Yes they do, same as guppies. Meaning they do not really hunt them down, like the minnows do, they are real hunters, but will make a little effort and if they catch it fine, if not they won't really pursue them.
However as all adults will dart at them a fair share will be eaten, same as with guppies.
So if you have lots of plants you will always have some fry survive, however if you want to increase the numbers quickly it pays to catch them as you see them floating around and raise them in another tank until they are big enough not to make a meal anymore.
They do not have so many babies compared to guppies or platies and also seem not to have babies as often, maybe because they are kept colder. So all in all their multiplying factor is relatively slow compared with other livebearers.