Tetraneura (Tetraneurella) akinire Sasaki, 1904

Watanabe, Tomoko, Lee, Wonhoon, Sano, Masakazu, Murakami, Keisuke & Akimoto, Shin-Ichi, 2022, Taxonomic revision of the Tetraneura akinire species group (Insecta, Aphididae, Eriosomatinae), with description of a new species and a correction of a nomenclatural confusion, Zootaxa 5183 (1), pp. 162-186 : 178-182

Tetraneura (Tetraneurella) akinire Sasaki, 1904

Tetraneura akinire Sasaki, 1904

Tetraneura fusiformis Matsumura,1917 ; Eastop & Blackman 2005

Tetraneura (Tetraneurella) akinire: Hille Ris Lambers, 1970

Tetraneura (Tetraneurella) nigriabdominalis: Hille Ris Lambers, 1970

Tetraneura nigriabdominalis: Eastop & Blackman 2005

See Favret (2021) for other synonymies.

Fundatrix first instar nymph: Body elliptical, becoming thinner posteriorly, 0.63−0.83 (on average 0.75) mm long, 0.27−0.37 (0.31) mm wide on abdominal segment II, 0.39−0.47 (0.42) times as wide as long ( Figure 4B ). All tergites sclerotized strongly, except for the posterior part of each segment. No wax gland plates present. Eyes each with 3 ommatidia. Capitated setae present on antennae, legs, and whole body dorsally.

Antennae short, 5-segmented, smooth and not imbricated, 0.15−0.18 (0.16) mm long, 0.19−0.25 (0.22) times as long as body, 0.58−0.75 (0.68) times hind femorotrochanter length ( Figure 4E ). Antennal segment V almost equal to or slightly shorter than segment IV; processus terminalis indistinguishable. Antennal segment II square-shaped. Antennal segment IV slightly oval-shaped and wider to the apex. Antennal segment III short, 1/4−1/6 length of segment IV. Primary rhinarium projecting as a horn with the tip not pointed, 0.010 −0.013 (0.012) mm long on segment IV and 0.012 −0.015 (0.013) mm long on segment V; that on segment V with 3−4 circular accessory rhinaria on the base. Segment V with 6−8 setae, of which the basal one is the longest with a conspicuously capitate tip, 0.054 −0.075 (0.064) mm long. Antennal segment IV with 4−7 setae.

Head and prothorax with 5–7 pairs of setae dorsally, 1 pair on the vertex, 1−2 pair(s) ventrally and 2 pairs laterally. Meso- and metanotum each with 1 spinal pair, 1 pleural pair and 2 lateral pairs of setae. Dorsal and lateral setae on head and thorax capitated. Rostrum reaching hind coxae; ultimate rostral segment rather slender, 0.10−0.12 (0.11) mm long, 0.44−0.52 (0.47) times as long as hind femorotrochanter, with 12−18 (12.8) setae. Legs smooth; fore femorotrochanter 0.13−0.17 (0.15) mm long, fore tibia 0.10−0.13 (0.12) mm long, hind femorotrochanter 0.18−0.27 (0.23) mm long and hind tibia 0.16−0.24 (0.21) mm long. Tarsal segment I completely fused with segment II, with an unsclerotized spot basally. One pair of dorsoapical setae on tarsus thick and capitate, 0.083 −0.104 (0.098) mm long on hind legs. One pair of ventrobasal setae on tarsus tapering but not pointed, 0.068 −0.097 (0.083) mm long on hind legs. One pair of empodial setae slightly longer than the claws. Spiracles with round rims, not projecting, 0.012 −0.015 (0.013) mm in diameter.

Abdominal tergites I−VI each with 1 spinal and 1 lateral pair of setae; tergite I with 1 pleural pair additionally; tergites II−IV sometimes with 1 pleural pair additionally. Tergite VII with 1 spinal and 1 lateral pair of setae; tergite VIII and cauda each with 1 pair of spinal setae. Cauda with 4 setae ventrally. Spinal setae on tergite V 0.014 −0.028 (0.019) mm long. Lateral setae on tergite II 0.031 −0.047 (0.037) mm long, on VI 0.041 −0.050 (0.045) mm long, on VII 0.045 −0.056 (0.051) mm long. Dorsal and lateral setae on abdominal segments capitated.

Exule first instar nymph: Body rather elongate, posteriorly broadly rounded, mostly membranous with wax grand plates on the whole body except posterior abdominal segments, 0.71−0.94 (0.81) mm long and 0.33−0.54 (0.39) mm wide, 0.43−0.57 (0.48) times as wide as long; eyes indistinct, with 3 ommatidia ( Figure 5B ).

Antennae short, 5-segmented, 0.26−0.30 (0.29) mm long, 0.32−0.38 (0.35) times as long as body, 1.22−1.28 (1.25) times as long as hind femorotrochanter. The length of antennal segment I 0.037 −0.050 (0.044) mm, II 0.045 −0.055 (0.050), III 0.015 −0.029 (0.022), IV 0.088 −0.119 (0.104), and V 0.047 −0.051 (0.049). Antennal segments I−III not imbricated and smooth, segments IV and V imbricated with transverse rows of spinules. Segment I with 4 setae, II with 3−4, III with 0−1, IV with 11−22 and V with 6. Segment II cylindrical. Segment III thicker apically. Segment IV imbricated, cylindrical, slightly thicker apically, with 17−25 transverse rows of spinules, which are dense on the apical half. Primary rhinarium on segment IV with 1 oval opening, the outer circumference of which is ciliated with 2 tongue-like projections. Segment V wholly with transverse rows of spinules, with an undeveloped processus terminalis. Primary rhinarium on segment V with 2 openings, the outer circumferences are ciliated with 1−3 tongue-like projections.

Suture on head visible; antennal tubercles not developed; vertex nearly flat. Head with 4−5 pairs of setae dorsally, 1 pair on the vertex, 2−4 pairs ventrally. Rostrum reaching over the hind coxae; ultimate segment convergent almost straightly, 0.11−0.12 (0.12) mm long, 0.48−0.57 (0.51) times as long as hind femorotrochanter, with 14−16 setae.

Femorotrochanters smooth. Tibiae imbricated with transverse rows of spinules apically ( Figure 5E ). Tarsi not smooth and imbricated with 6−10 transverse rows of spinules ( Figure 5H ). Spinules in apical tibiae and tarsi absent in 23.8% of the individuals examined (n = 84) ( Figure 5I ). Fore femorotrochanters 0.17−0.21 (0.19) mm long and fore tibiae 0.15−0.19 (0.18) mm long. Hind femorotrochanters 0.19−0.25 (0.23) mm long, 0.35−0.42 (0.39) times as wide as long. Hind tibiae 0.20−0.26 (0.23) mm long. Tarsal segments I and II completely united without a slit. Hind tarsi 0.056 −0.068 (0.063) mm long; hind claws 0.060 −0.078 (0.071) mm long, 1.02−1.28 (1.12) times as long as hind tarsal length.

Body setae acute. Each thoracic segment pleurally with 2 pairs of setae. Each of abdominal segments I−VII pleurally with 1 pairs of setae. Mesonotum, metanotum and abdominal tergites I−VI spinally with 3 pairs of setae. Tergite VII with 2−4 spinal setae. Lengths of spinal setae on abdominal tergite III 0.039 −0.053 (0.045) mm long. Wax gland plates present on head, thoracic segments, and abdominal segments I−VII; head ventrally with 2 pairs of wax gland plates, which are nearly circular; prothorax with 1 pair pleurally; mesothorax and metathorax respectively with 2–3 small and inconspicuous pairs; abdominal segments I−VII respectively with 2−4 pairs, which are inconspicuous and circular or long oval ( Figure 5L ). Abdominal sternites III−VII respectively with 2−6 setae. Cauda dorsally with 1 pair of setae spinally, 1 pair laterally, and 1 longer pair ventrally.

Emigrant adult: Body 1.79−2.84 (2.14) mm long, without wax gland plates ( Figure 6B ). Head and thorax dark brown; antennae and legs brown. Wings wholly shaded in brown, slightly darker along veins.

Antennae 6-segmented, 0.60−0.80 (0.68) mm long, 0.28−0.37 (0.33) times as long as body, 0.96−1.10 (1.02) times as long as hind tibia ( Figure 6E ). Antennal segments V and VI pigmented thinly; segment V and VI imbricated with numerous transverse rows of spinules. Segment IV, depending on the individuals, with spinules sparsely between secondary rhinaria. Segments I−III not imbricated and smooth. Antennal segment III variable in length, 0.18−0.25 (0.22) mm long, 0.59−0.71 (0.62) times the length of IV, V and VI combined. Segment IV rather oval in profile, 0.44−0.74 (0.53) times as wide as long. Segment V 0.16−0.24 (0.19) mm long, 0.73−0.99 (0.87) times as long as segment III, 0.14−0.21 (0.17) times as wide as long at the middle point. Segment VI 0.41−0.55 (0.46) times as wide as long, thickest at the middle point, with a depression at the primary rhinarium, which is elongated transversely; segment VI wholly with spinules arranged in 14−17 transverse rows, without secondary rhinaria ( Figure 6H ). Secondary rhinaria present on segments III−V, narrow, slightly projecting, microscopically represented as blight lines on dark pigmented background, covering usually 1/4−2/3 circumference of the segments from the ventral side. Antennal setae on segments III−V short and scarce, present on the dorsal side; the longest seta on segment V 0.011 −0.016 (0.014) mm long; segment III with 8−14, IV with 1−4, V with 8−21 and VI with 5−7 setae, of which 3−4 are present apically and 1−3 on the basal half.

Suture on head invisible; antennal tubercles not developed; vertex nearly flat. Head dorsally with 5−7 and ventrally with 6−9 pairs of setae, respectively; of them, 5−7 pairs of ventral setae situated near the base of clypeus. Rostrum short, not reaching the middle point between the coxae of fore and middle legs. Ultimate rostral segment short, with gently convex margins and 6−7 pairs of short setae, 0.077 −0.095 (0.087) mm long, 0.45−0.60 (0.51) times as long as the second segment of hind tarsi ( Figure 6K ). Femorotrochanter not imbricated and smooth; hind femorotrochanter 0.42−0.58 (0.51) mm long, 0.73−0.79 (0.76) times as long as hind tibia. Tibia slightly spinulose at the terminal; hind tibia 0.56−0.76 (0.67) mm long. Tarsi with numerous spinules neatly arranged in numerous transverse rows; second segment of hind tarsus 0.16−0.18 (0.17) mm long; first tarsal chaetotaxy 3:2−3:2; empodial setae slightly shorter than claws ( Figure 6N ). Abdomen membranous except genital plate, anal plate and cauda, which are slightly pigmented. Cornicles absent. Genital plate, slightly brown-pigmented, with 32−46 (39.1) setae ( Figure 6Q ). Cauda semicircular, with 2 setae. Fore wings with unbranched media; the veins rather broad, not conspicuously bordered. Hind wings only with 1 inconspicuous oblique vein.

Sexupara adult: Since the sexupara is morphologically close to the emigrant in many respects, the characters that differ between the two morphs and are indispensable for identification will be referred to.

Body 1.77–2.44 (2.20) mm long. Wax gland plates present on the whole body except the posterior segments of abdomen ( Figure 7B ).

Antennae 6-segmented, 0.76–0.90 (0.83) mm long, 0.37−0.43 (0.38) times as long as body, 0.93–1.03 (0.99) times as long as hind tibia ( Figure 7E ). Antennal segments III–VI pigmented thinly; segments V, VI imbricated with numerous transverse rows of spinules; segment IV sparsely with spinules between secondary rhinaria; segments I-III not imbricated and smooth; segment III 0.27–0.37 (0.33) mm long, 1.54 times as long as that of the emigrant, 0.71–0.96 (0.89) times as long as segments IV, V and VI combined; segment IV rather oval in outline, 0.50–0.75 (0.57) times as wide as long; segment V cylindrical, 0.21–0.25 (0.23) mm long, 0.13–0.17 (0.16) times as wide as long, 0.63–0.82 (0.69) times as long as segment III; segment VI 0.059 –0.068 (0.064) mm long, 0.46–0.54 (0.49) times as wide as long, with the middle thickest; segment VI with spinules arranged in 12–15 transverse rows, without secondary rhinaria. Primary rhinarium present on segment VI, tongue-like, elongate transversely with ciliated rims ( Figure 7H ). Secondary rhinaria present on the segments III–V, 0.002 –0.009 (0.003) mm wide, slightly projecting, microscopically represented as the blight lines on dark pigmented background, covering usually 1/2 to the whole circumference from the ventral side, more numerous than in emigrant. Antennal setae short and scarce, present on the dorsal surface, 0.017 –0.030 (0.022) mm long on segment V.

Suture on head invisible; antennal tubercles not developed; vertex nearly flat. Median ocellus and 1 pair of wax gland plates situated posteriorly to the ocellus, forming a triangle ( Figure 7K ). Head dorsally with 6−8 pairs setae, ventrally with 6−12 pairs setae; of them, 5−11 pairs of ventral setae situated around the wax gland plates. Ultimate rostral segment 0.10–0.12 (0.11) mm long with 7 pairs of setae, convergent with almost straight margins, 0.59–0.74 (0.68) times as long as the second segment of hind tarsus, 1.34 times as long as that of the emigrant ( Figure 8B ). Pronotum with 2 pairs of wax gland plates spinally, metanotum and mesonotum each with 1 pair of them spinally. Femorotrochanter and tibia slightly longer than those of the emigrant. First tarsal chaetotaxy 3:2−3:2. The second segment of hind tarsus slightly shorter than that of the emigrant; second segment of hind tarsus 0.17–0.21 (0.19) times as long as hind tibia (in emigrant, the proportion is 0.23–0.32 (0.25)) ( Figure 8E ). Abdominal tergites membranous without sclerites. Wax gland plates present on II−VII abdominal tergites, 1 pair spinally, 1 pair marginally, and sometimes 1−2 pair(s) of small ones pleurally; round or oval in the outline, with variation in the size, consisting of 1–44 (20) minute round facets ( Figure 8H, K ). Cornicles present on the pleural and posterior positions of the fifth abdominal tergite, 0.041 –0.049 (0.044) mm in diameter, with slightly projecting rim, which is sclerotized slightly ( Figure 8N ). The second to sixth abdominal tergites with fine setae sparsely; the seventh tergite with 7–8 slightly long setae. The second to sixth abdominal sternites with 20–29 short setae spinally, respectively. Genital plates slightly brown-pigmented, with 12–26 (15.9) setae on each of the right and left sides ( Figure 8Q ).

Host plant: Primary host: U. davidiana var. japonica , U. parvifolia , U. carpinifolia , U. rubra , U. minor , U. campestris , U. laciniata , and U. americana . Secondary host: Setaria spp. , Eleusine indica and other gramineous species.

Specimens examined: Fundatrix first instar nymph: 20 exs, Kyoto, Kyoto, 25.IV.1981, on U. parvifolia, S. Akimoto ; 24 exs, Beltsville, Maryland, USA, 3.V.1982, on U. carpinifolia, D. R. Miller ; 20 exs, Mandavit, Gradignan, Gironde, France, 2.V.2010, on Ulmus minor, T. Yoshida ; 10 exs, JC Raulston Arboretum, Raleigh, North Carolina, USA, 1.V.1999, on U. × cathedral, S. Aoki; 10 exs, Schenk Forest, North Carolina, USA, 2.V.1999, on U. rubra, S. Aoki ; 2 exs, San Martín del Agostedo, León, Spain, 11.VI.2003, U. minor, Nicolás Pérez Hidalgo; 2 exs, Bronte, Sicily, Italy, 10.VI.2009, on U. minor, S. Akimoto ; 26 exs, Jeongseon, Gangwon-do, South Korea, 25–27.V.2012, on U. davidiana var. japonica, S. Akimoto ; 7 exs, Aokizawa, Minakami, Gunma, 3.VI.1983, on Ulmus sp. , Y. Matsumoto; 20 exs, Kashiwa, Chiba, 29.IV.2015, on U. davidiana var. japonica, S. Akimoto ; 20 exs, Bibai, Hokkaido, 5.VI.1981, on U. davidiana var. japonica, S. Akimoto ; 20 exs, Ukiha, Fukuoka, 8.IV.1985, on U. parvifolia, S. Akimoto ; 5 exs, Sapporo, Hokkaido, on U. davidiana var. japonica, S. Akimoto ; 6 exs, Iwamizawa, Hokkaido, 15.VI.2004, on U. davidiana var. japonica, S. Akimoto. Emigrant adult: 10 exs, Sapporo, Hokkaido, 17.VI.2000, on U. davidiana var. japonica, M. Sano ; 10 exs, Sapporo, Hokkaido, 20.VI.1984, on U. davidiana var. japonica, S. Akimoto ; 2 exs, Miami-Dade County Homestead, Florida, USA, 15.III.2000, ex Zelkova serrata (probably misidentification of Ulmus parvifolia ), Duraid Hanna. Exule first instar nymph: 2 exs, Sapporo, Hokkaido, 6.X.1983, on grass roots, S. Akimoto; 3 exs, Sapporo, Hokkaido, 4.X.1983, on grass roots, S. Akimoto; 4 exs, Bibai, Hokkaido, 1.X.1983, on grass roots, Y.Yamaguchi; 3 exs, Hirosaki, Aomori, 29.IX.1983, on grass roots, S. Akimoto; 6 exs, Madang Province, Papua New Guinea, VII. 2014, on rice roots, M. Kanamoto; 12 exs, Utsunomiya, Tochigi, 5.IX.1982, on grass roots, S. Akimoto; 5 exs, Kashiwa, Chiba, 6.IX.1982, on grass roots, S. Akimoto; 4 exs, Kyoto, Kyoto, 31.VIII.1982, on grass roots, S. Akimoto; 6 exs, Kuroyama, Osaka, 1.IX.1982, on grass roots, S. Akimoto; 6 exs, Ochide, Ehime, 22.V.1974, on U. parvifolia, S. Aoki ; 3 exs, Chiba, Chiba, 16.VIII.1990, on grass roots, Y. Matsumoto; 14 exs, Kashiwa, Chiba, 26.X.1984, on grass roots, S. Akimoto. Embryos in emigrant adults: 5 exs, Ochide, Ehime, 22.V.1974, on U. parvifolia, S. Aoki ; 2 exs, Yoshi-machi, Fukuoka, 14.V.1980, on U. parvifolia, S. Aoki. Sexupara adult: 1 ex, Moftituck, New York, USA, IX.1999, on U. americana, Daniel Gilrein ; 1 ex, Adams Co., Bendersville, Bear Mtn. Orchards, Pennsylvania, USA, 28.IX.2000, J. Stimmel, on grasses in orchard ground cover; 10 exs, Sapporo, Hokkaido, 30.IX.1989, on the roots of Setaria viridis, S. Akimoto.

Distribution: Almost world-wide ( Blackman & Eastop 2021).

Figures

FIGURE 4. Fundatrix first instar nymphs: T. ovaliformis sp. nov. (A), T. akinire (B), T. sorini (C). Antennae: T. ovaliformis sp. nov. (D), T. akinire (E), T. sorini (F).

FIGURE 5. First instar nymphs produced by emigrants: T. ovaliformis sp. nov. (A), T. akinire (B), T. sorini (C). Hind tibiae and tarsi: T. ovaliformis sp. nov. (D), T. akinire (E), T. sorini (F). Setae on hind tarsi and tibiae: T. ovaliformis sp. nov. (G), T. akinire (H), hairless type T. akinire (I), T. sorini (J). Abdominal wax gland plates: T. ovaliformis sp. nov. (K), T. akinire (L), T. sorini (M).

FIGURE 6. Emigrant adults: T. ovaliformis sp. nov. (A), T. akinire (B), T. sorini (C). Antennae: T. ovaliformis sp. nov. (D), T. akinire (E), T. sorini (F). Apex of antennae: T. ovaliformis sp. nov. (G), T. akinire (H), T. sorini (I). Ultimate rostral segments: T. ovaliformis sp. nov. (J), T. akinire (K), T. sorini (L). Hind tarsus: T. ovaliformis sp. nov. (M), T. akinire (N), T. sorini (O). Genital plates: T. ovaliformis sp. nov. (P), T. akinire (Q), T. sorini (R).

FIGURE 7. Sexupara adults: T. ovaliformis sp. nov. (A), T. akinire (B), T. sorini (C). Antennae: T. ovaliformis sp. nov. (D), T. akinire (E), T. sorini (F).Apex of antennae: T. ovaliformis sp. nov. (G), T. akinire, (H), T. sorini (I). Median ocelli and wax gland plates on heads: T. ovaliformis sp. nov. (J), T. akinire (K), T. sorini (L).

FIGURE 8. Sexupara adults: Ultimate rostral segments: T. ovaliformis sp. nov. (A), T. akinire (B), T. sorini (C). Hind tarsus: T. ovaliformis sp. nov. (D), T. akinire (E), T. sorini (F). Wax gland plates around the cornicles: T. ovaliformis sp. nov. (G), T. akinire (H), T. sorini (I). Wax gland plates on abdomen: T. ovaliformis sp. nov. (J), T. akinire (K), T. sorini (L). Cornicles: T. ovaliformis sp. nov. (M), T. akinire (N), T. sorini (O). Genital plates: T. ovaliformis sp. nov. (P), T. akinire (Q), T. sorini (R).