BIO2231 Lecture Notes - Lecture 12: Palaeoptera, Apterygota, Exopterygota
Lecture 12 – Arthropoda IV: Hexapoda: Insects
Hexapod Diversity
• Large number of orders
• Relationship not clear
• Terrestrial, freshwater
• Very different ecologies
Class Insecta: Apterygota (no wings)
Class Insecta: Pterygota (winged species)
• Most familiar insects
• Two pairs of wings in most adults
• Grouped based on wing function
o How they’re developed and work
• Paleoptera – oldest group, ancient wings
o Wings thought to be most similar to ancestral condition – unable to be
folded
o E.g. dragonflies
• Neoptera – new wings
o Wings folded when the insect is at rest
o Includes all other orders
o Divided into two groups based on development pattern
o Exopterygota
▪ Wings developed externally to the body
▪ Nymphal stages – no differential stages (hemimetabola)
▪ E.g. Orthopteroid orders (grasshoppers, mantids, termites)
• Biting mouthparts
• Herbivores and predators
• Hemimetabolous
▪ E.g. Hemipteroid orders (aphids, cicada and backswimmers)
• Piercing and sucking mouthparts
• Plant feeders
• Predators
o Endopterygota
▪ Wings developed inside the body
▪ Different developmental stages (holometabola)
▪ Larvae undergo a complete change through a pupal stage to an
adult
▪ E.g. Lepidoptera orders (butterlies and moths)
• Wings covered in scales
• Active larvae
• Modified mouthparts
▪ E.g. Coleoptera (beetles)
• Fore wings modified into protective elytra
• One pair for flight, one for protection
• Biting and chewing mouthparts
▪ E.g. Diptera (flies, mosquitoes)
• 2 winged flies
• Hind wings modified into halters
find more resources at oneclass.com
find more resources at oneclass.com
