Tripartita formosana Yeh, 2017

Ko, Chiun-Cheng, 2017, A new genus and two new species of galling aphids (Hemiptera: Aphididae) from Distylium (Hamamelidaceae) in Taiwan, Zootaxa 4323 (2), pp. 209-218 : 213-217

Tripartita formosana Yeh sp. n.

( Figs. 3 , 4 , 5 , 6 )

Fundatrix. (Description is based on 13 specimens). ( Fig. 3A–C , 5A, 5B ). Body puffed out, cuticle soft, 1.38–2.50 mm long. Head without horns or dagger-like setae. Antennae 3-segmented; segment III with imbricate sculpturing, 170–215 µm long, about 1.13 (1.06–1.21)-times length of tibia of foreleg, with a circular sensorium and 5 or 6 terminal setae on tip. Eyes with 3 facets. Rostrum stout, last 3 segments 170–210 µm long; ultimate rostral segment about 1.40–1.60-times length of 2nd tarsus of hindleg. Two pairs of spiracles with large spiracular plates raised on intermediate areas between prothorax-mesothorax and mesothorax-metathorax; abdominal spiracles without sclerites nor turbercles nearby. Legs short. Siphunculi absent. Abdominal tergite VIII slightly sclerotized with imbrications, with 5–7 setae; genital plate with 9–16 setae. Cauda transverse, not constricted at base, with 6–8 setae which are divided into 2 clusters on each side. Anal plate bilobed, with 5 or 6 setae on each lobe.

Alate viviparous adult. (Description is based on 34 specimens). ( Fig. 4A–D , 5C–F ). Body length 1.53–2.34 mm. Head width (distance between 2 apices of ocular tubercles) 0.42–0.50 mm. Antennae long, about 0.69 (0.59– 0.85)-times body length and 2.83 (2.33–3.41)-times width of head, 3-segmented (some individuals obviously 4- segmented, but segments III and IV not definitely delimited), segment III usually thickened on basal 1/3–1/2, with 61–110 annular secondary sensoria, with 4–6 terminal setae. Rostrum short, not reaching coxae of mid-leg; ultimate rostral segment blunt, about 0.64 times length of 2nd tarsal segment of hindleg. Prothorax well-developed and prominent, with 2 groups of wax glands on tergite. Tibiae imbricate, with distinct spinules; tarsi with minute imbricate spinules, 1st tarsal segments with 3-3-3 setae, 2nd tarsal segments with 4-4-4 capitate distal setae. Groups of wax glands present on abdominal segments I–VII, which are arranged in a row on each tergite; abdominal tergites I–VII covered with pale minute sculpturing with a slightly reticulated pattern; tergites VII and VIII slightly sclerotized; 4 pairs of spiracles on each side of segments II–V. Siphunculi absent. Cauda transverse, not constricted at base, with 6–12 setae which are divided into 2 clusters on each side. Anal plate bilobed, with 5–11 setae each.

Material examined. Holotype, one alate viviparous adults, Hengchun Township, Pingtung Co., on D. racemosum , 29-vi-2006, H. T. Yeh (#491). One fundatrix, Hengchun Township, Pingtung Co., on D. racemosum , 9-x-2006, H. T. Yeh (#520). ( The individuals of holotype are marked by circles on the slide.)

Holotype-specimen deposition: NTU, Taipei, Taiwan.

Paratypes, 3 alate viviparous adults, Hengchun Township, Pingtung Co., on D. racemosum , 29-vi-2006, H. T. Yeh (#491)(NTU). 6 alate viviparous adults (on 2 microscope slides), Hengchun Township, Pingtung Co., on D. racemosum , 29-vi-2006, H. T. Yeh (#493)(NTU); 6 alate viviparous adults, Hengchun Township, Pingtung Co., on D. racemosum , 9-ix-2006, H. T. Yeh (#501)(NTU); 6 fundatrices, Hengchun Township, Pingtung Co., on D.

racemosum , 9-x-2006, H. T. Yeh (#520)(NTU); 6 fundatrices, Hengchun Township, Pingtung Co., on D. racemosum , on 18-xi-2006, H. T. Yeh (#559)( NTU) ; 3 alate viviparous adults, Hengchun Township, Pingtung Co., on D. racemosum , 25-ii-2007, H. T. Yeh (#582)( NTU) ; 23 alate viviparous adults (on 7 microscope slides), Hengchun Township, Pingtung Co., on D. racemosum , 24-iii-2007, H. T. Yeh (#586)( BMNH, NMNS, NTU, TARIIC) ; 6 alate viviparous adults, Yuanshan Township, Ilan Co., on D. racemosum , 1-vi-2007, H. T. Yeh (#593)(NTU); 3 alate viviparous adults, Hengchun Township, Pingtung Co., on D. racemosum , 26-v-2007, H. T. Yeh (#607)( NTU) ; 3 alate viviparous adults, Hengchun Township, Pingtung Co., on D. racemosum , 31-v-2008, H. T. Yeh (#681)( NTU) ; 9 alate viviparous adults, Xitou ( Lugu Township), Nantou Co., on D. racemosum , 20-iii- 2013, H. T. Yeh ( NTU) ; 6 alate viviparous adults, Xitou ( Lugu Township), Nantou Co., on D. racemosum , 24-v- 2013, H. T. Yeh ( NTU) ; 12 alate viviparous adults, Hengchun Township, Pingtung Co., on D. racemosum , 2-iv- 2017, H. T. Yeh ( NTU) . 7 alate viviparous adults, Yuanshan Township, Ilan Co., on Distyliopsis dunnii , 31-iii- 2007, H. T. Yeh (#591) (NTU); 3 alate viviparous adults & 1 fundatrix, Yuanshan Township, Ilan Co., on Distyliopsis dunnii , 8-vii-2007, H. T. Yeh (#619)(NTU).

Etymology. The species name ‘ formosana ’ is derived from the first-recorded place, Taiwan (‘Formosa’ is an old toponym of Taiwan).

Remarks. Incipient galls of T. formosana were found in early October, and each gall contained a fundatrix. The fundatrix existed in the gall from October until the following May, and its body was gradually puffed out, ultimately exceeding 2.5 mm in length. Alate viviparous adults, offspring of the fundatrix can be found from late February to early June in the galls. After all alates emigrated from the galls, a few first-instar larvae were observed walking around on the surfaces of the galls and leaves. We consider that these first-instar larvae ( Fig. 6A ) to be functionally sterile soldiers. The antennae of alate viviparous adults are usually divided into three segments, with a very long undivided flagellum (segment III). However several individuals (n=4) had one antenna that was four- segmented ( Fig. 6B ). Because the antennae of last instar nymphs are four-segmented ( Fig. 6C ), the antenna III and IV are fused together in the adult stage. For these reasons, we consider the three-segmented antennae of the alates is an apomorphic character state, which does not contradict our placement of T. formosana in the tribe, Nipponaphidini .

This species was first found to induce spindle-like galls on leaves of D. racemosum , opening on the underside of the leaf ( Fig. 3D, E ). Moreover, T. formosana was subsequently found to induce similar galls on leaves of Distyliopsis dunnii , which also belongs to Hamamelidaceae . The alates obtained from the two different hosts are not significantly different in morphology, and there is no doubt that the two belong to the same species. This is the first case of a single nipponaphidine species inducing galls on two primary hosts that belong to different genera. The size of mature galls on D. racemosum was 8.5–15.6 (average, 11.3) mm long and 4.0–8.1 (average, 5.8) mm in diameter, and that on Distyliopsis dunnii was 10.0–19.2 (average, 13.8) mm long and 4.2–9.4 (average, 6.5) mm in diameter. Several galls were formed on a single leaf.

Figures

FIGURE 3. Galls and morphology of Tripartita formosana sp. n.; (A) body, (B) head, and (C) abdomen of a fundatriX; (D) open, spindle-like galls on leaves of host plant; (E) the arroW indicates a fundatriX inside a gall.

FIGURE 4. Alate adult of Tripartita formosana sp. n. (A) Body, (B) abdomen, (C) head, and (D) Wings

FIGURE 5. Tripatita formosana sp. n. (A) Head, (B) anal plate (right) and cauda (left) of a fundatriX. (C) Head+antennae segments I, II, (D) antenna segment III, (E) Wings, (F) anal plate (right) and cauda (left) of an alate adult (Scale bar=0.2 mm.)

FIGURE 6. Tripartita formosana sp. n. (A) Presumed sterile soldier. (B) Alate adult With a 4-segmented antenna (C) Last instar nymph