North resounds with the mating call of cicadas

IF YOU thought the noise of cicadas in the bush around Northern Tasmania this year was louder than usual, you would be correct.

Launceston entomologist Simon Fearn said our first wetter summer for a while had seen the hatching of millions of the large and loud black insects.

``Up to about three or so years ago, we had a good eight or nine years of drought and there were very few cicadas around,'' Mr Fearn said. 

``Now we're into our first pretty wet summer, or normal rainfall summer, and we're starting to get another cycle of great big pulses of cicadas hatching.

``It's been the same all over the North of the state and all the way down the Tamar.

``There's been millions of them.''

Mr Fearn is an honorary associate researcher with the Queen Victoria Museum and Art Gallery and is working on expanding its entomological exhibits.

He said the urban myth of cicada swarms every seven years didn't apply to the red eye cicada (scientific name psaltoda moerens) in Tasmania.

And it's only the males, seeking a partner for sex, that make the deafening racket now dominating our bush.

``For two or three years they [cicada nymphs] spend their time underground in a vertical tunnel feeding on the sap of tree roots,'' Mr Fearn said.

``Then on a nice humid evening in late November or early December, preferably with a little bit of rain, they will all crawl out of the ground and climb up the trunk of a tree to a height of 1.5 or two metres.''

In a favourable year like 2013, that can mean millions of cicada nymphs are on the move.

Mr Fearn said that by noon on the following day, they hatch into cicadas ready to fly up into the treetops to mate and continue feeding on the tree sap.

They usually make a whirring noise, but when the temperature gets over 25 degrees they start their ear-piercing ``love song''.

Their favourite perch is the trunk or branch of a smooth-barked gum or white gum, and sometimes there will be thousands of cicadas, some over six centimetres long, attached to a single tree.

The cycle starts again when the eggs of the female cicada develop into nymphs and drop to the ground under their tree.

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