Trends in Economic Zoology Exercise Solutions | KalviGavani

Sericulture is the rearing of silkworms for commercial silk production. Life cycle of Bombyx mori: 1. Egg: Laid by female moth; hatches in 7-14 days 2. Larva (caterpillar): Goes through 5 instars (moulting stages) over 25-30 days; feeds on mulberry leaves; grows rapidly 3. Pupa (cocoon): The larva spins a cocoon of silk around itself; pupation takes 10-12 days 4. Adult moth: Emerges from cocoon; female lays eggs; adults do not feed Silk is obtained by boiling/steaming the cocoons to kill the pupa, then unwinding the continuous silk filament.

Apiculture (beekeeping) produces: 1. Honey: Sweet, viscous fluid; used as food and medicine; contains sugars, enzymes, vitamins, minerals 2. Beeswax: Secreted by worker bees; used in candles, cosmetics, polishes, pharmaceuticals 3. Royal jelly: Special food for queen bee larvae; rich in proteins and vitamins; used as health supplement 4. Propolis: Resinous substance collected from plants; used to seal gaps in the hive; has medicinal properties 5. Pollen: Collected by bees; used as protein supplement 6. Pollination service: Bees pollinate crops, increasing yield by 20-25%

Vermiculture (rearing earthworms) is important because: 1. Vermicompost: Earthworms convert organic waste into nutrient-rich organic fertiliser (NPK + micronutrients) 2. Eco-friendly: Reduces the need for chemical fertilisers 3. Waste management: Converts kitchen waste, crop residue, and cow dung into useful compost 4. Soil improvement: Vermicompost improves soil structure, water retention, and microbial activity 5. Vermimeat: Earthworms can be used as protein-rich animal feed 6. Income generation: Vermicompost can be sold as organic fertiliser

| Feature | Aquaculture | Pisciculture | |---|---|---| | Definition | Rearing of all aquatic organisms | Rearing of fish only | | Scope | Broader (fish, prawns, crabs, molluscs, seaweed) | Narrower (fish only) | | Relation | Aquaculture includes pisciculture | Pisciculture is a type of aquaculture | | Examples | Shrimp farming, pearl culture, fish farming | Catla, Rohu, Mrigal farming |

Sericulture is the rearing of silkworms for commercial silk production. It involves mulberry cultivation, silkworm rearing, cocoon production, and silk extraction. Process of Sericulture: 1. Mulberry Cultivation: - Mulberry trees (Morus spp.) are planted and maintained - Leaves are harvested and fed to silkworm larvae - Mulberry quality directly affects silk quality 2. Silkworm Rearing: - Silkworm eggs (seed) are obtained from grainages - Eggs are incubated at 23-25°C and hatched in 7-14 days - Newly hatched larvae are placed on mulberry leaves - Larvae go through 5 instars (moulting stages) over 25-30 days - During the final instar, the larva stops feeding and spins a cocoon 3. Cocoon Production: - The larva secretes silk from its silk glands through the spinneret - The silk hardens on contact with air - The cocoon is made of a single continuous filament (300-900 m) - The pupa develops inside the cocoon for 10-12 days 4. Silk Extraction: - Cocoons are boiled or steamed to kill the pupa and soften the sericin (gum) - The filament is unwound from the cocoon (reeling) - Several filaments are twisted together to form a silk thread - The thread is woven into silk fabric Economic Importance of Sericulture: 1. Employment: Provides livelihood to millions of farmers, weavers, and traders 2. Income: Silk is a high-value product; India is the second-largest silk producer 3. Export: India exports silk to many countries, earning foreign exchange 4. By-products: Silkworm pupae are used as poultry feed; mulberry leaves are used as cattle fodder 5. Women empowerment: Sericulture provides employment opportunities for rural women 6. Eco-friendly: Silk is a natural, biodegradable fibre

Caste System in a Honey Bee Colony: A honey bee colony has three castes: 1. Queen Bee (1 per colony): - The only fertile female in the colony - Larger than other bees with an elongated abdomen - Sole function: Lay eggs (up to 2000 per day) - Lifespan: 3-5 years - Produces queen substance (pheromone) that maintains colony cohesion - Developed from a fertilised egg fed on royal jelly throughout larval life 2. Worker Bees (thousands per colony): - Sterile females (underdeveloped reproductive system) - Smallest bees in the colony - Perform all the work: collecting nectar and pollen, building comb, feeding larvae, guarding the hive, cleaning, producing honey - Lifespan: 4-6 weeks (summer), several months (winter) - Have wax glands, pollen baskets, and a stinger - Developed from fertilised eggs fed on royal jelly for only 3 days, then pollen and honey 3. Drone Bees (few hundred per colony): - Male bees (developed from unfertilised eggs — parthenogenesis) - Larger than workers, smaller than queen - No stinger, no pollen basket, no wax glands - Sole function: Mate with a virgin queen during nuptial flight - Die after mating; killed by workers in autumn/winter when not needed Products of Apiculture: 1. Honey: Sweet, viscous fluid produced by bees from nectar. Contains sugars (fructose, glucose), enzymes, vitamins, minerals. Used as food, medicine (wound healing, cough), and sweetener. 2. Beeswax: Secreted by worker bees from abdominal wax glands. Used to build honeycomb. Commercial uses: candles, cosmetics, polishes, pharmaceuticals, dental wax. 3. Royal Jelly: Special food produced by worker bees for queen bee larvae. Rich in proteins, vitamins, and minerals. Used as health supplement and in cosmetics. 4. Propolis: Resinous substance collected from tree buds by bees. Used to seal cracks and gaps in the hive. Has antibacterial and antifungal properties. Used in medicine and cosmetics. 5. Pollen: Collected by bees from flowers. Rich in protein. Used as a nutritional supplement. 6. Pollination service: Bees are the most important pollinators. They increase crop yield by 20-25% through cross-pollination of fruits, vegetables, and oilseed crops.

Aquaculture is the rearing of aquatic organisms (fish, prawns, crabs, molluscs, seaweed) under controlled conditions for food and commercial purposes. Types of Aquaculture: 1. Based on Environment: - Freshwater aquaculture: In ponds, lakes, rivers (e.g., carps, catfish, freshwater prawns) - Brackish water aquaculture: In estuaries, backwaters (e.g., shrimp, mullet) - Marine aquaculture (mariculture): In sea cages, coastal farms (e.g., salmon, sea bass, pearl oysters) 2. Based on Organism: - Pisciculture: Fish farming (Catla, Rohu, Mrigal, Tilapia) - Prawn culture: Shrimp/prawn farming (Penaeus monodon, Macrobrachium rosenbergii) - Pearl culture: Pearl oyster farming (Pinctada fucata) - Seaweed culture: Kappaphycus, Gracilaria 3. Based on Intensity: - Extensive: Low stock density, natural food, low investment, low yield - Semi-intensive: Moderate stock density, supplementary feeding, moderate investment - Intensive: High stock density, complete feeding, aeration, high investment, high yield Common Fish Species in India: | Fish | Type | Habitat | |---|---|---| | Catla (Catla catla) | Indian major carp | Freshwater (surface feeder) | | Rohu (Labeo rohita) | Indian major carp | Freshwater (column feeder) | | Mrigal (Cirrhinus mrigala) | Indian major carp | Freshwater (bottom feeder) | | Tilapia | Exotic | Freshwater | | Salmon | Cold water | Marine/freshwater | Advantages of Aquaculture: 1. High protein food: Fish is a rich source of protein, omega-3 fatty acids, and vitamins 2. Employment: Provides livelihood to millions of fishermen and farmers 3. High yield: Controlled conditions give higher yield per unit area than traditional fishing 4. Food security: Reduces dependence on wild fish stocks 5. Export earnings: Shrimp and fish exports earn foreign exchange 6. Integrated farming: Can be combined with agriculture (paddy-cum-fish culture) 7. Year-round production: Unlike seasonal fishing, aquaculture can produce fish throughout the year 8. Waste utilisation: Fish waste can be used as fertiliser