Kerria lacca

Kerria lacca is a species of insect in the family Kerriidae, the lac insects. These are in the superfamily Coccoidea, 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 and other products.[1] This insect is native to Asia.[2]

Kerria lacca
Drawing of the insect Kerria lacca and its shellac tubes, by Harold Maxwell-Lefroy, 1909
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hemiptera
Suborder:	Sternorrhyncha
Superfamily:	Coccoidea
Family:	Kerriidae
Genus:	Kerria
Species:	K. lacca
Binomial name
Kerria lacca (Kerr, 1782)
Synonyms
Coccus lacca Kerr, 1782 Coccus ficus Fabricius, 1787 Chermes lacca Roxburgh, 1791 Carteria lacca Signoret, 1874 Lakshadia indica Mahdihassan, 1923 Tachardia lacca Chamberlin, 1923 Laccifer lacca Cockerell, 1924

Lac tubes created by Kerria lacca

Biology

K. lacca also produces a dye and a wax as natural secretions. The life cycle of this scale insect proceeds with the first instar of the larval stages, which are known as "crawlers". Larvae in this stage crawl along the branches of their host plants and feed on the phloem. As they pierce the branches to reach the phloem, they cover the holes with their wax secretions.[3]

More than 400 host plants have been noted.[2] Three are used for the majority of commercial cultivation of the insect: palas (Butea monosperma), kusum (Schleichera oleosa), and ber (Ziziphus mauritiana).[3]

There are at least two strains of the insect that are characterized by aspects of their life cycle and their host plant preferences.[4]

Ecology

Natural predators of this species include several parasitoids, 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.[5]

These insects, as well as many types of fungal pathogens, form an ecological web that is important to local biodiversity.[4]

K. lacca has been reported as a pest insect. It is reared on ber trees (Ziziphus mauritania), but these trees are also cultivated for fruit, the Indian jujube. K. lacca sometimes invades Indian jujube orchards and degrades the fruit crop.[6]

Economy

Millions of people are engaged in the farming of lac insects.[4] 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.[4] In Vietnam, the introduction of K. lacca cultivation has brought economic recovery to impoverished mountain villages and has helped to revegetate deforested hillsides.[7][8] Demand, while still strong, is shrinking over time, reducing the economic viability of lac growing.[4]

This species is also one of several similar insects used to produce a strong red dye historically used to color wool and silk.[9] The dye originates in the hemolymph of the insect; the fluid analogous to blood.[4]

While K. lacca is the most commonly cultivated species in many areas, the related K. yunnanensis is the most widely used species in China.[10]

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.[11]

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.[12]

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.[13]

References

1. 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.
2. Ahmad, A., et al. (2012). Mouthparts and stylet penetration of the lac insect Kerria lacca (Kerr) (Hemiptera: Tachardiidae). Arthropod Structure & Development 41, 435-441.
3. 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. Archived 2016-03-02 at the Wayback Machine Journal of Entomology and Zoology Studies 2(1) 1-5.
4. 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.
5. Pemberton, R. W., et al. (2006). Host acceptance trials of Kerria lacca (Kerriidae) parasitoids from northern Thailand on the pest lobate lac scale (Paratachardina lobata) (Kerriidae). Florida Entomologist 89(3), 336-339.
6. Lakra, R. K. and Kher, S. (1990). Effect of incidence of lac insect, Kerria lacca (Kerr) on bearing and quality of jujube fruits in Haryana. Indian Journal of Plant Protection 18(1), 125-127.
7. New rural development in Huoi Leng commune, Điện Biên Province. Vov World Service. December 5, 2013.
8. More than 900 ethnic minority households in Mường Lát District escape from poverty. Archived 2017-07-27 at the Wayback Machine Press Release: United Nations Development Programme, Vietnam. June 27, 1014.
9. Wouters, J. and Verhecken, A. (1989). The coccid insect dyes: hplc and computerized diode-array analysis of dyed yarns. Studies in Conservation 34(4), 189-200.
10. Chen, Y., et al. (2014). Multiple ant species tending lac insect Kerria yunnanensis (Hemiptera: Kerriidae) provide asymmetric protection against parasitoids. PLoS ONE 9(6), e98975.
11. Shamim, G.; et al. (2016). "Lac dye as a potential anti-neoplastic agent". Journal of Cancer Research and Therapeutics. 12 (2): 1033–1035. doi:10.4103/0973-1482.155975. PMID 27461693.
12. Shamim, G.; et al. (2016). "Genes Involved in the Biosynthesis of Lac Dye Constituents in Indian Lac Insect, Kerria lacca (Kerr)". Journal of the Entomological Research Society. 18 (1): 07–17.
13. Shamim, G.; et al. (2014). "Identification of genes related to resin biosynthesis in the Indian lac insect, Kerria lacca (Hemiptera: Tachardiidae)". International Journal of Tropical Insect Science. 34 (2): 149–155. doi:10.1017/S1742758414000277. S2CID 84673193.

External links