How many cicadas can an oak tree support?

I’m looking for info on the relationship between Cicadas (particularly in the eastern United States) and oak trees. Specifically an estimate on how many nymphs a single tree can support over a given year, or in the case of magicicada, 17 years.

Went to a lecture several years ago by an entomologist who’s name I’ve since forgotten. He brought up information on the importance of oaks and how many species they support including information relating to cicada nymphs.

I want to dive into this subject but I don’t know where to start.

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Might this person have been Doug Tallamy? He’s made lots of great stuff about the relationships between insects and native plants.


I do believe that’s him, yes!

He also wrote a book entirely about the importance of native oak trees. Maybe some of the answers you’re looking for is in there.


If you were to determine the area of the drip zone of a large tree (subtracting the area of the trunk’s diameter) and multiply it by the emergence density, that would give you an idea of the number of Magicicada nymphs supported by that tree. Measuring the emergence density under a given tree can be accomplished by marking off a square meter, sticking some kind of marker into each emergence hole you find, and then collecting and counting the markers. (In our studies, we’ve used plastic spoons. It’s a fun process :)

I’m having trouble tracking down the paper in which he published this, but the highest Magicicada emergence density Gene Kritsky (my husband) has observed is 356 holes/square meter, and that happened to be beneath a mature oak. Additionally, the hatch rate of cicada eggs laid in oak twigs is among the highest measured, at around 50%. Egg mortality is greater in some other tree species, and highest in conifers.

Broods XIII and XIX will be emerging simultaneously in 2024, so there will be an opportunity to study this soon!


How does one measure this?

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Twigs with cicada oviposition can be collected and carefully dissected to remove the eggs. Hatched eggs are transparent, while unhatched eggs will be opaque ivory or brownish, so it’s simple to count hatched vs. unhatched eggs and determine hatch rate/egg mortality. Live twigs should be sampled for this, rather than flagged ones, as the drying of branches can increase mortality.


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