Have you ever heard a constant buzzing during summer months whenever you have walked near a forest or park with lots of trees? Click here to hear that sound. Do you know who or what makes that sound?
They are made by a family of insects called the Cicadas. They are fascinating because of their unusual life cycle. Cicadas spend most of their life underground clinging to the roots of a tree and emerge annually during summer. They stay above ground for a few weeks just to mate and lay eggs. Then their life ends! Isn’t that amazing. Let’s learn a bit more about them.
There are around 3000 species of Cicadas in the world. Almost all follow an annual cycle in different multiples. There are a few fascinating species in North America that follow a strict periodic cycle. The life cycle is their progress from egg to nymph, and finally adult. Eggs are laid in slits on tree branches. When the eggs hatch, the nymphs fall and burrows underground to find a root to cling to. They will remain there for the most part of their lives living off the sap from the roots. When conditions, like the temperature of soil and time, are right, they will emerge from the ground and molt into a colorful adult leaving behind an exoskeleton. The male then sings to find an ideal mate. That singing is the buzzing we hear! The female lets her presence known by clicking her wings. Once the Cicadas mate, they die soon after thereby ending their life cycle.
The annual cicadas emerge from the underground every year in batches. That is, only a fraction of any particular species will surface to mate while the rest of them remain underground. Most of the Cicadas in India and around the world follow this cycle.
Periodic Cicadas emerge after a fixed number of years in its entirety. The number of years is 13 and 17. Such a large prime number for its period is thought to be because it avoids surfacing at the same time as other Cicada species with different periods. However, research is still inconclusive. When they emerge they will overwhelm the region with their presence and noise from buzzing. They are not considered pests. Insect predators like birds and frogs will gorge on this bounty until they are too full to eat. Since their numbers are so huge the majority will survive to continue the cycle.
So, next time you are in a forest during summer watch out for these enigmatic insects and recall it’s strange life.
Further reading:
https://www.nationalgeographic.com/animals/invertebrates/group/cicadas/
http://indiasendangered.com/decoding-the-lives-of-mystery-insects/
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