what is called moulting?...

Excellent summary of moulting in crustaceans!

*Key Points:*

1. Moulting: periodic shedding of old exoskeleton, replaced by new one.

2. Allows growth, weight increment, and reproductive changes.

3. Moult cycle: Post-moult, Inter-moult, Pre-moult, Moult.

4. Types of moulting: Instar (growth-related), Terminal (reproductive-related), Induced (environmentally stimulated).

5. Changes during moulting: inactivity, no feeding, increased infection risk, behavioral changes.

*Moult Cycle Stages:*

*Pre-moult	Preecdysis/Peeler stage	Calcium reabsorption, epidermal cell enlargement, appendage regeneration.
Moult*		Old exoskeleton splits, crustacean extracts itself, vulnerable until new exoskeleton hardens.
Post-moult	Metecdysis/Soft back stage	New exoskeleton hardens, calcium deposition.
Inter-moult	Anecdysis	Tissue growth, water replacement, organic matter enrichment.

*Moult Cycle Duration:*

1. Varies by species, size, sex, age.

2. Juveniles: shorter cycle (e.g., 30-80 days).

3. Adults: longer cycle (e.g., 40-80 seconds).

*Hormonal Control:*

1. Ecdysone: steroid hormone regulating moulting.

2. MIH (Moult Inhibiting Hormone).

3. Ecdysteroids.

4. MF (Methyl Farnesoate).

5. CHH (Crustacean Hyperglycemic Hormone).

*Behavioral Changes:*

1. Intense swimming, walking, jumping, rolling, rotating before ecdysis.

2. Aggressive behavior among prawns.

*Immune Response:*

1. Higher during inter-moult stage.

2. Lower during pre-moult and post-moult stages.

*Example Species:*

1. Giant freshwater prawn.

2. Penaeus merguiensis.

3. P. duorarum.

This comprehensive overview covers the essential aspects of moulting in crustaceans.