I always have worms in my pots and think that they help with aeration and produce castings. These are natural red worms from manure compost or other earth worms that get into the pot through the bottom hole. However, with cups it is problematical because there is not much space for them and I doubt there is much food for them. Red worms are heavily dependent on semi-decomposed manure or vegetable material, and earth worms need semi-decomposed leaves. Do you put that staff in your cups? I doubt it. It is mostly mature compost, moss, perlite, and vermiculite which is not a good medium for worms to thrive.
I know exactly why worms like my pots and this is because I mix rabbit droppings into my soil or add them on top of the soil - that's something delicious for any worm. Attention! Rabbit droppings mixed into the soil will make it hold too much water and it would be easy to go wrong with the quantity. The safest way is to not fill the pot all the way with soil and to add the droppings on top in a 2-3" layer.