Phys - Integument & Moulting 1

Front 1

Four main components of cuticle chemistry

Back 1

lipids, chitin, proteins, phenolics

Front 2

Cuticular lipids

Back 2

Water conservation, behavioral/pheromonal/ecological/taxonomic significance, complex mixture of lipids not just waxes, composition varies across species/life stages/response to environ

Front 3

Chitin

Back 3

Chain of acetylglucosamine and glucosamine (both carbon rings) linked together, formed into chitin rods, embedded into protein matrix

Front 4

Arthropodin

Back 4

Faenkel & Rudall proposed single cuticular protein, turned out actually complex protein mix in cuticle

Front 5

CPR proteins

Back 5

Largest cuticular protein family, two major groups of proteins within family (RR-1 and RR-2)

Front 6

RR-1

Back 6

Proteins from soft flexible areas of insect cuticles and don't become scleoritized tend to contain this sequence

Front 7

RR-2

Back 7

Proteins from hard sclerotized cuticle tend to contain this sequence

Front 8

Reslin

Back 8

Like rubber but less deformation, in wing hinges of some insects and jumping hinges of fleas/cicadas, part of distensible cuticle of ticks, likely secreted by epidermal cells

Front 9

Sclerotization/Tanning

Back 9

Process by which cuticle is hardened by substances other than chitin

Front 10

Phenols

Back 10

Aromatic hydrocarbons with -OH group directly attached to aromatic ring

Front 11

What gives rise to phenols?

Back 11

Tyrosine metabolism

Front 12

Two main types of phenols

Back 12

Catechol, Quinone

Front 13

Catechol

Back 13

Phenol with 2 -OH groups attached to the ring, cross link with proteins (beta-sclerotization)

Front 14

Quinone sclerotization

Back 14

reactive intermediates that cross link at ring position via covalent bonds with protein's functional group

Front 15

Intermoult period

Back 15

Epidermal cells attached to cuticle by plaques that anchor to base of cuticle to microvilli on epidermal cells

Front 16

Apolysis

Back 16

Separation of cuticle from epidermis, caused by epidermal cells being stimulated by hormones to grow in density/change shape, exuvial space created

Front 17

Exuvial space

Back 17

Space between epidermis and cuticle

Front 18

Inactive moulting gel + outer epicuticle

Back 18

Exuvial space fills with inactive moulting gel, epidermal cells secrete new outer epicuticle, layer becomes tanned/impervious to activated enzymes, epidermal cells release factors that activate enzymes in exuvial space

Front 19

Active moulting gel digests endocuticle

Back 19

90% of old endocuticle digested/reused, epidermal cells secrete new procuticle

Front 20

Active moulting gel

Back 20

Contains chitinases and proteases to digest endocuticle

Front 21

Growth of pro/epicuticle, wax layer, stereotyped behaviors

Back 21

New pro/endo epicuticle form using recycled materials, ecdysal lines become points of weakness, pore canals release components of wax layer, moulting fluid is reabsorbed, stereotyped behaviours

Front 22

Ecdysis

Back 22

Old cuticle splits, cement layer secreted by dermal glands, tanning precursors released, differentiation of procuticle into endo/meso/exo, growth of endo continues until next apolysis

Front 23

Moulting process steps

Back 23

Intermoult stage, apolysis, secretion of fluid, growth of epidermis, secretion of new cuticle, activation of enzymes in moulting fluid, shedding of old cuticle

Front 24

Pre-ecdysis behaviour

Back 24

Loosen old cuticle via rotational movements of abdomen

Front 25

Ecdysis behaviour

Back 25

Shed cuticle via peristaltic contractions that move anteriorly

Front 26

What causes eclosion behavior?

Back 26

Cascade of neurohormones