Cicada Facts: Their Larvae Stay Underground for 17 Years

Did you know that cicadas spend most of their lives underground, waiting for the right moment to mate and die? Step into the fascinating world of cicadas and prepare to be amazed! There’re more facts about them than just their noisy songs!

1. Cicadas live at the same time with dinosaurs

The cicada appeared for a very long time. Fossil records indicate that these creatures have existed for over 250 million years, aligning with the era of dinosaurs in the Triassic period. This remarkable fact signifies that cicadas shared the Earth with dinosaurs for an astonishing duration of 165 million years. Remarkably, even when dinosaurs were extinct, the insect still endured and flourish to this day.

The insect is usually mistaken for locusts and has been associated with biblical plagues. Although they look similar, these two insects belong to different orders. Locusts are a specific type of short-horned grasshopper and are classified under the order Orthoptera, which also includes other grasshoppers and crickets. On the other hand, cicadas belong to the order Hemiptera, categorized as “true bugs” alongside aphids and planthoppers.

Cicadas come in different colors, such as green, brown, black, green and black, or grey. Some have stripes on the abdomen. Like other insects, these species have 3-part bodies: the head, thorax, and abdomen. The head is equipped with antennae, eyes, and a clypeus that connects the beak to the rest of the head.

One special thing about these creatures is that they have 5 eyes. Positioned on each side of their heads are a pair of compound eyes, while nestled between these compound eyes are 3 small yet radiant simple eyes called ocelli. These miniature eyes are thought to serve as detectors of light and darkness. Furthermore, the colors of their eyes are various, from grey, white, red, orange, and blue to even multiple colors.

The thorax part comprises 2 pairs of wings, with the longer forewing overlapping the shorter hindwing. It also possesses spiracles for breathing, 6 legs, opercula that protect the eardrums, and, in certain male species, tymbals and its covers. The abdomen has additional spiracles, reproductive organs, tergites, and sternite.

When it comes to their size, cicadas can attain remarkable dimensions, with certain species stretching beyond 2 inches in length, encompassing their wings. The largest cicada is from Malaysia – the colossal Megapomponia imperatoria, measuring 8 inches long. In North America, this title belongs to the Megatibicen auletes, a.k.a the northern dusk singing cicada.

There are about 3000 cicada species all over the world. Australia stands out with its impressive collection of more than 200 types, while the US hosts approximately 190 species. In contrast, the United Kingdom has the distinction of having only one known species, the new forest cicada (Cicadetta montana), which unfortunately may be extinct at present.

Some of the species are the Kempfer, dog-day (heatbug), white cicada (milky or white ghost), empress, razor grinder, bladder, parnkalla, scissors-grinder, black and white Batwing,  red devil, clanger, tacua speciosa, Walker’s cicada, and giant cicada (coyoyo, chichara grande, or coyuyo).

2. Habitat

Cicadas can be found across the globe, except for Antarctica due to its extremely cold climate. Although annual cicadas live everywhere, you can only find periodical species in the US. They are predominantly located in the central and eastern regions of the country, with certain areas hosting multiple broods simultaneously.

For instance, Brood X, known as Brood 10 or the Great Eastern Brood, exclusively inhabits the eastern parts of the US, including DC, New Jersey, or Washington. It is one of 15 broods of 17-year cicadas. Similarly, Brood XI can also be found in the eastern of the US.

While Brood XIII, commonly emerges in the midwestern like Wisconsin, Michigan, and particularly in Northern Illinois, Brood II is regularly seen in the northeastern. Another brood, Brood XIX, also referred to as The Great Southern Brood, spans a wide expanse of the southeastern US, such as Florida, Georgia, North Carolina, and South Carolina.

During the summer season, adult cicadas can typically be spotted residing on the trunks or branches of trees. However, the smaller ones tend to inhabit low shrubs or grassy areas.

3. They eat sap

The main diet of both adult and juvenile cicadas is tree sap. As cicada nymphs venture beneath the ground, they skillfully dig their way near the tree’s roots. Once they find a suitable spot, they attach themselves and indulge in the nourishing sap, fueling their growth and development. When the nymphs become adults, they burrow through the bark of a tree, persistently feeding on the sap.

These insects have a diverse diet, consuming various plants such as eucalypts and grasses. Although they can cause harm to young trees, older and well-established trees typically endure the damage without long-term consequences.

To eat, cicadas use specialized mouthparts to puncture plant tissues and draw out fluid from the xylem, the conduit responsible for transporting nutrients and water from a plant’s roots to its leaves.

This mouthpart consists of four delicate, needle-like styles to take sap. It is protected in a slender, elongated beak-like structure known as the labium. Additionally, these creatures possess unique internal pumps located within their head that assist in the transportation of water.

This distinctive feeding mechanism sets cicadas apart from other insects such as beetles, grasshoppers, caterpillars, and cockroaches. Those species possess mouthparts designed for biting and chewing.

While the fluids transported through the phloem from the leaves to the roots are rich in sugars, the sap that cicadas take through the xylem is not nutritious. That’s why they developed a symbiotic relationship with particular species of bacteria, like Hodgkinia cicadicola, in their digestive systems.

The bacteria perform a vital role by transforming the sap’s chemicals into amino acids and other necessary nutrients crucial. This adaptation enables them to survive and thrive despite the limited nutritional value of their diet.

You can see this kind of relationship in other creatures, such as termites, wood-boring beetles, sloths, and beavers. These creatures rely on bacteria to assist them in extracting nourishment from unnutritious food sources.

4. They have a weird survival mechanism

Cicadas face lots of predators, such as birds, cicada killer wasps, frilled lizards, possums, spiders, raccoons, mantids, bats, platypuses, frogs, tree crickets, squirrels, and ants. Their nymphs underground are attacked and parasitized by feather-horned beetle larvae.

To protect the population, they sacrifice themselves. Utilizing their vast numbers, which can reach densities of up to 1.5 million per acre, these organisms employ a survival tactic called “predator satiation.”

By allowing predators to feast on them and satisfy their appetites, cicadas ensure the continuation of their reproductive activities. Once the predators reach their saturation point and can no longer consume any more, these insects are then able to carry on with their crucial task. This remarkable strategy guarantees that there is enough population to reproduce and generate the next generations.

5. They are musical instruments

You may hear cicadas singing so much that it’s so annoying. This is the mating sound that is exclusively generated by the male. Each species boasts its unique and identifiable call, allowing them to distinguish themselves even when surrounded by similar species.

Certain large species have the ability to generate songs of exceptional volume, reaching levels that verge on the threshold of human ear pain. Conversely, certain smaller species produce songs of such high pitch that they surpass the range of human hearing.

To produce sound, these males depend on a sophisticated mechanism. The tymbals, located at the base of the abdomen, serve as the main organs responsible for producing sound. The tymbals, located at the base of the abdomen, serve as the main organs responsible for making noise. These ribbed membranes can generate sound pulses by contracting the internal tymbal muscles, causing the tymbals to buckle inward. When the muscles relax, the tymbals return to their original position. Some cicada species produce a sound pulse with each buckle of their ribs.

These species produce different sounds to match different circumstances. When cicadas are bothered or under threat from predators, they emit short and vigorous distress calls. Before producing the loud mating songs, cicadas engage in warm-up or pre-calls, often described as “tra la la’s.” The mating songs, alternatively called advertising songs, are the most powerful, prolonged, and intricate songs they create.

Males from various species, such as the greengrocer/yellow monday and the double drummer, often gather in groups while producing their calls. They assemble in designated “singing trees,” alluring more females and aiding in the process of finding mates.

Certainly, implementing this approach will result in a greater overall level of noise. Nevertheless, it has the potential to mitigate the risk of bird predation because the noise can cause the paint on the birds’ ears and interfere with their communication.

6. They are the loudest insects on earth

Cicadas claim the distinguished honor of being the loudest insects on the planet. Certain species can outshine the decibel levels produced by an outboard boat motor. For example, the Brevisana brevis, an African cicada, claims the top spot as the world’s loudest cicada, emitting a sound of 106.7 decibels at a distance of 50 cm (20 in).

The Australian species Double Drummer (Thopha saccata) can produce ear-splitting sounds that can reach approximately 120 decibels when heard up close. In the US, the loudest cicada is the Megatibicen pronotalis walkeri (formerly known as Tibicen walkeri). It has been measured to produce a sound of 105.9 decibels at 50 cm.

To provide a sense of scale, cicadas’ volume sounds like the clamor generated by a nearby jackhammer or a garbage truck. This sound level can damage hearing. The noise is so raucous that even the cicadas themselves find it intolerable.

To protect their delicate membranes that are responsive to vibrations from potential harm, the insects disconnect them while singing so they don’t hear their own sounds.

Fact: These species occasionally confuse the noises generated by power tools and lawn maintenance equipment with the calls of their own kind. As a result, they can become disoriented and may mistakenly land on individuals operating such machinery. To prevent these encounters, you can do the lawn in the early mornings or near dusk when cicadas are least active.

7. Behavior

Spotting cicadas in their natural habitat is not easy. Despite their loud calls resonating all around, it can be quite challenging to locate their exact source. Adding to the difficulty, many species possess camouflage that seamlessly merges with the lush greenery of summer foliage. They also prefer to dwell high up in the trees, making it even more unlikely for us to come across them.

These insects only sing during daylight hours, even in the most scorching moments of the day. Astonishingly, they have been observed singing persistently at temperatures exceeding 110°F (43°C)! Enduring the intense heat like this helps them avoid potential predators who reduced activity during the sweltering mid-to-late afternoon.

To do this, cicadas have developed an impressive adaptation through their feeding habits. Since their main diet consists of xylem sap, which is mostly composed of water, they require significant quantities to sustain themselves. As a result, they need to get rid of excess water from their bodies.

To achieve this, the insects employ a mechanism called evaporative cooling, much like how humans sweat to cool down in hot environments. Specialized ducts in their bodies facilitate the release of excess water through openings in their thorax. By consistently drawing in freshwater through their beak, they can sustain a continuous flow. This ongoing mechanism of evaporative cooling empowers cicadas to reduce their body temperatures by 9°F (5°C) or even more.

As previously stated, cicadas need to eliminate a significant amount of excess water from their bodies. Besides doing this through evaporative cooling, they also dispose it by excreting a sugary and watery substance known as honeydew. This liquid can spurt out from their bodies. The other sap-sucking insects like planthoppers have the same mechanism.

The honeydew excreted by nymphs while underground keeps the soil surrounding their tunnels adequately moistened. This makes it easy for them to form tunnels and chambers, which serve as pathways for reaching their favored food source: the roots of the plants.

Cicadas are not dangerous. While they’re capable of clinging to our skin with their sharp claws, they do not bite or sting humans.

8. They can become zombies

Cicadas around the world have formed unsettling relationships with parasitic fungi. In Japan, certain species have established a symbiotic bond with Ophiocordyceps fungi. These fungi play a vital role in transforming sugary plant juice into nourishing sustenance, essential for the survival of these insects.

Nevertheless, not every cicada exhibits a favorable response to the existence of the fungi. Different types of parasitic fungi have a less cooperative interaction with cicadas, infiltrating their bodies while they reside underground. Upon infection, these zombie fungi manipulate the insects’ behavior, forcing them to emerge to the forest floor, eventually leading to their demise and the emergence of mushrooms from their deceased bodies.

In America, these insects encounter a frightful parasitic fungus known as Massospora cicadina. This fungus targets them during their nymph stage when they are in the ground. When the species emerge for mating, the fungus initiates the consumption of their internal organs.

Furthermore, Massospora exerts control over the behavior of cicadas by introducing cathinone, an amphetamine, and psilocybin, a psychedelic compound commonly found in magic mushrooms, into their system. This chemically causes the cicadas unaware of their own mutilation and compels them solely to pursue mating.

These zombie insects, emptied from within and serving as carriers of spores, persistently fly and mate, unknowingly dispersing the lethal spores to other cicadas they come across and any areas of soil they traverse while airborne. Known as the “death-dealing aerial dispensers,” these infected insects unintentionally contribute to their own destruction and accelerate the expansion of the parasitic fungus.

9. Life cycle

The life cycle of cicadas comprises three main life stages: eggs, nymphs, and adults, with the majority of their lives spent underground. Females lay approximately 400 eggs in trees, creating grooves that serve as both shelter and a source of tree fluids to nourish their offspring. However, these grooves have the potential to harm small branches, resulting in their withering and the leaves taking on a brown hue.

After 10 weeks, the eggs hatch and find their way to the ground, digging into the soil to eat sap. The young stay under the ground throughout their entire developmental phase, shedding their exoskeletons around five times until they eventually come out of the ground through holes and climb up to the trees.

They shed their exoskeletons and undergo a remarkable incomplete metamorphosis into winged adults, known as imagoes. Initially appearing in a pale hue with delicate wings, these adults swiftly transform, their bodies becoming more robust and their coloration deepening, preparing them for flight. Their primary objective becomes seeking out potential mates, creating a new generation. A new life of a cicada begins.

The time the insects stay underground varies, ranging from 1 to 17 years. Annual cicadas emerge yearly, from June to August. On the other hand, protoperiodical species may emerge annually but exhibit synchronized emergences in significant numbers every few years.

Periodical cicadas emerge simultaneously after every 13 – 17 years. There are recorded occurrences of Magicicada emerging after 22 years. They patiently await favorable conditions, such as when the ground temperature reaches 65°F (18°C) during their designated year.

For example, in 2021, a massive Brood X emerged and swarmed. Some 17-year species may come back in 2024. There were no periodical cicadas in 2022 and maybe in 2023 too.

When compared to other insects, cicadas have a longer lifespan. Upon their emergence, adults can live for 4 – 6 weeks.

10. Threats

Cicadas are affected by climate change. In 2017, some members of Brood X emerged four years earlier than expected. Warmer temperatures and extended growing seasons may have influenced their behavior. Adding to this trend, Brood XIX also deviated from its usual schedule in 2020, joining a growing list of broods with notable straggler populations.

This shift in emergence patterns could lead to unforeseen consequences, such as the establishment of a new brood on a 13-year cycle. Alternatively, there could be other unpredictable outcomes.

These insects hold a wealth of information accumulated over 17 years, reflecting the health and condition of the forest. Should the forest face disturbances or disruptions, the repercussions would become evident through the behavior of the cicadas.

11. Cicadas vs Crickets vs Katydids

References:

• Guloinnature.com
• Cicadamania.com