They’re ugly, they’re loud and they’re crawling out of the ground.
Brood XIV is a 17-year periodical cicada that last surfaced in 2008.
When the soil eight inches below ground reaches 64 degrees, Brood XIV emerges and lives up to 5 weeks. In that time, the cicadas shed their exoskeletons, males begin their shrill mating call and females lay fertilized eggs inside tree twigs using a knife-like organ. Females can lay up to 600 eggs in their lifetime.
The eggs hatch within seven weeks. The larvae, which look like little white ants, drop down from the twigs and dig into the soil. They spend the next 17 years eating sap from tree roots until the temperature is just right for them to emerge and repeat the cycle.
Midhula Gireesh, an assistant professor and extension specialist with University of Tennessee’s Department of Entomology and Plant Pathology, said periodical cicadas like Brood XIV act as a source of food for other creatures and the soil beneath.
“The food chain is balanced,” she said. “A lot of predators, like other insects, feed on them.”
Data collected by UT from Brood XIV’s previous emergence predicts a large concentration of the cicadas is expected in most East Tennessee counties.
“Wherever they emerged last is where they will be concentrated,” Gireesh said.
Gireesh said UT will continue collecting data on where Brood XIV appears to better understand future broods.
Unlike annual cicadas that are light green and appear during summer, periodical cicadas have black bodies, red eyes and translucent wings. There are two kinds of periodical cicadas: one that appears every 13 years and another that appears every 17 years. Both are native to eastern North America but differ in location. The 13-year cicadas are mostly found in the South, while 17-year cicadas are found farther north. Due to Tennessee’s location, the state sees both kinds of cicadas.
Cicadas are harmless to humans and pets. But Gireesh advised protecting valued plants with cheesecloth or tobacco canvas to prevent cuts from the females. Insecticides are not recommended.
“If the purpose is not served, then it could also cause problems to the beneficial insects,” she said.
Gireesh encourages people who experience the emergence of Brood XIV to learn more about the insect. After all, this brood won’t be back until 2042.
“It's the best time to show [kids] ... what nature has to offer,” she said.
Brood XIV can be tracked on Cicada Safari.
