Climate Matters: Cicadas change with the climate

Even in a record-breaking stretch of heat, the periodical cicada broods emerged right on time in late spring and early summer in Mid-MO. But more changes to the climate in the future could also mean more changes to cicadas and their behavior.

Cicada emergence is directly tied to the temperature and climate of their location. They typically come out of the ground when the soil temperature reaches 64 degrees. In Mid-Missouri, this occurs in late April to early May in a seasonal year. However, as the climate continues to deviate from average this could mean more spring and summer heat waves that drive cicadas above ground ahead of schedule.

Locally the summertime started out near average so cicadas showed up on time, but they arrived weeks early in parts of the south where it remained warmer. The south and midwest are expected to see earlier arrival of spring and summer conditions in the future according to Climate Central, and this impacts how cicadas calculate their emergence.

Cicadas count the passage of seasons and years through tree roots. Periodical cicadas feed on tree sap as a nymph for the majority of their life, and trees undergo changes throughout the year affecting how much sap they produce. Cicadas count these cycles to know how many years have passed, and what time to emerge.

The changing climate can cause trees to produce sap irregularly, which in turn affects the cicada's count of the passing seasons. Warmer springs can push the bugs above ground early while there's still a risk of dangerous late-season freezes. Researchers also believe the periodical cycles of cicadas may shorten to 9 and 13 year broods rather than the 13 and 17 years.