There are two different types of cicadas, periodical and annual. While both are cicadas, their lifecycles and appearance are drastically different. Annual cicadas typically emerge every year throughout the United States and may vary from green, brown and black in appearance. Periodical cicadas are found in eastern North America and have either a 13-year or 17-year lifecycle, emerging at different times and areas depending on their developmental time.
Periodical cicadas have bulging red eyes and red/orange colored wings. They are referred to in “brood numbers,” but these are arbitrarily assigned by scientists that track them based on where they emerge geographically over either a 13-year or a 17-year period.
Cicadas are beneficial and provide food for many animals, including birds, reptiles, snakes and even spiders and other arthropods. When underground, the nymphs construct tunnels that aerate the soil and also allow roots to gain more access to nutrients and oxygen for growth. The cicadas that emerge don’t live for very long and the large piles of cicadas that have died increases nitrogen in the soil that enhances plant and tree growth.
The most striking feature of cicadas aside from their large size are their sounds. In areas with large numbers of cicadas emerging, sound volume can reach 100 decibels. The males make loud, shrill buzzing noises to attract females for mating. They make these sounds using a specialized structure called a tymbal located on their abdomen.
Cicadas typically stay outside, are active at daytime and not attracted to light. In areas with high concentrations of cicadas, trees may sustain cosmetic damage when female cicadas use their ovipositor to cut trees and lay eggs inside young tree branches. This is typically not a threat to the tree’s overall health. A few weeks after being laid, the eggs hatch and the tiny nymphs drop to the ground where they burrow into the ground and feed on tree roots, molting and growing for several years, depending on the species.
Cicadas do not pose a threat to people or property and they do not bite or sting. Therefore, they don’t require control but when clients become concerned, more education might be needed.
BY BRITTANY CAMPBELL, PHD, BCE, DIRECTOR OF TECHNICAL SERVICES, NPMA
PHOTO: TORU KIMURA/SHUTTERSTOCK.COM