Newly discovered fungi turn flies into zombies & devour them

Two newly discovered fungi species have similar macabre mode of action: They eat flies alive while using-them to drop spores on new victims.

The species, Strongwellsea tigrinae & Strongwellsea acerosa attack the fly species Coenosia tigrina & Coenosia testacea, who look like an ordinary house flies, but undergo a horrific change once they’re invaded by the fungi. The fungi eat one or more holes in the abdomens of the flies, then produce clumps of orange spores which spread by dropping out of the holes.

The infected, now become zombie flies, remain alive for days during this process, that means they inadvertently spread the spores far & wide, particularly when mating with other flies. Meanwhile, the fungi still devour the flies alive. Finally, the fungi ravaged insects collapse to the ground in spasms & die. Even after death, flies can spread the spores of their killers: The flies- abdomens gradually crumble, releasing more spores from inside.

These spores have thick walls which will help them lie dormant over winter, infecting more flies when the insects become active in the spring.

Danish researchers discovered dozens of fungi infected flies during fieldwork in Jægerspris & Amager, Denmark. The flies were found in both rural areas & residential neighborhoods, hinting of a horror-story struggle playing-out in seemingly peaceful fields & yards. The researchers reported their findings in September 2020 issue of the Journal of Invertebrate Pathology.

“This is an exciting & bizarre aspect of biodiversity that we’ve discovered in Denmark,” study leader Jørgen Eilenberg, a biologist at University of Copenhagen, said in a statement. “In & of itself, this mapping of new & unknown biodiversity is valuable. But at the same time, this is often basic new knowledge which will serve as a basis for experimental studies of infection pathways & the bioactive substances involved.”

Eilenberg & his colleagues suspect that the fungi “dope” the flies with some substance that keeps them flying & active whilst their abdomens are devoured from the inside-out. Other fungi that prey on insects use amphetamine type substances to keep their victims moving, so perhaps the newly discovered fungi do same, Eilenberg said. The fungi may additionally produce antimicrobial substances that keep other pathogens away from the abdomen holes so as to keep the flies alive longer.

“We would definitely wish to continue our research, as doing so has the potential to discover and later make use of these substances, perhaps in medicine,” Eilenberg said.