One of the main differences between insects and spiders is that they have different lifestyles and body parts. The insects’ lifestyle is through metamorphosis, which means that they change their form several times to become new creatures. They lay eggs, hatch as larvae, then turn into pupae, then finally emerge as adults. Spiders, on the other hand, usually start life as a spider and never change their form. They are spiders until they die.
Spiders and insects have different bodies. Insects have a body segmented into three parts, the abdomen, thorax, and head. On the other hand, spiders do not have these segments or ahead. Instead, they are made up of two body segments with an abdomen on the front of them, and all their legs come off from there (although some spiders have three parts). Another difference between the two is their antennae. Insects have antennae, and spiders do not.