A Chimney Building Cicada Nymph is Seen in Brazil! - Observation of the Week, 5/24/20

Our Observation of the Week is this Fidicina cicada nymph, seen in Brazil by @siddantas!

Here in North America, we’re used to seeing cicada exuviae on tree trunks, but I’d never heard of a cicada tower until coming across Sidney Dantas’s photo. Sidnei tells me they’re very common in Amazonia, especially near the end of the rainy season, but in over twenty years of exploring the Amazon, he has never actually seen a nymph actually building one until May 9th of this year.

As a child growing in eastern Brazil, where much of the forest had already been removed, Sidnei says he learned about nature “[mostly] from tv shows and books/magazines.” But that didn’t stop him from becoming a biologist later in life, earning a masters and a PhD  in bird ecology and taxonomy, mainly in the area of Belém do Pará. “After my PhD,” he tells me, “I got some postdoc grants and continued to do research on birds in Belém, and did not focus much on other kinds of creatures for a long time.”

That changed in 2018, however, when Sidnei changed career directions and became a guide for tourists at the Cristalino Lodge in the Brazilian state of Mato Grosso. “Here in Cristalino, I have to speak about birds and many other things, so I got in contact with my ‘naturalist side’ again, and activated my curiosity for nature in general, especially for butterflies and frogs. Now I am...spending the quarantine [here], and taking my time to look for more amazonian wonders everyday.”

Which, of course, brings us to the very busy cicada nymph. “On that day, me and my friend Jéssica Martins, another guide in Cristalino Lodge, were walking in the forest, and in fact she saw the cicada first, after I passed by it unaware, and called me back. 

We were amazed to see it in action, and spent some minutes taking photos and observing the cicada building the tower by placing the mud with its big front legs from side to side, being annoyed by some ants, and even pulling the sides of the tower to cover itself when we did some sudden movement close to it...After some time taking photos, we decided to leave it alone.

Cicadas spend much of their lives as nymphs, tapping into the roots of plants and slurping up xylem. Many will spend years doing this (perhaps most famously the 13 and 17 year cicadas of North America) before metamorphosing into adults who will live no more than several weeks or months. The nymphs which Sidnei and Jéssica found were likely in the genus Fidicina, and their towers would perhaps more accurately be called “chimneys”, as they are believed to aid the nymphs in regulating the microclimates of their underground chambers, as well as providing a place to escape during heavy rains.

“I started using iNaturalist for uploading my butterfly and reptile photos, in order to contribute to projects cataloging the butterflies and reptiles of the Cristalino region,” says Sidnei (above, on one of the observation towers in Cristalino Lodge). “Soon I was posting observations of other taxa as well, excited by the possibility of getting them identified by specialists! I’ve learned a lot about insects, frogs, and other things...and I started to learn how poorly many of these taxa are known for this region…

I have contributed photos and sound recordings to people’s work on membracids, crickets, wasps, and I find it amazing to get in contact with people from these areas and learn so much! At this point, the iNaturalist experience stimulated me to pay more attention to and record unusual species or behaviors, to share with other people and possibly contribute to knowledge about amazonian biota.

- by Tony Iwane. Some quotes have been lightly edited for clarity and flow.

- iNat user @belgianbirding commented on Sidnei’s observation and linked to his own blog post about his encounters with these chimneys.

- The Animal Architecture project has some pretty sweet examples of structures created by animals.

- Of course David Attenborough did a segment on periodical cicadas.

- An emergence of 17 year cicadas is actually occurring right now in a small area of North America. 

Posted on 24 de maio de 2020, 08:12 PM by tiwane