(a) What is lac culture? Explain the life cycle of lac insect and describe cultivation and processing of lac in India. Also add a…

(a) Lac culture

Lac culture is the rearing of the lac insect, Kerria lacca, on host trees to obtain lac, a natural resin, together with lac dye and wax. Life cycle: Step 1: A fertilised female lays 200 to 500 eggs in her lac cell, and the eggs hatch into tiny red crawlers. Step 2: The crawlers leave the cell, walk over twigs and settle thickly on tender shoots, where they pierce the bark and suck phloem sap. Step 3: Dermal glands secrete resin that hardens in air and forms a cell round each insect. Legs and eyes are lost after the first moult. Step 4: The female has three nymphal instars, stays fixed and grows into a swollen sac, and secretes most of the lac. Male nymphs form pupal cells and become winged or wingless adults without mouthparts. They fertilise the females and die. Step 5: The female lays eggs, dies, and her body forms a chamber of lac. Cultivation in India: Host trees: palas (Butea monosperma), ber (Ziziphus mauritiana) and kusum (Schleichera oleosa), pruned to give fresh succulent shoots. Inoculation: twigs bearing mature insects (brood lac) are tied to the host branches, and when the crawlers have settled the spent brood twigs are removed. Harvest: the lac encrusted twigs are cut as sticklac, usually twice a year. Processing: Step 1: Sticklac is scraped off, crushed and washed to remove dye and impurities, giving seedlac. Step 2: Seedlac is packed in long cotton bags, melted over a fire and squeezed through the cloth, then stretched into thin sheets of shellac. Economic importance: lac is a forest product that provides income to tribal growers in Jharkhand, Chhattisgarh, Madhya Pradesh and Odisha, and India is a leading producer and exporter. Shellac is used in varnish, polish, sealing wax, electrical insulation, tablet coating, cosmetics and food glaze.

(b) Project Tiger: threats and conservation strategies

Project Tiger is a centrally sponsored scheme launched on 1 April 1973 at Corbett National Park, to maintain viable populations of the tiger in its natural habitats and preserve areas of biological importance. It began with nine reserves and now covers 58 tiger reserves in 18 states. The tiger count was 3,682 in the 2022 estimate. Threats: Poaching for skin and bones, which feed illegal trade. Loss and fragmentation of habitat by mining, dams, roads and railways, and expanding villages. Fall in prey from hunting of deer and wild pig. Human-wildlife conflict, which leads to retaliatory killing, and small isolated populations with inbreeding. Conservation strategies: Reserves with an inviolate core and a buffer zone, and voluntary relocation of villages from the core. National Tiger Conservation Authority, statutory since the 2006 amendment of the Wildlife (Protection) Act, 1972. Special Tiger Protection Force and M-STrIPES for patrolling and monitoring, and camera-trap census. Corridor protection, prey augmentation, reintroduction as in Sariska and Panna, and compensation for livestock loss. International cooperation through the Global Tiger Forum.

(c) Imprinting: definition, mechanism and examples

Definition: imprinting is a rapid, irreversible form of learning in which a young animal forms a lasting attachment to an object, usually its parent, during a short critical or sensitive period in early life. No reward is needed. Mechanism: Step 1: In the critical period, which for ducklings and goslings lasts hours to a day or two after hatching, the young follow the first moving object they see and hear. Step 2: The exposure produces lasting changes in particular parts of the forebrain, such as the intermediate medial mesopallium of chicks, through synaptic changes and protein synthesis. Step 3: The attachment cannot be undone easily and later directs social and sexual behaviour. Examples: Filial imprinting: Konrad Lorenz's greylag goslings followed him as their mother when he was the first moving object they met. Sexual imprinting: young zebra finches reared by another species later prefer mates of that species. Olfactory imprinting: salmon learn the smell of their home stream and return to it to spawn. Value: it secures protection and food from the parent. In captive breeding, whooping cranes are reared by keepers in crane costumes to avoid imprinting on humans.