How Long Do Cicadas Last? | Unpacking Their Lifespans

Understanding cicada lifespans offers a fascinating window into biological strategies for survival and reproduction. These insects, known for their distinct calls, employ remarkably different timelines for their development, presenting a compelling case study in ecological adaptation.

The Core Distinction: Annual vs. Periodical Cicadas

The duration of a cicada’s life cycle varies significantly based on its classification. Biologists categorize cicadas into two main groups: annual and periodical. This distinction centers on the length of their nymphal development underground and their emergence patterns.

Annual Cicadas: A Yearly Presence

Annual cicadas, often called “dog-day cicadas” due to their summer emergence, complete their life cycle within a few years. While individual insects live for approximately 2 to 5 years, their staggered emergence means some adults appear every summer. This continuous presence gives the perception of a yearly cycle, even though no single generation lasts only one year.

• Life Cycle: Typically 2-5 years from egg to adult.
• Emergence: Adults appear every summer, but these are different individual broods.
• Appearance: Often larger than periodical cicadas, with green, black, or brown bodies.

Periodical Cicadas: The Long Game

Periodical cicadas, belonging to the genus Magicicada, are renowned for their synchronized, multi-year developmental periods. These species spend either 13 or 17 years as nymphs underground before emerging in massive numbers. Their long, synchronized cycles are a unique evolutionary strategy, overwhelming predators with sheer abundance.

• Life Cycle: Precisely 13 or 17 years from egg to adult.
• Emergence: Highly synchronized, occurring in specific geographic regions during designated emergence years.
• Appearance: Smaller than annual cicadas, with distinct black bodies, red eyes, and clear wings with orange veins.

The Underground Years: Nymph Development

The vast majority of a cicada’s life is spent in its nymphal stage, hidden beneath the soil. This subterranean phase is a period of slow, steady growth and development, where the insect prepares for its brief adult existence.

After hatching from eggs laid in tree branches, tiny cicada nymphs drop to the ground and burrow into the soil. They attach themselves to tree roots, using specialized mouthparts to feed on xylem sap. This sap provides the necessary nutrients for their growth, albeit slowly.

Throughout their underground tenure, nymphs undergo several molts, shedding their exoskeletons as they grow. Each stage between molts is known as an instar. Periodical cicadas typically pass through five instars during their 13 or 17 years below the surface. The depth at which nymphs reside can vary, from a few inches to several feet, depending on soil conditions and root availability.

The Emergence: A Brief, Intense Surface Phase

The transition from nymph to adult is a remarkable event, particularly for periodical cicadas. This synchronized emergence is a biological phenomenon, driven by specific environmental cues.

When soil temperatures at a depth of 8 inches reach approximately 64 degrees Fahrenheit (18 degrees Celsius), mature nymphs begin to tunnel upwards. They construct exit tunnels, often capped with small mud chimneys called “nymphal chimneys” or “cicada towers.” The mass emergence usually occurs over a few nights, often after a warm rain.

Upon reaching the surface, nymphs climb onto vertical surfaces like tree trunks, shrubs, or even walls. They anchor themselves and undergo a final molt, splitting their nymphal shell (exuvia) to reveal the soft-bodied adult cicada. The adult’s wings expand and harden, and its exoskeleton darkens over several hours. This process transforms the burrowing nymph into a winged, reproductive insect.

Life Stage	Location	Duration
Egg	Tree twigs	6-10 weeks
Nymph	Underground (on tree roots)	2-17 years
Adult	Above ground	2-6 weeks

Adult Lifespan Above Ground

The adult stage of a cicada’s life is remarkably short, lasting only a few weeks. This brief period is dedicated entirely to reproduction. Males produce their characteristic buzzing songs to attract females, a sound generated by vibrating specialized drum-like organs called tymbals on their abdomens. Females respond with wing flicks, signaling their receptiveness.

After mating, females begin laying eggs. They use a sharp, saw-like ovipositor to cut slits into the bark of young tree twigs and deposit their eggs inside. A single female can lay hundreds of eggs across many different twigs. The adults consume very little during this phase, primarily focusing on their reproductive tasks. Their short adult life means they face intense pressure to mate and lay eggs quickly.

Egg Laying and Hatching

The eggs remain in the tree twigs for several weeks, typically 6 to 10 weeks, before hatching. Once hatched, the tiny, ant-like nymphs emerge from the twigs. These first-instar nymphs then drop to the ground and immediately begin to burrow into the soil. They seek out suitable tree roots, where they will settle in for their long underground development, restarting the cycle.

The process of egg-laying can cause minor damage to young tree twigs, sometimes referred to as “flagging,” where the tips of branches may wilt and turn brown. This is a natural part of the cicada life cycle and generally does not pose a serious threat to mature trees. The United States Department of Agriculture provides resources on managing cicada impacts on plants. USDA

Periodical Cicada Broods: Synchronized Spectacles

Periodical cicadas emerge in distinct groups known as “broods.” Each brood is designated by a Roman numeral (e.g., Brood X, Brood XIX) and represents a population that emerges in the same year across a specific geographic range. These broods are either 13-year or 17-year cicadas, and their cycles are precisely timed.

The synchronized emergence of a brood is a defense mechanism. By appearing in overwhelming numbers, they saturate the local predator population, ensuring that a sufficient number of individuals survive to reproduce. This strategy is highly effective, as predators cannot consume all the cicadas present.

There are 15 recognized broods of 17-year cicadas (Broods I-XVII, with Broods XI and XXI extinct) and 3 recognized broods of 13-year cicadas (Broods XIX, XXII, and XXIII). Not all broods emerge in the same year, and their geographic ranges often overlap, creating complex emergence maps. The Smithsonian Institution offers extensive information on cicada broods and their historical emergences. Smithsonian Institution

Brood Number	Cycle Length	Last Emergence
Brood X (The Great Eastern Brood)	17-year	2021
Brood XIII (Northern Illinois Brood)	17-year	2007
Brood XIX (The Great Southern Brood)	13-year	2024

Factors Influencing Cicada Lifespan

While cicada life cycles are remarkably consistent, various factors can influence their survival and, indirectly, the success of their broods. These influences span biological, climatic, and human-induced elements.

• Predation: Birds, mammals, reptiles, and insects feed on cicadas, particularly during their vulnerable emergence and adult stages. The mass emergence strategy helps mitigate this pressure.
• Disease: Fungi, such as Massospora cicadina, can infect adult cicadas, altering their behavior and reproductive capacity. This fungus can spread rapidly within dense populations.
• Habitat Disturbance: Urbanization, deforestation, and extensive land development can destroy cicada nymph habitats by removing host trees and disturbing soil. This directly impacts the survival of underground nymphs.
• Climate Variations: Extreme weather events, such as prolonged droughts or severe cold snaps, can affect nymph survival. Soil temperature also plays a critical role in triggering synchronized emergence, making consistent climate patterns important for successful brood cycles.

The Ecological Role of Cicadas

Cicadas, despite their brief adult presence, contribute significantly to their ecosystems. Their life cycle provides several ecological benefits, highlighting their role in natural processes.

• Food Source: During emergence years, cicadas provide an abundant and readily available food source for a wide array of wildlife, including birds, raccoons, opossums, and even fish. This influx of protein can impact local food webs.
• Natural Pruning: The egg-laying activity of female cicadas can cause minor damage to small tree branches. This “tip pruning” can stimulate new growth in trees, acting as a form of natural pruning.
• Soil Aeration: The nymphs’ extensive burrowing activities underground help to aerate the soil. Their tunnels allow for better water penetration and nutrient distribution, benefiting tree roots and soil microorganisms.
• Nutrient Cycling: When adult cicadas die, their bodies decompose, returning essential nutrients to the soil. This contributes to the nutrient cycle within the forest ecosystem.