What a wasp eats depends on both the age of the wasp and the particular species; some adult wasps are carnivores, while others get all of their nutrition from nectar in the same way as bees. In most cases, wasp larvae eat insects and other prey brought to them by the adults. In some species, the adults liquefy the prey for the larvae, while others simply eat them whole.
In some species, the adults and larvae have a symbiotic relationship, in that the adult brings prey to the larvae to eat, after which the larva regurgitate a sugary substance that the adults then eat. However, other wasp larvae are purely vegetarians and subsist entirely off plants until they transform into adult wasps.
Some species of wasps are parasitic as larvae. The adult lays eggs inside a spider or insect, and after the eggs hatch, the larvae then feed on it from the inside until it dies. In most parasitic wasp species, the adults feed only on nectar after they emerge from their dead host.
Predatory wasps are often attracted to high-protein foods, such as meat from dead animals, whereas many other species are primarily attracted to sugary substances such as fruit.