Entomology Module 5

Insect Physiology 

1. Insect cuticle layers – epicuticle, exocuticle, endocuticle.
2. Molting hormone – ecdysone (from prothoracic gland).
3. Juvenile hormone (JH) – secreted by corpora allata, prevents metamorphosis.
4. Brain hormone (PTTH) – activates prothoracic gland.
5. Chitin – polysaccharide forming main cuticular component.
6. Haemolymph functions – nutrient transport, immunity, wound healing.
7. Haemocytes types – plasmatocytes, granulocytes, oenocytes.
8. Thermoregulation – maintained by behavior, not physiology.
9. Oxygen transport – via diffusion through tracheal system.
10. Fat body – similar to liver; stores lipids, glycogen, and proteins.
11. Midgut enzymes – amylase, protease, lipase.
12. Excretion – via Malpighian tubules (uric acid excretion).
13. Reproduction – mostly sexual; few parthenogenetic (aphids).
14. Vitellogenesis – yolk formation in developing eggs.
15. Accessory glands – produce cement, milk, silk, etc.
16. Oviposition – laying of eggs using ovipositor.
17. Spermatheca – stores sperm in female insects.
18. Male accessory gland – secretes spermatophore (ejaculatory packet).
19. Copulation – exchange of sperm during mating.
20. Fertilization – internal in all insects.

Biological Control Agents

1. Biological control – use of natural enemies to reduce pest population.
2. Predators – kill and consume prey (ladybird beetle, chrysopa).
3. Parasitoids – develop inside/on host, kill host (Trichogramma).
4. Pathogens – disease-causing microorganisms (Bt, NPV, fungi).
5. Bacterial control – Bacillus thuringiensis (Bt toxin).
6. Fungal control – Beauveria bassiana, Metarhizium anisopliae.
7. Viral control – Nucleopolyhedrosis Virus (NPV), Granulosis Virus (GV).
8. Protozoan control – Nosema locustae.
9. Trichogramma chilonis – egg parasitoid for Helicoverpa.
10. Chelonus blackburni – egg-larval parasitoid in cotton.
11. Bracon hebetor – larval parasitoid of moths.
12. Encarsia formosa – parasitoid of whitefly.
13. Aphidius colemani – parasitoid of aphids.
14. Cryptolaemus montrouzieri – predator of mealybugs.
15. Chrysoperla carnea – green lacewing, predator of aphids.
16. Rodolia cardinalis – predator of cottony cushion scale.
17. Ladybird beetle (Coccinella septempunctata) – predator of aphids.
18. Predatory mite (Amblyseius spp.) – controls thrips and mites.
19. Augmentation – mass release of biocontrol agents.
20. Conservation – protecting existing natural enemies.
21. Importation (Classical) – introducing exotic natural enemies (e.g., Rodolia cardinalis).

Insect–Plant Relationships

1. Phytophagous insects – feed on plant tissue.
2. Monophagous – feed on one host (rice stem borer).
3. Oligophagous – few hosts (cotton bollworm).
4. Polyphagous – many hosts (Spodoptera litura).
5. Gall formation – abnormal tissue growth due to insects.
6. Pollination – mutualistic relation (bees, flies, butterflies).
7. Vector insects – transmit pathogens (aphids, whiteflies).
8. Mechanical transmission – passive (housefly).
9. Biological transmission – pathogen multiplies inside vector (aphids).
10. Transovarial transmission – virus passes to eggs (whitefly).
11. Plant resistance mechanisms – antixenosis, antibiosis, tolerance.
12. Antixenosis (non-preference) – insect avoids plant (color, texture).
13. Antibiosis – plant toxins affect insect survival.
14. Tolerance – plant tolerates pest damage without yield loss.
15. Resistant varieties – an eco-friendly pest management method.

Important Scientific Names & Discoveries

1. Father of Modern Taxonomy – Carl Linnaeus.
2. Father of Indian Entomology – T.B. Fletcher.
3. Father of Biological Control – Paul DeBach.
4. Father of Economic Entomology – W.F. Kirby.
5. First insect described – Apis mellifera (Linnaeus, 1758).
6. Father of Insect Physiology – Wigglesworth.
7. Father of Apiculture – Lorenzo Langstroth.
8. Father of Sericulture – Sir Thomas Wardle.
9. Inventor of Bt – Berliner (1911).
10. Karl von Frisch – discovered bee dance language.
11. Metcalf (1944) – classified insecticides.
12. Daly & Doyen – insect classification (1993).
13. Berliner – discovered Bacillus thuringiensis.
14. Müller – discovered DDT’s insecticidal property.
15. Riley (1883) – concept of biological control.