Food webs are central to fundamental aspects of ecology, including complexity, diversity, stability and functioning1 and powerful tools for the management of complex ecosystems2 and fisheries3. Even though parasitism is the most common consumer strategy in the animal kingdom and parasites can be involved in 50% of interactions in trophic networks4, they have been ignored in food webs until recently. This is partially due to difficulties involved in studying parasites. It also reflects the common, but often mistaken, assumption that parasites contribute little to the energy flow in an ecosystem5. Parasites can augment and redirect the flow of energy in an ecosystem through the modification of their hosts' behaviour, leaving them more vulnerable to predation, and therefore increasing the energy flow between prey and predator. In fact, productivity is high in parasites since they circumvent metabolically expensive activities such as movement and homeostasis and parasite biomass can even exceed that of top predators in some ecosystems6. Food webs are commonly used to study the resilience of an ecosystem to species loss and other perturbations. Parasite inclusion amplifies complexity and initially increases food web robustness, due to apparently functional redundancy in parasites. However, the life cycles of most parasites include multiple life stages that undergo diet and niche changes that are not accounted for. There is a need for more accurate methods of parasite inclusion to improve ecological realism in food web ecology.