An extraordinary event is taking place in the Midwest right now as millions of cicadas are emerging after 17 and 13 years underground. However, this year, as Broods XIII and XIX take to the air, many of these cicadas are infected by a parasitic fungus that takes over their minds and bodies, turning them into hypersexual “zombies.” Yes, you read that right. A fungus known as Massospora cicadina is driving these insects to engage in relentless mating attempts even as parts of their bodies are replaced by fungal growths.
Periodical cicadas spend a large portion of their lives as nymphs underground, where they slowly develop until the next generation of cicadas emerges, sometimes more than a decade later. When these cicadas finally emerge, they do so in synchronized, massive numbers and focus their efforts on mating and reproduction. During this brief aboveground phase, cicadas are more susceptible to infections like those from the Massospora cicadina fungus since they focus less on individual survival and more on reproducing.
Massospora cicadina spores attach to cicadas during close contact, especially during mating, and once the fungus establishes itself, it starts to take over the cicada’s body. It gradually replaces the rear part of the abdomen with a mass of fungal spores that appear as a chalky, white, protruding plug. Infected cicadas also lose their reproductive organs, meaning male cicadas can completely lose their genitalia, which is replaced by a fungal growth. Regardless, they will continue to engage in mating behaviors driven by the fungus’s manipulation.
The fungus causes severe psychological and behavioral changes in cicadas, causing them to become hypersexual and extremely active. Even when the fungus replaces a third of a cicada’s body, the infection ensures that the insects continue to mate to maximize spore dispersal.
Male cicadas have even been observed mimicking the mating behavior of females, flicking their wings to attract other males to spread the infection. As a result, the fungus spreads rapidly both through direct contact during mating and indirectly as cicadas fly and shed the spores over a wide area, earning them the nickname “flying salt shakers of death”.
Image Source: Katja Schulz via Wikimedia Commons
The fungus has recently been detected in several parts of the Midwest, including areas around St. Louis, Missouri, and southern Illinois. Yet, despite how lethal Massaporia cicadena is to individual cicadas, scientists don’t believe it poses a major threat to cicada populations as a whole since the periodic emergencies of cicadas offer a buffer against localized fungal outbreaks. And while the fungus may have dramatic effects on cicadas, rest assured that it does not pose a significant risk to humans or other animals.
