''Bombyx mandarina'', the wild silk moth, is a species of

moth Moths are a group of insects that includes all members of the order Lepidoptera that are not Butterfly, butterflies. They were previously classified as suborder Heterocera, but the group is Paraphyly, paraphyletic with respect to butterflies (s ...

in the family Bombycidae. It is the closest relative of ''

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

domesticated Domestication is a multi-generational mutualistic relationship in which an animal species, such as humans or leafcutter ants, takes over control and care of another species, such as sheep or fungi, to obtain from them a steady supply of reso ...

silk Silk is a natural fiber, natural protein fiber, some forms of which can be weaving, woven into textiles. The protein fiber of silk is composed mainly of fibroin and is most commonly produced by certain insect larvae to form cocoon (silk), c ...

moth. The silkworm is the

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

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 ...

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 ( ) or lepidopterans is an order (biology), order of winged insects which includes butterflies and moths. About 180,000 species of the Lepidoptera have been described, representing 10% of the total described species of living organ ...

n. Its main difference from the domesticated

taxon In biology, a taxon (back-formation from ''taxonomy''; : 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 name and ...

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 of the genus ''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 an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

species that 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 nucleot ...

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 ...

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 Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

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 or New Stone Age (from Ancient Greek, Greek 'new' and 'stone') is an archaeological period, the final division of the Stone Age in Mesopotamia, Asia, Europe and Africa (c. 10,000 BCE to c. 2,000 BCE). It saw the Neolithic Revo ...

. 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 to Korea and Japan, 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 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 discerned by de ...

from those of inland China. Domestic silk moths are closer to the latter regarding

mtDNA Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the DNA contained in ...

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 ha ...

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 a domesticated environment, females release

pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...

s 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 of a single species; in this case, the name ''Bombyx mori'', which was published first, applies to 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, ethology, behaviors and physiology, physiological processes critical for speciation. They prevent members of different species from producing offspring, or ensu ...

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