3 115–120. Setae on tergite IX: S1 410–415, S2 400–410. Tube length 445, maximum width 140, width at apex 57; terminal setae 200–220.

Male (macroptera). Distended body length: 2.6–3.1mm. Colour and structure very similar to female. Prothorax and fore legs stouter. Fore wing with 17–25 duplicated cilia. Tube 1.00–1.05 times as long as head, weakly swollen at base.

Measurements (small–large males in μm). Body length about 2650–3100 (distended). Head length 295–320, from anterior margin of eyes 280–296, width across eyes 245–245, maximum width across cheeks 240–240; eyes length 85–95, width 60–65; postocular setae 145–165.Antenna total length 628–645, segments I–VIII length (width) as follows: 73–85 (48–50), 63–60 (37–37), 83–88 (42–43), 98–100 (41–41), 100–100 (38–40), 85–80 (30–32), 63– 63 (27–27), 50–48 (15–15). Pronotum length 170–206, width 335–380. Setae on prothorax: am 30–40, aa 30–45, ml 40–67, pa 105–125, epim 133–130. Fore wing length 1170–1230. Sub-basal wing setae: S1 45 –52, S2 52 –72, S3 100–135. Setae on tergite IX: S1 350–360, S2 340–350. Tube length 310–320, maximum width 120–124; terminal setae 230–260.

Specimens-examined. Taiwan, 1 female and 1 male paratypes, Fenggu, 23.vii.1993 . Thailand, Bangkok, Bangkhen, Campus of Kasetsart University , 3 females and 1 male, on dead branches, 19.viii.1991 , TN & SO, 2 females and 2 males, same locality and habitat, 26.xii.1987 , SO, same locality, 2 males, on dead branches of Bougainvillea ?glabra, 28.xii.1987 , SO; Saraburi, 3 females and 1 male, on dead leaves and branches, 10.ix.1991 , TN & SO; Nakornprathom , Puttamonton, 2 females and 2 males, on dead branches, 18.ix.1991 , P. Jangvitaya; nr. Chiang Mai, Phrow , 1 female, on dead leaves and branches, 22.viii.1992 , TN & SO; nr. Chiang Mai, Doi Inthanon, 1 female, on dead leaves and branches, 29.viii.1992 , TN & SO; nr. Chiang Mai, Lam Pang, 1 male, on dead leaves and branches, 28.viii.1992 , TN & SO; nr. Chiang Mai, Pha Sang, 1 female, 31.viii.1992 , SO; Chiang Dao , 1 female, on dead leaves, 23.viii.1992 , TN; Phuket Is. , Rang Hill, 23 females and 11 males, on dead leaves and branches, 14.ix.1992 , 1 female, without detailed locality, on dead leaves, 20.viii.1976, SO. Singapore, Macritchie Res., 1 female, 8.viii.1990 , TN & SO. Vietnam, Dong Nai Prov., Tan Phu, Phu An, 1 female and 1 male, on dead leaves and branches, 29.xii.2001 , SO. Indonesia, Bali Is. , Buleleng, Melanting, 1 female and 1male, on dead branches, 17.viii.2006 , SO.

Remarks. Wang et al. (2019) described the tube length of this species as about same length of head, but it is distinctly longer than head even in the paratypes.

Figures

FIGURES 121–126. Ethirothrips rubeus from Thailand, female. (121) Head; (122) antennal segments II–VIII; (123) mesopresternum; (124) metanotum & pelta; (125) tube; (126) fore tarsus.

FIGURES 223–234. Ethirothrips species, female. (223) E. longiceps sp. n.; (224) E. longisetis; (225) E. malaya sp. n.; (226) E. obscurus; (227) E. oculus sp. n.; (228) E. ommatus sp. n.; (229) E. puiensis sp. n.; (230) E. quadratus sp. n.; (231) E. rubeus, paratype; (232) E. rubeus from Thailand; (233) E. saigon sp. n.; (234) E. setosus sp. n.