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INSECT BODY PLAN AND EXOSKELETON

INSECT BODY PLAN AND EXOSKELETON. PHYLOGENY. Hexapoda. Mandibulata. Crustacea (crabs, lobsters, barnacles). Pauropoda. Diplopoda (millipedes). Myriapoda. Chilopoda (centipedes). Arthropoda. Symphyla. ?. Arachnida (spiders, mites, ticks). Eurypterida (sea scorpions). Chelicerata.

sigourney-buckley
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INSECT BODY PLAN AND EXOSKELETON

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  1. INSECT BODY PLAN AND EXOSKELETON

  2. PHYLOGENY Hexapoda Mandibulata Crustacea (crabs, lobsters, barnacles) Pauropoda Diplopoda (millipedes) Myriapoda Chilopoda (centipedes) Arthropoda Symphyla ? Arachnida (spiders, mites, ticks) Eurypterida (sea scorpions) Chelicerata Xiphosura (horseshoe crabs) Pycnogonida (sea spiders) Trilobita (trilobites)

  3. Arthropod Lineages

  4. Insect Body Plan Tagmata Head Thorax Abdomen 6 segments - sensory & feeding • 11 segments • digestion & reproduction 3 segments - locomotion Total of 20 segments (primitively)

  5. Insect Body Plan Tagmata Head Thorax Abdomen Cross section tergum (notum) pleuron pleuron sternum

  6. Insect Body Plan tergum (notum) pleuron pleuron sternum Note: The bits of exoskeleton (the pieces in the puzzle) that make up the outer surface of an insect are collectively referred to as sclerites. Each surface of an insect has its own sclerites which are referred to as tergites, sternitesand pleurites.

  7. Insect Body Plan Segments 1) Primitive Condition (annelids, larval insects) primary segment primary segment primary segment longitudinal muscle intersegmental fold

  8. Insect Body Plan Segments 2) Intermediate Stage (hypothesized) primary segment primary segment primary segment longitudinal muscle segmental sclerite intersegmental sclerite

  9. Insect Body Plan Segments 3) Third Stage (seen in Apterygota) secondary segment primary segment 4) Final Stage (seen in Pterygota) phragma

  10. Insect Integument (Exoskeleton) Why are insects crunchy? Outer epicuticle Epicuticle Inner epicuticle Exocuticle Procuticle Endocuticle Schmidt’s layer Epidermis Basement membrane Pore canals

  11. Insect Integument (Exoskeleton) Why are insects crunchy? Outer epicuticle Epicuticle Inner epicuticle cement wax oriented wax cuticulin Inner epicuticle Exocuticle (procuticle) pore canal

  12. cement wax Insect Integument (Exoskeleton) oriented wax Wax Layers - Control of Water Movement WATER IS RETAINED WATER WATER

  13. Structure of Chitin - Albert Hoffman (1906 – 2008)

  14. Insect Integument (Exoskeleton) N - acetylglucosamine polymer O = C - CH2 NH H CH2OH O O H H H H OH O H H OH O NH CH2OH H O = C - CH2 n

  15. Insect Integument (Exoskeleton) O = C - CH2 NH H CH2OH O H H H H OH O H H OH O NH CH2OH H O = C - CH2 CO NH CO NH CO NH NH CO NH CO NH CO CO NH CO NH CO NH NH CO NH CO NH CO hydrogen bonds

  16. Insect Integument (Exoskeleton) microfibril N - acetylglucosamine polymer sheets of microfibrils orientation of microfibrils changes

  17. Insect Integument (Exoskeleton) Protein Matrix

  18. Insect Integument (Exoskeleton) Cross linking of protein matrix

  19. Insect Integument (Exoskeleton) Cross linking of protein matrix OH O OH OH O OH OH OH Protein Protein CH2 CH2 CH2 Protein Protein C CH2 CH2 CH2 CH2 N-acetyl dopamine N-acetyl dopamine quinone

  20. What other common material has cross-linked fibres in a matrix? Oriented Strand Board (OSB) Plywood Plywood Plywood Plywood

  21. Insect Integument (Exoskeleton) kg/mm2 Tensile strength of sclerotized chitin (sclerotin)

  22. Some days you’re the bug, some days you’re the windshield. - Mark Knopfler

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