All wasps by definition are predators / parasites of many different prey insects. There are a few varieties of larger wasps that are actually known to carry off hornworms and tomato fruitworms to feed their young after chewing them up. While browsing, the wasp will often skip past worms already parasitized by another species of smaller parasite. The wasp will hover nearby, "drumming" her antennae on the worm to determine if it is a suitable meal. Some smaller species are actually known to pace off the size of their prey.
Wasps have the ability to determine the sex of their offspring. They will feed their male offspring with the smaller prey insects, and give their female offspring the larger ones, because the females are in need of greater nutrition to produce more and fertile eggs.