Animal as source of Lac - Lac culture

 

Lac is used in toys, bracelets, sealing wax also used in  filling ornaments, for manufacturing of varnishes and paints, for silvering the back of mirrors etc. Waste materials produced during the process of stick lac are used for dying purposes. Nail polish is a good example of the by-product of lac.

Lac culture refers to the domestication and rearing of lac insects on the  scientific basis  to get  a high amount of quality lac. Lac is a kind of resin secreted by the lac in­sects.

India is a major lac producing country followed by Thailand.

Lac is best said to be a  mixture and  resin is the main constituent which make about 68 to 90 % of total lac composition.The rest composition are made of dye Wax, mineral and water.

Remember 👌🏽👌🏽👌🏽 Kerr used the term  Coccus  for lac insect.  Later on, Green  and Chatterjee called the lac insect as Tachardia  Finally, the name was given as Laccifer . 

The lac insects flourish as a parasite and  feed on the sap of certain trees and shrubs.The important trees on which the lac insects are domesticated or reared are  Plum or Ziziphus jujuba,Acacia arabica, Acacia catechu Pigeon pea or Ca]anus indicus.

The lac insects are Dioecious and have   a  well marked sexual dimorphism. The male and female insects are differentiated on the basis of  shape, size and presence or absence of certain body parts.

General characters of Male Lac insect

They are larger in size and red in color. The body is divided into the head, thorax and abdomen. The head bears a pair of antennae and a pair of eyes as sensory organs. Mouth parts are absent so a male adult insect is not able to browse the leaves on which they remain present. Thorax bears three pairs of legs. Wings may or may not be found. 

Abdomen is the largest part of the body bearing a pair of caudal setae and penis at the posterior end.

General characters of female Lac insect

They are smaller in size. Head bears a pair of antennae and a single proboscis. Eyes are absent. Thorax is devoid of wings and legs. They lose their eyes, wings, and legs  because the female larvae after settling down once never move again Abdomen bears a pair of caudal setae. Female lac insects produce more silk  than male.

After  the coitus, the male dies. but one male is capable of fertilizing several females. Females develop very rapidly after fertilization and  take more sap from plants and produce more resin and wax.

After fertilization,female produces average the five hundred egg but development of egg takes place in ovary before

their release. Before egg release, females develop incubating chambers by modifying their body.These eggs are deposited Inside the incubation chamber. Now  the eggs are  hatched into larvae.

The larvae are minute, boat shaped, red coloured and about half millimeter in length. Larva consists of the head, thorax and abdomen.

Head has a pair of antennae, a pair of simple eyes and a single proboscis. Thoracic segments had pairs of walking legs and pairs of spiracles for respiration. 

These larvae start to move to the new off-shoots of the host plant. This is called swarming.

The larvae come out from anal tubular opening of females and pass out for three weeks. The larvae feed continuously when they get fixed with the twig. Meantime the larvae whether male or female release a resinous substance around their body through certain glands.. After some-time the larvae get fully covered by the lac capsule.Lac capsule which is formed in male and female are differ in morphology but female produces more lac than male. This secretion appears first as a shining layer which soon gets hardened after coming in contact with air.

In addition to this, a white thread-like structure also released by lac insect .This release signifies that lac insect is alive and is in healthy condition. These filaments also prevent the blocking of the pore during excess secretion of lac. After first moulting it undergoes the  pseudo pupation for a brief time, whereby it changes into adult stage.

When the population of lac insects are more on a host plant than Inoculation is done. It is the method by which the lac insects are introduced to the new lac host plant.

Lac is extracted  from the host plant in the form of stick lac. Lacs can be scraped from the twigs before or after the emergence of larvae. When it is extracted before the emergence of larvae, the type of lac is called Ari lac and if it is extracted after swarming of larvae then  the lac is said to be Phunki lac.

The scraping of lac from twig is done by knife, after which they should not be exposed to sun. The scraped lac is grinded in hard stone mills. The unnecessary materials are sorted out In order to remove the finer particles of dirt and color, this lac is washed repeatedly with cold water.Now it is called  as Seed lac. and  seed lac is exposed to sun for drying. Seed lac is now subjected to the melting process. The melted lac is sieved through cloth and is given the final shape by molding. The final form of lac is called Shellac.