Scientists in Denmark have discovered two new types of deadly fungi that devour from the inside and burst from the bellies of their living prey.
The parasites – Strongwellsea acerosa and Strongwellsea tigrinae – infect adult flies, which keep buzzing with huge holes in their bodies for days.
As they do so, the fungi rain spores from these holes onto other unsuspecting flies.
Thousands of torpedo-shaped tracks can shoot like a missile from a single fly.
Researchers believe the flies are kept alive by powerful dope-like chemicals secreted by the fungi that also keep other microorganisms away from the wound site.
Scroll down for video
The corpse of a fly with two large holes in the abdomen caused by the fungus Strongwellsea tigrinae. After being cut by its host, the parasite keeps it alive and baptized so it can buzz around and cast spores on other unsuspecting flies
Researchers from the Natural History Museum of Denmark and the Department of Plant and Environmental Sciences at the University of Copenhagen have reported on the two new fungi.
“They work like little missiles,” said University of Copenhagen ecologist Jørgen Eilenberg to The Guardian.
“They are almost torpedoed and designed to go fast.”
“When they land on another fly, they stick to the cuticle and wriggle their way to the abdomen, where they begin to multiply.”
“Thousands of spores will be released from a single fly.”
Strongwellsea acerosa spores. The fungi appear as thick-walled orange resting spores through the cold Danish winters and germinate in the spring
One species, Strongwellsea acerosa, was discovered on Amager, the country’s most populous island and home to its capital, Copenhagen.
The other, Strongwellsea tigrinae, was found in Jægerspris, a more rural area in the north.
The host-specific fungi infect only two Danish fly species, Coenosia testacea and Coenosia tigrina.
The host-specific Strongwellsea tigrinae fungus (below) only infects adult Coenosia tigrina flies. Researchers believe that only 3 to 5 percent of the fly population is infected, enough for the fungus to reproduce
As they do that, they create a large hole in their host’s abdomen.
But the gaping wound doesn’t kill the fly, it turns it into a ‘zombie’, buzzing around and hitting more fungal spores in the air and new victims.
The fungi feed on the bodies of their hosts to the end.
After a few days, the fly finally gives up, falls on its back and spasms in its last hours before dying.
“This is an exciting and bizarre aspect of biodiversity that we have discovered in Denmark,” said Eilenberg.
‘In itself, mapping new and unknown biodiversity is valuable. But at the same time this is new basic knowledge that can serve as a basis for experimental research into infection routes and the bioactive substances involved. ‘
Strongwellsea acerosa (bottom) of adult Coenosia testacea flies. Researchers believe the fungus secretes substances that keep its host alive and alive and other microorganisms away from the wound area
The fungi endure the cold Danish winters with the help of their thick-walled orange resting spores and germinate in the spring.
Eilenberg believes they don’t infect many flies, maybe three to five percent, just enough to reproduce.
“It is fascinating how the life cycles of these fungi are so well adapted to the life of the flies they target,” he said.
Ironically, the gruesome life cycle of these parasites can have health benefits for humans.
Researchers believe the fungi release an amphetamine-like substance to keep their hosts going even when their intestines are devoured.
They also likely produce something to keep other microorganisms away from the flies’ wounds.
“We would certainly like to continue our research as it has the potential to discover these substances and use them later, perhaps in medicine,” said Eilenberg.
The findings are published in the Journal of Invertebrate Pathology.
This isn’t the only fungus turning its fly host into a zombie: another genus, massospora, that uses crickets in a similar way.
Another fungus, Cordyceps, also infects flies, but as a larva.
Another deadly fungus, Cordyceps, infects fly larvae. When the fly matures, it takes control of its muscles and forces it on top of a plant. It then sprouts antenna-like stems through its victim’s exoskeleton, firing spores to the ground below to infect more insects
Once the fly matures, the fungus controls its body and forces it to walk to the top of a plant, hold it, and wait to die.
Cordyceps then sprouts antenna-like stems through the victim’s exoskeleton, which then fires spores to the soil below, where the fungus can infect more insects.
Experts initially believed that Cordyceps had infected the brains of its hosts, but research published this month found that it takes over the muscles of its victims.
Researchers described this behavior as “like a puppeteer pulling the strings to make a marionette move.”