Knowledgebase
Cicada singing #754862
Asked June 08, 2021, 3:59 PM EDT
Washington County Maryland
Expert Response
Hello Dave,
There are three different species which comprise the brood that's out now, and their calls vary. When the males chorus in the treetops, their overlapping starts-and-stops of calls can create either a cyclical whir or an even drone. As with many insect and bird calls, it can sometimes be difficult to tell where exactly the sound is originating from.
Here are sample soundbytes from the three species in our area - Magicicada septendecim, M. cassini, and M. septendecula:
https://www.cicadamania.com/cicadas/cicada-songs-audio-sounds-noise/
The flying-saucer sound is probably M. septendecim, our most common species. The buzzing is probably either of the other two species.
Miri
On 06/09/2021 2:37 PM Ask Extension <<personal data hidden>> wrote:
You're welcome!
On 06/09/2021 4:36 PM Ask Extension <<personal data hidden>> wrote:
It's a plausible theory, certainly; unfortunately we gardening educators don't have in-depth knowledge of the physics of how sounds like these carry, so we'd just be speculating. To some degree, the overall chorus volume is also impacted by how loud surrounding (and competing) sounds are, like traffic, planes passing overhead, and so forth, because the cicadas react to it and try to be the loudest thing in the area. How much one species of cicada impacts the other in this regard while calling we don't yet know.
Individual cicadas also change "vocalization" type depending on their goals - to startle a predator, to help aggregate males for a chorus, or to communicate with a nearby female. There's so much activity in a well-populated tree that all these minute-to-minute events could also change the overall sound we detect.
There could also be temporal changes to the chorus sounds - meaning, in this case, that maybe one species emerged slightly earlier and began chorusing earlier, or that maybe one species calls primarily in the morning/afternoon hours and another in the afternoon/evening. Perhaps temperature also plays a role, where one species might call within a certain temperature range, while others are less likely to call in cooler or warmer temperatures. (Of course, there would be lots of overlap, and differences may only vary by a few degrees.) They're all interesting theories to think about, and maybe some researchers are working on studying these details.
Miri
