Bombyx mandarina

Taxobox
name = Wild Silkmoth
regnum = Animalia
phylum = Arthropoda
classis = Insecta
ordo = Lepidoptera
familia = Bombycidae
genus = "Bombyx"
species = "B. mandarina"
binomial = "Bombyx mandarina"
binomial_authority = Moore, 1872
synonyms ="Bombyx mori mandarina"

"Bombyx mandarina", the Wild Silkmoth, is an insect from the moth family Bombycidae. It is the closest relative of "Bombyx mori" the Domesticated Silkmoth or "silkworm" (properly, this refers to the caterpillars only). Unlike the domesticated relative which is unable to fly or indeed persist outside human care, the Wild Silkmoth is a fairly ordinary lepidopteran. Its main difference from the domesticated taxon is the more slender body with well-developed wings in males, and the dull greyish-brown color.

Phylogeny and systematics

Together, the two species constitute the genus "Bombyx", the true or mulberry silkmoths. The origin of the Domesticated Silkmoth is enigmatic. It has been suggested that it is the survivor of an extinct species which diverged from the ancestors of "Bombyx mandarina" millions of years agoFact|date=July 2007. However, this is based on an untenable molecular clock hypothesis that assumes that wild and domestic silkmoths evolved equally fast after their lineages diverged. Rather, the effects of artificial selection have accelerated evolution in the domestic form to a point where it is hard to trace the origin of the numerous breeds of domestic silkworms even with the most modern molecular phylogeny methods. (Yukuhiro "et al." 2002)

It is not inconceivable that today's domestic silkworms are all descended from an initial stock of "B. mandarina" collected as late as 5000 years ago (Yoshitake 1968). While wild silk could have been collected and used as threads etc since much earler, the technology to breed and utilize silkworms from a domesticated stock did not exist before the late Neolithic.

However, it has been possible to trace the geographical origin of the domestic silkmoth. The wild species occurs over a considerable range from inland China to Korea and Japan, and shows much (albeit subtle) variation. The populations from the northeastern end of the range, for example, differ in karyotype from those of inland China. Domestic silkmoths are closer to the latter regarding mtDNA sequence data, and especially lack some genetic apomorphies of the northeastern "B. mandarina". Thus, it has been concluded that the initial domestic stock came from China. (Yukuhiro "et al." 2002, Arunkumar "et al." 2006)

"Bombyx mandarina" is able to hybridize with its domestic relative. In a natural setting, this inevitably involves domestic females and wild males, as the former do not move abnout even in the wild taxon but release pheromones and wait for males to be attracted and fly to them, which of course is impossible for "B. mori" males. Consequently, the two silkmoths have been united as subspecies 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 Silkmoth is entirely dependent on human care for its survival and thus has a level of reproductive isolation from its wild relatives.

References

* (2006): Molecular phylogeny of silkmoths reveals the origin of domesticated silkmoth, "Bombyx mori" from Chinese "Bombyx mandarina" and paternal inheritance of "Antheraea proylei" mitochondrial DNA. "Molecular Phylogenetics and Evolution" 40(2): 419–427. doi|10.1016/j.ympev.2006.02.023 (HTML abstract). [http://www.sciencedirect.com/cache/MiamiImageURL/B6WNH-4JTR94V-1-H/0?wchp=dGLbVzW-zSkWb Supplementary figure 1 (JPG)] [http://www.sciencedirect.com/cache/MiamiImageURL/B6WNH-4JTR94V-1-G/0?wchp=dGLbVzW-zSkWb Supplementary figure 2 (JPG)] [http://www.sciencedirect.com/cache/MiamiImageURL/B6WNH-4JTR94V-1-6/0?wchp=dGLbVzW-zSkWb Supplementary figure 3 (JPG)]
* (1968): Phylogenetic aspects on the origin of Japanese race of the silkworm, "Bombyx mori" L.. "Journal of Sericological Sciences of Japan" 37: 83–87.
* (2002): Significant Levels of Sequence Divergence and Gene Rearrangements have Occurred Between the Mitochondrial Genomes of the Wild Mulberry Silkmoth, "Bombyx mandarina", and its Close Relative, the Domesticated Silkmoth, "Bombyx mori". "Molecular Biology and Evolution" 19(8): 1385–1389. [http://mbe.oxfordjournals.org/cgi/reprint/19/8/1385.pdf?ck=nck PDF fulltext]

External links

* [http://www.jpmoth.org/Bombycidae/Bombycinae/Bombyx_mandarina.html Japanese moths] : "Bombyx mandarina". Contains many photos. Retrieved 2007-JUL-18.
* [http://papilio.ab.a.u-tokyo.ac.jp/bioresource/shimada/images/insects/Bombyx_mandarina/B.mandarina-adult/manF_moriM_copulation.jpeg Copulation between female "B. mandarina" (left) and male "B. mori"] in captivity. Note stunted wings of male. Retrieved 2007-JUL-18.