Team discovers manipulative qualities of fungus-infected flyers

According to research led by the University of West Virginia, cicadas infected with the parasitic fungus Massospora unwittingly perform tricks on their fellow insects, resulting in effective transmission of the disease.

Massospora manipulates male cicadas to move their wings like females, a mating invitation, which tempts unsuspecting male cicadas and infects them.

It’s a recent discovery in the weird world of cicadas riddled with a psychedelic mushroom that contains chemicals, including those found in hallucinogenic mushrooms. The research, “Behavioral Betrayal: How Selected Fungal Parasites Enlist Live Bugs to Do Their Will” was published in the journal PLOS Pathogens.

“Essentially, cicadas are attracting others to become infected because their healthy counterparts are interested in mating,” said Brian Lovett, study co-author and postdoctoral researcher at the Davis College of Agriculture, Natural Resources and Design. “Bioactive compounds can manipulate the insect to stay awake and continue to transmit the pathogen longer.”

These actions linger amid a haunting display of horror movie B proportions: Massospora’s spores gnaw on a cicada’s genitals, butt, and abdomen, replacing them with fungal spores. Then “they wear out like an eraser on a pencil,” Lovett said.

Lovett compared transmission of the behavior-modifying virus to rabies.

Both rabies and entomopathogenic fungi (parasites that destroy insects) recruit their living hosts for successful “active active transmission,” Lovett said.

“When you are infected with rabies, you get aggressive, you fear water and you don’t swallow,” Lovett said. “The virus passes through saliva, and all of those symptoms essentially make it a machine for spreading rabies where it is most likely to bite people.”

“In that sense, we are all very familiar with active host transmission. Since we are also animal like insects, we like to think that we have complete control over our decisions and take our free will for granted. But when these pathogens infect cicadas , it is very clear that the pathogen is pulling the cicada’s behavior levers to make it do things that are not in the interest of the cicada but in the interest of the pathogen. “

Lovett’s colleague and co-author of the paper, Matthew Kasson, associate professor of plant pathology and mycology, first helped discover the existence of psychoactive compounds in cicada fungi infected by Massospora last year.

“Our previous literature always mentioned the strange behaviors associated with Massospora and some closely allied fungi, but what was missing was a synthesis of all this new information that had come to light,” Kasson said. “The most interesting finding is things we don’t know yet. We realized there were some possible infection scenarios that we hadn’t considered before.”

Kasson noted that it is generally accepted that cicada nymphs encounter Massospora in their seventeenth year when they emerge from the ground to move into adults. But the researchers also concluded that the nymphs could encounter Massospora on their way down to feed on roots for 17 years.

“The fungus could wait more or less within its host for the next 17 years until something wakes it up, perhaps a hormonal signal, where it possibly remains dormant and asymptomatic in its cicada host,” Kasson said.

Working alongside Lovett and Kasson was PhD student Angie Macías, who believes that their research will lead to a better general understanding of insects.

“These discoveries are not only super cool, but they also have great potential to help us better understand insects and perhaps learn better ways to control pest species using fungi that manipulate host behaviors,” he said. “There are almost certainly undiscovered Massospora species, regardless of the other AHT (active host transmission) fungi, and each of them will have developed their own intimate connection to their host’s biology.”

The team managed to investigate baby cicadas earlier this year in southeastern West Virginia.

Lovett also explained why we see the cicadas emerge again so soon.

“Different hatchlings come out at different time periods,” he said. “There are our periodic cicadas that come out every 13 years and there are other periodic cicadas that come out every 17 years. Time is staggered in different states.”

And, grotesque as a decomposing infected cicada may seem, they are generally harmless to humans, he said. They also reproduce at such a rate that the extermination of the cicada hordes by fungi has little effect on their general population.

“They are very docile,” Lovett said. “You can walk up to one, pick it up to see if it has the fungus (a white to yellowish cap on its back end) and put it back. They’re not a major pest by any means. They’re just a really interesting quirky bug that has developed a style strange life. ”