Entomology
Week 3
Graham Holloway
Archaeognatha to Polyneoptera
- Insects are 1 x 10^18 diversity by Sir Robert May
o Low extinction rates; small body size, high population density, high dispersal
through flight, phytophagy [feeding on plants]
o Ability of lineage to generate phenotypic diversity over evolutionary time;
Evolutionary time = differential segment evolution/ decoupling of segments //
Developmental time = lifecycles and stages // Developmental plasticity; ability
to respond to changing conditions.
o Insect = Insecta = 3 segments.
1. Wingless Insects;
a. Archaeognatha [Bristletails]
b. Thysariura [Silver fish]
o Similar but silverfish don’t jump [they run quickly instead]/ don’t have
compound eyes and don’t have second articulation of mandible [dycondylic
mandible = feature of winged insects]
2. Palaeoptera;
a. Meganisoptera; [Extinct]
o Wingspan 70cm/ 325-245MYA/ stem group to dragonflies/ carnivorous/
larvae were possibly aquatic predators.
b. Odonta; [Dragonflies]
o 5,500spp/ predatory/ adults and nymphs carnivorous/ aquatic nymphs- naiads/
appear lower Permian 250mya
o Suborders; Anisoptera & Zygoptera
o Hunting; visual predator with large eyes/ enlarged pterothorax with
flight muscles, 360 colour vision// prey grasp in spiny legs, fliers
consume food in the air, perchers return to a roost to eat.
o Lifecycle; M terminalia evolves grasping structures/ territorial/ remain
coupled. Larvae of Anisoptera & Zygoptera easily differential.
o Flight; 50kph, direct flight muscles, wing beat = figure of 8 movement =
30bps. Thickened pterostigma at wing
tip = counterweight.
c. Ephemeroptera; [Mayfly]
o 3,100 spp / basal extant lineage of
winged insects/ adults don’t feed
[vestigial mouthparts]/ only live a
couple days/ soft bodied/ short
antennae/ long cerci and single long tail
filament = caudal filaments/ hind wings
small or missing/ paired peni
o Mating swarms of M; synchronous,
bushes used as markers, copulation in
flight, fly together for 10 mins, eggs laid in water – 10,000
Week 3
Graham Holloway
Archaeognatha to Polyneoptera
- Insects are 1 x 10^18 diversity by Sir Robert May
o Low extinction rates; small body size, high population density, high dispersal
through flight, phytophagy [feeding on plants]
o Ability of lineage to generate phenotypic diversity over evolutionary time;
Evolutionary time = differential segment evolution/ decoupling of segments //
Developmental time = lifecycles and stages // Developmental plasticity; ability
to respond to changing conditions.
o Insect = Insecta = 3 segments.
1. Wingless Insects;
a. Archaeognatha [Bristletails]
b. Thysariura [Silver fish]
o Similar but silverfish don’t jump [they run quickly instead]/ don’t have
compound eyes and don’t have second articulation of mandible [dycondylic
mandible = feature of winged insects]
2. Palaeoptera;
a. Meganisoptera; [Extinct]
o Wingspan 70cm/ 325-245MYA/ stem group to dragonflies/ carnivorous/
larvae were possibly aquatic predators.
b. Odonta; [Dragonflies]
o 5,500spp/ predatory/ adults and nymphs carnivorous/ aquatic nymphs- naiads/
appear lower Permian 250mya
o Suborders; Anisoptera & Zygoptera
o Hunting; visual predator with large eyes/ enlarged pterothorax with
flight muscles, 360 colour vision// prey grasp in spiny legs, fliers
consume food in the air, perchers return to a roost to eat.
o Lifecycle; M terminalia evolves grasping structures/ territorial/ remain
coupled. Larvae of Anisoptera & Zygoptera easily differential.
o Flight; 50kph, direct flight muscles, wing beat = figure of 8 movement =
30bps. Thickened pterostigma at wing
tip = counterweight.
c. Ephemeroptera; [Mayfly]
o 3,100 spp / basal extant lineage of
winged insects/ adults don’t feed
[vestigial mouthparts]/ only live a
couple days/ soft bodied/ short
antennae/ long cerci and single long tail
filament = caudal filaments/ hind wings
small or missing/ paired peni
o Mating swarms of M; synchronous,
bushes used as markers, copulation in
flight, fly together for 10 mins, eggs laid in water – 10,000
