ACOSMERYX Boisduval, [1875]

Acosmeryx Boisduval, [1875], in Boisduval & Guenée, Hist. nat. Insectes (Spec. gen. Lepid. Heteroceres) 1: 214.

Type species: Sphinx anceus Stoll, 1781.

A genus containing eight to ten species from the Oriental, Australasian and eastern Palaearctic regions. One penetrates the western Palaearctic.

IMAGO: Upperside of wings predominantly brown and grey, the markings forming a tessellated pattern; outer margin of forewing serrate, sinuate between veins R4 and R5. Antennae rod-like, with terminal segment very long, filiform and rough-scaled. No eyelashes. Labial palpus large, rounded in side-view. Spines of abdomen numerous, the short ones pale, rather weak, the long ones stronger. Eighth tergite deeply sinuate, separate from sternite. Hindtibia with two pairs of spurs, the proximal spur twice as long as the distal.

Genitalia. In male, uncus simple, long, slender, slightly curved; gnathos shorter, broader, somewhat boat-shaped, with apex always sinuate. Valva large, sole-shaped, with three or four rows of large friction scales. Sacculus dilated at end, the dilated part armed with spine-like teeth which are directed upwards. Aedeagus with a dentate lobe on left side, continuous with a slender, acute process at right side. In the female, lamella postvaginalis suddenly narrowed distally; ostium bursae transverse, postmedian, sometimes covered with a bilobate ridge.

OVUM: Ovoid, smooth, shiny green.

LARVA: Head small, body tapering forward from the first abdominal segment, thoracic segment 3 and abdominal segment 1 with ventro-lateral flanges; horn of medium length, erect but sharply curved. Dorso-lateral longitudinal line present. Thoracic segments dark ventrally.

PUPA: Proboscis fused with body; abdominal segment 7 deeply undercut around its posterior margin; cremaster thick and short with a pair of apical spines, or extended into a shaft (Acosmeryx naga Moore, 1857).

HOSTPLANT FAMILIES: Climbers and ramblers of the Vitaceae, Actinidiaceae and Dilleniaceae.


ACOSMERYX NAGA (Moore, 1857)


ACOSMERYX NAGA HISSARICA Shchetkin, 1956

GB: Naga Hawkmoth, RU: Gissarskii vinogradnyi Brazhnik

Acosmeryx naga hissarica Shchetkin, 1956, Soobshch. Akad. Nauk tadzhik. SSR (19): 24--27.

Type locality: Vakhsh Valley, Gissar Mountains, Tajikistan.


BIOGEOGRAPHICAL AFFILIATION

Holarctic; western Palaearctic region. Pleistocene refuge: Monocentric -- northern section of Sindian refuge.


ADULT DESCRIPTION AND VARIATION

Male Acosmeryx naga hissarica, Kabul, Afghanistan. Male Acosmeryx naga hissarica, Tigrovaja Balka Reserve, Tajikistan.

Wingspan: 82--103mm. The most obvious feature which separates this from the nominate subspecies is the form of the dark brownish bar which stretches from the forewing costa, along vein M2, towards the centre of the outer margin. In Acosmeryx naga naga this is straight, in Acosmeryx naga hissarica it is noticeably arched. The primary body colour in subsp. hissarica is also greyer and lighter in appearance than in subsp. naga.


Male Acosmeryx naga hissarica, Afghanistan. Photo: © C. M. Naumann.

ADULT BIOLOGY

Occurs in cultivated as well as uncultivated mountain valleys and ravines. Along the southern slopes of the Gissar Mountains of Tajikistan (Shchetkin, 1956) it is confined to damp locations in gorges at 1100--1700m which support wild stands of Juglans regia (walnut) and Acer turkestanicum (Turkestan maple) overgrown with wild Vitis vinifera (grape vines). In Afghanistan it occurs at 1500--2500m (Daniel, 1971).


FLIGHT-TIME

Bivoltine; late April to June, and again in late July (Ebert, 1969; Daniel, 1971; Derzhavets, 1984).


EARLY STAGES

OVUM: Size unrecorded; almost spherical, smooth, a deep rich green, becoming whitish before hatching (Bell & Scott, 1937).

LARVA: Full-fed 70-90mm. Dimorphic: green or brown.


Full-grown larva of Acosmeryx naga naga on Actinidia, Gusevskiy mine, near Zanadvorovka village, Khasansky District, Primorskiy Kray, Russian Far East; 18.vii.2010. Photo: © Anton Kozlov. Full-grown larva of Acosmeryx naga naga. Image: © Tony Pittaway.

According to Bell & Scott, 1937, in the first instar, the head and body are green, the horn black, long and straight. In the second instar, thoracic segment 1 is as narrow as the head, with the body tapering sharply anteriorly from the first abdominal segment. The black horn is still long and straight, but reddish at the base and with a white tip. The head and anal segments are yellow, the body green dotted with white, with the spiracle of abdominal segment 1 surrounded by a black spot. A yellow dorso-lateral stripe runs from the head to the horn. This colour pattern remains the same for the next two instars, but a lateral flange develops on the third thoracic and first abdominal segments and a yellow ventro-lateral stripe appears on the thoracic segments and abdominal segment 1. In the final instar of the green form, the head is grass-green, with a narrow, pale yellowish dorso-lateral stripe and a broader stripe of the same colour separating face from cheek; thoracic segments 1 and 2 grass-green with short darker stripes; the rest of the body bluish green, mottled with yellow above the dorso-lateral stripe and pale greyish blue below. The dorso-lateral stripe is narrow and white on thoracic segments 1 and 2, broader and pale yellow on thoracic segment 3 and abdominal segment 1, then white to the base of the horn, and edged narrowly above with orange on segments 3--7. The narrow, white ventro-lateral stripe on thoracic segments 1 and 2 becomes broad and yellow as it outlines the flange before turning upwards on abdominal segment 1 to form an oblique stripe. There are also pale yellow, oblique lateral stripes on segments 1--7. The horn is lilac-grey dotted with purple. There are dark purple patches on the body above the bases of the legs, increasing in size caudally, and extending along the lower edge of the flange on thoracic segment 3 and abdominal segment 1. Upper part of prolegs bluish, the lower part pale yellow; feet brown, anal clasper bluish, anal flap edged broadly with pale yellow. Spiracles deep orange. In the brown form the green pigmentation is replaced by pinkish brown. The whole body is smooth and moderately shiny.

At rest on the underside of a leaf or stem, the larva throws back its head and anterior segments in a sharp curve, the head held so that the face is in the same plane as the dorsum of thoracic segment 1. The thoracic legs are pressed close to the body and the flange is dilated laterally. As in Clarina kotschyi (Kollar, [1849]), which it closely resembles, the alarmed larva withdraws the head and first two thoracic segments into segment 3; unlike Clarina kotschyi, thoracic segment 3 and abdominal segment 1 are puffed out and the flanges further dilated.

Occurs from June until September.

Major Hostplants. Vitis and Ampelopsis (both Vitaceae). On Vitis vinifera in Kabul, Afghanistan (Daniel, 1971).

Minor Hostplants. Actinidia and Saurauia (both Actinidiaceae).

PUPA: 44--55mm. Very similar in shape to Clarina but dark brown with the hind margin of abdominal segment 7 deeply undercut. Between the frons and the proboscis, there is a knobbly pentagonal sclerite. Abdomen marked with dark pits and stripes. Cremaster small, basal half bulbous, distal half a cylindrical shaft ending in two small hooks. Formed in a slight cocoon on the ground. Very sensitive to desiccation (Shchetkin, 1956), but highly tolerant of moisture. The overwintering stage.


Pupa of Acosmeryx naga naga. Image: Mell, 1922b Pupa of Acosmeryx naga naga. Image: Mell, 1922b

PARASITOIDS

None recorded.


DISTRIBUTION

As subsp. hissarica, only the Gissar Mountains of southern Tajikistan (Shchetkin, 1949; Shchetkin, 1956; Derzhavets, 1984) and Afghanistan (Ebert, 1969; Daniel, 1971; C. M. Naumann, pers. comm.). According to Shchetkin (1956), Acosmeryx naga hissarica may be an arcto-tertiary relict (along with numerous plants ) which developed in the western Tian Shan and which has since spread to Afghanistan, where it has come into contact with the nominate subspecies, which spread from the east. However, a more plausible explanation is that subsp. hissarica is of Pleistocene origins, having evolved in the Sindian refuge, from whence it spread as far northwestwards as the present-day climate would allow. This refuge has been important in the evolution of several other sphingid species and subspecies, most notably Hemaris rubra Hampson, [1893], Hyles nervosa (Rothschild & Jordan, 1903) and Deilephila rivularis (Boisduval, [1875].

Extra-limital range. None.


OTHER SUBSPECIES

As subsp. naga (Moore, [1858]), from the Himalayan foothills of Pakistan, India and Nepal (Haruta, 1992) across southern and eastern China (Bell & Scott, 1937) to Taiwan, Korea and Japan (D'Abrera, 1986). Also Burma/Myanmar, Thailand, Laos, Vietnam (Sa Pa) and Peninsular Malaysia. Several migrants have been reported from the Russian Far East since 2002-2003; it may even have established a resident population southeast of Ussuriisk (Dubatolov, pers. comm. 2013).

[It should be noted that some of the individuals of this subspecies recorded from southern China and northern Vietnam may, in fact, be the newly-described Acosmeryx purus Kudo, Nakao & Kitching, 2014.]


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