Insects Flashcards
Apterygotes
Wingless
Procuticle
Forms exo and endocuticle
Chitin microfibrils in protein, water and lipid matrix - stiff fibres and soft matrix prevent cracks spreading
Fibrils orientate for mechanical properties (helicoidal or parallel)
Exopterygotes
Larvae and adults look similar, wings gradually develop
Discontinuous gas exchange
Cyclical spiracle opening and closing pattern so gas exchange is in bursts
-close, O2 decreases as it’s used so pressure decreases
-flutter and air in
-fluttering until CO2 builds up and they fully open
(decreases O2 and water loss)
Epicuticle
No chitin
Layer between wax layer/cuticulin and procuticle
Proventriculus
Muscular valve that controls passage of food into midgut
Koinobiont
Host alive so doesn’t need to be protected
Narrow host range
Derived
20-HE
Hormone involved in moulting that signals body size and nutrition state
Synchronous flight muscle
Neurogenic, 1 impulse = 1 contraction
Frequency up to 100Hz
Rapid Ca2+ release and uptake
Endopterygotes
Adult and larvae forms different
Pupal stage
Metamorphosis
Qualitative defences
In quick growing/pioneer plants
E.g. Toxins
Cheap, small amounts, effective against generalists
Apolysis
First moulting stage
Epidermal cells detach from cuticle and cells rapidly divide
Mandibles
Cutting, chewing
Labrum
Extension of the head and therefore not a true articulated appendage
Forms roof of mouth
Hyperparasitoid
Feeds on another parasitoids larva
Standing defence
Defence that is present all the time (incurs a cost if no parasitoids present to defend off)
Labium
Derived from second pair of maxillae, fused together
Forms floor of mouth
Young’ Modulus
Stress/Strain
=stiffness
e.g. High in extensor tibia, low in larvae
Peritrophic membrane
Mesh like cuticular film lining midgut and separating food from midgut tissue and protecting the epithelium from abrasion and microorganisms
N-acetyl-dopamine
Tanning agent, release triggered by bursicon
Activates cross linking enzyme
Quantitative defences
In slow growing/long-lived plants
E.g. Tannins
Many produced, expensive, very effective but dosage dependent
Resilin
Procuticle form
Returns 97% elastic energy
For rapid repeated moving because reduced heat and fatigue
Or as a power amplifier to replace muscles
Nasoria Vitripennis
Son-killer biological agent, maternally inherited
Male eggs die because bacterium from mother kills it
(Males can’t pass on bacterium but females can do killing males frees up space for females so more bacteria passed on)
Indirect flight muscles
Dorsal and longitudinal (length of thorax)
Contract –> thorax top arches up and dorsoventral muscles lengthen, pulling wings down
