Cicadas Emerge When Predators Are At Their Lowest


Always Something to Learn


A behavioral ecologist with Cornell University, Walter Koenig, lead author of a paper on the Periodical Cicada, found a very interesting discovery about the insect, something so remarkable that the scientists had a hard time believing the findings. It makes one admire the complexity of nature every time science makes a hypothesis or discovery.

Many are aware that the cicada has the longest lifespan of any known insect and how they live underground for long periods of time. It has been a strange mystery how millions of them signal each other simultaneously every 13 to 17 years to undergo transformation to shed their skin and appear in mass. Partially soil temperatures, but is it something else too? After they shed, they become the winged insect we know, filling the air with the droning noise of their multitudes in flight. They are almost a horror story in the making.

They are a bane of farmers and growers everywhere as they engulf trees and lay damage in their path. The eggs are laid in the trees and by mid-summer, then they drop to the ground for their long underground stay. The cycle of 13 to 17 years begins once again.

There are two basic types of Cicadas:

Periodic, 2-8 year cycle – These insects are seen each year, although from a different brood each year. Their life cycle is staggered. Because a different brood is hatching each year it seems like they are an annual hatching. They should be wriggling out of the ground many places about now when soil temperatures are 64°.

13 to 17 year cycle – This group does not appear every year. When they do emerge, it is  in huge numbers. They are the ones in the study. The last major swarm, Brood X, surfaced in 2004, but Brood II is scheduled for the East coast this year. (source)


Cicada are seen in many areas of the country in small numbers each year. When a cicada brood hatches, it is a completely different occurrence. They emerge by the thousands, or even by the millions.


What Science Thinks is Happening

Suggested by scientists, the Cicada is timing the event to coincide with a drop in bird populations. Birds are their main predator. This hypothesis was developed with 45 years of avian population data compiled by the North American Breeding Bird Survey. The group noted the rise and fall of 15 species of birds that target the Periodical Cicada in the study.

This disparity of predator/prey is not what occurs in nature on a normal basis, in fact, it is quite the opposite generally. Predator and prey usually correspond in proportional numbers. It was noted that birds will decimate a cicada population that emerges out of sequence.


“So how do the cicadas manage to manipulate the birds over these long cycles?” was a question asked by the study. It certainly helps to explain the long time spent underground if they are correct. It has been long thought that avian predation was a factor in periodical insects, but they still do not know how the cicada regulates bird populations to low levels.


The 15 bird species were selected because they were birds known to dine on the Cicada. The analysis showed a decrease in the number of these birds when the Cicada emerged. After the cicadas emerged, the birds increased. It seemed more than a coincidence, to where the cicada is manipulating the population in some way, at least in that more birds were hatched after they became abundant.

Another study Koenig did reveals there is an enormous effect of biomass that cicadas have on the environment. They improve environmental conditions by enriching nutrients for soil after their death. For such a destructive insect, it has a lot science does not know about it, and some it does which shows it as an important part of the ecology of an area.


This image above of the very alive, but mortally wounded cicada, is from the post Plants Can Call 911 – So Says Science. It really was an interesting study.

This article, from Science Now is a bit more readable than the scientific paper in the link above if you want to know more on this fascinating study. (source)

Did you know adult Cicadas don’t eat? “Rather, damage to trees is caused by the adult female as she cuts slices into twigs to lay her eggs. Shortly after mating, the male Cicada dies.” (source) This site also lists the states where the 2013 brood will affect. They list plants and trees that are most damaged as well.

How about frying them up? Here is a reporter that did just that and he said they don’t taste like chicken! (source)


About Garden Walk Garden Talk

This entry was posted in Bugs, environment, garden, science and tagged , , , , , , , , , . Bookmark the permalink.

37 Responses to Cicadas Emerge When Predators Are At Their Lowest

  1. I love learning – great post – those buggers have a creep factor going on too – ha! Happy Weekend:)

  2. Bonnie Lee says:

    Interesting article. Cicadas are the sound of summer of me in Japan, where they are an annual event. If you ever watch Japanese movies or anime, you will hear them at the peak of summer. They are the sound of sweltering heat and humidity, of nights with cold beer and hot food on sticks. They are noisy. They are ugly. And they are everywhere.

    So are the birds. I wonder what is different between the Japanese species and those in the United States?

    • I never realized they had them in Japan. I will have to make note of that next movie I watch from there. I wonder if they are different from here? I agree they are noisy and not very handsome. Those bug eyes are what really gives me the creeps, but I still find them kinda interesting.

    • Rebecca says:

      I grew up in Northern Kentucky. The sound of the buzzing cicadas can instantly make me feel like I am sweltering.

  3. Wonderful, informative post, Donna. We generally get a trickle of the cicadas from the Iowa and Illinois broods, which looks like it will be next summer. The next one that specifically lists Wisconsin is 2024. I do remember summers with Cicadas. They fascinate me, too. Thanks for all the info about the bird/cicada cycles.

  4. Fried cicadas? Shoot, I just ate! It is so fascinating how different species interact with each other as they evolve.

  5. This was very interesting. I enjoyed reading it and then going to the net then to find even more information. Thank you for sharing.

  6. Victor Ho says:

    Informative! My family experienced them when they stayed in a rental home in Glen Cove in the ’80s. All I remember is the constant drone of noise when I visited.

  7. Fascinating research! They really are LOUD! We had a lot last year. I often found their external skeletons under leaves and they are really alien looking things.

    • I agree, very loud. I never really find the exoskeletons because they never make a home in the city and I am not that observant on hiking trips. The live ones where photographed in my yard though. They were from last year.

  8. HolleyGarden says:

    What an interesting study. There is so much we have yet to learn, especially in the way in which we are all seemingly interconnected.

  9. catmint says:

    thanks for the cicada info and pics – they remind me of balmy summer nights, and are a sign that the next day will be hot. Occasionally I see their discarded shells, but rarely have seen the insects themselves.

  10. Bill S says:

    What a fascinating article, having never heard or seen these creatures, all I can say is I hope they don’t try to take over the planet !!

    • The birds see to keeping them in check. They must be tasty to birds. At least they are a big meal!

    • Rebecca says:

      Bill, go on youtube and view clips of the old black and white movie War of the Worlds. The buzzing noise you hear in the background is exactly what they sound like. In the midst of a huge invasion, the noise can drive you crazy. Ah, memories of summer.

  11. Nope I won’t eat bugs…. fascinating how they are so integral in so many ways with nature…I have been reading about these amazing creatures. Thankfully we will not have to deal with them.

  12. It was very interesting to learn that they somehow know to appear when predators are low. When food is in abundance, the number of predators usually grows. With the cicadas, by the time the number of predators has grown, they’re underground again waiting for the time when the bird population dips again. Fascinating!

  13. A.M.B. says:

    This is so interesting! I hadn’t realized there were two types of cicadas. I’m not looking forward to Brood II.

    • I am not sure if they mean two distinct types, but two ways in which they emerge. I did not see where there was a physiological difference. But what was interesting is that there are different timing.

  14. We’re slated to have cicadas this year in Maryland. Living on the Chesapeake Bay, we have sandier soil, so at our house we don’t get as many as they do closer to DC. Can’t wait to have the little buggers.

  15. I’ve always HATED their emergence, but at least you’ve made them interesting!

  16. Fossillady says:

    Wow, you do learn something new everyday. The area in Michigan where I live misses the mass swarm regions. That would be something to see. We see quite a few of them and can’t help but hear them at night, but not in huge quantities. I often see thier shed exoskeletons . . . Great article Donna, Kathi :O)

  17. Fergiemoto says:

    Fascinating information to learn! Thanks for sharing your knowledge.

  18. We had a big infestation last summer here in SC. The daytime singing of the males sounded like flying saucers all day long. As evening came, everything was silent….very eerie. Ours were the red eyed cicadas, also some of the longer 13- 17 year life span ones. They did such damage to my new trees and tender stems of shrubs. I have pruned out a lot of the damaged limbs before they get large and can cause damage to either the tree they fall from – ripping the bark- or falling on something causing damage.

Comments are closed.