Rise of the Cicadas, Part 1
3Digest
This episode of Stuff to Blow Your Mind dives deep into the world of cicadas, starting with a discussion about the etymology of the word "bug" and its surprising origins. The hosts then explore the fascinating life cycle of cicadas, highlighting the difference between annual and periodical cicadas. They discuss the unique mechanism cicadas use to produce their loud mating calls, which can reach up to 106 decibels. The episode also delves into the reasons behind the long nymph stages of periodical cicadas, particularly their prime-numbered emergence cycles, which help them avoid predators and parasites. The hosts also touch upon the cultural significance of cicadas, including their use as a food source in some cultures. The episode concludes with a discussion about the evolution of periodical cicadas and their connection to glacial movements.
Outlines
Introduction
This Chapter introduces the topic of cicadas and the podcast's exploration of their fascinating world. It also mentions the podcast's previous season focused on betrayal and the upcoming episodes on Afghan Star and Part Time Genius.
Cicadas: A Taste of the Great Biomass
This Chapter begins with a personal anecdote about finding a cicada wing in the house, leading to a discussion about cicadas as a regular feature of summer in Atlanta. The hosts then discuss the difference between annual and periodical cicadas, highlighting the unique characteristics of the latter, including their long subterranean nymph stages and synchronous emergence.
The Loudest Insects on Earth
This Chapter focuses on the remarkable sound-producing abilities of cicadas. The hosts discuss the decibel levels of cicada calls, comparing them to the sounds of powerful machines. They explain the unique mechanism cicadas use to produce their sounds, called "timbling," and compare it to other sound-producing methods in insects.
The Function of Cicada Sounds
This Chapter explores the various reasons why cicadas make sounds, including mate attraction, courtship, and disturbance calls. The hosts also discuss the different sound-producing mechanisms used by different cicada species, including "crepitation" and "timbling."
Cicadas vs. Locusts
This Chapter clarifies the distinction between cicadas and locusts, emphasizing that they are not the same insect. The hosts discuss the historical misidentification of cicadas as locusts and the misconceptions surrounding their potential destructiveness.
The Cicada Life Cycle
This Chapter delves into the life cycle of cicadas, outlining the three stages: egg, nymph, and adult. The hosts discuss the process of egg-laying, the nymph's subterranean existence, and the final emergence into winged adulthood.
The Mystery of the Long Nymph Stage
This Chapter explores the reasons behind the long nymph stages of periodical cicadas, particularly their prime-numbered emergence cycles. The hosts discuss the theories behind how cicadas track time underground and the evolutionary benefits of their long dormancy.
Keywords
Cicada
A large insect known for its loud, buzzing song, particularly during the summer months. Cicadas belong to the order Hemiptera, commonly known as "true bugs." They have a distinctive life cycle that includes a long nymph stage spent underground, followed by a brief adult stage focused on mating and egg-laying. There are two main types of cicadas: annual cicadas, which emerge every year, and periodical cicadas, which emerge every 13 or 17 years.
Hemiptera
An order of insects commonly known as "true bugs." Hemiptera are characterized by their piercing and sucking mouthparts, which they use to feed on plant sap or other insects. Cicadas belong to the suborder Auchenorrhyncha within the order Hemiptera.
Periodical Cicada
A type of cicada that emerges synchronously every 13 or 17 years. Periodical cicadas are native to the Eastern and Midwest United States and are known for their long subterranean nymph stages. Their prime-numbered emergence cycles are thought to be an evolutionary adaptation to avoid predators and parasites.
Annual Cicada
A type of cicada that emerges every year. Annual cicadas are found around the world and have shorter nymph stages than periodical cicadas. They are often preyed upon by cicada killer wasps.
Timble
A specialized sound-producing organ found in most male cicadas. Timbles are ribbed, corrugated membranes located near the base of the abdomen. They produce sound by rapidly collapsing and snapping back into place, creating a clicking sound that, when repeated hundreds of times per second, results in the characteristic buzz or whir of cicadas.
Crepitation
A sound-producing mechanism used by some cicada species. Crepitation involves slapping the wings together over the body or against the body surface, creating a different type of sound than the "timbling" method.
Ovipositor
A specialized organ found in female cicadas used for laying eggs. The ovipositor is a sharp, rigid, spike-like structure that the female uses to slice and gouge slits into woody plant tissue, where she lays her eggs.
Xylem
The vascular tissue in plants that transports water and dissolved minerals upwards from the roots. Cicada nymphs feed on xylem sap, which they extract from the roots of plants using their piercing and sucking mouthparts.
Parasitoid Wasp
A type of wasp that lays its eggs inside or on other insects, using the host insect as a food source for its developing larvae. Some parasitoid wasps have evolved to be in sync with annual cicadas, but periodical cicadas have evolved to avoid them due to their long nymph stages and prime-numbered emergence cycles.
Cicada Killer Wasp
A type of solitary wasp that preys exclusively on annual cicadas. Female cicada killer wasps capture adult cicadas, paralyze them with a sting, and transport them back to a burrow where they lay their eggs. The wasp larvae then feed on the paralyzed cicadas.
Q&A
What is the difference between annual and periodical cicadas?
Annual cicadas emerge every year and have shorter nymph stages, typically lasting two to five years. Periodical cicadas, on the other hand, emerge every 13 or 17 years and have much longer nymph stages, spending over a decade underground. Periodical cicadas are native to the Eastern and Midwest United States, while annual cicadas are found around the world.
How do cicadas produce their loud mating calls?
Most male cicadas have specialized sound-producing organs called "timbles." Timbles are ribbed, corrugated membranes located near the base of the abdomen. They produce sound by rapidly collapsing and snapping back into place, creating a clicking sound that, when repeated hundreds of times per second, results in the characteristic buzz or whir of cicadas.
Why do periodical cicadas spend so long underground?
The long nymph stages of periodical cicadas are thought to be an evolutionary adaptation to avoid predators and parasites. Their prime-numbered emergence cycles make it difficult for predators and parasites to evolve synchronous life cycles with them, as there are no intermediate life cycle steps that could easily evolve synchrony.
How do cicadas track time underground?
The exact mechanism by which cicadas track time underground remains somewhat of a mystery. One theory is that they track the seasonal variations in the fluid flow of the xylem sap they feed on, using this information to time their emergence.
Are cicadas harmful to plants?
While cicadas can damage plants by laying their eggs in woody tissue, their overall impact on healthy trees is minimal. Their slow metabolic rate during the nymph stage ensures that their thirst does not overpower the tree's ability to thrive.
Are cicadas eaten by humans?
Yes, cicadas are eaten by humans in some cultures. The episode mentions that cicada cuisine is a topic for a future episode, and listeners are encouraged to share their experiences with cicada eating.
What is the evolutionary history of periodical cicadas?
Periodical cicadas are a relatively recent evolution, with the different species diverging from their common ancestor over the past 2.5 million years. Their emergence is thought to have been influenced by ice age glacial movements, which created new niches and opportunities for speciation.
What is the significance of the prime-numbered emergence cycles of periodical cicadas?
The prime-numbered emergence cycles of periodical cicadas are thought to be a key evolutionary adaptation that helps them avoid predators and parasites. By emerging every 13 or 17 years, they disrupt the ability of predators and parasites to evolve synchronous life cycles with them, ensuring their survival.
What are some of the cultural beliefs and folklore surrounding cicadas?
The episode mentions that cicadas have been associated with various cultural beliefs and folklore, including superstitions about them causing illness and the use of their wing patterns to predict war or peace. These beliefs are likely rooted in the unusual and seemingly cyclical nature of their emergence.
What is the next episode of Stuff to Blow Your Mind going to be about?
The next episode of Stuff to Blow Your Mind will continue the exploration of cicadas, delving into their history, mythology, folklore, and general science. The hosts encourage listeners to share their own experiences and thoughts about cicadas.
Show Notes
In this episode of Stuff to Blow Your Mind, Rob and Joe explore the world of the periodical cicada, from their curious lifecycle to their mythological and culinary roles in human cultures.
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