8 minute read
Wings of Desire: Crepitation
Wing-Tapping Cicadas: A Bug of Musical Restraint
By Zach Phillips, Ph.D., Terrestrial Invertebrate Conservation Ecologist
It is a banner year for cicadas in North America. The 13- and 17-year broods of periodical cicadas (Magicicada spp.) are emerging en masse through early summer in the eastern United States, inundating the landscape in a cacophony of mating calls. The total solar eclipse was 2024’s eye-protection event of the year, and this is undoubtedly the year’s earprotection event. If you haven’t heard the cicadas yourself, you’ve at least heard about them in the news or on social media. Or perhaps you’ve read about them in the Evanston North Shore Bird Club newsletter that your mom mailed to you, because she knows that you can’t get enough cicada gossip — even if it’s long-distance, Chicago-area cicada gossip — and that you need reading material for the bus (thanks, Mom).
For those who missed the ENSBC newsletter, it describes the cicada emergence as “cicada-mania,” and a raucous kind of natural “alarm clock” (Lundy, 2024). This is an apt description for periodical cicadas in Illinois, but not all cicadas make such a big production out of reproduction. The courtship of some species is quiet (at least to our ears), and more like a windup watch than an alarm clock. California, which is not home to any periodical cicadas, is a diversity hot spot for one of the quietest groups, the wing-tapping cicadas (Platypedia spp.). Unlike periodical cicadas, wing-tappers emerge annually, and do so with little noise and even less fanfare. They don’t need the attention. They don’t want it. In fact, they’re miffed that this article is even being published. A predator might read it and get ideas. Sorry, wing-tapping cicadas. If it’s any consolation, I don’t think our readers will hunt you down and eat you. No promises, though — people have a thing for eating cicadas. The ENSBC newsletter even includes the following recommendation for consuming your more famous relatives: “Periodical cicadas are best [eaten] when they are still white; they taste like canned asparagus.” Regarding Ironwood readers, all I can promise is that they will be strongly advised to read this article on a full stomach. Hopefully, a few folks will simply be inspired to tune into your song and appreciate the subtle insect acoustics of our soundscape.
Wings of Desire: Crepitation
Most cicadas, including periodical ones, use a drumlike organ in their abdomen, called a tymbal, to produce courtship calls. People are generally familiar with these cicada calls, which can sound like a raspy bike chain or a utility pole buzzing in the rain.
Wing-tapping cicadas court each other to the beat of a different drum, and it’s not a tymbal. Instead, they produce “clicking” courtship calls by tapping their wings together or by banging their wings against their own body or the surface of a plant. This behavior is termed “crepitation,” and the resulting sounds have been described as “snapping the thumb nails one off the other,” and “exactly like some one [sic] winding a watch,” and, if many cicadas are calling at once, resembling “a shower of hail” (Davis, 1943, 187–188). Professor Sherman C. Bishop once claimed that the calls “can be closely imitated by tapping a dime on a nickel” (Davis, 1943, 187). For shame, Professor Bishop! It isn’t right to nickel-and-dime anyone, not even a cicada. Other researchers have successfully mimicked wing-tapping cicadas by clapping and snapping to the rhythm of their calls, drawing them in to collect and study (Cole, n.d.).
When not being tricked by biologists, female and male wing-tapping cicadas use crepitation to find each other. Males produce a series of multiple clicks, and relatively stationary females respond with fewer clicks, acting as beacons for the mobile males. After they mate and the female lays her eggs, the immature cicadas, called nymphs, feed on plant roots and develop underground, eventually emerging and molting into adults. The season of courtship then begins again.
Tracking Cicadas in Santa Barbara
If you see me clapping around Santa Barbara Botanic Garden, I’m not just applauding the work of our gardeners — I’m trying to seduce the cicadas. So far, no luck. As a jilted entomologist, I must go to them, and wing-tappers can be a challenge to locate. Throughout spring, you can hear them at the Garden and around Santa Barbara, but they’re often too high in the canopy to get a good look at. If you hear one in a lower shrub, approach cautiously. They have large eyes and a prey’s vigilance, and readily go silent, spin around a branch, or hop or fly away.
Fortunately, the Garden is full of bug-curious folks that report their encounters to me (Thanks Steph, Adam, Christina, Scot, and Sophie). A couple highlights this year include a nymph found attached to the outer wall of the Entrance Kiosk, and a freshly molted adult resting on a post, waiting for its wings to inflate and expand before flying away.
Bird Food and a Fungal End
The lives of wing-tappers are still a mystery. They have not been studied as thoroughly as periodical cicadas, and we don’t know much about wing-tapper interactions with other creatures or the impact they might have on ecosystems. For instance, we don’t know what plant species they feed on as nymphs.
As food themselves, it’s possible wing-tapping cicadas are a substantial resource for birds. In Montecito, I’ve seen a Hammond’s Flycatcher (Empidonax hammondii), which was identified by local birder Conor McMahon, moving through a coast live oak (Quercus agrifolia) and liquid amber (Liquidambar styraciflua sp.) canopy, apparently picking off wingtapping cicadas that were broadcasting their calls. If you, the reader, spend any time watching birds, cicadas, or trees, please keep an eye out for any similar predation events, and post your observations online (e.g., on iNaturalist or eBird), or email me directly. If you, the reader, are my mom, snail mail is still much appreciated. Don’t underestimate the value of such observations, which, especially when accumulated, can help us better understand these animals and their ecological roles.
There is at least one creature whose dependence on wing-tapping cicadas is well documented: Massospora, a fungal parasite that “effectively hijacks cicadas, turning them into efficient vectors” of fungal transmission (Boyce et al., 2019, 5). Periodical cicadas are also infected by Massospora but by a different species. The fungus can manipulate its wing-tapper hosts by manipulating males to sound more like females, which produce fewer clicks. Since females — and fungal-infected female-sounding males — are beacons to courting males, this can increase encounters with other cicadas and thus increase host transmission opportunities for the fungus.
It isn’t clear exactly how Massospora chemically hijacks the cicadas, but psilocybin, a compound also found in “magic mushrooms,” seems to play a part (Boyce et al., 2019, 41). If you’re wondering, “Will eating a Massospora-infected cicada get someone high?” or “Is there a market for ‘cicadibles’?,” you should know that other great minds have pondered the same deep questions (at least the first one). And the answer is no (Shetlar, 2021). So don’t eat the wing-tapping cicadas. Stick to canned asparagus. But do watch the cicadas, listen to them, appreciate and celebrate them, and take notes. Let me know what you discover at zphillips@SBBotanicGarden.org.
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Boyce, G. R., Gluck-Thaler, E., Slot, J. C., Stajich, J. E., Davis, W. J., James, T. Y., Cooley, J. R., Panaccione, D. G., Eilenberg, J., De Fine Licht, H. H., Macias, A. M., Berger, M. C., Wickert, K. L., Stauder, C., Spahr, E. J., Maust, M. D., Metheny, A. M., Simon, C., Kritsky, G., … Kasson, M. T. (2019, October). Psychoactive Plant- and Mushroom-Associated Alkaloids from Two Behavior Modifying Cicada Pathogens. Fungal Ecology, 41, 147–164. https://doi.org/10.1016/j. funeco.2019.06.002
Cole, J. (n.d.).
Davis, W. T. (1943). Two Ways of Song Communication Among Our North American Cicadas. Journal of New York Entomological Society, 51, 185–190.
Lundy, M. (2024, April). Cicada-Mania!! Evanston North Shore Bird Club. https://www.ensbc.org/ sites/default/files/Bird%20Calls%20April%202024.pdf
Rosi, C. (2021, June 7). Will eating cicadas get me high? Myths debunked with OSU's BugDoc. NBC4. https://www.nbc4i.com/news/local-news/will-eating-cicadas-get-me-high-mythsdebunked-with-osus-bugdoc/
A special thanks to wing-tapping cicada biologists Elliott Smeds and Jeffrey Cole, Ph.D., for generously answering my questions and providing photos. And thank you to Nava.
