Why did insects win?

It basically starts from this blog post. The question is: why are Insecta the most diverse group of arthropods, if not of living beings, on Earth's land, while Arachnida and other arthropod groups aren't?

Here I collect some material for further posts on the subject.


Evolution of Arthropoda

  • Marine evolution of Arachnida: "The oldest known scorpions lived around 430 million years ago in the Silurian period, on the bottom of shallow tropical seas.[15] These first scorpions had gills instead of the present forms' book lungs." ( Scorpion )
  • Sea scorpions ( Eurypterida ) gills were in the tail; also no polyramous limbs?

Genes in evolution of arthropod body plans

Evolution of insect flight

Evolution of metamorphosis

  • "The evolution of complete metamorphosis in insects is a key innovation that has led to the successful diversification of holometabolous insects," Suzuki et al. (molecular biology of pupa)


  • The Pancrustacea hypothesis is intriguing because Crustaceans show also considerable diversity. Clades away from Pancrustaceans show less diversity? Measurement of morphological characters?
  • gg :
  • segmentation difference
  • compound vs single eye

Wings problem

  • It seems that wings arose from pre-crustacean gills. Arachnida precursors (eurypterids?) had no comparable structure to transform into wings. That's why we don't see flying spiders.

Metamorphosis problem