Ants live in colonies, Butterflies do not.
That’s one difference, but we can also look at the lifestyle of named creature also.
The Ants, like I’ve said live in colonies, they have a ‘society’ in which they have ants assigned and ‘designed’ for certain jobs such as infertile female workers and soldiers, drones (fertile males) and 1 or more queens (fertile females), in which all play a certain role, in which workers can be assigned into many differently roles which they may switch now and again.
Such as (make sure you note differences to butterflies here) building, gathering, cleaning, looking after young, scouting out new sources of food, (some ants) ‘milk’ caterpillars and aphids as well as cultivate fungus and many more jobs.
Butterflies are all fertile, no society of butterflies, caterpillars are independent as well as having 3 pairs of true legs and 5 pairs of prolegs, in total 16 legs.
Butterflies don’t build structures, they don’t hunt like ants do, they are sometimes eaten by ants, eat plant based products and foods.
Hope this helps and highlights some differences, good luck!