So these robots have heart-shaped pumps and may be human like mouths to eat the flies and organic waste and a kind of digestive system to turn that waste into energy and also discard the remaining waste from the bottom.
Looks almost like a human system!
these bots should be equipped with software that makes them feel hungry when the batteries deplete, so that they can move and find suitable food themselves instead of somebody feeding them.
It wasn't enough that we had nightmares (and movies) where the robots would enslave us and kill us all; they are now going to eat us!
This is actually an interesting concept as some of the jobs that we would like robots to do will be in environment where organic material is available. Eg: a swarm of farming robot could eat the bugs it finds to rid the field of pests. (Just make sure they don't like the taste of mammals...)