Tucson Standard

Once the cicadas begin their distinctive buzzing in Arizona, it signals the end of spring and the onset of June's heat. Gene Hall, manager of the University of Arizona Insect Collection, shared insights about these unique insects.

Cicadas can remain underground for years before emerging in large numbers. "Cicada life cycles can range from three years for our local species to up to 17 years for those in the Midwest and eastern United States," Hall explains. This mass emergence is thought to be a survival strategy against predators. In some areas, up to a million cicadas may emerge per acre.

In Tucson, cicadas avoid predators by being active during the hottest part of the day when other animals seek shelter from the heat. Cicadas have an ability akin to evaporative cooling. "They feed on plant sap... as they start to overheat, they remove water from their blood and pass it through ducts in their body," says Hall.

Female cicadas lay eggs in twigs; nymphs then fall to the ground and burrow underground where they feed on plant roots. When ready to molt into adults, nymphs emerge at night. "They're very vulnerable when they emerge because the body of the adult starts out soft," Hall notes.

Cicada populations are known as broods, with maps detailing their locations and emergence times. This year saw a rare simultaneous emergence of two broods: "It's the first time in over 220 years that this has happened," according to Hall.

Cicadas produce sound using air-filled spaces within their bodies that amplify noise like a resonating chamber. Males use a structure called a tymbal to create loud mating calls, which females do not produce.

These insects are difficult to locate despite their loud calls due to strategic movement and silence when approached. Cicadas face threats from predators such as cicada killer wasps and fungi that infect them during their underground phase.

Arizona hosts diverse cicada species ranging from large Southwestern giant floodplain cicadas to smaller ones like Beameria venosa. "In our insect collection, we have 36 species of cicadas from the state," says Hall.

This article updates information originally published in 2017.