How are round island day gecko teeth adapted to what they eat?

Geckos don't have teeth, they eat crickets and stuff like that for two main reasons: geckos aren't that big, epically as babies so insects and worms are the only thing they can eat, and to get the nutrients that they need, this is going back to the food chain the cricket gets the nutrients it needs by eating grass, then the lizard eats the cricket getting the grass and the cricket, which is eaten by the snake, which is eaten by the hawk, which is eaten by the coyote, which will mostly likely be killed by the human (hopefully not to be eaten by the human)