Annual cicadas have large, wide-set black eyes and a camouflage pattern on their bodies.
Ginger E. Long, ©2023 HGIC, Clemson Extension
Cicadas are large, plant-feeding insects known for their loud, shrill noise and discarded shells (called exoskeletons) that cling to trees and other vegetation. Cicadas belong to the suborder Auchenorrhyncha along with other hemipterans, such as leafhoppers and spittlebugs. These insects are found worldwide, though their presence in the United States is restricted to the southern and eastern parts of the country.
Description
This adult periodical cicada from Brood XIX emerged in 2024. Note the red eyes, black body, and orange-veined translucent wings.
Ginger E. Long, ©2024, HGIC, Clemson Extension
Cicadas are thick-bodied insects, measuring about 1 to 2 inches long. Their large compound eyes come in shades of black and red, though they sometimes emerge with white or blue eyes. Cicadas also have three simple eyes (called ocelli) in the middle of their head. The cicada’s wings are large and have thick, prominent veins. Despite their size, cicadas have relatively small antennae.
Annual, or dog-day, cicadas are often green or camouflaged in color. These cicadas feed up to five years as nymphs underground, but populations emerge every 1 to 3 years. Periodical cicadas have a black body and spend 13 or 17 years underground. Cicada adults die shortly after mating.
Cicadas have an incomplete metamorphosis, meaning eggs hatch into nymphs, which then turn into adults. Cicada nymphs go through four instars, or life stages, before the adult stage. Cicada nymphs bear some resemblance to adults but, at the same time, look quite different. They are cream or tan in color and do not have wings; instead, they have six legs, the front two of which are large and used for digging their way through the soil. Young nymphs appear almost translucent and look a little bit like termites. As they mature, they look more like their adult form but more subdued in color, keeping the nymphal cream hue.
Newly hatched cicada nymphs are translucent or cream-colored and look like ants or termites.
Photo by Roy Troutman, https://www.cicadamania.com/cicadas/cicada-larvae-pictures/.
Older cicada nymphs can be over 1 inch long and can move through the soil, feeding on plant roots. Photo by Jim Baker, North Carolina State University, Bugwood.org.
Cicadas have a membrane known as a tymbal, which they use to make their well-known shrill calling sound.
Photo courtesy of Amanda Hevel, https://www.flickr.com/photos/nmnh/2607912292.
Life Cycle
The cicada life cycle starts with the well-known characteristic mating call. Males call females using a special body part known as a tymbal. By moving tiny muscles in the abdomen, the tymbal, made of a thin membrane, vibrates and creates a shrill-sounding noise to attract females.
After mating, females insert their eggs into small twigs on a tree. Eggs hatch after six to ten weeks and fall to the ground. Nymphs burrow into the ground and make an underground network where they feed on fluids in tree roots. When ready, cicada nymphs crawl out of the ground and grab onto a tree or other nearby plant. The back of their exoskeleton splits open, and the winged adult emerges. Annual cicadas appear every year, though some cohorts may spend several years underground. Periodical cicadas only appear every 13 or 17 years. In South Carolina, the next cohort of periodic cicadas is expected to emerge in 2037. This cohort, known as Brood XIX, is a 13-year group and will emerge in several Upstate counties.
Adult cicadas crawl out of the last larval exoskeleton. These exoskeletons are often found clinging to trees and other vertical objects.
Image courtesy of Bob Doblina, https://pixabay.com/photos/cicada-insect-bug-nature-molt-4242624/.
An adult cicada emerges from its exoskeleton after crawling out of the soil onto a tree.
Photo by Joseph O’Brien, USDA Forest Service, Bugwood.org.
Periodical cicada nymphs from Brood XIX emerge from underground every 13 years. Ginger E. Long, ©2024 HGIC, Clemson Extension
Hosts
Cicadas use deciduous trees, such as hickory, oak, and pear, and shrubs as hosts. When choosing a specific host for egg-laying (oviposition), light and the architecture of a host plant’s branches influence their selection. Plants with longer and broader branches are favored by cicadas looking for a place to lay their eggs. It is unknown if nymphs prefer any host preference for feeding.
Impacts
Cicadas, especially periodical species, serve as an important resource to the ecosystem. The mass emergence of cicadas provides a food source for many other animals in the ecosystem, and their dead bodies serve as a significant nutrient addition to plants.
Feeding by cicada nymphs is not known to cause significant damage to the host plant. Adult oviposition results in branch flagging, where the end of the branch dies and breaks off. This type of damage generally will not harm the tree. However, during the mass emergence of periodical cicada, damage can be severe, and young trees and shrubs may be seriously impacted.
Periodical cicadas can be affected by a Massospora fungus. This fungus is parasitic and can infect the cicada in two ways. If it infects the nymph as it burrows through the soil prior to emergence, the fungus resides in the abdomen of the cicada and causes it to act strangely, generally remaining on the ground, spreading fungal spores as it drags its abdomen. Male cicadas that are infected will answer other males’ mating calls posing as females, further spreading the infection. Towards the end of the cicada’s life, its abdomen will start to fall off, revealing more signs of the infection as it displays a white mass of the fungus. The fungus renders the insect infertile. The fungus is harmless to people.
Cicada carcasses add nutrients to the soil.
Photo by David Coyle, Clemson University
Cicada damage from oviposition results from adults inserting their eggs into the stem.
Photo by David Coyle, Clemson University
Massospora fungus (white mass) on cicada.
image courtesy of Roy Troutman, https://www.cicadamania.com/cicadas/which-fungus-attacks-magicicadas-massospora-cicadina/
Management
Cicadas are usually harmless to plants, regardless of whether the cicada is annual or periodical. However, younger and more vulnerable plants may be more prone to dying and heavy damage due to oviposition. Netting vulnerable plants during the emergence season will keep them protected. This is generally only done if there is an emergence of periodical cicadas since their emergence can be predicted. It is impossible to predict the emergence of annual cicadas.
Physically protect vulnerable trees and shrubs from cicadas using netting.
Photo by James B. Hanson, USDA Forest Service, Bugwood.org
Originally published 07/21
