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scaffold for strength, muscle attachments
• pleural (suture) (example)• critical for flight
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Two major sections:
1. epicuticle2. procuticle
epidermal cells
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• Epicuticle –made up of cuticulin and inner epicuticle
epicuticle
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epidermis and associated cells
• epidermal cells• glandular cells• oenocytes
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Basic unit of chitin is n-acetylglucosamine
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Chitin makes up as much as half of the exoskeleton
forms long chains
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chains interact with each otherhydrogen bondsform microfibrils
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Across insect cuticle, sclerotization varies
• Exocuticle = hardened region
• Endocuticle= not hardened
Exocuticle
Endocuticle
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Degree of sclerotization varies in different body parts, stages,
species … etc
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Regions of unsclerotized cuticle give points/lines that can bend
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a cuticle protein
• “cleft” full of aromatic residues, which form “flat”surfaces of aromatic rings, for protein–chitin interactions
• outer surface (lower side) important for protein–protein interactions in cuticle.
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A protein in hard cuticle
• Histidines (blue) are in right position to participate in sclerotization
• Or to be involved in water binding capacity of cuticle
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A protein in soft cuticle
• lacks histidinesfor sclerotization
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Young’s modulus
= stiffness
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Dermaptera• very important in
wing flexibility and resilience
• blue areas contain resilin
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engineers at work
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Pore Canals
epidermal cells have extensions that reach up through the epicuticle
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Multilayer reflectors
Seago A E et al. J. R. Soc. Interface 2009;6:S165-S184
©2009 by The Royal Society
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• layer spacing has peak green reflectance
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• the broader the range of thicknesses, the closer to pure silver or gold
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The iridescent scales of the Morpho sulkowskyi butterfly give a different optical response to different individual vapours. This optical response dramatically outperforms that of existing nano-engineered photonic sensors.
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What happens if these cells make new cuticle?
• It will be the same size as the one before
• FIRST, cell division!
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APOLYSIS-separation of old cuticle
from epidermis, formation of space
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• Molting fluid
• New cuticulinand epicuticle
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Enzymes activatedInner epicuticle produced
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Endocuticledigested
Fluid reabsorbed
Procuticle laid down
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Expansion, sclerotization