Economic Importance of Insects (Beneficial and Harmful)

Insects play a crucial role in the ecosystem, influencing agriculture, medicine, and industries. They are found in diverse environments ranging from tropical forests to arid deserts and even arctic regions. Some insects are economically beneficial, while others cause significant harm.

1. Beneficial Insects and Their Importance

a) Ecological Importance of Insects

i) Pollination:

• • Bees, butterflies, wasps, ants, beetles, and flies pollinate crops and flowering plants.
  • Essential for fruit and seed production in plants like apples, oranges, coffee, and sunflowers.
  • Honeybees contribute to 70-80% of pollination in commercial crops.

ii) Soil Aeration and Nutrient Recycling:

• • Ants and beetles burrow into the soil, improving air and water movement.
  • Termites and decomposer beetles break down dead organic matter, returning nutrients to the soil.
  • Dung beetles help decompose animal waste, reducing disease spread.

iii) Natural Pest Control:

• • Dragonflies, ladybugs, praying mantis, and spiders control pest populations naturally.
  • Parasitic wasps attack insect pests, reducing crop damage.
  • Birds and amphibians feed on grasshoppers and caterpillars, keeping their numbers in check.

b) Commercial and Industrial Importance

1. Silk Production (Sericulture): Silkworm (Bombyx mori) produces silk, a high-value textile product. India and China are the largest silk producers.
2. Honey and Wax Production (Apiculture): Honeybees (Apis spp.) produce honey and beeswax, used in the food, cosmetic, and pharmaceutical industries. Wild honey has medicinal properties and is a nutrient-rich food source.
3. Lac and Dyes (Lac Culture): Lac insects (Kerria lacca) produce lac, used in wood polish, paints, and dyes. Used in cosmetics, printing inks, and confectionery.
4. Edible Insects as Protein Sources: Grasshoppers, crickets, mealworms, and ants are rich in protein and consumed in Asia, Africa, and Latin America. Sustainable alternative to meat production.
5. Medical and Pharmaceutical Uses:
   • Maggot therapy: Used in wound healing to remove dead tissue.
   • Bee venom therapy: Used to treat arthritis and other inflammatory conditions.
   • Antibiotics and drugs: Derived from insects to combat bacterial infections.

2. Harmful Insects and Their Economic Impact

a) Agricultural Pests

a) Crop Destroyers:

• • Locusts (Schistocerca gregaria): Destroy vast areas of crops, leading to famine.
  • Aphids, whiteflies, and thrips: Suck plant sap, reducing crop yield.
  • Stem borers (Sugarcane borer, Rice stem borer): Damage cereals like rice, wheat, and sugarcane.

b) Fruit and Vegetable Pests:

• • Fruit flies (Bactrocera spp.): Damage mangoes, citrus, guava, and other fruits.
  • Brinjal shoot and fruit borer: Reduces vegetable production.

c) Stored Grain Pests:

• • Rice weevil, pulse beetle, and khapra beetle: Damage stored food grains, causing huge losses.
  • Moths (Indian meal moth): Attack stored cereals and dry fruits.

b) Livestock and Human Pests

i) Blood-Sucking Insects:

• • Mosquitoes (Anopheles, Aedes, Culex): Spread malaria, dengue, chikungunya, and filariasis.
  • Tsetse fly: Causes sleeping sickness in humans and nagana disease in cattle.
  • Fleas and bed bugs: Affect human health and hygiene.

ii) Parasitic Insects on Animals:

• • Lice and mites: Affect poultry and livestock, causing reduced productivity.
  • Horseflies and stable flies: Cause irritation and disease transmission in cattle.

iii) Structural and Material Damage

1. Termites (White Ants): Damage wooden structures, books, and furniture. Cause billions of dollars in losses annually.
2. Fabric and Wool Pests: Clothes moths and carpet beetles: Damage wool, silk, and fur products.
3. Stored Food Contamination: Flour beetles and cockroaches: Contaminate food and spread disease.

Insects and Their Commercial Products

i) Honey and Wax Production (Apiculture)

Honeybees (Apis species) are cultivated for honey and beeswax. These products are widely used in:

• Food industry (honey as a natural sweetener)
• Cosmetics (beeswax in lotions and lip balms)
• Pharmaceuticals (honey for wound healing and antimicrobial properties)

ii) Silk Production (Sericulture)

Silkworms (Bombyx mori) produce silk, which is used in:

• Textile industry (making soft, breathable, and temperature-regulating fabrics)
• Skincare (silk proteins benefit the skin)
• Medical applications (biocompatible silk sutures for surgeries)

iii) Insects in the Food Industry

Edible insects are rich in nutrients such as protein, minerals, dietary fiber, riboflavin, and vitamins. They are consumed directly or processed into food products like flour, protein bars, pasta, and snacks.

a) Popular Edible Insects

• Crickets
• Locusts
• Houseflies
• Mealworms
• Ants
• Mantis

b) Chitin and Chitosan These substances, derived from insects, serve as: Dietary fibers used in baked goods, Flavors and coloring agents in processed foods

c) Medicinal Properties

• Apitoxin and melittin from honeybees help relieve pain and inflammation associated with multiple sclerosis.
• Cantharidin, a fatty acid from beetles, is used to treat cutaneous warts and certain tumors.

iv) Insects in the Pharmaceutical Industry Insects provide various bioactive compounds beneficial for human health:

• Antimicrobial Peptides (AMPs) Insects like ants and wasps produce AMPs (e.g., alloferons, defensin), which help fight bacterial, fungal, and viral infections.
• ACE Inhibitors Insects such as mealworms, leafworms, and silkworms contain angiotensin-converting enzyme (ACE) inhibitors, used in drugs for treating high blood pressure and obesity.
• Antioxidant Enzymes Catalase, peroxiredoxin (Prx), and superoxide dismutase improve metabolism and food storage stability.

v) Insects in the Cosmetics Industry

• Carmine Dye Extracted from the female insect Dactylopius coccus (native to Mexico and South America). Used in lipsticks, blush, and food coloring.
• Shellac Resin from lac insects (Laccifer lacca), found in India and Thailand. Used in nail polish remover, mascara, hair spray, and eyeliner.
• Essential Oils Extracted from locusts, crickets, and spider flies, these oils are safe for facial application and improve skin hydration and cellular healing.
• Beeswax and Honey Used in face washes, scrubs, lip balms, and hair conditioners. Provide moisturization, healing, and anti-aging properties.
• Sericin from Silkworms Found in creams and shampoos. Enhances skin elasticity, hydration, and anti-wrinkle effects.

vi) Insects in Agriculture Insects play a dual role in agriculture:

• Pest Control Beneficial insects like ladybird beetles, lacewings, and syrphid flies help control pest populations. Reduce the need for chemical pesticides, making farming more sustainable.
• Pollination Around 72% of the world’s crops depend on insect pollinators. Key pollinators: bees, wasps, butterflies, and moths. Enhance crop yield and quality.
• Herbivorous Insect Damage Around 18% of global agricultural production is lost due to insect pests like aphids. Farmers rely on biological control and integrated pest management to mitigate losses.

Harmful Aspects of Insects

i) Pests of Crops, Fruits, and Stored Products

• Insects such as aphids, locusts, and beetles attack crops, causing significant yield losses.
• Stored products like grains, wool, and tobacco are susceptible to insect damage.
• Locust swarms can devastate entire agricultural fields.

ii) Household Pests

• Blood-sucking insects: Mosquitoes and bedbugs bite humans, causing discomfort and disease transmission.
• Destructive insects: Cockroaches, termites, and silverfish spoil food, damage clothes, books, and wooden furniture.
• Carpet beetles and cloth moths damage fabrics, furs, and upholstery.

iii) Insects Harmful to Domestic Animals

• Ectoparasites: Fleas, lice, and ticks cause irritation and transmit diseases to livestock and pets.
• Endoparasites: Bot-fly larvae infest sheep and other animals, causing discomfort and economic losses.

iv) Insects as Disease Vectors

Several insects act as carriers of diseases by serving as intermediate hosts for pathogens:

• Anopheles Mosquitoes: Transmit malaria (Plasmodium parasite).
• Aedes Mosquitoes: Spread viral diseases like dengue and yellow fever.
• Culex Mosquitoes: Act as hosts for filarial worms, causing filariasis.
• Houseflies (Musca): Contaminate food and water, spreading diseases such as diarrhea and cholera.