Cicada (family Cicadidae)
Cicadas, belonging to the family Cicadidae, are fascinating insects related to aphids and leafhoppers, known for their distinctive life cycles and vocalizations. This family includes over three thousand species, broadly categorized into annual cicadas and the more elusive periodical cicadas, which are famous for their synchronized emergence after spending ten to twenty years underground. Typically emerging in vast numbers, these periodical cicadas coincide their arrivals with specific soil temperatures to mate and lay eggs, resulting in an impressive, albeit brief, adult life lasting only four to six weeks.
These insects are characterized by stout bodies, large compound eyes, and transparent wings, often reaching about three inches in span. Male cicadas produce unique sounds through specialized membranes, using them to attract mates or signal danger. Cicadas primarily feed on plant sap, with some species potentially damaging young trees but generally causing little harm to established plants.
Despite being perceived by some as a nuisance, cicadas play a beneficial role in their ecosystems by aerating soil and enriching it with nutrients upon their death. Culturally, cicadas have been respected in various traditions, symbolizing resilience and even being considered a delicacy in some cuisines.
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Cicada (family Cicadidae)
Cicada (family Cicadidae) is a type of insect related to aphids and leafhoppers. One branch of cicada, known as the periodical cicada, is renowned for its surprising and mysterious ability to spend ten to twenty years underground before emerging in massive numbers according to an instinctive schedule. Millions of cicadas may emerge at the same time to mate, lay eggs, and die, all within a few weeks.
Background
Cicadas are insects in the order Hemiptera. This order, which also includes similarly structured creatures such as leafhoppers, shield bugs, and aphids, is known as “true bugs,” as opposed to the wide variety of other insects commonly, but erroneously, referred to as “bugs.” Cicadas are included in the superfamily Cicadoidea and the family Cicadidae.
More than three thousand species make up the cicada family, but scientists have broadly classified them into two main types. The first is annual cicadas, which may be seen every year. The more enigmatic and better-known category is the periodical cicada, which burrow underground, where they spend most of their lives and only emerge once. Periodical cicadas usually only emerge from their burrows every one or two decades.
Cicadas share the basic distinctive shape of other members of the “true bugs” order. They have stout dark heads and thoraxes, strong legs, and clear wings with black veins. They have large compound eyes, usually with a red tint. Cicadas typically grow to about 1 inch in length, although the span of their large wings may reach about 3 inches. Larger cicadas may be about 2.25 inches long.
Male cicadas are equipped with special membranes that vibrate, creating clicking or buzzing sounds. Each species creates its own type of sound, with some species being more vocal. Specific sounds serve to communicate important messages, such as mating calls or warnings of danger. When large groups of cicadas are congregated, their combined sound may become very loud. Many people find it annoying or even overwhelming at full volume.
Overview
Annual cicadas are fairly common creatures and may be found in many regions of the world. However, the more famous periodical cicadas live exclusively in North America. Mainly, they concentrate in the eastern and central parts of the United States. Cicadas favor areas in which deciduous trees and shrubs are common. These bugs use their mouth to draw nourishing sap and other juices from plants, rather than chewing on the plants themselves. Larvae under the ground drink from plant roots. Adults that have emerged onto the surface drink from the external parts of plants.
The cicada is best known for its unique life cycle, which encompasses the stages of egg, nymph, and adult. Female cicadas may lay as many as four hundred eggs, usually in trees and often in multiple locations. Females may dig small furrows into wood in which to deposit eggs. In about eight weeks, the eggs hatch, revealing cicadas in the nymph stage. The nymphs work their way to the ground and dig into burrows under the tree, where they will attach to the roots of the tree and nearby plants. The nymphs will remain in this position, constantly eating and growing, for many years.
Finally, after a cycle of usually thirteen to seventeen years, the nymphs are activated by instinct to mobilize. Even broods of many millions of insects will emerge within weeks of one another. The exact reasons for their instincts and the processes by which they mobilize are not fully understood; however, they seem related to the temperature of the soil. When soil reaches a temperature of about 65 degrees Fahrenheit, cicadas seem to instinctively know the surface conditions are right for breeding.
The long duration between periodical cicadas’ emergences may relate to evolutionary responses to predation. Many animals will eat cicadas. A few of these predators include raccoons, foxes, birds, opossums, and mice. Even frogs, turtles, fish, and certain types of fungus may prey on cicadas. By emerging from the ground in giant broods, cicadas use their numerical advantage to assure the survival of their species. Cicadas instinctively know that many of them—perhaps thousands or millions—will be eaten or killed, but their sheer number will be so great that it can tolerate those losses. Enough will survive to create a sufficient new generation of the brood.
Activated cicadas molt the shells they have formed and leave their burrows, becoming fully formed adults. Their lives will now be brief and focused almost solely on the tasks of mating and laying a new generation of eggs to restart the life cycle. Male cicadas choose areas to gather and then begin creating their distinctive buzzing and clicking sounds to attract females. After a pair mates, the female will lay its eggs. Adults only live for about four to six weeks after they leave their burrows.
Scientists have tracked and analyzed many types of cicadas as well as broods, or “year classes” of insects expected to emerge at the same time. Scientists often announce when large broods are expected to emerge in an area at a particular time. For example, the so-called “Brood X” emerged in many areas in the early summer of 2021. Local residents often view these announcements with curiosity or concern. Many people fear that cicadas are a destructive force like locusts—and indeed the group names of cicadas include “plague” and “cloud.” Scientists reported on a noteworthy cicada brood in 2024 that was characterized by the simultaneous emergence of thirteen-year and seventeen-year cicadas estimated to number in the billions. Prior to 2024, the last known dual emergence occurred in 1803.
Despite their numbers, cicadas are generally not very destructive creatures. They do not bite or attack humans. At worst, they may be a nuisance when they gather in huge numbers in yards, parks, woods, and other locations. Their effect on plant life may vary. Cicadas may damage young trees by draining sap and laying eggs, though most large older trees escape serious harm. People who own young trees may cover them with cheesecloth to reduce their likelihood of danger.
Cicadas may actually present benefits for other living things. Their burrowing helps to aerate soil, and their gathering in a tree may help to remove old or dead limbs and leaves. After cicadas die, their bodies decompose and return nutrients to the trees and other vegetation. Many ancient cultures respected and honored cicadas, not only for their benefits to the land but also their apparent ability to resurrect themselves after long periods of dormancy. In some cultures, cicadas are even considered a tasty treat for humans.
Bibliography
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“Brood X Periodical Cicadas FAQ.” National Park Service, 2021, www.nps.gov/articles/000/cicadas-brood-x.htm. Accessed 2 June 2021.
Chow, Denise. "Billions of Cicadas Will Emerge in the U.S. this Year in a Rare Double-Brood Event." NBC News, 20 Jan. 2024, www.nbcnews.com/science/science-news/cicadas-2024-emergence-periodical-brood-2024-map-cicada-rcna134152. Accessed 16 Apr. 2024.
“Cicadas, Facts and Photos.” National Geographic, www.nationalgeographic.com/animals/invertebrates/facts/cicadas. Accessed 2 June 2021.
Graber-Stiehl, Ian. “To Study Swarming Cicadas, It Takes a Crowd.” Science, 1 June 2021, www.sciencemag.org/news/2021/06/study-swarming-cicadas-it-takes-crowd-citizen-scientists. Accessed 2 June 2021.
“Magicicada Broods and Distributions.” University of Connecticut, 2011, hydrodictyon.eeb.uconn.edu/projects/cicada/magicicada‗central/about/brood‗pages/broods.php. Accessed 2 June 2021.
“Periodical Cicadas.” National Wildlife Federation, www.nwf.org/Educational-Resources/Wildlife-Guide/Invertebrates/Periodical-Cicadas. Accessed 2 June 2021.
Smith, Jen Rose. “Brood X is almost here. Billions of cicadas are emerging in Eastern US.” CNN, 23 May 2021, www.cnn.com/2021/05/23/world/cicadas-2021-emergence-scn/index.html. Accessed 2 June 2021.
Weiss, Haley. “Unfortunately, Some Cicadas Taste Like Nature’s Gushers.” The Atlantic, 31 May 2021, www.theatlantic.com/health/archive/2021/05/cicadas-taste-like-gushers/619059/. Accessed 2 June 2021.