Mushrooms devour flies from the inside and carve holes in the belly of their living victim

Scientists in Denmark have discovered two new species of deadly mushrooms that gobble up the inside and burst from the belly of their live prey.

The parasites – Strongwellsea acerosa and Strongwellsea tigrinae – infect adult flies that float around with massive holes in their bodies for days.

The mushrooms rain spores from these holes on other unsuspecting flies.

Thousands of torpedo-shaped spores can shoot out of a single fly like a rocket.

The researchers believe that the flies are kept alive by strong, dope-like chemicals secreted by the fungi, which also keep other microorganisms away from the wound site

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The corpse of a fly with two large holes in its belly, caused by the fungus Strongwellsea tigrinae.  After cutting through its host, the parasite keeps it alive and doped it so it can buzz around and throw spores on other unsuspecting flies

The corpse of a fly with two large holes in its belly, caused by the fungus Strongwellsea tigrinae. After cutting through its host, the parasite keeps it alive and doped it so it can buzz around and throw spores on other unsuspecting flies

Researchers from the Natural History Museum of Denmark and the Institute of Plant and Environmental Sciences at the University of Copenhagen have reported on the two new mushrooms.

“They work like little rockets,” University of Copenhagen ecologist Jørgen Eilenberg told The Guardian.

“They are shaped almost like torpedoes and designed for fast travel.”

“When they land on another fly, they stick to the cuticle and then twist into the stomach, where they start to multiply.”

“Thousands of spores are released from a single fly.”

Strongwellsea acerosa spores.  The mushrooms come through the cold Danish winters as thick-walled orange dormant spores and germinate in spring

Strongwellsea acerosa spores. The mushrooms come through the cold Danish winters as thick-walled orange dormant spores and germinate in spring

One species, Strongwellsea acerosa, was discovered on Amager, the country’s most densely populated island and home to its capital, Copenhagen.

The other, Strongwellsea tigrinae, was found in Jægerspris, a more rural area to the north.

The host-specific fungi only infect 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 multiply

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 multiply

In doing so, they create a large hole in the stomach of their host.

But the gaping wound doesn’t kill the fly, it turns it into a “zombie” that buzzes around, throwing more fungal spores into the air and onto fresh victims.

The mushrooms feed on the bodies of their hosts until the end.

After a few days, the fly finally gives in, falls on its back and cramps for the last few hours before it dies.

“This is an exciting and bizarre aspect of biodiversity that we discovered in Denmark,” said Eilenberg.

‘In and of itself, this mapping of the new and unknown biodiversity is valuable. At the same time, this is fundamentally new knowledge that can serve as a basis for experimental studies of the pathways of infection and the bioactive substances involved. ‘

Strongwellsea acerosa (below) from adult Coenosia testacea flies.  Researchers believe that the fungus secretes substances that keep its host alive and well, as well as other microorganisms that are kept away from the wound area

Strongwellsea acerosa (below) from adult Coenosia testacea flies. Researchers believe the fungus secretes substances that keep its host alive and well, as well as other microorganisms that are kept away from the wound area

The mushrooms get through the cold Danish winters with the help of their thick-walled orange dormant spores and germinate in spring.

Eilenberg believes they don’t infect many flies, maybe three to five percent, just enough to reproduce.

“It is fascinating how well the life cycles of these mushrooms are adapted to the life of the flies they target,” he said.

Ironically, the terrible life cycle of these parasites could have health benefits for humans.

Researchers believe that the mushrooms emit an amphetamine-like substance to keep their hosts going, even when their insides are devoured.

They also likely produce something to keep other microorganisms off the flies’ wounds.

“We definitely want to continue our research, as this has the potential to discover these substances and use them later, perhaps in medicine,” said Eilenberg.

The results were published in the Journal of Invertebrate Pathology.

This isn’t the only mushroom that turns its fly host into a zombie: another genus, Massospora, uses cicadas in a similar way.

Another fungus, Cordyceps, also infects flies, but as a larva.

Another deadly fungus, cordyceps, infects fly larvae.  As the fly matures, it takes control of its muscles, forcing it onto a plant top.  It then sprouts antenna-like stems through its victim's exoskeleton, which fires spores onto the ground to infect more insects

Another deadly fungus, cordyceps, infects fly larvae. As the fly matures, it takes control of its muscles, forcing it onto a plant top. It then sprouts antenna-like stalks through its victim’s exoskeleton, which fires spores onto the ground to infect more insects

As soon as the fly ripens, the fungus controls its body, forcing it to go to the top of a plant, hold on, and wait for death.

Cordyceps then sprouts antenna-like stems through the victim’s exoskeleton, which then fires spores to the ground, where the fungus can infect more insects.

Experts originally thought Cordyceps infected its hosts’ brains, but research published this month showed that it is actually taking over the muscles of its victims.

The researchers described this behavior as “like a puppeteer pulling the strings to set a puppet in motion”.

HOW THE PARASITE TAKES OVER

Previous studies have shown that the zombie parasite controls the behavior of carpenter ants, causing them to climb onto vegetation and bite the underside of leaves or twigs.

However, the mechanism by which the zombie fungus infected the ants was unknown for years.

Earlier this month, researchers from Penn State University suggested that the zombie ant fungus actually surrounds and invades muscle fibers throughout the ant’s body to control the host’s behavior.

The researchers infected ants with the zombie parasite or a common fungal pathogen and created 3D visualizations to understand how the fungi moved inside the ants.

Using AI and machine learning algorithms, the researchers analyzed the images and found that the zombie parasite cells had spread to virtually every region of the ants, including the head, thorax, abdomen and legs.

The researchers described this behavior as “like a puppeteer pulling the strings to set a puppet in motion”.

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