I don't think camera system size has been limiting factor in surveillance for a while. For robotics (either walking or flying) the locomotion and power are more

I don't think camera system size has been limiting factor in surveillance for a while. For robotics (either walking or flying) the locomotion and power are more restricting aspects, and using live insects for surveillance seems too slow and unpredictable to be useful. Check out Black Hornet Nano for what was state of art almost a decade ago https://en.wikipedia.org/wiki/Black_Hornet_Nano https://en.wikipedia.org/wiki/Black_Hornet_Nano