Any day now...

Right now, at this very minute, billions of cicada nymphs are snug in their tunnels, just waiting for the warm spring night when they'll emerge from the ground, shed their skins, unfurl their wings, fly, sing, mate, lay eggs, and die. It's a spectacular phenomenon, and we in the eastern United States are lucky to see it.

Thanks to iNaturalist and the power of citizen science, we now have the opportunity to create the most complete and detailed map in history of a periodical cicada emergence. Although all of the observations of periodical cicadas on iNaturalist provide valuable data, I've put together this project ( to collect the observations that go a step further, including photos or sounds that enable species-level identification of individual cicadas or choruses.

This data and genus-level observations of Magicicada for 2021 will be pooled with records from Cicada Safari, a free smartphone app developed by Dr. Gene Kritsky* and the Center for IT engagement at Mount St. Joseph University in Cincinnati, Ohio (

Ideal observations for this project should include photos of the underside of the cicada. We all love to get that beautiful photo of an unmolested cicada perched on a branch with the morning dew beading its gossamer wings, but that's not gonna help with species ID. We need to see that cicada belly! (Lateral views are also helpful.) Species are differentiated by orange markings that appear on the abdomen and pronotum:

Magicicada septendecim: orange patch behind the eye; orange pleura; orange bands on abdomen that are usually about half the width of each segment, often with fuzzy edges
Magicicada cassinii: no orange anywhere on the body; all black
Magicicada septendecula: tidy, narrow orange bands on abdomen, generally less than one-quarter the width of each segment; no orange on pronotum or pleura

Sounds are also useful for species-level ID, especially if you can get one male singing on its own.

Observations will be added to the project automatically if they meet its criteria, but if you join, you'll be in the loop to see journal posts and get updates on cicada sightings. Thanks in advance for all your contributions!

*Full disclosure: he's my husband. :)

Posted on March 31, 2021 09:34 PM by weecorbie weecorbie


Found the 1st pre-emergence holes in my yard tonight under dead leaves. I am expecting at least some will emerge tonight or very, very soon!

Posted by jeffdc over 3 years ago

This isn't directly related to the emergence, but to a retailer's preparations for it. A story in today's Columbus, Ohio, Dispatch newspaper told of a Cincinnati company eager to protect consumers from the coming "'hailstorms' of oversized bugs." Under the Weather, sells the "NEW Limited-Edition!" WalkingPod Mesh with Bug-Screens for $89.99. Just FYI (I hope you'll pardon me if this comment is inappropriate here!)

Posted by wardwriter over 3 years ago

@wardwriter - I saw the WalkingPod! And it's hilarious! I kinda want to get one for my husband...that would be a great photo-op :)
@jeffdc - Exciting! We saw a fair number of holes along trails at Withrow Nature Preserve yesterday, but no nymphs. They seem to be waiting for that first warm, rainy night.

Posted by weecorbie over 3 years ago

I finally saw my first nymph in a chimney! Holes are now very numerous.

Posted by rvignarajah about 3 years ago

Great project. I'm curious about your project terms that limit the collection to "research grade" observations. It seems to me that many potentially valuable observations would be excluded because the observer doesn't know how to network and get the observation confirmed. If you collect "needs ID" observations, they will show up in the project and be visible to people who come to the project because they're interested in cicadas, which should get many of the "needs ID" observations verified to "research grade." Just a thought -- if you open it up now, it will collect those retrospectively.

Posted by janetwright about 3 years ago

@janetwright - good questions! The primary purpose of this project is to present, with one click, a map of the highest-quality data that has been submitted to iNaturalist this year. For this reason, I'm filtering out "needs ID" observations, as well as observations of holes, nymphs, and skins - all of which can be misidentified and confused with other species of cicadas and even other organisms. The project also aims to discern reproducing populations of Brood X from isolated stragglers, and for that, we need to see where viable adult cicadas have been observed.

I'm personally vetting every Magicicada observation as well as sifting through Cicadoidea to find observations of cicadas as yet unidentified as periodicals. Several other observers are also actively searching for cicada observations, and (so far) we've been keeping up pretty well with IDing them as they come in.

One of my goals, enabled by the strict RG filters, is to try to establish a map that will reflect the distribution of species within Brood X...something that hasn't really been feasible until now. There is currently a strong identification bias toward M. septendecim, because it's the only cicada identifiable from a three-quarter or side view. I'm hoping that we can encourage users to post photos of cicada undersides so that we can get a better sense of the abundance and distribution of the other two species, cassini and septendecula.

Posted by weecorbie about 3 years ago

Sounds great, @weecorbie! This will be my fifth "brood X" experience. I remember them in NC in 1953 and 1970 and PA in 1987 and 2004. I'm delighted to see iNaturalist used to map the distribution of emergence along with the other species. Nice work!

Posted by janetwright about 3 years ago

@janetwright - Five Brood X experiences? That's an enviable achievement! My husband was born in 1953, but he can't count that emergence because he lived in North Dakota (and, well, he was an infant). I'm only on my third Brood X emergence, but I've gotten to see more Magicicada than the average American because we make it a point to travel and survey the various broods as they come out. I have a few more to go before I can say I've seen them all.

iNaturalist (and GPS/smartphone-enabled citizen science in general) is a dream come true for Magicicada researchers. It's a small community, and mapping efforts have been limited in the past by lack of person-power, but now there are literally hundreds of thousands of observers looking out for cicadas. It's amazing!

Posted by weecorbie about 3 years ago

I'll be back in range at the end of May and I'll be watching for them! iNaturalist is the best!

Posted by janetwright about 3 years ago

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