From the Midwest to the East Coast, cicadas from Brood X have emerged in full force, making a lot of racket while trying to find a mate and then actually doing the deed. Although their days are numbered, they’ll leave behind billions of eggs and millions of holes in the ground. These pits, created when the cicadas emerge from the soil, will stick around for the duration of the growing season, venting greenhouse gases. There are a number of effects from this, says Richard Phillips, an ecologist at Indiana University whose team is exploring the tunnels’ influence on water infiltration, gas exchange, and fertilization.
Ordinarily, when subterranean species tunnel through the soil, the holes collapse behind them. Phillips explains that cicadas produce chemicals that act as a glue, holding the tunnel’s shape for the entirety of the season. With as many as 400 holes per square meter going down about three meters underground, the soil is aerated in a deep and lasting way.
Using two types of infiltrometers—instruments used to monitor the rate at which precipitation permeates soil—Phillips’s team compares how the density of emergence holes affects the penetration of deep rainwater into the soil. Although it is fairly intuitive that the tunnels will bring water beneath the topsoil, he says, these measurements will be taken over the next several months to determine how the soil is affected over the course of the season.