What are cicadas?

Cicadas are winged insects related to aphids. Apparently, there are at least 3,000 species of them globally. Among them are three species that form the Brood X (for Roman numeral 10) cicadas, noted for their unusual lifecycle. What is it? Let’s find out!

There are two types of cicadas -annual and periodical. As the name suggests, the annual cicadas emerge every year, and the periodical, well, periodically. And the period is either once every 13 or 17 years. Brood X cicadas are periodical, and emerge once every 17 years. The females lay their eggs on trees, and when the wingless nymphs emerge from the eggs, they fall from the trees and burrow into the ground. And then the 17 year wait begins. Through the 17 years, the nymphs feed on the fluids in tree roots and grow slowly, molting through five growth cycles. After 17 years, they emerge from the ground en masse. Once they come out, the nymphs shed their skin to become winged adults. Of course, it may take a short while for the adults to get their hard exoskeleton, making them more vulnerable to predators. But the number of nymphs that emerges is so high-we’re talking billions here – that despite threats from predators, these insects manage to survive in large numbers.

While there are many theories, it’s not clear why they take so many years to come out. But what is apparent is that they know when exactly to come out, thanks to ‘an “internal tally system” that tells them when it’s time to surface. Though the timing of emergence could vary slightly among different locations, they always wait for the soil to be warm enough”.

Between this May and June, billions of Brood X cicadas will emerge in at least 15 States of the U.S. They will be extremely noisy, but will not harm humans or agriculture. Within the few weeks that the adults live, they’ll mate and lay eggs. The last time they emerged was in 2004. The next time they emerge will be in 2038!

 

Picture Credit : Google

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