Periodical cicada
Periodical cicadas are fascinating insects known for their unique and lengthy life cycles, which can span either thirteen or seventeen years, depending on the region. Inhabitants of southern Canada and the eastern United States (excluding Florida) often experience mass emergences of these large, noisy insects during late spring, creating a striking spectacle. Commonly referred to as 17-year cicadas, they are distinct from locusts, as they do not jump. After emerging as adults, males attract females with loud mating calls and the females lay hundreds of eggs in tree bark. Once the eggs hatch, the nymphs burrow into the ground, feeding on tree root juices until they resurface years later. Their striking appearance includes black bodies with orange accents and clear wings. Although these cicadas are generally resilient, urban development and insecticides pose threats to their populations. The cicadas' synchronized emergence in large numbers helps ensure sufficient reproduction despite predation, showcasing a remarkable aspect of their life cycle.
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Periodical cicada
Among the many marvels of the insect world is the life cycle of the periodical cicada. As a newly-hatched nymph, or young, it burrows into the earth and feeds on tree root juices. Depending on the specific species, circadas emerge either thirteen or seventeen years later. They surface as adults, mate, and then die. The cycle then repeats.
Kingdom: Animalia
Phylum: Uniramia
Class: Insecta
Order: Hemiptera
Family: Cicadidae
Genus: Magicicada
Species: Septendecim
Every thirteen or seventeen years people in parts of southern Canada and the eastern half of the United States, except Florida, find their suburban neighborhoods and surrounding woodlands covered with thousands of large, noisy insects. These are the periodical cicadas, which are also called the 17-year cicadas. They are also commonly called 17-year locusts, however, this name is misleading as they do not jump.
The unusual name of this insect comes from its life cycle which spans either thirteen or seventeen years, depending on where it lives. Those that live in the north have a 17-year life cycle, while those in the warmer south grow more quickly and have a 13-year cycle. Its species name is Latin for "seventeen."
Between May and June, the males fly in search of mates and call loudly to females. These calls fill the air, and some people say they sound like the word "pharaoh" said slowly. Females lay 500 to 600 eggs each with special tubes called ovipositors. They lay their eggs underneath the bark of certain trees. The females and all the males will then die. One month later, the white-bodied nymphs, or young, hatch and drop to the ground. They burrow several feet (about one meter) into the ground, and live in chambers near the underground roots of trees. They will remain submerged underground until they emerge more than a decade later.
Like other insects in the order of bugs, periodical cicadas have mouthparts called rostrums. These rostrums are sharp, needle-like tubes which are able to pierce tree roots and suck the juices from within. Deep in the earth, the nymphs are safe from predators. They live alone and feed on the tree saps and juices and then dig to the surface with the claws on their front legs.
17-year cicadas are black with orange eyes and legs. They may also have an orange stripe on their abdomens.
Evidence suggests that cicadas can track years by counting the number of times their host tree produces sap. Cicadas require deciduous trees, or a tree type that loses its leaves at the end of the growing season. Sap production is something a deciduous tree will do once a year in the spring. When a tree has produced sap seventeen times, this indicates to dormant cicadas that it is time to emerge.
The cicada nymphs in one area are from the same generation and entered the ground at the same time. Each generation contains a group of thousands of cicadas, called a brood. All the cicadas of one brood emerge from the ground the same year at the same time. Two or three other broods may be in the ground nearby, but these are from other generations and emerge at least four years apart from another brood. The greatest threat to this species of cicadas is that they are not able to emerge from the ground where people have put down pavement for houses, malls, streets, sidewalks, and parking lots. Insecticides and other lawn chemicals can also negatively impact cicadas, though they are generally considered of little to no environmental concern.
When they emerge from the ground, the cicadas climb into trees. Then they molt, or shed, their skins. These brown skins are called exuviae and fall to the ground. As adults, the cicadas are one to one and a half inches (2 1/2 to 3 3/4 centimeters) long. They are pale colored with two black patches on their backs, but their ringed bodies quickly darken into black. They have red, bulging eyes and short antennae. Their strong, new wings are clear with orange-yellow veins and span two and a half to three inches (six to 7 1/2 centimeters).
Some adults feed on tree sap, but many do not eat and simply mate before they die a few weeks later. During this time, skunks and birds eat thousands of cicadas, but the population of the insects is so great that thousands more are able to reproduce the next generation.
Similar species:
- Magicicada cassini
- Magicicada septendecula
Bibliography
Bartels, Meghan. “Periodical Cicadas Emerge Every 13 or 17 Years. How Do They Keep Track of Time?” Scientific American, 4 Apr. 2024, www.scientificamerican.com/article/how-do-periodical-cicadas-know-when-to-emerge. Accessed 14 Apr. 2024.
Gulker, Matthew. “Magicicada septendecim Linnaeus’ 17-Year Cicada.” Animal Diversity Web, 1999, animaldiversity.org/accounts/Magicicada‗septendecim. Accessed 14 Apr. 2024.
O’Kane, Caitlin. “Maps Show Where Trillions of Cicadas Will Emerge in the U.S. This Spring.” CBS News, 11 Apr. 2024, www.cbsnews.com/news/cicadas-2024-maps-will-emerge-in-the-u-s-this-spring-mid-may-where-to-see-cicada. Accessed 14 Apr. 2024.