Pathogenic fungi – Department of Biology - University of Copenhagen

Fungi, plants and animals all descend from different unicellular, flagellated and aquatic protists that became multicellular and radiated extensively. The arthropod ancestors of insects colonized the land ca. 450 million years ago and the plants ca. 425 million years ago. The common ancestor of the fungi is likely to be even older.

The most basal branches of the fungal tree of life are unicellular endoparasites of insects and other fungi, but the remaining fungi evolved filamentous growth, which enhanced their efficiency to absorb nutrients through extracellular digestion and to attach to the substrate. Saprotrophic and mutualistic life styles evolved later as did the ability to break down the chitin of the insect cuticle. Numerous transitions from pathogenic to saprophytic life histories and vice versa have occurred, so that today’s insect pathogenic fungi are scattered among both the basal and the evolutionarily derived fungal lineages. In some cases parasite-host relationships are highly specific, but quite often a fungal parasite can infect a rather broad range of insect hosts.

CSE has long-standing expertise in the study of insect pathogenic fungi through the track record of the Eilenberg group. Cooperative projects in recent years have addressed the defences to infection with generalist fungal pathogens such as Metarhizium in leaf-cutting ants and garden ants. Our current work on social insect diseases investigates how costly fungal infections are for colonies of ants and honey bees, and how colony-level genetic diversity and/or individual defences may limit the impact of fungal parasites. We focus on chalk brood (Ascosphaera) disease-pressure in honey bees, on Ophiocordyceps infections in Camponotus and leaf-cutter ants, and on Pandora infections of Formica ants. CSE research also tries to address general questions about infection characteristics across the major clades of insect pathogenic fungi and about the general ecological and evolutionary forces that determine the prevalence of sexual and asexual stages. We jointly wrote a review on the evolutionary interaction networks of insect pathogenic fungi, which was published in Annual Review of Entomology (2014).

Questions asked

  • What are the major trade trade-offs between individual and collective defence of social insects against pathogenic fungi?
  • How do immune parameters affect social insect mating systems?
  • How variable are life-history traits of Ophiocordyceps fungi, are host defences against behavioural manipulation by the parasite possible, and how do interactions with competitors and parasites affect Ophiocordyceps life histories?
  • How variable are Ascospharea apis infections at local, regional and European scales?
  • Are subspecies of honey bees equally susceptible to chalk brood and is there genetic variation for chalk brood resistance in Danish honey bees?
  • What gene expression pathways are activated or silenced when ants are infected with Methahizium?
  • How do Pandora infections affect populations of wood ants and what genetic and infection mechanisms are involved?
  • How virulent are bee diseases in seminatural landscapes?

Research themes

Disease and Immunity

Research tools

Behavioural experimentsGenetic analyses; Immune assays; Laboratory colonies; Microscopy; Fieldwork