''Samia cynthia'', the ailanthus silkmoth, is a saturniid moth, used to produce silk fabric but not as domesticated as the silkworm, ''

Bombyx mori The domestic silk moth (''Bombyx mori''), is an insect from the moth family Bombycidae. It is the closest relative of ''Bombyx mandarina'', the wild silk moth. The silkworm is the larva or caterpillar of a silk moth. It is an economically imp ...

''. The moth has very large wings of , with a quarter-moon shaped spot on both the upper and lower wings, whitish and yellow stripes and brown background. There are eyespots on the outer forewings. The species was first described by

Dru Drury Dru Drury (4 February 1724 – 15 December 1803) was a British collector of natural history specimens and an entomologist. He had specimens collected from across the world through a network of ship's officers and collectors including Henry Sme ...

in 1773.

Eri silk

The common name, ailanthus silkmoth, refers to the host plant ''

Ailanthus ''Ailanthus'' (; derived from ''ailanto,'' an Ambonese word probably meaning "tree of the gods" or "tree of heaven") is a genus of trees belonging to the family Simaroubaceae, in the order Sapindales (formerly Rutales or Geraniales). The genus ...

''. There is a subspecies, ''S. cynthia ricini'' in India and Thailand that feeds upon the leaves of

castor bean ''Ricinus communis'', the castor bean or castor oil plant, is a species of perennial flowering plant in the spurge family, Euphorbiaceae. It is the sole species in the monotypic genus, ''Ricinus'', and subtribe, Ricininae. The evolution of ca ...

, and is known for the production of

eri silk Eri silk (Khasi'': Ryndia)'' is the product of the domesticated silkworm '' Samia ricini'', found mainly in North East India and some part of China and Japan. It was imported to Thailand in 1974. The name "eri" is derived from the Assamese word ...

, and is often referred to by the common name eri silkmoth. The eri silk worm is the only completely domesticated silkworm other than ''Bombyx mori''. The silk is extremely durable, but cannot be easily reeled off the cocoon and is thus spun like cotton or wool. Ailanthus silkmoth from the Philippines

Range

Peigler & Naumann (2003),Peigler, R.S. & Naumann, S., 2003. ''A Revision of the Silkmoth Genus'' Samia. San Antonio: University of the Incarnate Word. 230 pp., 10 maps, 228 figs. in their revision of the genus ''Samia'', listed material of true ''Samia cynthia'' examined as follows:

Indigenous populations

* Asia: China (Zhejiang, Shanghai, Jiangxi, Jiangsu, Shandong, Beijing, Shanxi, Liaoning, Heilongjiang); Korea (North Pyongan, South Pyongan, Pyongyang, Kangwon, South Kyongsan, Chungcheongnam-do province)

Introduced populations

These include moths that have escaped from cultivation or were introduced and naturalized: * Asia: Japan; India; Thailand * Australasia: Australia * America: Canada; United States; Venezuela; Uruguay; Brazil * Africa: Tunisia * Europe: France; Austria; Switzerland; Germany; Spain; Bulgaria; Italy

Life cycle

Eggs

Whitish eggs, marked with brown, are laid in rows of 10 to 20 on leaves in crescents. Hatching takes 7 to 10 days.

Larvae

Larvae are

gregarious Sociality is the degree to which individuals in an animal population tend to associate in social groups (gregariousness) and form cooperative societies. Sociality is a survival response to evolutionary pressures. For example, when a mother wasp ...

and yellow at first. Later

instar An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ass ...

s are solitary, and whitish green with white tubercules along the back, and small black dots. There are five instars, and they reach a maximum length .

Pupae

A silken off-white to grey cocoon is spun on the leaves of the host. It has an obvious escape hatch.

Adults

Females prepare to mate in the evening or night after emerging in late morning. Adult flight is during May and June in northern Europe, as one generation. In southern Europe a partial second generation may occur in September. Adults lack mouth parts and can neither eat nor drink.

Food plants

Larvae will feed on other trees and shrubs, but all eggs are laid on the "tree of heaven" (''

Ailanthus altissima ''Ailanthus altissima'' , commonly known as tree of heaven, ailanthus, varnish tree, or in Chinese as ''chouchun'' (), is a deciduous tree in the family Simaroubaceae. It is native to northeast and central China, and Taiwan. Unlike other membe ...

'') and growth is best on it. This tree is commonly grown as an ornamental in cities, but is considered a

noxious weed A noxious weed, harmful weed or injurious weed is a weed that has been designated by an agricultural or other governing authority as a plant that is injurious to agricultural or horticultural crops, natural habitats or ecosystems, or humans or liv ...

and vigorous

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

and is one of the worst invasive plant species in Europe and North America. The subspecies ''S. cynthia ricini'' feeds upon

References

External links

*
Cynthia moth (''Samia cynthia'') mating
(YouTube video).
Cynthia moth (''Samia cynthia'') laying eggs
(YouTube video).
''Lepiforum e. V.''
{{Taxonbar , from=Q1462214 Saturniinae Moths of Japan Moths of Europe Moths of North America Moths of New Zealand Moths described in 1773 Taxa named by Dru Drury Sericulture