Lac insects and their products are in use since ancient times. Lac insects are beneficial for their three valuable products: lac dye, lac wax and lac (resin). All these items are both of trade and commercial value. The first scientific description regarding the lac insect and its economic value was presented by Kerr and Glover in 1782. From then immense literature is now available regarding organization, distribution, taxonomy, host plants, culture, production, enemies, chemistry and technology of lac insects. India has its monopoly on lac production. Other countries including Africa, Australia, Brazil, Burma, Sri Lanka, USA also work in this prospect.

The lac insect is scientifically designated as Tachardia lacca belonging to class Insecta and order Hemiptera. Lac insect is a minute, resinous, crawling insect that sucks the juices of host plants and secretes lac from the hinder end of its body. Its own body ultimately gets covered with the lac. Commercial production of lac is basically done by the females. There is a well marked sexual dimorphism in lac insects. The males are red in color and 1.2-1.5 mm in length, red eyed with ten segmented antennae. The thorax bears three pairs of legs and one pair of membranous wings. Abdomen bears eight segments that terminate into penis. The males secrete bright creamy lac. The females are larger than males ranging 4-5 mm in length. Their body is pyriform, enclosed in a resinous cell. The head, thorax and abdomen are not clearly demarcated. Legs are also degenerated. Both male and female insects bear piercing and sucking type of mouth parts.

The life cycle includes three stages: egg, nymph and adult. A fertilized female lays 200-500 eggs by contracting its body in forward direction. Eggs are laid in the cell in which she is enclosed. Eggs are generally laid in the month of October and November. Hatching of eggs occur after six weeks and first instar nymphs hatch out. The number of hatched nymphs is very high, so this mass emergence is termed as ‘swarming’.

The first instar nymphs are 0.5 mm in length, red colored and boat shaped. Head bears paired antennae, ocelli and piercing and sucking type of mouth parts. Three segmented thorax bears two spiracles and one pair of walking legs. Abdomen bears two pairs of walking legs and caudal setae. The notorious nymphs soon after their emergence search for their food and hover here and there and reach their host plants and start sucking sap from the tender, succulent twigs as at this time they are unable to feed on hard twigs. They settle very close to each other so that a twig may contain 150-200 nymphs. Soon after their settlement they start secreting a resinous substance by special dermal glands present all over their bodies. As they come in contact with air it hardens and forms a covering over the body of the nymph termed as ‘cell’. Inside this cell metamorphosis commences.

The male cell is elongated and has two openings, one anterior and the other posterior. The male comes out from the posterior end. After six weeks of stationary life adults emerge out in the form of 70% wingless females and 30% winged males. The female never leaves her cell, the male walks over the encrustations of the female and fertilizes her. One male is capable of fertilizing many females. The fertilized female lays eggs in October and November. The female insect dies secreting lac all the time. Due to their short life span the males do not participate in lac production. The females secrete valuable quantity of lac. Life cycle period depends upon the ecological factors.

113 varieties of host plants have been reported for the lac insects. Quality of lac is greatly affected by the quality of the host plant. The lac obtained from the insects is a complex substance made up of resin, dye, wax, albuminous matter, mineral matter and water. It is easily soluble in alcohol and fuses on heating. Lac has adhesive property and it is bad conductor of heat. The lac is used by the jewellers and the goldsmiths as a filling material in the hollows of gold ornaments. It is also a component of paints, polishes and is generally used as a sealing wax.

Lac insects have predators also like squirrels, rats, monkeys. Parasites are also known to harm them. High temperature, heavy rainfall, high intensity of light, high humidity also cause damage to them. Man is the worst enemy of lac insects.

So, it can be convicted that the lac insects are of immense value for us. Lac insects not only provide us with valuable products but also make our environment beautiful.

Navodita Maurice

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