feed (up)on (someone or something)
Literally, to eat or consume something for sustenance. Ugh, as soon as I go outside, I feel like the mosquitos are just feeding on me!
feed (up)on someone or something
to eat someone or something. (Upon is formal and less commonly used than on.) They say that some Bengal tigers feed upon people. They feed on anything that moves.
feed on
v. To be nourished or sustained by something. Used especially of animals: Pigs feed on corn husks.