I study a fungus that turns cicadas into ‘flying salt shakers of death’—AMA!

Flying salt shakers. Please enlighten?

When Massospora infects a cicada it doesn’t kill it. In fact it hijacks the typical behaviors of healthy cicadas like flying. So when infected cicadas fly around with a mass of spores erupting out from the end of its abdomen, spores fall down like salt grains from a tipped salt shaker. Those spores can then infect unsuspecting cicadas below.

Of death. Don't forget that part. If they went around salting our sidewalks and roads for the winter or giving our grilling steaks a little bit of seasoning that's fine. But the death part sounds sketchy

The phrase was coined by my grad student at a time when our understanding of these fungi was incomplete. Based on our observations, this pathogen doesn’t shorten the lifespan of cicadas compared to healthy counterparts. This makes sense as the fungus only has a few weeks every 17 years to proliferate. But let’s remember that this is effectively sterilizing cicadas either consuming existing eggs in the abdomens of infected mated females or preventing reproduction altogether. That in itself is death of the next generation.

When I first heard about this fungus and cicadas, it was described as "a STD that makes their butt fall off", and then makes a fungal mass that spreads where their abdomen was.

I have made no effort to look it up further, but can I ask you to comment on that colorful description and correct it, please?

Certainly the headlines are sensational regarding Massospora infected cicadas. The reality is the fungus does consume the back end of their abdomen which includes their genitalia. The fungus replaces these tissues and then infects via the genitalia of healthy cicadas during mating attempts. In this way it is sexually transmissible even if that sexual attempt is unsuccessful.

Thank you for doing this AMA! How do these fungi benefit from targeting periodical cicadas specifically? It would seem difficult to rely on a 13 or 17 year cycle.

Similarly, have the cicadas in any of the broods evolved a defense against this parasitism?

There are over a dozen described Massospora species that infect either annual or periodical cicadas. It does seem like a huge risk to co-evolve alongside an animal that spends only a few weeks above ground every seventeen years. But fungi are patient and the payout is exceptional.

Does this fungus act like the one that turns ants into zombies? How does it affect the cicada population regarding numbers (does it work as a population number controller)? Thanks for this specific and really interesting AMA!

PS: do people call you a fun guy at parties?

It’s similar in that it modifies behavior but the behaviors are quite different. The zombie ant fungus directs its host to an elevated position where it affixes, dies, and the fungus then erupts out. With Massospora, the cicada remains alive and its regular activities such as flying and attempting to mate maximize spore dispersal!

Is this process at all similar to the pscilocibe fungus that infects cicadas?

The behavioral manipulation by both Massospora species is essentially the same. We suspect psilocybin in infected annual cicadas and cathinone in infected periodical cicadas may serve similar functions.

What're your thoughts on the recent Scientific American article?

Fungi continue to pose threats to animals and plants! We need to continue to invest in basic science to ensure we are prepared to respond to the next emerging disease.

When does the fungus first infect the cicadas? And does this fungus infect other insects/animals? Is there any possible effect of the fungus on humans?

From all the literature that exists on this interaction as well as our own observations, cicada nymphs first interact with the overwintering spores of Massospora as they await just below the leaf little in the days to weeks leading up to emergence. Periodical cicadas are the only known hosts. The fungus poses little risk to anything or anyone else.

Do the cicadas taste better with or without the fungi? Asking for a friend...

Not sure. I would not eat a fungus-infected cicada!

I noticed that some of the shed exoskeletons around my house have little white strings sticking out from the insides. Is this the fungus?

Also, does this prevent them from mating or egg laying? Will the population be smaller the next time around?

No that’s trachea!

Hi there! How did you get interested in studying fungi and cicadas? And what’s something you wish other people knew/appreciated more about your field?

I owe my interest in cicadas and their fungi to my grad students. They got me hooked! Fungi are incredible and perform such critical yet overlooked services in our environment! For example, if fungi didn’t degrade downed woody debris, our forests would be mile high piles of wood.

Is there any concern for humans or other animals handling, breathing, or ingesting an infected Cicada? (besides other Cicadas)

Although stimulants have been reported by our lab group from Massospora infected periodical cicadas, the risk to us is extremely low given the dosage detected from individuals.

I’ve heard more about fungi in the last year than I’ve heard my whole life, especially as they interact with trees and forests. Was there a giant breakthrough in the last few years regarding the basic nature of fungus?

Certainly fungi have been doing incredible things for millions of years. We are only now starting to understand how crucial they are in many living things! I think the field of mycology is in a really productive phase right now unlocking some of the most perplexing mysteries!

Hi! do you think this fungus will effect the next brood or is this just a once in a lifetime thing?

All broods of both 13 & 17 year cicadas are susceptible to this fungus. It generally has little impact on the overall reproductive success of these species across the larger landscape!

I would love your opinion on why or what advantage the fungus has when it’s using a host who comes out so infrequently, and is this of any benefit to the cicada species as a whole?

It’s an extremely specialized lifestyle with a huge payout.

There are some really good questions here. So I have a softball question: What's your favorite fungus?

That’s like asking who is my favorite kid. I love all fungi!

Is Massospora fungi present in Mexico?

Undoubtedly!

Fleeting curiosities, feel free to ignore for more engaging convo.

First: Cicadas are loud, and while I'm sure you're not exactly in an enclosed lab with those things screaming away at all hours of the day, any hearing protection required on the regular?

Secondly: its believed some (or all, just learning about it,) Massospora can produce psychoactive chemicals or effects in their hosts, is it known if this is how the fungus "convinces" the cicada to take flight and "carpet bomb" its fledgling cousins with a bad case of buttrot?

I won't bother with the "any signs it causes pain/discomfort" thing since that not exactly easy to measure, and if it can "convince" the host to go on a joyride after making its ass fall off I'm sure it can trick whatever version of nerve endings they have not to feel it (also considering they still try to do the sexy time when their sexy time parts are lying on the forest floor somewhere, but that could just be their "programming.")

Decibel wise, cicada noise likely falls between bar conversations and lawnmower noise. So prolonged exposure could impact hearing assuming you are sitting among them as they call.

It’s true about the compounds and although they provide a plausible explanation of how behavior is modified, further study is needed. We are working on that.