Citation: Lee W, Kanbe T, Akimoto S-i (2014) A new species of Megoura (Hemiptera, Aphididae) from Japan. ZooKeys 417: 37–44. doi: 10.3897/zookeys.417.7167
A new species of the genus Megoura, M. lathyricola sp. n., was collected from Lathyrus japonicus subsp. japonicus (Leguminosae) in seashore areas of northern and southern Japan. This species is described and illustrated, and a revised key to the identification of the world species of Megoura is presented.
Macrosiphini, Megoura, Lathyrus japonicus subsp. japonicus, new species
The genus Megoura Buckton 1876, nested within the tribe Macrosiphini of the subfamily Aphidinae (
Until now, three species of the genus Megoura have been reported from Japan; Megoura crassicauda, Megoura lespedezae, and Megoura brevipilosa. Recently, we collected a macrosiphine aphid species from the leguminous plant Lathyrus japonicus subsp. japonicus, in Hokkaido (northern Japan) and Nagasaki Prefecture (southern Japan). This species has morphological characters in common with the genus Megoura, such as swollen siphunculi, smooth head, and antenna approximately as long as body (
The present paper describes this new species, and provides a revised key to species of Megoura of the world.
Aphid samples for this study were collected in 2012 on Lathyrus japonicus subsp. japonicus in Japan. Each sample of aphid colonies was preserved in 80% alcohol, and mounted specimens were prepared in Canada balsam, following methods by
Abbreviations used for descriptions and table are as follows: al. – alate viviparous female, alata; apt. – apterous viviparous female, aptera; Ant. – antennae; Ant.I, Ant.II, Ant.III, Ant.IV, Ant.V, Ant.VI, and Ant.VIb – antennal segments I, II, III, IV, V, VI, and base of VI, respectively; BDAnt.III – basal diameter of antennal segment III; BL – length of body; GP – genital plate; 2HT – second segment of hind tarsus; PT – processus terminalis; SIPH – siphunculi; URS – ultimate rostral segment (segment IV + V).
http://zoobank.org/2B8624A7-184C-438C-B439-779B72966F5B
Figs 1, 2, Table 1Apterous viviparous female, Coll#.120605WH26/ap.1, Muroran, Hokkaido, Japan, 05.vi.2012, leg. Wonhoon Lee, on Lathyrus japonicus subsp. japonicus.
9 apterous viviparous females and 2 alate viviparous females, same data as for holotype; 5 apterous viviparous females, Coll#.120309WH16, Nagasaki, Nagasaki prefecture, Japan, 09.iii.2012, leg. Wonhoon Lee, on Lathyrus japonicus subsp. japonicus.
The type specimens, including holotype and paratypes, are deposited in the Laboratory of Systematic Entomology, Graduate School of Agriculture, Hokkaido University, Japan.
The specific epithet is composed of the root of the plant genus (lathyr) and the lexeme “col” that, in this case, means ‘living on’.
(Figs 1A–H, 2A) Color alive: Head yellowish brown with antennae dark brown, thorax and abdomen pale green. Legs pale yellowish brown except distal 1/9 of tibiae including tarsi dark brown. SIPH dark brown. Cauda pale. Color of macerated specimens: Head yellowish brown and antennae dark brown. Rostrum pale, except the tip of URS dark brown. Thorax yellowish brown and abdomen entirely pale. Legs pale except distal 1/9 of tibiae and tarsi dark brown. SIPH dark brown and cauda pale except extreme end. Morphology: Body spindle shaped. Head: smooth on ventrum and dorsum including three pairs of acuminate setae. Antennal tubercle well developed with 3–5 setae on both side, frons U–shaped with four setae on vertex, including weakly developed median tubercle. Ant.I smooth; Ant.II granulate; Ant.III weakly imbricate with short setae, bearing 40–59 secondary rhinaria irregularly spaced; Ant.IV imbricate with 12–18 setae with no secondary rhinaria; Ant.V imbricate with 8–13 setae, primary rhinarium ciliate, longest diameter of which is shorter (0.63–0.83 times) than middle width; Ant.VI imbricate with 3–7 short setae on Ant.VIb. Rostrum attaining posterior margin of mesocoxa; mandibular laminae with 4–6 setae on each side; URS longest seta 0.78–1.00 times as long as apical primary ones. Thorax: pronotum smooth with two spinal setae and one marginal seta on anterior margin. Hind coxa weakly spinulose with 6–7 acuminate setae; hind trochanter wide at base, 1.63–1.65 times as long as apical width, bearing three setae; hind femur smooth on basal 1/17, spinulose on apical 16/17 ventrally, bearing short setae, longest seta 0.43–0.48 times as long as basal width of segment; hind tibia smooth, longest seta 0.80–1.07 times as long as middle width of segment; first segment of each tarsus smooth with three setae at apex; 2HT imbricate with 10–11 setae. Abdomen: dorsum smooth, membranous with 11–13 setae on tergite III, 0.37–0.47 times as long as basal width of hind femur. SIPH swollen, weakly spinulose except smooth base, irregularly reticulated on distal end, apex flanged. Cauda elongate, triangular, ventral spinules strong and dense, in groups of one or two; dorsal ornamentation composed of ribbed imbrication.
Apterous viviparous female (A–H) and Alate viviparous female (I–P) of Megoura lathyricola sp. n.: A whole body of apterous vivipara B siphunculus C hind tibia and tarsus D antennal segments III–IV E antennal segments V–VI F head focused on dorsum G ultimate rostral segment H cauda I whole body of alate vivipara J siphunculus K hind tibia and tarsus L antennal segments III–IV M antennal segments V–VI N head focused on dorsum O ultimate rostral segment P cauda.
Photographs of Megoura lathyricola sp. n. and host plant: A apterous viviparous female B alate viviparous female C Lathyrus japonicus subsp. japonicus.
(Figs 1I–P, 2B) Color alive: Head, antennae and thorax black, abdomen pale green. Abdomen with black patches on tergites III–VI. Legs pale yellowish brown except distal 1/2 of femora and distal 1/9 of tibiae including tarsi dark brown. SIPH dark brown. Cauda pale. Color of macerated specimens: Head, antenna, and thorax dark brown. Legs pale except dark distal 1/2 of femora, 1/9 of tibiae and tarsi. Abdomen with marginal sclerites on II–VI segments. SIPH and Cauda dusky. Wings pale with veins bordered by narrow dark pigmentation. Morphology: Antennae with 60–62 secondary rhinaria irregularly scattered on whole of Ant.III, and 20–32 secondary rhinaria scattered on whole of Ant.IV. Cauda triangular, pointed at apex. SIPH strongly imbricate. Otherwise like apterous viviparous female.
So far collected and observed only on Lathyrus japonicus subsp. japonicus in Muroran, Hokkaido and Nagasaki, Japan. This plant is distributed only in seashore areas.
This species seems to be rare. Colonies were observed on stem and young leaves of host plants. In nature it appears to be specific to Lathyrus japonicus. However a clonal lineage from Nagasaki was readily reared in the laboratory of Systematic Entomology, Hokkaido University under long day conditions by using broad bean seedlings as a host. When the clone was reared at 15 °C and 8L16D, it produced viviparae but no sexual morphs, suggesting that the Nagasaki population of this species is anholocyclic.
Biometric data of Megoura lathyricola sp. n.
Part | Apterous vivipara (n=10) | Alate vivipara (n=2) | |
---|---|---|---|
Range(Mean) | Range(Mean) | ||
Length (mm) | BL | 4.06–4.47(4.30) | 4.13–4.86(4.49) |
Whole antennae | 4.11–4.75(4.40) | 4.62–4.91(4.76) | |
Ant.I | 0.20–0.24(0.22) | 0.22–0.26(0.24) | |
Ant.II | 0.11–0.16(0.14) | 0.13–0.16(0.14) | |
Ant.III | 1.09–1.26(1.18) | 1.22–1.28(1.25) | |
Ant.IV | 0.65–0.90(0.80) | 0.91–0.96(0.93) | |
Ant.V | 0.70–0.78(0.74) | 0.75–0.82(0.75) | |
Ant.VIb | 0.22–0.30(0.27) | 0.27–0.35(0.31) | |
PT | 1.01–1.12(1.04) | 1.03–1.20(1.11) | |
URS | 0.13–0.15(0.14) | 0.13–0.14(0.14) | |
Hind femur | 1.38–1.58(1.48) | 1.53–1.59(1.56) | |
Hind tibia | 2.50–2.78(2.60) | 2.72–2.81(2.78) | |
2HT | 0.16–0.21(0.19) | 0.19–0.20(0.19) | |
SIPH | 0.60–0.73(0.68) | 0.58–0.66(0.62) | |
Cauda | 0.56–0.66(0.62) | 0.54–0.57(0.55) | |
Setae on Ant.III | 0.03–0.06(0.05) | 0.04–0.05(0.05) | |
No. of hairs on | Mandibular lamina. | 4–6(5) | 5–6(6) |
Ant.I | 9–18(13) | 10–12(11) | |
Ant.II | 5–7(6) | 5–5(5) | |
Ant.III | 22–33(26) | 20–25(22) | |
URS (subsidiary) | 6–6(6) | 6–6(6) | |
Abdominal tergite VI between SIPH | 5–7(6) | 6–6(6) | |
Abdominal tergite VIII | 6–7(6) | 6–6(6) | |
Median of genital plate | 2–2(2) | 2–2(2) | |
Posterior margin of genital plate | 17–21(19) | 18–18(18) | |
Cauda | 10–13(12) | 13–14(14) | |
No. of Rhinaria on | Ant.III | 40–59(48) | 60–62(61) |
Ant.IV | 0 | 20–32(25) | |
Ratio (times) | Whole Antennae / BL | 0.96–1.06(1.02) | 1.00–1.13(1.06) |
PT / Ant.VIb | 3.50–4.75(3.85) | 3.41–3.80(3.58) | |
PT / Ant.III | 0.83–0.95(0.88) | 0.84–0.95(0.89) | |
URS / 2HT | 0.67–0.82(0.75) | 0.69–0.76(0.73) | |
URS / Ant.VIb | 0.43–0.64(0.52) | 0.39–0.53(0.46) | |
SIPH / BL | 0.14–0.16(0.16) | 0.12–0.16(0.14) | |
SIPH / Ant.III | 0.47–0.64(0.58) | 0.46–0.54(0.50) | |
SIPH / Hind femur | 0.39–0.50(0.46) | 0.37–0.43(0.40) | |
SIPH / Cauda | 1.00–1.16(1.09) | 1.08–1.15(1.12) | |
Cauda / Width of cauda | 1.92–3.03(2.49) | 2.10–2.23(2.17) |
1 | Median cephalic frontal tubercle well developed, and Ant.III with no secondary rhinaria. Cauda with 5–7 hairs. On the genus Carmichaelia. In New Zealand | Megoura stufkensi |
– | No median cephalic frontal tubercles, and Ant.III with 0–64 secondary rhinaria. Cauda with more than 10 hairs | 2 |
2 | Cauda dark brown or black. On the genus Vicia or Lathyrus | 3 |
– | Cauda pale yellow. Not on the genus Vicia | 5 |
3 | Body totally dark brown or black in life. Tibia pale yellow except apical 1/5. URS 0.88–1.00 times as long as 2HT. Ant.I, mandibular lamina, abdominal tergite III, and GP with 13–20, 6–8, 16–21, and 24–33 hairs, respectively. Ant.III with 28–67 secondary rhinaria. On the genus Vicia (Leguminosae). In Korea | Megoura nigra |
– | Body green except antenna, legs, SIPH, and cauda black in life. Tibia black or dark brown. URS 0.63–0.87 times as long as 2HT. Ant.I, mandibular lamina, abdominal tergite III, and GP with 8–15, 4–5, 15–18, and 14–23 respectively. Ant.III with 5–42 secondary rhinaria | 4 |
4 | Ant.III with more than 20 secondary rhinaria which are scattered irregularly over two–thirds of, or throughout the segment. SIPH as long as or longer than cauda. On the genera Vicia, Lathyrus, Amphicarpaea, and Pisum (Leguminosae). In Japan, China, India, Korea, Russia (Siberia), and Taiwan | Megoura crassicauda |
– | Ant.III with less than 20 secondary rhinaria which are situated on basal half or two–thirds, in a line. SIPH shorter than cauda. On the genera Vicia and Lathyrus (Leguminosae). In Europe, Central Asia, Middle East, and Ethiopia | Megoura viciae |
5 | All legs pale, except that apices of tibiae and tarsi are pale brown | 6 |
– | Legs dark brown, or at least fuscous on distal half of femora and tibiae | 7 |
6 | SIPH 0.67–0.95 times as long as cauda. Ant.III with 6–21 secondary rhinaria. PT 2.70–3.70 times as long as Ant.VIb. On the genus Lathyrus (Leguminosae). In Denmark, Finland, Germany, Norway, Poland, and Sweden | Megoura litoralis |
– | SIPH 1.00–1.16 times as long as cauda. Ant.III with 40–59 secondary rhinaria, PT 3.50–4.75 times as long as Ant.VIb. On Lathyrus japonicus subsp. japonicus (Leguminosae). In Japan | Megoura lathyricola sp. n. |
7 | URS 0.89–1.17 times as long as 2HT and 0.68–0.88 times as long as Ant.VIb. Antennal tubercle weakly developed. Frons more than twice as wide as median depth. Antenna 0.83–0.94 times length of body. SIPH 1.07–1.31 times as long as Ant.III. On the genera Lespedeza, Cajanus, Desmodium, and Indigofera (Leguminosae). In Japan, China, India, Korea, Siberia, Switzerland, and Taiwan | Megoura lespedezae |
– | URS 0.71–0.83 times as long as 2HT and 0.47–0.54 times as long as Ant.VIb. Antennal tubercle well developed. Frons V–shaped, as wide as median depth. Antenna at least 1.3 times length of body. SIPH shorter than Ant. III | 8 |
8 | Cauda about 0.50 times as long as SIPH. SIPH with narrow base, basal diameter shorter than middle diameter. Hairs on Ant.III about 0.50 times as long as BDAnt.III. On the genera Indigofera, Hedysarum, and Tephrosia (Leguminosae). In Afghanistan, India, Kashmir, Pakistan, and Thailand | Megoura dooarsis |
– | Cauda more than 0.7 times as long as SIPH. SIPH widest at base. Hair on Ant.III 0.25 times as long as BDAnt.III. On the genus Lespedeza (Leguminosae). In Japan and Korea | Megoura brevipilosa |
This research was financially supported by Grants–in–Aid for Scientific Research (No. P.11079 for Postdoctoral Fellowship for Foreign Researchers, No. 20570011 and No. 23370037) from the Japan Society for the Promotion of Science.