Hi all! Do you want to participate in a project collecting cicada shells nationwide? Are you curious if we can determine their diet just from the chemistry of their bodies and shells?
Alex Reis and I are looking to collect cicadas from across the country. Previous scientists have found that cicada isotope chemistry is influenced by location and diet, and we're curious what the larger scale trends might be. We'd love it if you could help us out and send us 5-10 cicada samples and the leaves from the tree they're found on/near (if possible). You're welcome to sample multiple trees or locations as well!
We have a google form to collect sample information: https://forms.gle/J1hDb5UHiZ3ypyqr6
Periodic vs Annual Cicada https://extension.entm.purdue.edu/cicadas/
How do isotope studies work?
Did you know that carbon and nitrogen can have slightly different masses? Sometimes, a carbon atom will have an extra neutron in it, making it just a little bit heavier. About 1% of the carbon atoms are heavier like this. However, that 1% of atoms isn’t evenly distributed! Different plants incorporate different amounts of the heavier carbon, and any organism that eats that plant has roughly that amount of the heavy carbon in them! The amount of heavy carbon can also change based on how stressed the plant is, the climate, what kind of soil its in…. In short, we can tell a lot of things by looking at the relative amounts of heavy versus light carbon in an organism!
Since a cicada spends years eating from tree roots, the amount of heavy carbon in its body is similar to the plant it was eating. If the cicada is eating from a maple tree, it will have a different carbon composition than if it was eating from an oak or a pine. As a side note, this works for people too- if you have a lot of corn in your diet versus a lot of rice, the carbon composition of your body will reflect that!
We want to see if there are changes across the country with the cicada populations. Do areas that experienced drought have different values than those that didn’t? Are all maple trees the same across the country? What else can we learn about these creatures?
We will dry their exoskeletons, and sometimes their entire body, crush them, and then weigh out a small amount to measure in the instruments in my lab. So, send along some samples, and come back here in Fall to see the results of our study!