This year has seen quite a good number of cicadas hatch, but still not as many as a few years ago QVMAG entomologist Simon Fearn said. 

There are thousands of cicada species, but there are only about half-a-dozen in Tasmania and the ones causing the current ruckus are the red-eyed cicada. 

Despite a common belief cicadas emerge on the dot after up to 17 years, Mr Fearn said this is only true of species overseas. The red-eyed cicadas emerge every year, but in varying numbers due to their three-year life cycle. 

“If you’ve got a massive emergence it’s because there was a really good season three years back in time,” Mr Fearn said. 

“A good season is good rainfall, nice hot days, healthy trees that have got really good sap, so if you get a nice wet summer like this summer you could almost predict that in three years time there’ll be another massive emergence.”

On years with good numbers of cicadas, there is often a gentle “rain” falling from beneath the trees they are in. 

“You’re being weed on, it’s a lovely cicada golden shower,” Mr Fearn said. 

“As they feed they constantly poo out all of the sugary stuff in the sap so you can be standing under a tree and it can be just raining cicada wee.”

The cicadas iconic mating call is created in hollow “drums” or chambers, which they vibrate to create noise. 

Mr Fearn said they begin making their noise when the ambient temperature reaches above about 18 degrees. And a cicada rarely calls alone. 

“Once one male starts calling all the others think, ‘Oh no, he might get the girl’ so they all start calling as well and it just turns into this massive crescendo,” Mr Fearn said. 

Cicadas spend most of their life as larvae underground in deep vertical holes, where they feed on the roots of trees. They emerge after three years, still in larva stage, climb up trees and hatch into their adult form. 

Mr Fearn said they will all hatch within a few days of each other.