Two new species of fungi have been discovered in Denmark that infect flies and expel spores from a large hole in the insect’s abdomen “like little rockets”.
The new species, Strongwellsea tigrinae is Strongwellsea acerosa, are host specific and are based on two species of Danish fly: Coenosia tigrina is Coenosia testacea, according to researchers from the University of Copenhagen.
While most fungus spores once the host is dead, with strongwellsea, the host continues to live for days, doing normal activities and socializing with other flies as the fungus consumes its genitals, fat stores, the reproductive organs and finally his muscle, all the while shooting thousands of spores at other individuals.
After a few days, the fly lies on its back, twitches for a few hours, and then dies, according to research from the University of Copenhagen and the Natural History Museum of Denmark published in the Journal of Invertebrate Pathology.
The unusual tactic of keeping the host alive while releasing the spores is called active host transmission (AHT). It is an effective way to access other healthy individuals. Scientists think the fungi could produce substances that “drug” their hosts (sometimes colloquially referred to as “zombies”), meaning they can stay cool enough to live for days after infection – only collapsing when nothing is left. in their abdomens except the fungus.
‘We therefore suspect that these fungi may produce amphetamine-like substances that keep a fly’s energy levels high until the end,’ said lead researcher Prof Jørgen Eilenberg of the Department of Plant and Environmental Sciences at the University of Copenhagen. Researchers also believe that the fungi produce substances that keep microorganisms away from the fly fungus wound and keep it clean, but they have yet to test it.
“They work like little rockets,” Eilenberg said. “They are almost shaped like torpedoes and are designed to go fast.” If they land on another fly, they attach to the cuticle and then move into the abdomen, where they begin to proliferate. Thousands of spores will be released from a single fly.
The parasites likely infect only a small percentage of individuals, between 3 and 5% in a healthy fly population. As the host continues to behave normally, it is difficult to identify when it was infected, which is why AHT is relatively poorly studied. It has only been discovered in two complete genera: strongwellsea and a similar fungal genus called massospora, which uses cicadas in a similar way.
Strongwellsea tigrinae it was discovered by Eilenberg in 1993 in northern Zealand in eastern Denmark. Strongwellsea acerosa it was first seen in a residential area in greater Copenhagen by one of his students, Dorthe Britt Tiwald, in 1998. Both have only now been officially declared new species. There are now a total of five known species of strongwellsea.
Dr. Matthew Kasson, an associate professor of forest pathology and mycology at West Virginia University who was not involved in this latest research, agrees that strongwellsea could produce the same “doping” compound as the massospore he studied. “It’s not clear how many species we have, but I really think we’ve barely scratched the surface,” he says.
“The reason this discovery is important is because we cannot draw broad and radical conclusions about host manipulation and behavioral modification based on a single gender. Having a second genus such as strongwellsea, which induces the same behavioral response, is important in solving this bigger enigma of active host transmission … Collectively, this group of insect-destroying fungi may represent the next frontier for the discovery of drugs “.