9. Future avenues of research

One of the challenges to studying hyperparasitic fungi includes the ability to recognize the morphology and natural history of both the primary host and the primary parasite in their uninfected states. Currently few experts are trained to identify all of the partners in the different trophic levels of hyperparasitic interactions, which explains the paucity of published literature on this topic. While these hyperparasitic fungal systems are potentially diverse, they are largely unexplored. Multitrophic, multiyear, multisite sampling efforts have been proposed to strengthen future analyses on host specificity patterns and community ecology (Cazabonne et al., 2022; de Groot et al., 2020; Haelewaters et al., 2021a).
In addition to the lack of sampling, little attention has been given to the theoretical framework for systems involving hyperparasites (Sandhu et al., 2021). Most of this work has focused on the use of hyperparasitic fungi in biocontrol experiments, directed toward reducing the damage caused by primary parasites (Day, 2002; Rosenheim et al., 1995). It is essential to understand how parasites interact with their own parasites to effectively control infectious diseases (Parratt et al., 2017).
While much is left unknown about hyperparasitic fungi, the presence and expression of secondary metabolite gene clusters (Quandt et al., 2016, 2018) and their antifungal activities (Wang et al., 2016) among many lineages of mycoparasites including hyperparasites are well documented. The advent of genomics has proven that many species and strains have the ability to produce countless compounds whose activities have the potential for myriad biotechnological and pharmaceutical uses (Keller, 2019). Hyperparasites, many mentioned here in this chapter, likely harbor antifungal compounds that have yet to be discovered and described (Kim et al., 2002; Wicklow et al., 1998). Without more work examining hyperparasitic fungi, these compounds and their potential uses will remain unknown.