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

Bombyx mori ''Bombyx mori'', commonly known as the domestic silk moth, is a moth species belonging to the family Bombycidae. It is the closest relative of '' Bombyx mandarina'', the wild silk moth. Silkworms are the larvae of silk moths. The silkworm is of ...

''. 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 1725 – 15 January 1804) was a British collector of natural history specimens and an entomologist. He received specimens collected from across the world through a network of ship's officers and collectors including Henry ...

in 1773.

Eri silk

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

Ailanthus ''Ailanthus'' (; derived from ''ailanto,'' an Ambonese Malay, 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 Geranial ...

''. There is a subspecies, ''S. cynthia ricini'' in India and Thailand that feeds upon the leaves of castor bean (''Ricinus communis''), and is known for the production of

eri silk Eri silk is a type of peace silk produced by the domesticated silkworm ''Samia ricini''. It is primarily produced in the Northeast India, northeastern Indian states of Assam, Nagaland and Eri silk in Meghalaya, Meghalaya, but it is also found in B ...

, 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; Philippines; 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 was ...

and yellow at first. Later

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

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 or ailanthus tree, is a deciduous tree in the quassia family. It is native to northeast and central China, and Taiwan. Unlike other members of the genus ''Ailanthus'', it is found ...

'') 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 harmful to agricultural or horticultural crops, natural habitats or ecosystems, or humans or lives ...

and vigorous

invasive species An invasive species is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native spec ...

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

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