First Massospora spores eat away at the cicada’s genitals, butt, and abdomen. They are then replaced with fungal spores used to transmit the fungus to other cicadas. From there, this new, fungal abdomen will slowly “wear away like an eraser on a pencil,” said study co-author Brian Lovett in the release.
The infected cicadas, which were found in West Virginia by university researchers in June, are the third cicada population discovered to have been infected by Massospora, according to study co-author, Matthew Kasson.
Since cicadas have either a 13 or 17-year lifecycle and live underground until they emerge more than a decade later, studying how Massospora infects these species can be very difficult.
How the fungus manipulates the cicada
While almost a third, if not more, of their bodies are replaced with fungal tissue, infected cicadas continue to move around oblivious of their sickness. This is because the fungus manipulates the insects’ behavior to keep the host alive rather than killing them to maximize spore dispersal.
“If one of our limbs were taken out or if our stomach was slashed open, we would probably be incapacitated,” Kasson told CNN. “But infected cicadas, despite the fact that a third of their body has fallen off, continue to go about their activities like mating and flying as if nothing happened. This is really, really unique for insect killing fungi.”
The study highlights recent findings including how infection leads to hypersexual behavior. Even though infected cicadas lose their ability to mate when their backsides become fungal plugs, they will still attempt to mate to sexually transmit the fungus to healthy cicadas.
The parasitic fungus even manipulates male cicadas into flicking their wings to imitate the females’ mating invitation so they can also infect unsuspecting male cicadas to rapidly transmit the disease.
While researchers believe sexual transmission of the fungus is the easiest way for Massospora to spread, cicadas can also come into contact with the pathogen in other ways.
“When they fly around or walk on branches, they spread spores that way too,” Kasson said. “We call them flying saltshakers of death, because they basically spread the fungus the way salt would come out of a shaker that’s tipped upside down.”
While a zombie army of cicadas sounds terrifying, Kasson reassures that infected cicadas are not a danger to humans. At this time, researchers believe the fungus does not pose a serious risk to the overall cicada population.