I would be kind of surprised if a day gecko would eat mealworms, but you could put some in a bowl and see how much it eats. Just do some trial and error.
it's eating, but i don't know how many to give because i don't want to be fatty. i this moment I can't find grasshoppers, crickets or something else...i give it some mealworms and babyhood.
the day gecko has 19 cm...i don't know if it's adult or not