Nature's Noisy Garden Guest: The Song of the Cicada

Like certain teenagers, periodical cicada spend much of their life out of sight, only to emerge with a ruckus. 

Periodical cicada are the newsworthy species of the superfamily Cicadoidea, and it’s easy to see why.

Found worldwide in tropical and temperate regions, immature cicada nymphs dwell underground for years — as long as 17 in one case — then make a synchronized entrance when triggered by soil temperatures or moisture.

It can be pretty dramatic to see billions of nymphs emerge en masse, shed their exoskeletons to reveal their adult forms, then begin their buzzing, mate-attracting song on blast. (There are also many cicada species that emerge annually, but these events are not synchronized and involve smaller numbers of insects. For all 3,000-plus species, though, the facts of life are this: the adults focus on mating and egg-laying for a few weeks then die. Which seems kind of anticlimactic given all the time waiting.)

Muscle music

Periodical cicadas may be the newsmakers, but they’re not the only noisemakers.

All male cicadas have a song (females are generally silent or emit a slight clicking noise), and how they “sing” is just one of the ways they differ from other insects.

Unlike crickets and some grasshoppers, which rub their legs together to make a chirping sound, male cicada have specialized membranes called tymbals on their abdomens that are attached to muscles.

When the cicada contracts and relaxes the muscles, the tymbals vibrate, producing the characteristic buzz. The sound is amplified by the cicada’s abdomen (which acts like a resonating chamber, similar to the body of a guitar, cello, or violin), which makes it surprisingly loud and able to travel long distances.

And just as every singer has a distinctive voice, so do different cicada species. Each song varies in rhythm, pitch, and complexity, with chirps, clicks, and trills layered over the main buzzing tone. 

Still, this isn’t exactly the symphony of nature. The deafening tune of a huge brood of cicadas can be annoying, to say the least. 

For your garden, though, cicada season isn’t something to fear. The overall effect of these noisy visitors isn’t meaningful, although their shed exoskeletons and dead bodies can leave a mess. 

No fuss

Cicada metamorphosis - the transformation into an adult insect

Their raucous call might be enough of an identifier, but knowing what adult cicadas look like helps you distinguish them from the non-singing insects they can be mistaken for, including treehoppers, froghoppers, and whiteflies. 

Adult cicadas are medium to large insects, typically ranging from 2 to 5 centimeters (0.8 to 2 inches) long. They’ve got prominent compound eyes forming a triangle on their heads, short antennae, and powerful legs capable of jumping. Their membranous wings are usually transparent with black veins. 

As for their effect on your garden, well, it’s not much, good or bad. 

Though the nymphs do munch on roots, it’s typically not enough to cause serious damage, especially if you’ve kept your soil and plants’ root systems healthy by mulching and applying compost. On the other hand, by burrowing underground nymphs contribute to soil aeration, which promotes air and water circulation.

Adult cicadas aren’t pollinators, so they won’t help your plants reproduce. But their shed exoskeletons and dead bodies can return nutrients to the soil, albeit just a tiny amount. Cicadas will feed on plant leaves but here, too, they don’t make much of a mark.

In most cases, the concern is more cosmetic than anything, as healthy trees can usually tolerate some minor leaf loss. One exception: Young trees might be more susceptible to cicada damage. You can protect recently planted or very young trees by covering them with netting during a cicada emergence event. 

It’s what’s for dinner

While their total effect on your garden will likely be minimal, cicadas do play an important role in the ecosystem — as food. Birds, racoons, squirrels, possums, and some amphibians (mostly frogs, toads, and lizards) love them. And in some Asian cultures, so do humans: People in China, Vietnam, and Thailand deep-fry, roast, or stir-fry nymphs and adult cicadas to eat as a snack or add to a recipe; in some parts of Japan, cicadas are a summer delicacy served boiled, candied or pickled.

But whether you consider cicadas a delectable treat or their emergence events one of nature’s most spectacular phenomenon, when they come out of hiding is something to remember – just like the appearance of that room-bound teen. 

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