''Kerria lacca'' is a species of insect in the family Kerriidae, the lac insects. These are in the superfamily

Coccoidea Scale insects are small insects of the order Hemiptera, suborder Sternorrhyncha. Of dramatically variable appearance and extreme sexual dimorphism, they comprise the infraorder Coccomorpha which is considered a more convenient grouping than the ...

, the scale insects. This species is perhaps the most commercially important lac insect, being a main source of lac, a resin which can be refined into

shellac Shellac () is a resin secreted by the female lac bug on trees in the forests of India and Thailand. It is processed and sold as dry flakes and dissolved in alcohol to make liquid shellac, which is used as a brush-on colorant, food glaze and ...

and other products.Raman, A. (2014)
Discovery of ''Kerria lacca'' (Insecta: Hemiptera: Coccoidea), the lac insect, in India in the late 18th century.
''Current Science'' 106(6), 886. This insect is native to Asia.Ahmad, A., et al. (2012)
Mouthparts and stylet penetration of the lac insect ''Kerria lacca'' (Kerr) (Hemiptera: Tachardiidae).
''Arthropod Structure & Development'' 41, 435-441.

Biology

''Kerria lacca'' produces a

dye A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution and ...

and a wax as natural secretions. The life cycle of this scale insect proceeds with the first

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

of 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. ...

l stages, which are known as "crawlers". Larvae in this stage crawl along the branches of their host plants and feed on the

phloem Phloem (, ) is the living tissue in vascular plants that transports the soluble organic compounds made during photosynthesis and known as ''photosynthates'', in particular the sugar sucrose, to the rest of the plant. This transport process is c ...

. As they pierce the branches to reach the phloem, they cover the holes with their wax secretions.Mohanta, J., Dey, D. G., and Mohanty, N. (2014)
Studies on lac insect (''Kerria lacca'') for conservation of biodiversity in Similipal Biosphere Reserve, Odisha, India.
''Journal of Entomology and Zoology Studies'' 2(1) 1-5. More than 400 host plants have been noted. Three are used for the majority of commercial cultivation of the insect:

palas A ''palas'' () is a German term for the imposing or prestigious building of a medieval '' Pfalz'' or castle that contained the great hall. Such buildings appeared during the Romanesque period (11th to 13th century) and, according to Thompson ...

(''Butea monosperma''),

kusum ''Schleichera'' is a monotypic genus of plants in the soapberry family, Sapindaceae. There is only one species, ''Schleichera oleosa'', a tree that occurs in the Indian Subcontinent and Southeast Asia. Species ''Schleichera oleosa'', kusum ...

(''Schleichera oleosa''), and

ber ''Ziziphus mauritiana'', also known as Indian jujube, Indian plum, Chinese date, Chinese apple, ber, and dunks is a tropical fruit tree species belonging to the family Rhamnaceae. It is often confused with the closely related Chinese jujube (' ...

(''Ziziphus mauritiana''). There are at least two strains of the insect that are characterized by aspects of their life cycle and their host plant preferences.Sharma, K. K., Jaiswal, A. K., and Kumar, K. K. (2006)
Role of lac culture in biodiversity conservation: issues at stake and conservation strategy.
''Current Science'' 91(7) 894-98.

Ecology

Natural predators of this species include several

parasitoid In evolutionary ecology, a parasitoid is an organism that lives in close association with its host (biology), host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionarily stable str ...

s, such as the parasitoid wasps '' Tachardiaephagus tachardiae'' and '' Coccophagus tschirchii''. Predators include the moths '' Eublemma roseonivia'' and '' Holcocera pulverea''. These moths can interfere with lac cultivation in

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area, the List of countries and dependencies by population, second-most populous ...

. These insects, as well as many types of fungal pathogens, form an ecological web that is important to local biodiversity. ''Kerria lacca'' has been reported as a pest insect. It is reared on

trees (''Ziziphus mauritiana''), but these trees are also cultivated for fruit, the Indian jujube. ''K. lacca'' sometimes invades Indian jujube orchards and degrades the fruit crop.

Economy

Millions of people are engaged in the farming of lac insects. At least half of lac production occurs in India, where about 20,000 metric tons of raw lac are produced annually. It is a versatile product used in a wide array of applications, and demand for it in many industries provides economic resources that filter down to rural tribes. In

Vietnam Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland Southeast Asia, with an area of and population of 96 million, making ...

, the introduction of ''K. lacca'' cultivation has brought economic recovery to impoverished mountain villages and has helped to revegetate deforested hillsides. Demand, while still strong, is shrinking over time, reducing the economic viability of lac growing. This species is also one of several similar insects used to produce a strong red dye historically used to color wool and silk. The dye originates in the

hemolymph Hemolymph, or haemolymph, is a fluid, analogous to the blood in vertebrates, that circulates in the interior of the arthropod (invertebrate) body, remaining in direct contact with the animal's tissues. It is composed of a fluid plasma in which ...

of the insect; the fluid analogous to blood. While ''K. lacca'' is the most commonly cultivated species in many areas, the related '' K. yunnanensis'' is the most widely used species in

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 ...

Lac dye

Lac insects showing diverse body colours have been reported, they may show crimson or yellow body colours. Colour difference in lac insect is inherited as a unit character and crimson is dominant to yellow. Wild type insect possesses crimson body colour due to the presence of a complex closely resembling water-soluble polyhydroxy-anthraquinones, collectively called lac dye. Apart from their usage in food and cosmetics, these anthraquinones also exhibit many pharmaceutical properties, including antibiotic, antiviral, antifeedant effect. A recent study has shown that the anthraquinone component of lac dye also possess antineoplastic or anticancer effects. It is proposed that lac insects employ polyketide pathway catalysed by polyketide synthase to produce laccaic acid D, a common precursor molecule for the biosynthesis of other lac dye constituents.

Lac resin

Lac is the only commercial resin of animal origin and is a natural polymer. It is made up of hydroxy fatty acids, principally aleuritic acid (9,10,16-trihydroxyhexadecanoic acid), and hydroxy sesquiterpenic acids. A recent study proposes the possible biosynthetic pathway for the constituents of lac resin which identifies acetyl-CoA as a common precursor molecule and the role of prenyltransferases in the biosynthesis of sesquiterpenes along with cytochrome P450 enzyme.

References

External links

{{Taxonbar, from=Q545269 Kerriidae Insects described in 1782 Hemiptera of Asia