Antheraea assamensis is semi-domesticated and reared outdoors on standing trees, which is the single fact that shapes everything about muga culture. Optimum growth occurs at 22–26 °C and 75–80 % RH; summer field conditions of 28–37 °C with 85–95 % RH, and winter minima below the optimum, mean the crop spends most of the year outside its comfort zone.
The life cycle
Summer durations; drag or use the arrow keys to turn the orbit. The cycle closes — moth to egg — which is why a single infected generation carries forward, and why mother moth examination sits where it does in the grainage sequence.
Life cycle by season
| Stage | Summer (days) | Winter (days) |
|---|---|---|
| Egg | 07 – 10 | 15 – 20 |
| Larva (5 instars, 4 moults) | 20 – 25 | 45 – 55 |
| Spinning | 03 – 04 | 05 – 07 |
| Pupa | 14 – 16 | 55 – 65 |
| Complete cycle | 44 – 55 | 120 – 147 |
Races and morphotypes
No ecorace is characterised in muga, unlike eri and tasar. What exists are morphotypes distinguished by larval, cocoon and moth colour, and collected biotypes — Haflong green, yellow mutant, Kokrapohia green and a wild hibernating type — maintained off-site for hybridisation.
- Larvae: green predominates; blue and yellow occur rarely. Moths are brownish, males darker; black mutants rare.
- Cocoons: oval or dumbbell, each pointed or plane. Wild cocoons are harder with longer peduncles.
- Cytogenetics: lowest chromosome number in the genus, n = 15, with a ZZ/ZO sex chromosome system.
- Diapause: in the pupal stage, November–March in some populations, with adults emerging March–April. Diapausing lines show higher cocoon and shell weight and are useful in breeding.
- Cocoon colour follows the leaf. Pigments taken up from foliage lodge in the sericin layer. Som and soalu give golden cocoons; Mejankari (Litsea cubeba) gives glossy white cocoons and the finest, highest-priced silk, now confined to pockets of Jorhat and Sivasagar.
Wild against cultivated stock
| Character | Wild stock | Cultivated stock |
|---|---|---|
| Voltinism | Bivoltine / multivoltine | Multivoltine |
| Moults | 4 or 3 | 4 |
| Food plants | Soalu, Dighloti | Som, Soalu |
| Egg size L × B (mm) | 2.5–3.0 × 2.0–2.5 | 2.1–2.8 × 2.0–2.4 |
| Mature worm weight (g) | 9.0 – 14.0 | 8.5 – 13.5 |
| Cocoon weight (g) | 4.5 – 8.55 | 2.90 – 7.70 |
| Shell weight (g) | 0.60 – 0.96 | 0.18 – 0.65 |
| Fecundity | About 300 eggs | About 175 eggs |
Wild stock outperforms cultivated stock on every measured character, including fecundity by a factor of nearly two — which is why the collected biotypes are maintained for hybridisation rather than as a museum collection.