What do the ants in Chapter 1 symbolize? What do the big black ones with shiny bodies represent? The little dusty ones?

The description of the ant caught in the sand trap foreshadows Kino's future. He will become a prisoner of his own ambition.

"The ants were busy on the ground, big black ones with shiny bodies and the little dusty quick ants. Kino watched with the detachment of God while a dusty ant frantically tried to escape the sand trap an ant lion had dug for him."