Have tomato plants on balcony,blossoming no bees to pollenate them, how can I attract bees?

I was not aware that bees were necessary for the development of the fruit, i say this because i grow them all the time and never notice the bees so much.

Normally you don`t need to have the flowers polinated unless you want to use the seeds from them . if there are no bees or other inscets to pollinate your tomato plants get a small artists paint brush with fine bristles and go around the flowers collecting and spreading the pollen about your self .