Thursday, March 6, 2008

Cicada Research

- Cicadas are linked to Summer (when they emerge to mate).
- Many children like to collect them (this may have been truer in previous decades).
- Common cicadas (the green ones) are known as "green grocers" or "Cyclochila Australasiae".

Cicadas have 3 main stages in their life. Which are, the egg, the nymph and as an adult.

The Egg
- Eggs are roughly cigar-shaped, 1.5-3mm in length, white or pale cream.
- The female uses her "ovipositor" to cut slits in the tree where she lays her eggs. She will lay around 200-300, but can lay up to 600, usually over a few days on different branches.
- Eggs can be laid almost anywhere from grass to hard dead eucalyptus trees, however they will usually be laid near a nymphal food source (e.g. a large tree).
- Cyclochila Australasiae take about 120 days to hatch, and can be effected by rain.

The Nymph
- Hatches as a "pronymph" encased in a thin transparent skin.
- It then wriggles out of the egg and out of the slit (of the tree).
- Cyclochila Australasiae are white with black eyes when they hatch.
- They dry out easily so they quickly drop to the ground, it doesn't matter from what height as they are so light it doesn't harm them.
- After reaching the ground they find an opening to tunnel down to make their cell before looking for food.
- They suck sap from tree roots with their "rostrums".
- They usually live about 40cm-1m under the surface.
- They shed their skin a few times under ground as they grow.
- Before emergence, a tunnel is dug to the surface for easy exit when the time comes.
- One they surface they find a spot to shed their skin (usually a tree), they pump blood in their wings to expand them and then let them dry.

Mating
- Singing attracts females, once the female arrives the male will chirp softer and they will sidle for a little while before mating.
- As adults they live for 2-4 weeks under favorable conditions.
- A female in captivity lived for 6 weeks.

Predators
Birds - Cicadas are considered as quality food and everything but their wings will be eaten. They are at risk when singing or flying through the air. Often they will congregate so their collective sound deters birds from attacking them.
Cicada killer wasps - These wasps will sting a Cicada paralysing it immediately before dragging it into their next where it stores it and lays eggs beneath it so when the larvae hatch they eat it alive.
Other predators - Spiders, Ants, Praying mantis', Lizards


Information sourced from:
Australian Cicadas
M.S.Moulds 1990

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