Question

Discuss in detail life cycle of Lac insect.

Hint:

Remember: Lac insect life cycle includes egg, crawler (mobile stage), settled nymph, and adult stages. Only crawlers are mobile; males are winged but short-lived. The insect completes 2 generations per year depending on the strain (rangeeni or kusmi).

Answer 1

Step 1: Understanding the Question
The question asks for a detailed description of the complete life cycle of the Lac insect (Kerria lacca).
Step 2: Detailed Explanation
The life cycle of the lac insect is complex and involves distinct stages. It is completed in about six months and there are typically two generations per year.

Egg: The female lac insect lays around 200-500 eggs inside a resinous cell (the lac encrustation) that she secretes around herself. The eggs are oval and reddish.

Nymph (Crawler Stage): The eggs hatch inside the cell, and tiny, red-colored nymphs emerge. This is called the 'crawler' stage. This is the only mobile stage in the insect's life. The crawlers move out in a large swarm to find a suitable spot on the tender shoots of the host tree (like Palas, Ber, Kusum).

Settlement and Metamorphosis: Once a crawler finds a suitable spot, it inserts its proboscis (sucking mouthpart) into the plant tissue to suck sap. It then becomes stationary for the rest of its life. It starts secreting the protective lac resin around its body. Both male and female nymphs undergo metamorphosis, but their development paths diverge.

Adult Stage:
Adult Female: The female loses her legs and antennae and becomes a blob-like creature inside her resin cell. Her primary function is to feed on sap, grow, and secrete large amounts of lac. After mating, she lays eggs and dies.

Adult Male: The male develops into a tiny, winged insect. He emerges from his cell, mates with several females, and dies within a few days as he does not have mouthparts to feed.


Mating and Egg-Laying: After mating, the female develops rapidly, becomes sac-like, and fills with eggs. The eggs hatch, and a new generation of crawlers emerges, starting the cycle anew.

Step 3: Final Answer
The life cycle of the lac insect consists of the egg, nymph (crawler), and adult stages. The mobile crawler stage is crucial for dispersal. After settling, the insect secretes lac resin. The female becomes a stationary sac for reproduction, while the winged male lives only to mate. This cycle repeats twice a year, producing two crops of lac.