Cicadas, those winged insects that lay dormant for long periods of time, have fascinated scientists and nature enthusiasts alike. With their unique life cycles and deafening mating calls, these insects have captured the attention of many. There are fifteen broods of cicadas, some with 13-year life cycles while others with 17-year life cycles. While adult cicadas only live for a mere 4-6 weeks, the nymphs can live underground for an astonishing 13-17 years. And when they finally emerge from the earth, they leave behind their shells, called “nymph exoskeletons,” which can take hours for the insect to fully emerge from. With their impressive numbers and distinct behaviors, cicadas are truly a wonder of the natural world.
Life Cycle of Cicadas
Cicadas have a unique life cycle that spans different stages. They belong to a group of insects known as Hemiptera, which includes insects like aphids and leafhoppers. Let’s explore the various aspects of their life cycle.
Broods and Life Cycles
Cicadas are known for their long dormancy periods and synchronized emergences. There are 15 known broods of cicadas, with some having a 13-year life cycle and others having a 17-year life cycle. These broods are identified by Roman numerals, such as Brood X or Brood VIII. Each brood has a specific geographic distribution and emerges in different years.
Dormancy Period
After cicadas hatch from their eggs, they drop to the ground and burrow into the soil. They spend the majority of their lives as nymphs, living underground and feeding on tree roots. During this stage, they undergo several molts, shedding their exoskeletons and growing in size. This period of dormancy can last anywhere from 13 to 17 years, depending on the brood.
Adult Lifespan
Once the nymphs have completed their final molt, they emerge from the ground as adult cicadas. They climb trees or other vertical surfaces and shed their nymph exoskeletons, revealing their fully-formed wings. The adult stage of a cicada’s life is relatively short, lasting only about 4 to 6 weeks. During this time, their main goal is to mate and reproduce.
Nymph Lifespan
While the adult cicadas have a short lifespan, the nymphs spend a significant portion of their lives underground. They can live underground for 13 to 17 years, depending on the brood they belong to. This extended period of underground life allows them to feed on tree roots and grow before emerging as adults.
Features of Cicadas
Cicadas possess several unique features and characteristics that distinguish them from other insects. Let’s take a closer look at some of these features.
Nymph Exoskeletons
One of the most identifiable features of cicadas is their nymph exoskeletons, commonly referred to as “shells.” These exoskeletons are left behind on trees after the cicadas have emerged. The cicada nymphs molt their exoskeletons to grow larger, and the process of emerging from the shell can take several hours. The abandoned shells provide evidence of the cicada’s presence and are often found in large numbers during their emergences.
Mating Calls
Male cicadas have a unique ability to produce loud mating calls, which can be heard from a distance. By vibrating their tymbals, which are organs located on their abdomens, they create a distinct sound that attracts females for mating. These calls can reach a volume of up to 100 decibels, which is equivalent to the noise level of a rock concert. Female cicadas, on the other hand, do not produce any sound and are silent during the mating process.
Brood X Cicadas
One of the most famous and widespread broods of cicadas is Brood X. This brood emerges every 17 years and is also known as the great eastern brood. Its emergence is expected in 2038, captivating the attention of cicada enthusiasts and researchers alike. Brood X covers an extensive geographic range, spanning 15 states in the eastern United States.
Classification
Cicadas belong to the order Hemiptera and the family Cicadidae. Within this family, there are two main classifications of cicadas: periodical cicadas and annual cicadas. Periodical cicadas spend the majority of their lives underground as nymphs, emerging in synchronized broods every 13 or 17 years. Annual cicadas, as the name suggests, have a shorter life cycle, with some species emerging on an annual basis.
Cicadas vs. Locusts
Cicadas are often confused with locusts due to their similar appearances and intermittent appearances in large numbers. However, they are two different types of insects. Locusts are a type of grasshopper that can form swarms and cause significant damage to crops and vegetation. Cicadas, on the other hand, do not pose the same level of threat to vegetation and are not considered destructive pests.
Edibility
In some cultures, cicadas are considered a delicacy and are consumed as a source of food. These insects can be cooked and prepared in various ways, such as stir-frying or baking. They are often praised for their crunchy texture and nutty flavor. While not commonly consumed in Western countries, cicadas are an important food resource in certain regions.
Characteristics of Cicadas
Cicadas have several distinct characteristics that contribute to their unique nature and behavior. Let’s explore some of these traits.
Loudness of Sound
Cicadas are renowned for the loudness of their mating calls. Male cicadas use specialized organs called tymbals to produce their distinctive songs. These songs can reach earsplitting volumes, often exceeding 100 decibels. To put this into perspective, that’s as loud as a rock concert or a power saw. The purpose of these loud songs is to attract females for mating and establish territories.
Vision and Eyes
Contrary to popular belief, cicadas are not blind insects. They have a fascinating visual system that allows them to detect predators and navigate their surroundings. Cicadas have five eyes in total, including two large compound eyes and three smaller simple eyes. Their compound eyes provide a wide field of vision, while the simple eyes help them detect changes in light intensity.
Activity Patterns
Cicadas are diurnal creatures, meaning they are most active during the day. They spend their time feeding on plant fluids and engaging in reproductive activities. However, cicadas are generally quiet at night and take refuge in trees or other shelters. Their activity patterns are strongly influenced by environmental factors such as temperature and sunlight.
Brood X Cicadas
Brood X, also known as the great eastern brood, is a highly anticipated emergence of cicadas that occurs every 17 years. Let’s take a closer look at the characteristics of Brood X.
Emergence Schedule
Brood X cicadas have a synchronized emergence pattern, with adults emerging from the ground en masse. This emergence typically occurs in the late spring or early summer. Once above ground, the cicadas shed their nymph exoskeletons and enter their adult stage. This synchronized emergence is a remarkable phenomenon that captures the attention of researchers and nature enthusiasts worldwide.
Geographical Coverage
Brood X is the largest brood of cicadas, covering an extensive geographical range. It spans 15 states in the eastern United States, including Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, and West Virginia. The widespread emergence of Brood X creates a spectacle that is witnessed by millions of people.
Species and Mating Calls
Brood X is comprised of three species of cicadas: Magicicada septendecim, Magicicada cassini, and Magicicada septendecula. Each species has its own unique mating call, enabling females to locate suitable mates during the emergence. These mating calls contribute to the cacophony of sound that fills the air during Brood X’s emergence.
Feeding Behaviors
Cicadas have interesting feeding behaviors that differ between their nymph and adult stages. Let’s delve into these feeding habits.
Adult Diet
Once cicadas reach their adult stage, their main focus shifts to reproductive activities rather than feeding. Adult cicadas do not require much food and may not feed at all during their short lifespan. However, if they do indulge in feeding, they primarily sip on plant fluids using their piercing mouthparts.
Absence of Biting or Stinging
Unlike mosquitoes or bees, cicadas do not possess biting or stinging mouthparts. They are harmless to humans and other animals in terms of direct physical harm. Cicadas are primarily focused on mating and are not interested in biting or stinging. Therefore, there is no need to fear these insects when encountering them in nature.
Interactions with Humans
Cicadas have a fascinating relationship with humans and can have both beneficial and cultural impacts. Let’s explore these interactions.
Harmlessness to Humans
As previously mentioned, cicadas are harmless to humans. They do not bite, sting, or pose any direct physical threat. This makes them a safe and non-threatening insect to be around. In fact, many people find the presence of cicadas during their emergences to be a captivating and awe-inspiring natural phenomenon.
Beneficial Aspects
Cicadas play important roles in the environment that benefit ecosystems and humans. They serve as a valuable food source for other animals, including birds, mammals, and reptiles. Additionally, when cicadas lay their eggs, they help prune trees by creating small wounds that promote new growth. Furthermore, the nymphs contribute to soil aeration as they tunnel underground.
Cultural Consumption
In certain cultures, cicadas are considered a culinary delicacy and have been consumed for centuries. These insects can be prepared in various ways, including stir-frying, boiling, or baking. Some people enjoy the nutty flavor and crunchy texture of cicadas, considering them a unique and sustainable source of protein.
Diversity of Cicadas
Cicadas are a diverse group of insects, with thousands of species found worldwide. Let’s explore the diversity and prevalence of cicadas.
Number of Species
There are over 3,000 known species of cicadas, making them a highly diverse group within the insect world. These species can be found across the globe, with varying distributions and habitats. Each species has its own unique characteristics and life cycle adaptations.
Prevalence of Periodical Cicadas
While there are thousands of cicada species, only a few of them are periodical cicadas that emerge in synchronized broods. The majority of cicadas are annual species that have shorter life cycles and do not exhibit the same timing and synchronization as periodical cicadas. The emergence of periodical cicadas in broods, such as Brood X, is a relatively rare and fascinating phenomenon.
Reproductive Cycle
A crucial aspect of a cicada’s life cycle is its reproductive cycle. Let’s delve into how cicadas reproduce and lay their eggs.
Egg Laying and Offspring
Female cicadas have the task of laying eggs to continue the next generation. They use their ovipositors to insert eggs into slits they make in tree branches or other woody surfaces. Each female can lay between 200 to 400 eggs during her lifetime. Once the eggs hatch, the nymphs drop to the ground and burrow into the soil, beginning the cycle once again.
In conclusion, the life cycle of cicadas is a fascinating and unique journey. From their long periods of dormancy to their synchronized emergences, cicadas captivate our attention and spark curiosity. Their features, characteristics, and interactions with humans and the environment make them an intriguing subject of study and observation. Whether it’s the loud mating calls, the abandoned exoskeletons on trees, or the cultural consumption, cicadas have left a lasting impact on various aspects of our lives.