''Bombyx mandarina'', the wild silk moth, is an insect from the

moth Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Bombycidae. It is the closest relative of '' Bombyx mori'', the domesticated silk moth. The silkworm is the

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...

caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder Sy ...

of a silk moth. Unlike the domesticated relative which is unable to fly or indeed persist outside human care, the wild silk moth is a fairly ordinary

lepidoptera Lepidoptera ( ) is an order of insects that includes butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 families and 46 superfamilies, 10 percent of the total described speci ...

n. Its main difference from the domesticated

taxon In biology, a taxon ( back-formation from '' taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular n ...

is the more slender body with well-developed wings in males, and the dull greyish-brown colour.

Phylogeny and systematics

''Bombyx mandarina'' and the domesticated '' Bombyx mori'' constitute two of the currently identified eight

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

''Bombyx'', the true or mulberry silk moths. The origin of the domestic silk moth is enigmatic. It has been suggested that it is the survivor of an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

species which diverged from the ancestors of ''Bombyx mandarina'' millions of years ago. However, this is based on an untenable

molecular clock The molecular clock is a figurative term for a technique that uses the mutation rate of biomolecules to deduce the time in prehistory when two or more life forms diverged. The biomolecular data used for such calculations are usually nucleo ...

hypothesis that assumes that wild and domestic silk moths evolved equally fast after their lineages diverged. Rather, the effects of

artificial selection Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant ma ...

have accelerated evolution in the domestic form to a point where it is hard to trace the origin of the numerous breeds of domestic silk moths even with the most modern molecular phylogeny methods. Conceivably, today's domestic silk moths are all descended from an initial stock of ''B. mandarina'' collected as far back as 5,000 years ago. While wild silk could have been collected and used as threads, etc., since much earlier, the technology to breed and use silkworms from a domesticated stock did not exist before the late

Neolithic The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several pa ...

. However, it has been possible to trace the geographical origin of the domestic silk moth. The wild species occurs over a considerable range from inland

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...

Korea Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republic ...

and

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the n ...

, and shows much (albeit subtle) variation; Chinese specimens have 56 chromosomes and Japanese specimens have 54. The populations from the northeastern end of the range, for example, differ in

karyotype A karyotype is the general appearance of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is disce ...

from those of inland China. Domestic silk moths are closer to the latter regarding mtDNA sequence data, and especially lack some genetic

apomorph In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have ...

ies of the northeastern ''B. mandarina''. Thus, the initial domestic stock came from inland China. ''B. mandarina'' is able to hybridize with ''B. mori''. Both in the wild and in a domesticated environment, females release pheromones and wait for males to be attracted and fly to them. However, ''B. mori'' males cannot fly. Hybridisation in the wild, therefore, inevitably means breeding between wild (''B. mandarina'') males and domestic (''B. mori'') females. Hybridization is possible in both directions in a domesticated environment. Consequently, the two silk moths have been united as

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics ( morphology), but that can successfully interbreed. Not all specie ...

of a single species; in this case, the name ''Bombyx mori'', which was published first, applies for both. However, today it is usually recognized that the domestic silk moth is entirely dependent on human care for its survival and thus has a level of

reproductive isolation The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation. They prevent members of different species from producing offspring, or ensure that any offsprin ...

from its wild relatives.

References

External links

''Japanese Moths''
''Bombyx mandarina''. Contains many photos. Retrieved 18 July 2007.
Copulation between female ''B. mandarina'' (left) and male ''B. mori''
in captivity. Note stunted wings of male. Retrieved 18 July 2007. {{Taxonbar , from=Q144548 Bombycidae Moths described in 1872 Moths of Japan