ACOSMERYX SERICEUS (Walker, 1856) -- Silky forest hawkmoth

Female Acosmeryx sericeus. Photo: © NHMUK Male Acosmeryx sericeus. Photo: © NHMUK

TAXONOMY

Philampelus sericeus Walker, 1856, List Specimens lepid. Insects Colln. Br. Mus. 8: 181. Type locality: [Bangladesh,] Sylhet.

Synonym. Philampelus sericeus Walker, 1856.

Synonym. Acosmeryx anceoides Boisduval, 1875.

Synonym. Acosmeryx sericeus rufescens Mell, 1922.


ADULT DESCRIPTION AND VARIATION

Wingspan: 96--106mm. Forewing with outer margin dentate. Forewing upperside general background colour violaceous-grey, with the brown lines more prominent than in other species of the genus; first discal line well-marked, running straight from vein M3 to the hind margin, merging anteriorly with an oblique line that reaches the outer margin just anterior to the hind angle; a grey submarginal band ends at or just beyond vein M3. Hindwing upperside with an indistinct brown discal line, distal to which is an equally indistinct, slightly tawny, paler band. Hindwing underside with conspicuous white scaling at costal margins, between the lines. Metanotum chocolate-tawny at sides. Abdomen upperside with chestnut brown markings of tergites prominent. Underside of abdomen, most of hindwing. and the disc of forewing along the marginal band bright tawny. Antenna shorter in male than in Acosmeryx naga naga.

In the male genitalia, gnathos widest in middle. Harpe with process more rounded distally than in Acosmeryx naga naga, with the ventral ridge higher and not dentate. Phallus with left process broad.


Male Acosmeryx sericeus, Daman, Bagmati Province, Nepal, 2600ml, bred ix.2024, leg. Serge Yevdoshenko. Photo: © Tony Pittaway. Adult Acosmeryx sericeus, Thailand. Photo: © Ian Kitching Adult Acosmeryx sericeus, Bukit Fraser, Malaysia. Photo: © CheongWeei Gan.

ADULT BIOLOGY

A nocturnal species. Emerges from the pupa in the dead of night and takes flight a few hours later. If disturbed during the day it will drop to the ground and scurry around like a mouse until it finds some dead leaves to hide amongst.


FLIGHT-TIME

China: vi (Yunnan); 2-17.vii (Xizang/Tibet); 24.vii (Hong Kong).

Kendrick (2002) states that it is multivoltine in Hong Kong, occurring from March until December, with a peak from June to September.


EARLY STAGES

OVUM:

LARVA: Full-fed 75--90mm.


Final instar green form larva of Acosmeryx sericeus. Image: Mell, 1922b Final instar pre-pupation form larva of Acosmeryx sericeus. Image: Mell, 1922b Final instar larva of Acosmeryx sericeus. Photo: Mell, 1922b

PUPA:


Pupa of Acosmeryx sericeus. Image: Mell, 1922b Pupa of Acosmeryx sericeus. Image: Mell, 1922b Pupae of Acosmeryx sericeus, Daman, Bagmati Province, Nepal, 2600m, viii.2024, leg. Serge Yevdoshenko. Photo: © Tony Pittaway.

Larval hostplants. Actinidia and Vitis (Inoue, Kennett & Kitching, [1996] 1997).


PARASITOIDS


LOCAL DISTRIBUTION

China: Yunnan (Laojun Shan, 2579m; Hekou; Gaoligong Shan); Xizang/Tibet (Xiachayu, Zayu County); Guangxi; Guangdong (Guangzhou; Dongguan); Hong Kong (Shek Kong); Hainan.


GLOBAL DISTRIBUTION

Nepal, Bhutan (Irungbam & Irungbam, 2019), northeastern India, Bangladesh, Thailand, southern China, Vietnam (Le & Vu, 2024) and Malaysia (Peninsular).


Global distribution of Acosmeryx sericeus. Map: © NHMUK.

BIOGEOGRAPHICAL AFFILIATION



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