ANTHERAEA PERNYI (Guérin-Méneville, 1855) -- Chinese Oak Silkmoth


ANTHERAEA PERNYI PERNYI (Guérin-Méneville, 1855)

Bombyx pernyi Guérin-Méneville, 1855, Revue Mag. Zool. (2)7: 296.

Type locality: Northern China.


BIOGEOGRAPHICAL AFFILIATION

Holarctic; eastern Palaearctic region. Pleistocene refuge: Monocentric -- Manchurian refuge. Introduced elsewhere.


ADULT DESCRIPTION AND VARIATION

Wingspan 110--152mm. The similarly marked and coloured sexes are unlike any other european saturniid except the introduced Antheraea yamamai, but it can easily be distinguished from that species in having the solid elongated black spot on the outer margin of the hindwing eyespot invaded by yellow. In males, the forewings are distinctly falcate.

This species is not very variable in colour, unlike Antheraea yamamai, with individuals differing little from the typical fawn colour of the male illustrated below; however, a chocolate-brown melanic form is known -- f. hartii Moore.


Male Antheraea pernyi, China. Photo: © Tony Pittaway.

ADULT BIOLOGY

A nocturnal species which frequents deciduous and evergreen forests dominated by oaks (Quercus).

Most adults emerge in the late morning, but few females call that same night. Pairing usually takes place just before midnight on the second night and lasts for about 24 hours. The female then clambers around laying eggs in clusters on the nearest leaves. The reason for this odd behaviour is that most females carry too many eggs at first and are 'bottom-heavy'. This stop-start process continues until about 30 eggs have been deposited. The rest of the eggs are laid on the wing over a larger area.

Both sexes of this species are readily attracted to light and can be found by day 'resting' on posts and walls below these.


FLIGHT-TIME

Mainly May and August as two generations.


EARLY STAGES

OVUM: Round to slightly oval, dorso-ventrally flattened, 2.6 x 2.5mm, china-white with brown gum. Laid in clusters of up to five on the leaves of the host, hatching 10--14 days later.

LARVA: Full-fed 80--90mm. Monomorphic.


First instar larva of Antheraea pernyi, Changyan, Hubei, China. Photo: Mark Boddington. Second instar larva of Antheraea pernyi, Changyan, Hubei, China. Photo: Mark Boddington. Third instar larva of Antheraea pernyi, Changyan, Hubei, China. Photo: Mark Boddington. Fourth instar larva of Antheraea pernyi, Changyan, Hubei, China. Photo: Mark Boddington. Full-grown larva of Antheraea pernyi, Changyan, Hubei, China. Photo: Mark Boddington.

The newly-hatched, 5mm long larvae are basically dull black with a glossy, dull orange head. The tubercles are also black, with several white setae. From the second instar the larvae are very similar to those of Antheraea yamamai, except for a raw sienna to fawn coloured head, which bears five dark spots on each lobe of the face.

Newly emerged larvae take some days to settle down under a leaf. From the third instar onwards many larvae exhibit a kind of 'wanderlust', feeding at one spot for about four days before wandering off along the branches to a new location. This may be a survival strategy, for in it's latter stages great quantities of foliage are consumed -- the stout and compact larvae rely on cryptic coloration for concealment as they hang among a leaf cluster.

Hostplants. Oaks (Quercus spp.) are preferred; however, it can also be found on beech (Fagus sylvatica), sweet chestnut (Castanea sativa), birches (Betula), hawthorns (Crataegus), hornbeams (Carpinus), Prunus and several other trees and shrubs.

PUPA: 35--45mm. Cylindrical, but tapering towards both ends -- mahogany-brown. Formed in a tight, hard, egg-shaped, single, sealed, buff, 50 x 25mm cocoon with a loose greyish outer wrap -- the source of Tussore silk. This is spun up in a cluster of leaves and twigs, and is fixed to the nearest twig by a silk peduncle. The adult breaks out of this by softening and partially dissolving one end. The overwintering stage.


PARASITOIDS

Eupelmidae: Eupelmus sp.


DISTRIBUTION

An introduced species whose natural home is the eastern Palaearctic region. It can now be found in Europe in northeastern Spain near Barcelona, and on the Balearic Islands (Majorca).

Extra-limital range. The Russian Far East (Izerskiy, 1999a), eastern and central China and Korea. Introduced into Japan (Honshu and Kyushu).


OTHER SUBSPECIES

Two, namely korintjiana Bouvier and roylei Moore, which occur in northern India and South East Asia.



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