Cicada Life Cycle: Unveiling Nature’s Mysterious Insects

Cicadas are fascinating insects known for their unique life cycle and distinctive mating call. Their life cycle involves several stages, from egg to nymph to adult, and can span a range of years depending on the species.

In the first stage, a female cicada lays her eggs in young, tender tree branches after mating [(source)). Once the eggs hatch, tiny nymphs emerge and burrow themselves into the ground. Here, they feed on fluids from various plant roots and grow through a series of molts.

Cicada Life Cycle Overview

Life Cycle Stages

Cicadas go through three main stages in their life cycle:

• Egg: Female cicadas lay their eggs on tree branches, using a sharp, knife-like structure on their abdomen to cut a slit in the soft branch for depositing their eggs¹.
• Nymph: Eggs hatch into nymphs, which drop to the ground and burrow underground, where they feed on plant roots². As they grow, nymphs shed their exoskeletons multiple times.
• Adult: After completing development, nymphs emerge from the soil, molt one last time, and become winged adults². Adult males attract females using their loud courting sounds, generated by a special body part called a tymbal³.

Developmental Period

Cicadas have varying developmental periods depending on the species. There are two main types:

1. Periodical cicadas: They remain underground as nymphs for 13 or 17 years, and their appearance above ground synchronizes among large populations⁴.
2. Annual cicadas: They emerge from the ground every year, with a shorter developmental period, usually 2-5 years⁴.

Cicada species have adapted to various environments and have unique life cycle characteristics, but all share these main stages and developmental periods.

Periodical and Annual Cicadas

Periodical Cicadas

Periodical cicadas are a unique group of cicadas found in North America. They have an unusual life cycle, with some species emerging only every 17 years, while others emerge every 13 years¹. Notable examples include the Brood X cicada, which is a 17-year species. Some key features of periodical cicadas are:

• Distinct reddish-orange eyes
• Emergence in massive quantities during specific years
• Males “sing” by vibrating a membrane to attract mates²

Annual Cicadas

Annual cicadas, on the other hand, belong to a broader group of over 3,000 species. They are found all around the world and have a more frequent lifecycle, with some cohorts spending several years underground³. Here are some distinguishing characteristics of annual cicadas:

• Green to brown bodies with black markings
• Emerge in midsummer every year
• Larger size compared to periodical cicadas⁴

Comparison Table

Underground Life

Feeding on Plant Roots

Cicadas spend the majority of their lives underground, feeding on plant roots. In this stage, they are known as nymphs. Specifically, they:

• Suck sap from roots, providing nutrients for growth
• Feed on various species of trees and shrubs

An essential note is that periodical cicadas may stay underground for up to 17 years in some species, while other cicada species require 3-8 years to complete their development.

Molting and Growing

As nymphs grow, they go through a series of instar stages. During each stage:

• Cicadas molt their exoskeletons
• Grow and develop new exoskeletons

After their final molt, the now mature cicadas emerge from the ground, ready to begin their short adult lives above ground.

Soil Temperature Effects

The emergence of cicadas is highly influenced by soil temperature. They prefer to come out when the ground has reached a specific consistency. For instance:

• A warm soil temperature triggers cicada emergence
• Periodical cicadas typically emerge once soil temperatures are consistently above 64°F (18°C) at a depth of about 8 inches (20 cm)

In conclusion, soil temperature plays a significant role in determining when cicadas will leave their underground habitats and start the next phase of their life cycle.

Emergence and Mating

Mating Calls

• Male cicadas produce mating calls using a special body part called a tymbal.
• Vibrating the tymbal creates a shrill noise to attract female cicadas¹.

Attracting a Mate

• Only male cicadas “sing” by vibrating a membrane on the sides of their body².
• Female cicadas respond to the calls by flicking their wings³.

Comparison Table: Male and Female Cicada Mating Behavior

Egg-Laying and Nymph Life

Egg-Laying Process

Female cicadas lay their eggs inside small tree branches. They etch a groove in the bark of a tree limb and deposit their eggs there (source).

Egg-laying features:

• Location: Tree branches
• Method: Groove etched in the bark of a tree limb

The eggs take around six to eight weeks to develop before they hatch into nymphs (source).

Nymph Development

Once they hatch, the cicada nymphs fall to the ground and start their life beneath the soil. Nymphs go through four instars, or life stages, before becoming adults (source).

Nymph characteristics:

• Initial appearance: Small, white, and mushy
• Life stages: Four instars

They tunnel underground in search of nutrients, feeding on fluids from tree roots (source).

Teneral adult: After the final nymph instar, the cicada nymph will molt one last time, emerging as a teneral adult. Teneral adults are soft and pale, but their exoskeleton will harden and darken over time.

Comparison table of nymph stages:

Predators and Defense Mechanisms

Common Predators

Cicadas face various predators throughout their life cycle. Some examples of these predators include:

• Birds
• Mammals (such as squirrels and raccoons)
• Reptiles (like snakes and lizards)
• Insects (spiders, ants, and wasps)

Protective Strategies

Cicadas have evolved various protective strategies to avoid these predators:

1. Camouflage: Their natural coloration helps them blend with their surroundings, making it difficult for predators to spot them.
2. Swarming: In certain species like locusts, cicadas form swarms, which can help in overwhelming and confusing predators.
3. Buzzing: Cicada males produce loud buzzing sounds which may serve as a defensive mechanism, as it can deter some predators.

Cicadas do not possess a highly effective defense against all their predators, which is evident from their high predation rates. However, these strategies help them survive in their environment and reproduce effectively.

Significance and Impact

Cicadas in Science

Cicadas are fascinating insects that play important roles in ecosystems. They contribute to the breakdown of organic matter, serving as food for various animals, and their emergence influences plant life. They are well-known for their unique life cycle, which varies across different cicada species. Some periodical cicadas, for example, emerge every 13 or 17 years in the Mid-Atlantic and Midwest regions of the United States. During this period, they feed on the xylem, a component within plants that transports water and nutrients.

Cicada research has contributed significantly to the fields of insect biology, natural history, and ecology. Scientists have identified over 3,000 cicada species worldwide and organized them into several distinct broods. Studies on cicadas have paved the way for understanding insect physiology, reproductive behavior, and evolution.

Cicadas in Literature and Culture

Cicadas have been deeply ingrained in human culture and traditions. They are widely referenced in literature, mythology, and folklore. Cicadas are celebrated for their symbolism of rebirth, transformation, and immortality, primarily due to their long life cycles and distinct molting process.

Some examples of cicada influence in literature and culture include:

• In ancient Greece and Rome, cicadas were considered sacred creatures and often depicted in art and literature.
• Various Native American cultures view cicadas as symbols of renewal and transformation.
• In East Asian cultures, cicadas are a symbol of summer and a metaphor for fleeting beauty and impermanence.

Overall, cicadas are an essential part of global ecosystems, representing an intriguing subject for scientific study and a rich source of cultural inspiration.