Pop quiz: Which of these is not like the others?
a) Leaf blower.
b) Table saw.
c) Pete Townshend’s guitar on “Won’t Get Fooled Again.”
d) Mating cicadas.
Trick question. To any human with reasonably functioning ears, they all sound alike. Loud. You can hear the first three any time, but cicada concerts curse the Coachella Valley seasonally, typically debuting in July. The insects emerge from their underground burrows this month as squishy nymphs ready to molt into adulthood, procreate, then die. Adult bugs are abundant, and horny. To us, their mating serenade, at about 100 decibels, is less romantic than repellent.
But cicadas have other lovely qualities. They’re a food source for birds, lizards, spiders, bats, and other animals. (Your dog relishes their crunchy-granola mouthfeel.) They’re not toxic, not interested in eating your plants, and they don’t bite. The holes from which they emerge are soil aerators. The notches they carve in trees and shrubs to lay their eggs enhance botanical health. Their decomposing bodies nourish the soil.
Globally ubiquitous, cicadas are revered by many cultures. A Greek poet wrote, “We call you happy, O Cicada, because after you have drunk a little dew in the treetops, you sing like a queen.”
Then again, somebody somewhere thinks Yoko Ono can sing.
Some species in Asia have been kept in cages because their captors found their voices melodic.
Your mileage may vary.
Closer to home, the Zuni find cicadas to be wilier than coyotes. Cicadas play key roles in Navajo creation myths, and the Hopi conduct cicada Kachina rituals. Our own Cahuilla Indians collected cicadas from saltbush every summer, roasting, drying, and storing them for future consumption.
Of the 3,000-some species of cicadas worldwide, seven U.S. species are classified as “periodical” and found east of the Rocky Mountains. They famously appear from their burrows in swarming broods in predictable 13- and 17-year cycles. They grab most of the media attention for their huge numbers — all individuals within a local population emerge in the same year — and because entomologists still don’t know why they keep such odd time.
In April, one North Carolina swarm was so huge and deafening that people called the cops to investigate why blaring sirens never stopped.
According to Doug Yanega, Ph.D., an entomologist at the University of California, Riverside, about 130 species of “annual” cicadas appear in the Western U.S. every year. The Coachella Valley genus is composed of scrub cicadas, about 20 species that emerge annually to hang out in trees, bushes, and on stucco to annoy the neighbors.
Unlike the 13/17 periodicals, individuals within annual populations are not developmentally synchronized, so “annual” does not denote a one-year life cycle, only that a reliable number of them emerge every year. Entomologists believe that Coachella Valley cicadas could reside underground for two to five years before appearing in our midst.
Periodical and annual cicadas look different — red-eyed, black-bodied easterners versus bigger (2.5 inches) green-eyed, black/brown/greenish-bodied westerners. Coachella Valley cicadas are stronger fliers than eastern broods, and their camo wear helps them better elude predators.
Periodicals present from April until mid-June; annuals hang around longer, until early autumn, but in smaller numbers. Unlike other members of the class Insecta, Yanega notes, cicadas are hemimetabolous; that is, they do not undergo a larval stage. They hatch from eggs as nymphs, with a soft exoskeleton that, above ground, renders them vulnerable as prey, like a molting soft-shell crab. If nymphs survive the day or so it takes to develop the hard adult exoskeleton, they wear it until death, after a few weeks of noisy mating.
Post-coitus, females gouge a twig, bush, or tree with the tip of their ovipositor and lay several hundred eggs in the tiny trenches. When nymphs hatch, they drop to the ground and burrow down in search of sustenance. Cicadas live their whole, root-sucking lives as subterranean nymphs except for their first moments and last few weeks, and our locals have evolved propitiously for their clime.
“Desert cicadas extract water from their blood and transport it through large ducts to the surface of the thorax, where it evaporates,” writes entomologist Robert L. Smith, in Sonorensis, a magazine published by the Arizona-Sonora Desert Museum. “The cooling that results permits a few desert cicada species to be active when temperatures are so high that their enemies are incapacitated by the heat. No other insects have been shown to have the ducts required for sweating.”
Call it the Insecta swamp cooler.
Another curious cicada trait recently was discovered and plumbed by researchers trekking through the Amazon. One felt a sprinkle and looked up to see tree-hugging cicadas, according to NPR, “feeding and peeing with abandon.” Larger animals depend on gravity to pull fluids out of their bladders in a stream. But petite pissers need surface tension and friction more than gravity to expel fluid, and they relieve themselves in droplets.
Except for cicadas. They pee in jets, possibly due to their huge appetite for sap and relatively wide guts. “Peeing one droplet at a time takes too long, and it’s not very efficient,” says Harvard’s Elio Challita, lead author of the Amazon pee paper. “So they have to get rid of that fluid in jets.”
Why do we care?
Because manipulating fluids in small scale has application for stuff like 3D printing, drug delivery, disease diagnostics, and outer-space testing.
So, like all God’s creatures, the insect order Hemiptera has a fascinating story to tell.
Both sexes vocalize, but it’s no surprise that all males are constitutionally louder than females. Like peacocks. Howler monkeys. Axl Rose. Female cicadas sing only in response to males, “as far as we know,” Yanega acknowledges about a species that remains mysterious because it is difficult to study beings that spend most of their lives underground.
Their two-chambered abdomens are covered with “tymbals,” membranes that vibrate to produce sound that varies according to circumstances but is always loud, even to its producers — males disable their own hearing while singing, effectively rendering them deaf.
But when you’re competing for a mate or repelling a predator, your intentions must be clear.
Loud and clear.
