Lesley Smitheringale Fine Art

Garden Guests Diary - Beauty is only skin deep [16 Jan 08]

I recently noticed a few cicada skins, still attached, in pristine condition, to branches in my garden and you can’t help but marvel at how amazing nature is and the natural life cycle of these insects.  As a result of macro photography, I am getting a lot closer to nature than ever before and I am learning all sorts of things about the tiny creatures who have been around me all the time …

Cicada skin

The loudest insects in the world, are cicadas - Their drone are one of the most recognisable sound in Australia, and herald the approaching summer. There are about 250 species.

The song of the cicada is only produced by the males as a mating call. How they produce their songs is still being researched today, but the organs that produce the sound are the tymbals, a pair of ribbed membranes at the base of the abdomen. Contracting the internal tymbal muscles causes the tymbals to buckle inwards and produce a pulse of sound. By relaxing these muscles, the tymbals pop back to their original position. In some species of cicadas, a pulse of sound is produced as each rib buckles.

Cicadas feed on a huge range of plants, including eucalypts and grasses. They feed by piercing the surface of plants with their mouth stylets. The sap is then sucked up through a tube formed by the concave surfaces of two of the stylets. They are not harmful to trees, although in some cases the growth of the tree may slow, due to the amount of sap consumed. Cicadas do not bite, even when handled, although their claws may feel sharp as they cling to the skin.  Birds, bats, spiders, ants, mantids and tree crickets all prey on cicadas.

Lifecyle
It is thought that the nymphs of the larger, common Australian species of cicada may live underground for around 6-7 years. This may explain why adult cicadas are more abundant during some seasons than others, with peaks occurring every few years.In contrast to its nymph stage, the life of the adult cicadas is very short, lasting a matter of weeks. Once the adult cicadas have mated, the female cicada lays its eggs by piercing the plant stems and inserting the eggs into the slits. The eggs hatch into small wingless cicadas known as nymphs. They fall to the ground and burrow below the surface, where they live on the sap from plant roots. Over the period of several years, the nymphs grow, shedding their skin at intervals.

Once the nymph reaches full size, it will dig its way to the surface with specially adapted front legs. It usually surfaces as night falls in the late spring or early summer. Then, climbing the nearest tree trunk or other fixture, it will shed its skin for the last time, emerging as a fully-winged adult cicada.

Info from:

http://lifecycle.cicadayear.comhttp://cicadablog.saltthesandbox.orghttp://rainforest-australia.com/cicadas.htm http://ausemade.com.au/fauna-flora/insecta/hemiptera/cicada/index.htm