Have you been wandering outside lately and heard a buzzing sound? If you tracked the sound back to some trees or shrubs (and not to a neighbor’s power tool!), chances are good that what you’re listening to is a cicada (or several of them!). Cicadas are among the loudest insects in the world, but because of their lifestyle we usually don’t get to see them up-close.
Cicadas (which all belong to the large family Cicadidae) are distinct-looking bugs; they’re typically big (about 1 to 2 inches long, with the largest reaching nearly 3 inches in length) and have large, transparent wings with prominent veins. They live on twigs, sucking the juices (specifically the xylem) out of the plants. And although we and many other animals hear their roaring buzzing, we’re actually not the intended audience. Using special membranous, drum-like organs, called “tymbals,” on the sides of their abdomen, the male cicadas make these sounds to attract female cicadas.
But perhaps what’s more interesting than the cicada’s noisy courtship song is the fact that all of this happens during its relatively short-lived adult stage; the cicada actually spends most of life in its immature, or nymph, stage.
As a nymph, the cicada lives underground, where it sucks the xylem out of the plants’ roots. When the time comes, the nymphs borrow out of the ground, molt, and emerge as adults. Cicadas usually spend several years as underground-dwelling nymphs, and only a few weeks or months as vocal adults. Probably the most famous examples of this lifestyle are the periodical cicadas (genus Magicicada) in eastern North America, which spend 13 or 17 years as nymphs. When the time is up, the nymphs emerge, synchronously and in huge numbers. (Because there are so many of them, this helps ensure the survival of the species; even if many are eaten by predators, still many more are left to mate.) The deafening calls of the adults only last for a few weeks before they’re gone and not seen again for another 13 or 17 years.
But most cicadas don’t live this long, and a lack of synchronicity in lifecycles results in hearing cicadas every year, usually in the afternoon or evening time, in summer or fall. And you can hear them in many places; with over 2,500 species belonging to this family, cicadas are found on every continent except Antarctica. They’re so common that they’ve become a part of people’s diets in many cultures around the world, with female bugs being prized for their meatiness.
If you do happen to handle one of these elusive vocalists, be careful that it does not mistake your skin for a plant; while cicadas don’t bite or sting defensively, they may try to painfully feed on a person if they get confused!
For further reading:
- W.S. Cranshaw and B. Kondratieff’s article “Cicadas” at Colorado State University Extension
- BioKIDS’ article “Cicadas” at the University of Michigan
- National Geographic’s “Cicada (Magicicada septendecim)“
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