(lac insect ppt, lac culture types of lac, lac insect, taxonomy, scientific name, order, life cycle, morphology, biology, lac insect host plant, strain, types, and its forms)
LAC INSECT PPT
lac is a resinous exudation from the body of a female scale insect. Since the Vedic period, it has been in use in India. Its earliest reference is found in Atharva Veda. there the Lac insect is termed as ‘Laksha’, and its habit and behavior are described.
The great Indian epic Mahabharata also mentions a ‘Laksha Griha’, an inflammable house of lac, cunningly constructed by ‘Kauravas’ through their architect ‘Purocha’ for the purpose of burning their great enemy ‘Pandavas’ alive.
LAC INSECTS Definition
Table of Contents
The English word lac synonyms Lakh in Hindi. lac insect is derivative of Sanskrit word Laksh meaning a lakh or hundred thousand. It would appear that Vedic people knew that the lac is obtained from numerous insects and must also know the biological and commercial aspects of the lac industry.
It is also worth mentioning that a laksh griha would need a lot of lac which could only come from a flourishing lac industry in that period.
Lac — Nature’s gift to mankind
- Lac is the only known commercial resin of animal origin.
- It is the hardened resin secreted by tiny lac insects belonging to a bug family.
- To produce 1 kg of lac resin, around 300,000 insects lose their life.
- The lac insects yields
The application of these products has been changing with time. Lac resin, dye, etc. still find extensive use in Ayurveda and Siddha systems of medicine.
IMPORTANCE OF LAC CULTURE
With increasing universal environment awareness, the importance of lac has assumed special relevance in the present age, being
- An eco-friendly
- Self-sustaining natural material
Since lac insects are cultured on host trees which are growing primarily in wasteland areas, the promotion of lac and its culture can help in eco-system development as well as reasonably high economic returns.
It is a source of livelihood for tribal and poor inhabiting forest and sub-forest areas.
LAC INSECT TAXONOMY
The first scientific account of the lac insect was given by J. Kerr in 1782 which was published in Philosophical Transaction of Royal Society of London (vol. 71, pp.374-382).
The first scientific name given to it was Tachardia lacca following the name of French Missionary Father ‘Tachardia’.
It was later changed to Laccifer lacca Kerr.
The other name given to it has been Kerria Lacca Kerr.
DISTRIBUTION OF LAC INSECT
Lac is currently produced in
YUAN PROVINCE OF CHINA.
India and Thailand are the main areas in the world, while India has a prime position in relation to lac production.
Lac cultivation is introduced into Thailand from India.
Lac Insect Definition
Lac insect is a minute crawling scale insect that inserts its suctorial proboscis into plant tissue, sucks juices, grows, and secretes resinous lac from the body.
Its own body ultimately gets covered with lac in the so-called ‘CELL’.
Lac is secreted by insects for protection from predators.
Male lac insect
- The Male is red in colour and measures 1.2 – 1.5mm in length.
- It has reduced eyes and antennae.
- Thorax bears a pair of hyaline wings.
Female lac insect
- Female is larger than male, measures 4-5 mm in length, and has a pyriform body.
- The head, thorax, and abdomen are not clearly distinct.
- The antennae and legs are in degenerated form, and wings are absent.
Lifecycle of Lac Insect
The Life cycle of lac insect takes about six months and consists of stages:
The lac insects have an ovoviviparous mode of reproduction.
Female lays 200-500 ready to hatch eggs, i.e. the embryos are already fully developed in eggs when these are laid.
- Eggs hatch within a few hours of laying, and a crimson-red first instar nymph called crawlers come out.
- The crawler measures 0.6 x .25 mm in size.
MALE LAC CELL
- After the first moult, both male and female nymphs lose their appendages, eye and become degenerate.
- While still inside their cells, the nymphs cast off their second and third moult and mature into adults.
- Both the male and female larvae become sexually mature in about eight weeks.
- Only the male one undergoes a complete metamorphosis or transformation into another form; it loses its proboscis and develops antennae, legs, and a single pair of wings.
- It is contained in a brood cell somewhat slipper-like with a round trap door (operculum) through which it emerges.
- The adult male is winged and walks over the females to fertilize them.
FEMALE LAC CELL
- The female brood cell is larger and globular in shape and remains fixed to the twig.
- The female retains her mouthparts but fails to develop any wings, eyes, or appendages.
- While developing, it really becomes an immobile organism with little resemblance to an insect.
- Females become little more than egg-producing organisms.
- The emergence of a nymph is called swarming, and it may continue for 5 weeks.
- The nymphs crawl about on branches.
- On reaching soft succulent twigs, the nymphs settle down close together at a rate of 200-300 insects per squire inch.
- At this stage, both male and female nymphs live on the sap of the trees.
- They insert their suctorial proboscis into plant tissue and suck the sap.
- After a day or so of settling, the nymphs start secreting resin from the glands distributed under the cuticle throughout the body, except mouth parts, breathing spiracles, and anus.
- The resin secreted is semi-solid which hardens on exposure to air into a protective covering.
- The nymphs molt thrice inside the cells before reaching maturity.
- The duration of each instar is dependent on several factors, viz. temperature, humidity, and host plant.
Ovoviviparous nature of lac insect
The female increases in size to accommodate her growing number of eggs.
- Lac resin is secreted at a faster rate, and a continuous layer coalesces or grows into one body.
- After fourteen weeks, the female shrinks in size allowing light to pass into the cell and the space for the eggs.
- About this time, two yellow spots appear at the rear end of the cell.
- The spots enlarge and become orange coloured.
- When this happens, the female has oviposite a large number of eggs in the space called ‘Ovisac’.
- The ovisac appears orange due to crimson fluid called lac dye which resembles cochineal.
- It indicates that the eggs will hatch in less time.
Brood Lac is Used for Inoculation
- When the eggs hatch, larvae emerge and the whole process begins all over again
- After the cycle has been completed and around the time when the next generation begins to emerge, the resin encrusted branches are harvested.
- They are scraped off, dried, and processed for various lac products.
- A portion of brood lac is retained from the previous crop for the purpose of inoculation to new trees.
Lac insects thrive on twigs of certain plant species, suck the plant sap, and grow all the while secreting lac resin from their bodies.
These plants are called host plants. Although lac insect is a natural pest on a host plant, these insects enjoy the privileged position of not being treated as pests.
This is because:
i) They yield a useful product,
ii) The host plants are economically not so important
iii) The insects cause only temporary and recoverable damage to the host plants.
- About 113 varieties of host plants are mentioned as lac host plants. Out of which the followings are very common in India:
- Butea monosperma (Vern. Palas)
- Zizyphus spp (vern. Ber)
- Schleichera oleosa (Vern. Kusum)
- Acacia catechu (Vern. Khair)
- Acacia arabica (Vern. Babul)
- Acacia auriculiformis (Vern. Akashmani)
STRAINS OF LAC INSECT
- In India, lac insect is known to have two distinct strains: kusumi and rangeeni.
- The kusumi strain is grown on kusum or on other host plants using kusumi brood.
- The rangeeni strain thrives on host plants other than kusum.
- The life cycle of lac insects takes about six months, hence, two crops a year can be obtained.
In the case of kusumi strain, two crops are:
I) jethwi (june / july) and
Ii) aghani (jan. / Feb).
In the case of rangeeni, two crops are:
I). Karrtiki (oct. / Nov.) And
Ii) baisakhi (may / june).
- The crops have been named after Hindi months during which these are harvested.
- The lac of rangeeni crops is harvested while it is still immature.
- Aghani and Baisakhi strain is the main corps contributing about 90% of lac production.
- The kusumi crop lac is considered superior resin, because of the lighter colour of resin, and it fetches a better price.
- lac is directly related to the host plant and to the strain of lac insects.
- Based on industrial parameters, kusumi lac is better and fetches a higher price in the market.
- In this respect, ber tree as a potential kusumi lac host is already getting momentum.
- These host species are available in plenty and can supplement and fulfill the kusmi brood lac requirement in many areas.
- Similarly, siris (Albizzia sp.) has also been identified as a good host for kusumi brood lac.
- The trees can be raised and utilized within a period of 5-6 years of plantation in comparison to around 15 years for kusum.
ARI LAC AND PHUNKI LAC
If lac crops are harvested by cutting down the lac bearing twigs a little before the larval emergence, that lac is known as ARI LAC ( immature lac )
If lac crops are harvested by cutting down the lac bearing twigs a little after the emergence is over, that is called PHUNKI LAC ( empty lac ).
LAC AND ITS FORMS
STICK LAC: The lac encrustations is separated by a knife or broken off with a finger from the twig of host plants and are known as STICK LAC or CRUDE LAC or RAW LAC.
SEED LAC: The stick lac, after grinding and washing, is called SEED LAC or CHOWRI.
SHELLAC : The manufactured product prepared from stick lac after washing and melting, which takes the form of yellow coloured flakes, is called SHELLAC.
BUTTON LAC: After the melting process, lac is dropped on a zinc sheet and allowed to spread out into round discs of about 3” diameter and 1/4” thickness is called BUTTON LAC
GARNET LAC: It is prepared from inferior seedlac or Kiri by the solvent extraction process. It is dark in colour and comparatively free from wax.
BLEACHED LAC: It is a refined product obtained by chemical treatment. It is repared by dissolving shellac or seedlac in Sodium carbonate solution, bleaching the solution with Sodium hypochlorite, and precipitating the resin with sulphuric acid. Bleached lac deteriorates quickly and should be used within 2-3 months of manufacture.
LAC PRODUCTION IN INDIA
India and Thailand are the two major producers of lac.
The main lac producing states in India are Chhattisgarh, Jharkhand, Madhya Pradesh, West Bengal, Uttar Pradesh, Orissa, Maharashtra, and Gujarat.
The cultivation of lac is at present mainly confined to the conventional lac hosts trees of Palas, Ber, and Kusum.
At present total annual average production of stick lac in India is approximately 20-22 thousand tons which form the raw material for lac industries.
Chhattisgarh ranks 1st among the states followed by Jharkhand, Madhya Pradesh Maharashtra, and West Bengal.
These five states contribute around 95 % of the national lac production.
Nearly 75-80% of the finished product is exported and only a small portion nearly 20 to 25 % is consumed within the country.