Cicadas are unusual insects, some years they are rare in terms of number; Other years there are so much of them, that their singing becomes deafening and even stunning.
Cicadas have a very short lifespan once they come out of the ground as they live on the surface for only 2 to 3 weeks (compared to 1 year for crickets and 6 months for grasshoppers).
The cicada remains on average 7 years underground in Europe before reaching adult size.
The minimum duration is 2 years and the maximum duration is 10 years. In North America, the American cicada can remain 17 years underground!