with most species, adult parasitic wasps themselves do not take any nutrients from their prey, and, much like bees, butterflies, and moths, those that do feed as adults typically derive all of their nutrition from nectar. parasitic wasps are typically parasitoids, and extremely diverse in habits, many laying their eggs in inert stages of their host (egg or pupa), or sometimes paralyzing their prey by injecting it with venom through their ovipositor. they then insert one or more eggs into the host or deposit them upon the host externally. the host remains alive until the parasitoid larvae are mature, usually dying either when the parasitoids pupate, or when they emerge as adults. farmers buy these parasitic wasps for insect control in their fields.