Featured Fungus: Massospora cicadina
by Loulwa Soweid
Photo by Dan Mozgai
In honor of the much-anticipated co-emergence of periodical cicada Broods XIX and XIII, I thought that now would be the perfect time to write a Featured Fungus article about the frankly horrifying but equally fascinating Massospora cicadina, an entomopathogenic fungus which exclusively infects 13- and 17-year Magicicada species! Brace yourselves mycophiles, because this one gets real weird, real fast.
Christened by mycologist Charles Horton Peck, Massospora cicadina gets its genus name from an interplay of the Greek words “masso” (which means “to grind”) and “spora” (which means, pretty self-explanatorily, “spore”). This scientific moniker is fitting, as it paints a fairly graphic description of how the fungus overtakes, sloughs off, and eventually entirely replaces a periodical cicada’s segmented abdomen with a white, chalky mass of fungal spores. This is not an exaggeration; M. cicadina transforms once-content periodical cicadas into what some scientists have termed “flying saltshakers of death,” as they take wing with snowy spores now flaking off what was once the lower portions of their bodies.
And if only that were all – after M. cicadina has successfully infected its cicada hosts, it does not focus on killing them, but on using them, rendering them both alarmingly horny and (because this fungus contains a chemical called cathinone, which is in the amphetamine family) pretty buzzed (no pun intended). Thus, afflicted cicadas become hyper-focused on manically mating. And while M. cicadina infects both male and female cicadas, it impacts males in a particularly interesting way, altering their mating behaviors so that they begin flicking their wings in a timing and manner normally reserved only for female cicadas, which more or less tricks other male cicadas into mating with them as well. This, of course, maximizes spore dispersal for the crafty M. cicadina, which is essentially functioning as a cicada STI, and unfortunately does not result in any eventual cicada babies since infected cicadas’ genitalia are located in their abdomens and have thus long been shed.
It should be noted that in some cases, M. cicadina infects periodical cicadas when they are still nymphs milling underground and slurping up xylem fluids from plants. Remember, mating is only one of the ways that M. cicadina spores can be spread – infected adult cicadas are also depositing them when they are walking or flying, and some of these spores land on the ground. It seems like at some point - either when nymphs are burrowing down into the soil right after they hatch or crawling up to the surface to molt after more than a decade underground - they come into contact with resting M. cicadina spores in the soil, which proceed to infect them and remain quietly inside them until after they molt into their adult forms.
But regardless of when the infection initiates, eventually M. cicadina’s spores have been efficiently and fully spent, M. cicadina’s own life cycle has ended, and all that remains is the top half of a periodical cicada clinging to tree bark and seemingly not very shook up about the fact that it is only a head and torso. These cicadas do eventually die, although I am not sure if this is solely because of what strange hell M. cicadina has put them through or if it is more a reflection of the fact that they don’t live very long above ground anyway (although I would confidently bet that losing their entire lower bodies probably speeds up the dying process).
To avoid ending this on a somber note, I will leave you all with both a reassurance and an action item. First, M. cicadina does not and cannot infect humans, so there is no need to fear coming into contact with affected cicadas. Which brings me to my second point: while the emergence of Broods XIX and XIII is already underway in Iowa, to my knowledge there have been no cases of M. cicadina recorded here (although there have been sightings in the surrounding states of Illinois, Wisconsin, and Missouri), so this is a wonderful chance for us to step up as citizen scientists; if you catch a glimpse of periodical cicadas in Iowa that are actively infected with M. cicadina, and if you also happen to have an iNaturalist or Cicada Safari account, please snap a photo, record the date, time, and place in which you sighted it, upload this information and tag University of West Virginia professor Dr. Matt Kasson (@imperfectfunguy), who conducts research on this shocking and arguably formidable fungus.
