CECHETRA MINOR (Butler, 1875) -- Lesser green hawkmoth

Female Cechetra minor. Photo: © NHMUK Male Cechetra minor. Photo: © NHMUK

TAXONOMY

Chaerocampa [sic] minor Butler, 1875, Proc. zool. Soc. Lond. 1875: 249. Type locality: [India, Uttar Pradesh,] Massuri [Mussoorie].

Synonym. Chaerocampa minor Butler, 1875.

Synonym. Theretra striata Rothschild, 1894.

Synonym. Cechenena minor Rothschild & Jordan, 1903.

Synonym. Cechenena minor olivascens (Mell, 1922).


ADULT DESCRIPTION AND VARIATION

Wingspan: 90--98mm. Similar to small specimens of more uniformly patterned Cechetra lineosa, but immediately distinguishable by the lack of a pale median dorsal band along the thorax. Forewing upperside with full complement of seven postmedian lines. Seven lines present in distal half of the wing but line 6 short and completely merged with 7, which is generally blacker posteriorly and somewhat undulating. Forewing underside ground colour orange-beige. Head, thorax and abdomen olive-brown; upperside of thorax lacking a pale medial band. Dorsal lines of abdomen less prominent than in Cechetra lineosa. Outer midtibial spur generally equal to the inner, but sometimes longer or shorter.

In the male genitalia, gnathos less triangular at tip than in Cechetra lineosa. Valve with large, asymmetrical stridulatory scales, proximal side of each enlarged, longitudinally folded or ribbed, darker than the distal side. Aedeagus almost symmetrical, apex rounded in dorsal view; the left process vestigial, with just a few teeth and no free projecting process; the right process somewhat widened at apically, dentate.


Adult Cechetra minor, Thailand. Photo: © Ian Kitching Adult Cechetra minor, Taiwan. Photo: © Felix Lin. Adult Cechetra minor, Jiucai Ling, Guizhou, China. Photo: © Viktor Sinjaev. Adult Cechetra minor (underside), Hangzhou, Zhejiang, China. Photo: © Tony Pittaway. Adult Cechetra minor, Hangzhou, Zhejiang, China. Photo: © Tony Pittaway.

ADULT BIOLOGY

A very nervous species, which will take flight on being disturbed or even if movement is detected nearby.


FLIGHT-TIME

China: iv (Guangdong); v-vii (Zhejiang); 11-25.vi (Hainan); 9.vii (Beijing); vii-viii (Sichuan; Fujian); viii-ix (Guangdong); ix (Shaanxi). Taiwan: iii-v (Kaohsiung Hsien); vi (Taipei).


EARLY STAGES

OVUM:

LARVA: Full-fed 85mm; width 11mm; horn 8mm. In the first instar, pale yellow with a long black horn. In the second instar, green with a long straight black horn. By the third instar, a very faint pale dorso-lateral stripe appears. There is an eye-spot on segment 5, blue in front, yellow behind. Horn long, base reddish, tip pure white, rest black with black tubercles. In the fourth instar, head green, body paler green with transverse rows of yellowish dots. There is a narrow dark green dorsal stripe from segment 2 to base of horn, and a dorso-lateral stripe from 2 to base of horn which is very pale bluish-green edged above with dark green. Eye-spot with pupil blue in front, green behind, edged broadly with yellow and narrowly with dark blue. Horn long, straight, cylindrical, thick at base and tapering evenly to a point, its surface shiny, basal half degraded reddish-brown becoming gradually darker, tip narrowly white (Bell & Scott, 1937).

In the fifth instar, very similar to that of Cechetra lineosa, but much paler. Head dull and smooth. Body dull and smooth. Eye-spot shiny as though enamelled; segment 5 swollen and both 4 and 5 somewhat dilated ventro-laterally. Horn of medium length, slightly flattened laterally, tapering slightly to a blunt point, down-curved; surface shiny and covered with bluntly pointed tubercles.

In colour, head brown dotted with paler brown. Body dorsal area coloured like the head, lateral area pinkish. There is a narrow black dorsal stripe on 2 to 5, and a broader dorso-lateral stripe from 2 to base of horn, this pale brown on anterior segments, nearly white on posterior segments, broken by the eye-spot on 5 and edged above with dark brown. Eye-spot with pupil deep indigo-blue dotted with yellow in the posterior half, edged narrowly with yellow and still more narrowly with black. There is a round whitish subdorsal spot in the posterior half of each of segments 6 to 11. Oblique lateral stripes are present on 6 to 10, these pale pink edged above with dark brown which shades into the body colour. These stripes reach the dorso-lateral stripe, that on 10 running across 11 and 12 to base of horn. Horn brown; legs reddish. Spiracles pink with a-brown suffusion on each side of the slit (Bell & Scott, 1937).

This species is very fond of mats of Cayratia japonica growing over shrubs in deep shade, particularly around woodland clearings (A.R. Pittaway, pers. obs. 2007). It is also a very nervous species, which will, in the final instar, go into a prolonged 'snake response' if disturbed, or if it detects movement nearby.


Third instar larva of Cechetra minor, Hangzhou, Zhejiang, China, 17.vii.2007. Photo: © Tony Pittaway. Part grown final instar larva of Cechetra minor, Hangzhou, Zhejiang, China, 17.vii.2007. Photo: © Tony Pittaway. Full grown larva of Cechetra minor, Hangzhou, Zhejiang, China, 19.vii.2007. Photo: © Tony Pittaway.

PUPA: 56mm; width 12mm. Head, thorax and wing-case dark brown. Broad dorsal stripe paler brown; tubercles on wing-case black; abdomen with a dark brown dorsal stripe, and a broader degraded ochreous stripe on each side of it. Lateral area dark grey with short whitish stripes. Spiracles black, those on segments 6 to 12 lying on a larger black patch; cremaster black. Tongue-case projecting considerably frontad (6mm), but not so much as in Cechetra lineosa. Antenna slightly longer than fore leg, which reaches to beyond middle of wing-ease; mid-leg to three-quarters length of wing-case. Surface dull, head and thorax slightly shagreened; wing-case with lines of pointed tubercles along the veins. Cremaster nearly equilaterally triangular, tip squarely truncate; a long thin spine at each lateral angle of the truncation and a short spine midway between them, all straight and pointing directly backward. From the base of each of the longer spines a spine of equal length, bifid at the tip, projects directly outwards; a dorso-lateral spine with three or four points near base; all the spines polished and shiny. Upperside of cremaster rugose, underside deeply hollowed (Bell & Scott, 1937).

The pupae obtained in the Khasi Hills of India were similar to the above, except for the cremaster in which the long terminal spines were curved inwards instead of being straight, and the dorso-lateral spine was replaced by a simple steel-blue pointed spine. The cremaster of the pupae obtained by Mell in southern China agrees with that of those from the Khasi Hills. The difference may be individual or may point to the existence of two subspecies (Bell & Scott, 1937).


Pupa of Cechetra minor. Image: Mell, 1922b Pupa of Cechetra minor. Image: Mell, 1922b Pupa of Cechetra minor (lateral view), Hangzhou, Zhejiang, China. Photo: © Tony Pittaway. Pupa of Cechetra minor (ventral view), Hangzhou, Zhejiang, China. Photo: © Tony Pittaway. Pupa of Cechetra minor (dorsal view), Hangzhou, Zhejiang, China. Photo: © Tony Pittaway.

Larval hostplants. Saurauia pundiana, Vitis and Amorphophallus in India (Bell & Scott, 1937). In Zhejiang, China, Cayratia japonica is the main host (Pittaway, pers. obs. 2007).


Cayratia japonica, Hangzhou, Zhejiang, China. Photo: © Tony Pittaway.

PARASITOIDS


LOCAL DISTRIBUTION

China: Beijing (Baihua Shan); Shaanxi (Xunyang, 1380m); Anhui (Mt. Huang Shan); Zhejiang (Tianmu Shan; Hangzhou); Hubei (Badong); Sichuan (Emei Shan, 3620'; Daxue Shan, Luhuo); Yunnan (Yanmen); Guizhou (Jiucai Ling); Hunan (Dayong); Fujian (Guangze, 1200m; Longqi Shan); Guangdong (Longtou Shan; Wanzishan, Deqing; Dongguan); Hainan (Duowen Ling, nr Lingao).

Taiwan: Taipei (Sindian); Taipei Hsien (Fushan); Kaohsiung Hsien (Shanping, 640m).

Japan: Kyushu; Okinawa.


GLOBAL DISTRIBUTION

Northern India, Nepal, Bhutan, Thailand, eastern and southern China, Taiwan, southern Japan, Vietnam.


Global distribution of Cechetra minor. Map: © NHMUK.

BIOGEOGRAPHICAL AFFILIATION



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© A.R. Pittaway & I.J. Kitching (The Natural History Museum, London)