Making up for what they 'lac'

Dull moths, secretions, and a schoolmaster's obsession

Some discoveries take a little longer than others.  In 1922, when Edward Meyrick described Syncola crypsimorpha, a rather plain little moth from India, he had no idea of its ecological associations.  Exactly one hundred years later, scientists determined that it is a predator of cultured lac.

What is, you may ask, is cultured lac?  These are scale insects.  And what they lack in visual appeal they more than make up for in secretions.  Kerria lacca is a source of resin, dye and wax.  The dye was used more widely in the past for coloring wool and silk but today is frequently replaced by dye from a different species, Dactylopius coccus, that feeds on Opuntia cactus native to Mexico and produces cochineal dye.

Lac is the only commercial resin derived from an animal source.  It is a natural polymer of hydroxy fatty acids and is refined to produce shellac with many applications, from coatings for pharmaceuticals, cosmetics, dry fruits, and confections to uses in inks, paints, sealants and varnishes.

Kerria lacca can be found on more than a hundred plant species in India alone.  India is the largest producer of lac in the world, with a million rural families involved in lac cultivation and an annual production of about 20,000 metric tons of raw lac.  Among the enemies of lac insects are a number of predatory moth species.  It turns out that Me yrick’s drab little moth is one of them.

Edward Meyrick has quite a story himself.  He was an English schoolmaster and an avid, amateur entomologist.  That’s avid with a capital ‘A.’  Born in 1854 and living to the age of 83, it is estimated that he named 20,000 species of Lepidoptera— the order of insects that include butterflies, moths and skippers.  He amassed a personal collection of more than 100,000 specimens which is now housed in the Natural History Museum in London.  Beyond his entomological contributions, he offered a few evolutionary rules that resemble closely those associated with Dollo.  Meyrick suggested that all new organs are the result of modifications of some previously existing structure;  that when an organ is lost, it is not regained; and, that rudimentary organs are rarely reversed to be again fully developed.

This little moth is typical of its family, the Blastobasidae, members of which are found worldwide in part due to transportation by humans.  Adults are small, slender, more or less uniformly reddish-brown in color which Meyrick described as “obscure and dull-coloured moths, decidedly the least attractive family of Lepidoptera.”  Whoh… easy on the compliments, Edward.  Their wingspan, tip to tip, varies from 12 to 24 mm and is about ten times the width of the thorax.  To date, there are fewer than 400 species in the family.

I will never see the shellac flakes in my woodworking shop the same again.  I will now be reminded that they are secreted by scale insects, caterpillars that depend upon them as prey, and Meyrick’s lifelong obsession.

Further Reading

Jadhav, M.M., Adamski, D., Shashank, P.R., et al. (2022) Syncola crypsimorpha (Meyrick, 1922) (Gelechioidea: Blastobasidae): A new pest species associated with cultured lac in India.  Zootaxa 5155: 539-548.