Im sitting outside and their noises are deafening me. Got me thinking how do they know its their time to emerge? It’s not that they dig underground, set their apple watch for a 17 year time and roll out of bed when the timer goes off 17 years later. .what is their DNA to give this 17 year nap and know when that time is up?
In: Biology
They don’t hibernate, they dig little tunnels while underground and feed off of tree roots. As the trees age, their sap changes, and it is believed they detect the passage of time through the sap changes
In other words… the tree sap is their Apple Watch
They take a *long* time to grow up. Similarly to human generations.
It’s not like we all set our clocks. Just happen to all mature and have children around the same ages, leading to generational gaps. Those gaps are less noticeable now, but years ago summer births were a lot more common as the winter months were, uh, *boring*.
So anyway back to the cicadas. They take years to develop, and they all were born at the same time by the last generation. This means they’ll all grow up into adults around the same time and emerge all those years later.
This is in contrast to other cicadas that don’t synch their mating cycles like this.
Long story short we think their “clock” is something to do with the soil temperature, just like we get cues to sneeze from bright light or we have to urinate a lot when we go from a cold environment to a hot one and back repeatedly. Just some involuntary biological reactions, that as you said, are really just genetic code.
Same way the human body know’s it’s time to start growing hair around your naughty bits. You grow to a certain point, and things happen. Same with all animals in the world.
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