Scientists in Denmark have discovered two new species of deadly fungi that come in from the inside, erupting from the abdomen of their surviving prey.
The parasites – Strongwellsea acerosa and Strongwellsea tigrinae – infest adult flies, which remain around for days with large holes in their bodies.
As they are, the fungi spray from these holes down to other indeterminate flies.
Thousands of torpedo-shaped spores can fire like a rocket from a single fly.
Researchers believe that the flies are kept alive by strong dope-like chemicals that are secreted by the fungi that also keep other microorganisms away from the site of the injury.
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The body of a fly with two large holes in its abdomen, caused by the fungus Strongwellsea tigrinae. After sculpting through its host, the parasite keeps it alive and doped until it goes around and shears spores on other careless flies.
Researchers from the Danish Museum of Natural History and the Department of Plant and Environmental Sciences of the University of Copenhagen have reported on the two new fungi.
‘They work like little rockets,’ Copenhagen University ecologist Jørgen Eilenberg told the Guardian.
‘They’re almost shaped like torpedoes and are designed to go fast. ‘
‘If they land on another fly they stick to the sickle and then move into the abdomen, where they begin to expand.’
‘Thousands of spores will be released from one fly.’
Spores Strongwellsea acerosa. The fungi survive through the cold Danish winters as thick-walled orange spores and germinate in the spring.
One species, Strongwellsea acerosa, has been found on Amager, the densest island in the country and home to capita, l Copenhagen.
The other, Strongwellsea tigrinae, was found in Jægerspris, a more rural area to the north.
The specific fungi host only two Danish fly species, Coenosia testacea and Coenosia tigrina.
The host-specific fungus Strongwellsea tigrinae (root) produces only adult Coenosia tigrina flies. Researchers estimate that only 3 to 5 percent of the fly’s population is infectious, enough to reduce the fungus.
As they do, they form a large hole in the abdomen of their host.
But the gaping injury doesn’t kill the fly, it turns it into a ‘zombie,’ going around stripping more fungal spores into the air and introducing new victims.
The fungi eat the bodies of the guests up to the end.
After a few days, the fly finally gives up, falling on her back and spasming in her last hours before she dies.
‘This is an interesting and bizarre aspect of the biodiversity we found in Denmark,’ said Eilenberg.
‘In itself, this mapping of new and unknown biodiversity is valuable. But at the same time, this is a fundamental new knowledge that could form the basis for experimental studies of infectious pathways and their bioactive substances. ‘
Strongwellsea acerosa (base) from adult flies Coenosia testacea. Researchers believe that the fungus hides substances that keep its host alive and fly live and other microorganisms away from the place of injury.
The fungi survive through the cold Danish winters with the help of their thick-walled orange spores and grow in the spring.
Eilenberg believes that catching many of the flies, perhaps three to five percent, is just not enough for multiplication.
‘It’s interesting how the life cycles of these fungi have changed as well as the lives of the flies they are targeting,’ he said.
Ironically, the horrible health cycle of these paraphernalia could bring people health benefits.
Researchers believe the fungi release amphetamine-like substances to keep the host going and going even as their insides consume it.
They also tend to do something to keep other microorganisms away from the wounds of flies.
‘We would like to continue our research, because that has the potential to find and use these products later, perhaps in medicine,’ said Eilenberg.
The findings were published in the Journal of Invertebrate Pathology.
This isn’t the only fungus that transforms its fly host into a zombie: another genus, massospora, that uses cicadas in the same way.
Another fungus, Cordyceps, also affects flies, but like larvae.
Another deadly fungus, Cordyceps, affects flying larvae. When the fly matures, it controls the muscles, pushing it onto the top of a plant. It then explodes antennae-like stalks through the victim’s exoskeleton, which burns spores on the ground below to catch more insects.
As soon as the fly matures, the fungus takes control of its body, causing it to walk to the top of a plant, catch it and wait for it to die.
Cordyceps then explodes antennae-like stalls through the victim’s exoskeleton, which then burns spores on the ground below, where the fungus can trap more insects.
Experts initially thought Cordyceps had infected the guests ‘brains, but research published this month showed that it actually overwhelms the victims’ muscles.
Researchers described this behavior as ‘a puppet pulling the strings to make a marionette move. ‘