Northern Rivers Talking Turkey

Nothing signifies the arrival of the summer more than the shrill, sizzling scream of a colony of cicadas.  Big bodied and gregarious they have inspired some creative names such as Green Grocers, Floury Bakers, Brown Bunyip, Cherry Noses, Redeye’s, Yellow Mondays, Squeakers, Black Prince, Whisky Drinkers, Razor Grinders and Double Drummer Australia’s largest and loudest cicada.  Many of these quirky names were given to the insects by children who once swapped them in the streets like football cards.  Australia is home to 250 species of cicada, each species has a distinct call which can be used to identify the species of cicada that is singing in the treetops.  Worldwide there are 2500 species of cicada, in some parts of the world they are found on the menu at the dinner table where the females are more highly regarded for having meatier flesh.
The loud calls of cicadas is produced by two vibrating drum like membranes called timbals, mounted on either side of the abdomen, the sound is amplified and resonated in the large airy cavity of the insects abdomen.  Cicadas only sing when the weather is hot and it is only the male insects that sing, they are doing so to attract the attention of a mate so most of their singing and romance is done during the hottest hours of a summers day.
The song of some cicadas can be as loud as 120 decibels and is amongst the loudest sound produced by any insect.  The song is loud enough to cause permanent damage to the human ear if it was produced just outside the listeners ear, it is safe to say that no human could tolerate a cicada singing beside their ear so the insect is not known for causing hearing loss, however their song can be uncomfortably loud even from the distance of the tree tops, it could be that the loud call forces birds to hunt alternative prey elsewhere.  The calls of some small species are so high in pitch; they are inaudible to the human ear.
Cicadas are closely related to the leaf hoppers and like other members of the family they are sap sucking insects.  They have sharp beak like mouth parts for penetrating into the circulatory system of the tree, then they suck the flowing sap from the plant.  The insects absorb the sugars from the sap which are vital to life and then release the undigested fluids that they do not require.  This is why it feels like it is raining if you are standing under a tree full of cicadas on a hot summer’s day.
The life cycle is interesting as it is with any creature that goes through metamorphosis.  Female insects cut a slit in the bark of the tree with their ovipositor, a saw like protuberance on the end of her abdomen; she then lays her eggs into these protected slots.  When the eggs hatch the nymphs fall to the ground and use their large shovel like front legs to dig into the soil and bury themselves.  They will spend several years underground of depths from 30cm up to 2.5 meters where they tap into the roots of the trees and feed on the sap.  Some species may spend more than a decade below ground.  The nymphs emerge from their subterranean home during the heat of summer, usually under cover of darkness, they use their strong front legs to pull themselves up onto the nearest tree or bush where their skin splits down the back and they hatch into their adult winged form.  The shell of the nymph is left clinging on the tree where they hatched and is a familiar sight on the trunks of trees during the summer months.  The adult insect is known as an imago which is the term in biology used to describe the final stage of development in insects.