You may have heard of “zombie ants” — insects that are infected with a fungal pathogen that can control their behavior, coercing them into climbing to a high location to better spread fungal spores before meeting their end. But did you know that another species of pathogenic fungus, Entomophthora muscae or “insect destroyer,” could be harnessed by humans to act as a more environmentally friendly insecticide? Although we’ve known for decades that the insect destroyer fungus can infect flies, including the common housefly, we lacked the laboratory tools necessary to actually study the fungus-fly interaction in much detail. 

Researchers at the University of California, Berkeley have identified a particular variety of this fungus that can infect the commonly-used fruit fly model organism, Drosophila melanogaster. This means that all of the tools we’ve accrued over the last century to study D. melanogaster in the lab can now be applied to its interaction with the fungus, making it much easier to learn how pathogens like the insect destroyer infect their host and control their behavior. 

Scientists are also investigating the fungus itself, especially the ways that the fungus spreads its spores, which is a key part of how the fungus is able to infect new victims. Scientists found that E. muscae spores are shot out from cannon-like structures on the dead, infected flies at roughly 10m/s or 22mph — very fast in the world of fungal spores. This even inspired a follow-up study by biophysicists in Denmark that specifically examined the physics of spore ejection. The scientists created tiny, squishy cannons made of silicone that they could load with 3D-printed projectiles and fire with pressurized liquid, mimicking the actual ejection system used by the insect destroyer fungus. It turns out there’s a very specific canon and spore size that maximizes ejection speed and distance, increasing the chances of further fly infection.