Pennsylvania State University
entomology and biology
Centre for Infectious Disease Dynamics
Pollock Road, University Park, W245A MSC
State College, PA 16802
Abstracts (first author)
In search of the fungal compounds that manipulate animal host behavior
Parasite-host co-evolution has driven parasites to evolve strategies to invade, overcome the immune system, and exploit their hosts for their own survival and dispersal. Some parasites also interact with the host’s nervous system, changing behavior. One of the most dramatic examples is the fungus Ophiocordyceps unilateralis s.l. infecting Camponotus species, where ants bite into vegetation before dying to facilitate spore dispersal. To establish this, the fungus not only overcomes the immune system, but also manipulates the brain and atrophies the muscles. Through extensive fieldwork on three continents we established that a high diversity of manipulation phenomena involving ants and fungi exists. This provides a framework for comparative profiling of manipulator compounds using a combination of metabolomics and proteomics.
We are combining metabolite and protein profiling with ex vivo insect tissue culturing to study compounds secreted in different areas of the host. Using this technique we established that generalist and specialist fungal entomopathogens react differently when presented with the same insect tissues. Next to that, these entomopathogens react heterogeneously to brain and muscle tissue by secreting a significantly different array of metabolites. Furthermore, O. unilateralis employs different metabolites when presented with brains from different ant species, while similar compounds are found as well. Identifying if the “behavioral manipulator” compounds are only found when the fungus is presented with its co-evolved host, or also when presented with other hosts, will inform us if host specificity lies at the level of behavioral manipulation or that of spore entry and overcoming the immune system. By combining metabolite and protein discovery we are identifying candidate compounds involved in manipulation. We are also testing the effect of potential brain manipulating compounds by combining artificial ant infection with behavioral assays.