Interview: Brood X Cicadas Have Emerged in East Tennessee

May 31, 2021

A Brood X cicada at Ijam Nature Park in South Knoxville. University of Tennessee entomologist, Jerome Grant, says East Tennessee is a hotspot for this 17-year periodical cicada.
Credit Claire Heddles

The longest-lived insect in North America, the Brood X cicada, is emerging from the ground in fifteen states, including Tennessee. WUOT’s Claire Heddles chatted with University of Tennessee entomologist Jerome Grant about what these noisy critters have been up to underground for the past 17 years.

JEROME GRANT, GUEST: A lot of people refer to these as an invasion, but they're not an invasion it's just a natural biological phenomenon that occurs every 17 years with this Brood X cicada. 

CLAIRE HEDDLES, HOST: What purpose do they serve in biodiversity, in maintaining our environment? For those 17 years, are they doing something useful underground for us? 

GRANT: Cicadas of all types, whether dog day or periodical cicadas are very beneficial to us in several ways. One is while they're underground, they're aerating the soil cause they're moving throughout the soil and that's a tremendous benefit. When they come above ground, they're an excellent food source for a lot of animals. So birds are going to really prey on them this year quite a bit. So I expect populations of birds to boom from the feeding. When they die they provide nitrogen and other minerals to the soil for recycling and they're natural tree pruners. 

HEDDLES: They don't do anything to harm fruits and vegetables or gardens, is that right? 

GRANT: When they come out as an adult, they feed very little. Their main damage is caused by the female when she inserts her eggs into the twig of a tree or a bush of some type. And what she does is her ovipositor or her egg-laying mechanism is like a knife and she makes a slit and she'll lay 20 to 25 eggs and she'll make another slit and another slit. And then everything beyond those slits will die because it can't get nutrients and it will break off and you'll get natural tree-pruning on there. 

In a home situation, you don't want that on young trees or on some of your bushes. If you have a low population, you're not going to see any, probably, impact of cicada egg-laying. But if you have a large population you might want to protect your trees in some way, your small young trees. 

HEDDLES: My garden, my strawberries, tomatoes — all of those are fine? 

GRANT: Strawberries and tomatoes are fine. They have been known to lay eggs on about 200 different types of plants but they prefer hickory, and oak, and dogwood, and a lot of the flowering fruit trees. 

This particular brood again will not be back until 2038, so it's a wonderful opportunity for people to get out and observe a wonderful phenomenon of nature, and then if you decide the noise is a little too much, you can always grab a few and cook them and put them on your dinner table. 

HEDDLES: Can you describe how one could cook a cicada or a few cicadas? 

GRANT: Well, believe it or not, there are about three cookbooks at least on cooking cicadas. But what I encourage people to do is, when they emerge at night these cicadas will come out of the ground at night. When they molt into an adult real early in the morning, they're what we call teneral adults, they're really soft and white. So I generally go out between 8 to 10 o'clock in the morning and I look for newly emerged adults and collect them in a paper bag, I blanch them for four to five minutes, and after you blanch them you can put them in the freezer and keep them for a while or you can go ahead and start cooking with them. 

Or you can roast them, so you can put them in an oven at 225 degrees for ten to fifteen minutes and roast them and that gives you a nutty flavor to them. So there are different ways you can prepare them, different ways you can cook them. If you have a favorite dish, cicadas fit right into that. 

HEDDLES: Well, thank you so much! Are there any facts that you think are especially interesting that you want to share? 

GRANT: Well I appreciate you. You can't get a more fascinating creature than a periodical cicada. They come out in such large numbers, they're very odd-looking creatures, they live 99% of their life underground which is unusual in itself. And these large numbers, they come out with one purpose and that's to mate and reproduce. In order to mate they have to produce the sounds, the male does. We find the sounds annoying without the sounds, that organism cannot continue survival.