If you were forced to live most of your life below ground tunneling through mud looking for the odd root to eat, I’m sure you would scream with joy as soon as you emerged into the sunlight. That’s just what the poor old cicada has to do.
The cicada spends most of its life below ground. The smaller ones around three years and some of the larger native species may spend up to seven years tunneling in the earth.
Upon their emergence the males begin their call, sometimes as loud as 90 decibels. With our home being surrounded by bush we are well aware of the noise they can make each summer right through autumn. The male cicada have two round tympani on the underside of their bodies. Underneath these tympani is a ribbed membrane. They create the noise by rapidly contracting muscles over these membranes. Some of the larger species keep a secondary rhythm going by clapping their wings against their bodies, just great a 6.00am on Sunday morning
The damage is caused by the females when they lay their eggs. They tend to pick pencil thin twigs often found on bonsai. The sharp sword like ovipositor is thrust into the bark and wood of the twig and an egg is laid. She then moves down a fraction and repeats the process until approximately 12 eggs are laid. Leaving a fish bone like scar on the branch. While your tree will normally heal it does weaken the area and quite often the twig will snap in a strong wind or if being wired.
We can do very little to control cicadas, bar chasing them away from our bonsai whenever you see them. The only thing you can do is protect damaged branches when you find them or preempt an untidy break by trimming it off. Any insect that climbs a tree and lets out a 90 decibel call makes itself a sitting target for birds and you will quite often see birds fly past with a panic stricken cicada in its beak.
The nymph as it moves up through the soil in preparation for emergence has become a very important part of the kiwis diet.