History, challenges, and opportunities in the study of entomopathogenic fungi in tropical regions: Borneo as a model ecosystem

Fungal pathogens tend to have a poor reputation as a disease among the general public and policy-makers. However, entomopathogenic fungi, adapted to infect and kill arthropod hosts, play a wide range of roles in ecosystems, provide key ecosystem services, and offer interesting models to understand pathogen interaction networks. Tropical regions provide especially favorable conditions for studying this highly diverse group of fungi and their infection patterns across environmental and landscape disturbance gradients. In this chapter, we review the current state of knowledge on entomopathogenic fungi in tropical ecosystems, with a focus on the island of Borneo, which we present as a useful model system for their study. We briefly present how research on these fungi has evolved from early taxonomic work to more recent molecular and integrated approaches, and summarize what is currently known – and still poorly understood – about their diversity, ecological roles, the ecosystem services they provide, and the influence of biotic and abiotic factors. We also highlight some of the key challenges and opportunities associated with studying entomopathogenic fungi in the tropics. These regions are among the most biodiverse on the planet, but also among the most threatened. A better understanding of these poorly studied fungi will help clarify how their diversity is structured, how they interact with other organisms, and how they respond to environmental change, ultimately supporting their conservation and their integration into biocontrol and ecosystem management strategies.