Quick Summary
Economic Zoology covers practical applications of animals for human benefit: sericulture (silk), apiculture (honey/wax), aquaculture (fish/prawns), lac culture (shellac), vermiculture (compost), animal husbandry, and poultry. This chapter is descriptive but carries direct marks in board exams.
Sericulture (Silk Farming)
Organism: Bombyx mori (mulberry silkworm) — most commercially important Food plant: Mulberry (Morus alba)
Life cycle: Egg → Larva (caterpillar) → Pupa (cocoon) → Adult moth
Silk production:
- Larva secretes fibroin (structural protein) from silk glands → wraps itself into cocoon
- Cocoon boiled → silk thread reeled → woven into fabric
- One cocoon = ~300–400 m of silk thread
Other silk moths: Tasar (Antheraea mylitta — oak leaves), Eri (Attacus ricini — castor leaves), Muga (Antheraea assamensis — semialata leaves, Assam only)
India: Second largest silk producer (after China); Karnataka is leading state.
Apiculture (Bee Keeping)
Commercial species in India:
- Apis mellifera (Italian bee) — most domesticated, gentle, high honey yield
- Apis cerana indica (Indian bee)
- Apis dorsata (rock bee) — largest, aggressive
- Apis florea (little bee) — smallest
Colony structure:
| Caste | Number | Role |
|---|---|---|
| Queen | 1 | Lays eggs (up to 2000/day); pheromone control |
| Workers | Thousands | Infertile females; foraging, honey-making, nursing, wax secretion |
| Drones | Hundreds | Males; fertilise queen; die after mating |
Products: Honey (anti-microbial, energy food), Beeswax (cosmetics, polish, candles), Royal jelly (queen's food), Bee venom (medical), Propolis (antibiotic resin)
Bee dance:
- Round dance: Food source < 80 m from hive
- Waggle dance: Food source > 80 m; angle and duration indicate direction and distance
Aquaculture and Pisciculture
Aquaculture: Controlled rearing of aquatic organisms — fish, prawns, oysters, mussels, seaweed.
Composite fish culture (polyculture): Multiple compatible fish species at different feeding levels:
- Surface feeders: Catla catla
- Mid-water: Rohu (Labeo rohita)
- Bottom feeders: Mrigal (Cirrhinus mrigala)
- Algae feeders: Common carp, Grass carp
Advantages: Maximises pond productivity; reduces competition.
Prawn culture: Penaeus monodon (giant tiger prawn) most commercially cultivated.
Pearl culture: Oysters (Pinctada) implanted with foreign particle → nacre coating → pearl.
Lac Culture
Organism: Laccifer lacca (lac insect, a scale insect) Host plants: Ber (Zizyphus), Kusum (Schleichera), Palas (Butea)
Lac production: Lac insects puncture host plant → secrete lac resin around themselves → harvested → processed into shellac (lac)
Uses of lac/shellac: Varnishes, lacquers, sealing wax, gramophone records, cosmetics, pharmaceutical coating.
Vermiculture
Organism: Eisenia fetida (red earthworm), Lumbricus terrestris
Process: Organic waste (kitchen waste, agricultural waste) fed to earthworms → digested → vermicompost (castings)
Benefits of vermicompost:
- Rich in N, P, K, and micronutrients
- Improves soil aeration and water retention
- Increases microbial activity
- Eco-friendly alternative to chemical fertilisers
Animal Husbandry
Cattle breeds:
| Purpose | Indian breeds | Exotic breeds |
|---|---|---|
| Milk (dairy) | Sahiwal, Gir, Red Sindhi | Holstein Friesian, Jersey |
| Draught (work) | Kangayam, Hallikar | — |
| Dual purpose | Tharparkar | Karan Fries (cross) |
Buffalo breeds: Murrah (highest milk yield), Surti, Mehsana
Poultry:
- Commercial layers (egg production): White Leghorn
- Commercial broilers (meat): Plymouth Rock cross
- Improved Indian breeds: Aseel, Chittagong
Fisheries: India has one of the world's largest fish-producing nations.
- Marine: Sardinella, Bombay duck, prawns
- Inland (freshwater): Rohu, Catla, Mrigal
Important Questions
One Mark
- Name the silkworm species most commonly used in sericulture.
- What is the food plant of Bombyx mori?
- Name the organism used in vermiculture.
- Which bee is the pacemaker/queen of the colony?
Short Answer (3 marks)
- Describe the caste system in a honeybee colony.
- What is composite fish culture? Name three species used and their feeding levels.
- What are the uses of lac? Name the host plant of the lac insect.
Long Answer (5 marks)
- Give a detailed account of sericulture — organism, life cycle, silk production, and economic importance.
- Explain apiculture. Name the commercial bee species used in India and list the products obtained.
Common Mistakes
- Bombyx mori is the mulberry silkworm — other silkworms (Tasar, Eri, Muga) are different species.
- Lac insect is Laccifer lacca — NOT the same as a beetle; it's a scale insect (homopteran).
- Drone bees are MALE (not worker); workers are infertile FEMALES.
- Vermiculture uses red earthworms — not all earthworm species.
Board Exam Tips
- Sericulture (life cycle, silk production, economic importance) is a standard 5-mark question.
- Apiculture (caste system, products, bee dance) is another 5-mark staple.
- Composite fish culture with 3–4 species names and feeding levels is a reliable 3-mark question.
- NEET: This chapter contributes 1–2 factual questions — scientific names and economic products are the key items.