In Denmark, two new fungi species have been discovered that infect flies and release spores from a large hole in the insect’s abdomen “like little missiles”.
The new kind, Strongwellsea tigrinae and Strongwellsea acerosa, are host specific and rely on two species of Danish fly – Coenosia tigrina and Coenosia testacea, said researchers at the University of Copenhagen.
While most fungi spore after the death of the host, with strong seas, the host continues to live for days, performing normal activities and socializing with other flies, while the fungus uses up its genitals, fat stores, reproductive organs and eventually its muscles. shooting thousands of spores on other individuals.
After a few days, the fly lies on its back, spasms 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 spores is called active host transmission (AHT). It is an effective way to access other healthy individuals. Scientists think the fungi can produce substances that “numb” their hosts (sometimes called “zombies”), meaning they can stay fresh enough to live for days after infection – only collapse when there is nothing left in their bellies. the fungus.
“We therefore suspect that these fungi can produce amphetamine-like substances that keep a fly’s energy levels high to the end,” says lead researcher Prof. Jørgen Eilenberg from 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 fungal wound and keep it clean, but they have yet to test this.
“They work like little missiles,” said Eilenberg. “They are almost torpedo-shaped and designed to go fast.” If they land on another fly, they will stick to the cuticle and squirm their way to the abdomen, where they will begin to multiply. Thousands of spores are released from a single fly.
The parasites probably only infect a small percentage of individuals – between 3 and 5% in a healthy fly population. Because the host continues to behave normally, it is difficult to determine when it is infected. Therefore, AHT has been relatively little researched. It has only been discovered in two complete genera – Strongwellsea and a similar fungal genus called Massospora, which uses crickets in a similar way.
Strongwellsea tigrinae was discovered by Eilenberg in 1993 in North Zealand in eastern Denmark. Strongwellsea acerosa was first seen in a residential area in 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 types of strongwellea.
Dr. Matthew Kasson, associate professor of forest pathology and mycology at West Virginia University, who was not involved in this latest study, agrees that strongwellsea may produce the same “dope” compound as massospora, which he studied. “It’s unclear how many types we have, but I really think we just scribbled to the surface,” he says.
“The reason this discovery is important is because we cannot draw broad, sweeping conclusions about host manipulation and behavioral modification based on a single gender. Having a second genus like strongwellsea, which induces the same behavioral response, is important in solving this larger puzzle of active gas transmission … Collectively, this group of insect-destroying fungi could set the next frontier for drug discovery. “