Even parasites have parasites. By definition, a hyperparasite is an; organism capable of parasitizing another parasite. Hyperparasitism; caused by fungi is a common phenomenon in nature, but it has been poorly; studied. This life history strategy evolved several times in the fungal; tree of life, and is crucial in the maintenance of ecosystems as well as; in the mediation of parasite–host interactions. Although the interest; for hyperparasitic fungi is growing in the context of biological; control, hyperparasitism is not ecologically and evolutionarily; understood. This chapter summarizes the most relevant aspects of the; terminology, diversity, and ecology of hyperparasitic fungi on both; fungal and non-fungal hosts. We also discuss the problems related to; molecular research on hyperparasitic fungi. As they represent a hidden; source of diversity, it is necessary to increase sampling efforts and to; undertake further morphological, molecular, and ecological studies to; understand these fungi and their potential biotechnological and; pharmaceutical uses.
