The sound of the cicada

Yes, the cicada announces the season’s change like no other. I wanted to know more about cicadas and their cacophonous songs. I spoke with entomologist Dr. Tracy Leskey.

So, what exactly are cicadas?

Dr. Leskey: Well, you know cicadas are insects that belong to what we call the order Hemiptera which is the order of insects to which the true bugs belong. Not all insects are bugs, but there are a group of insects that are literally referred to by entomologists as bugs and cicadas are one of those.

Are they special in any kind of way?

Oh yeah. Cicadas are really interesting. Cicadas are conspicuously known because of their interesting developmental attributes and one of these, in the case of our annual or dog day cicadas, is their very conspicuous emergence during the later part of the summer.

The cicadas actually have a really interesting life history-sort of how they grow up. In that the juvenile stage of adult cicadas, the nymphs, live in the soil, but what’s interesting is those nymphs that are in the soil, they actually spend two to five years in the soil completing their development. So, you know some of the dog day cicadas that you see emerging literally are the same age of some of our kindergarteners going to school this year.

And how do they make that sound?

Well, that’s the adult stage and so in this case, it’s the males that make the sound. The females do not make those sounds. The males have what we would call almost a pair of built-in drums in their abdomen and we refer to these as tymbals. And these tymbals produce the sound based on this very tiny ribbed membrane that is there on their abdomen and then it is powered by muscle contractions. So, those muscles contract and relax and as they do that, it creates a sound. The other piece that’s interesting is the male’s abdomen is nearly hollow and so this allows the sound to be amplified.

These are males calling to females? Why are they doing this?

So, yeah, the males are doing this literally to find a mate. They are trying to attract females to their location. So, it may sound like a bit of a cacophony to us, but you know it’s sweet music to a female cicada. (laughter)

So, while we hear this…

(Sound: cicada buzzing)

Female cicadas might be hearing this…

(Music: Sinatra/Jobim- Baubles, Bangles and Beads)

Credit William P. Gottlieb / Wikimedia Commons

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Wikimedia Commons