Lac Culture
Lac culture is the scientific management of lac insects to obtain high-quality lac. It involves selecting and maintaining host plants, inoculating these plants with healthy lac insects, collecting and processing the lac, and protecting it against enemies. India is the leading lac-producing country in the world.
What is Lac?
Lac is the resinous secretion of lac insects. It is primarily composed of resin (70-80%), wax (4-6%), sugar (2-4%), and other minor components. Lac is used in various industries, including food, cosmetics, electronics, and varnishes.
Species of Lac Insects
There are four species of lac insects:
- Kerria lacca – Predominant in India.
- Tachardia signoret – Less common.
- Tachardiella cockrell – Rare.
- Tachardina cockrell – Found in specific regions.
Kerria lacca is the most important species for commercial lac production in India. The first scientific study of lac insects was by J. Kerr in 1782, published in the Philosophical Transactions of the Royal Society of London. The scientific name was initially Tachardia lacca but was later changed to Laccifer lacca Kerr and then Kerria lacca.
Taxonomic Classification
- Phylum: Arthropoda
- Class: Insecta
- Order: Hemiptera
- Suborder: Homoptera
- Superfamily: Coccoidea
- Family: Lacciferidae
- Genus: Laccifer
Morphology of Lac Insect
- Minute, crawling scale insect.
- Inserts suctorial proboscis into plant tissue and sucks sap.
- Secretes resinous lac from its body, eventually covering itself in a protective ‘cell’.
- Head, thorax, and abdomen are not clearly distinct.
- Crimson-red first instar nymphs called crawlers (0.6 x 0.25 mm) emerge from eggs.
- Both male and female nymphs live on the sap of trees.
- Secretes semi-solid resin that hardens into a protective covering.
- Nymphs molt three times before reaching maturity, with the duration dependent on temperature, humidity, and host plant.
Biology and Behavior
- Eggs
- Female lays 200-500 eggs inside the encrustation, which can be fertilized or unfertilized.
- Three types of eggs: Equal number of male and female eggs. More males and fewer females. More females and fewer males. Eggs hatch within a few hours (ovoviviparous type).
- Nymphs
- Minute (0.6 mm long), soft-bodied, pointed posteriorly, deep red with black eyes.
- Crawl upward on twigs (swarming) and settle on tender branches to feed.
- Insert suctorial proboscis into the shoot and suck the sap.
- Secrete resin over the body after 1-2 days of settling.
- Molt thrice before becoming adults.
- After the first molt, both male and female nymphs lose eyes, antennae, and legs.
- Sexual Dimorphism becomes prominent after the first molt:
- Male cell: Elongate with a pair of holes at the anterior end.
- Female cell: Globular with irregular margins and six holes.
- Adult
- Male: Two types: Winged (during dry seasons) and wingless. Only one pair of wings, survives for 3-4 days, and dies after copulation. Regains lost appendages at the last molt.
- Female:
- Larger (three times the size of males).
- Short, spherical, and never regains lost appendages.
- Mesothorax has an appendage with spiracles for respiration.
- Copulates inside the cell and produces a large amount of lac.
- Before laying eggs, the female develops two yellow spots that turn orange during oviposition.
- Twigs containing eggs are used as Brood Lac to inoculate new host plants.
Host Plants Lac insects thrive on certain plant species by sucking their sap and secreting lac. These plants are called Host Plants. About 113 host plant species are known, but the most common in India are:
- Butea monosperma (Palas)
- Zizyphus spp (Ber)
- Schleichera oleosa (Kusum)
- Acacia catechu (Khair)
- Acacia auriculiformis (Akashmani)
- Cajanus cajan (Pigeon-pea or Arhar)
- Ficus benghalensis (Bargad)
- Ficus religiosa (Peepal)
- Albizzia lebbek (Siris/Gulwang)
- Flemingia macrophylla (Bholia)
Palas, Kusum, Ber, and Khair are of major importance, while others are regionally important.
Key Points: The quality of lac depends on the host plant and strain of lac insects. Kusumi lac is superior in quality and fetches a higher market price. Ber, Siris, and Flemingia semialata are recognized as good hosts for Kusumi lac. Prosopis juliflora is also emerging as a potential host in Gujarat.
Importance of Host Plants
- Host plants provide nutrition to lac insects.
- They influence the quality and yield of lac.
- Plants like Kusum produce high-quality lac used in food and pharmaceutical industries.
- Palas and Ber are more commonly used for general-purpose lac.
