The lac bug is renowned for producing a valuable natural resin known as lac. The term “lac” originates from a Sanskrit word signifying “hundred thousand,” reflecting the immense number of these minute insects required to yield this commercial resin. Lac stands as a unique product, being a commercial resin of animal origin.
Understanding the Lac Bug
The lac bug, scientifically classified as a scale insect, primarily Kerria lacca (formerly Laccifer lacca), belongs to the family Kerriidae within the order Hemiptera. These insects typically measure between 0.5 and 1.5 millimeters in length, though the female can grow to about 4-5 mm. The adult female lac insect possesses a bag-like body, with an indistinct head, thorax, and abdomen, rudimentary antennae, and a proboscis for feeding. Due to her sedentary lifestyle once settled, she lacks eyes, legs, and wings.
The life cycle of the lac bug spans approximately six months. Ovoviviparous females lay between 300 and 1000 eggs beneath their resin. These eggs hatch into mobile first instar larvae, often called “crawlers.” These crawlers then disperse, settle on new plant tissue, and begin feeding on the host tree’s sap. As they feed, they start secreting the resin that will eventually form their protective covering.
Lac bugs inhabit various host trees and shrubs, including species like Kusum (Schleichera oleosa), Palas (Butea monosperma), Ber (Ziziphus mauritiana), and the sacred fig (Ficus religiosa). They can thrive on over 300 different tree species. These insects are predominantly found in tropical and subtropical regions, with significant populations in India, Thailand, Myanmar, Laos, Vietnam, China, Bangladesh, and Mexico. India remains a leading producer of lac globally.
The Versatile Product: Lac
Lac is a resin secreted through glands in the insect’s abdomen, beginning immediately after the larvae settle on tender shoots. Upon contact with air, the semi-liquid secretion hardens, forming a protective, encrusted coating around the insect and the twig it inhabits.
Harvesting of lac involves cutting the lac-encrusted twigs, known as “sticklac,” from the host trees. Sticklac is then processed by crushing and sieving to remove impurities, followed by washing to separate insect parts and other debris, yielding “seedlac.” Seedlac is further refined through heat treatment or solvent extraction to produce “shellac,” which is commonly sold as dry flakes.
In wood finishing, shellac is applied as a varnish, sealer, or primer, forming the basis for traditional “French polish.” Shellac dries quickly, allowing for multiple coats in a short period, and can be tinted to provide amber or orange hues for darker woods, or remain clear for lighter wood types. While not as durable as some synthetic finishes, its ease of application and repair makes it a preferred choice for many applications.
Shellac is also widely used as a glazing agent in the food industry (E904). It provides a shiny, protective coating for a variety of products, including chocolates, confectionery, chewing gum, snacks, nuts, and fruits such as apples, citrus, and melons. This coating helps to maintain internal moisture levels, extending shelf life and enhancing visual appeal. Shellac is safe for consumption.
In the pharmaceutical sector, shellac serves as a coating for tablets and capsules. It protects medications from moisture, masks unpleasant tastes, and facilitates controlled release. This includes enteric coatings, which resist dissolution in stomach acids, ensuring the medication reaches the intestines.
The cosmetic industry uses shellac in products like hair sprays, eyeliner, mascara, nail polish, and moisturizers. It acts as a film-forming agent, providing shine, binding ingredients, and emulsifying. Furthermore, lac is a source of lac dye, a crimson-red pigment extracted from the insect bodies during processing. This dye colors textiles, leather goods, and various food and beverage items like soft drinks, jams, and candies.