Nature of Tasmania

Thursday, 17 December 2009

Cicadas of Tasmania

Two other bloggers have recently posted on cicadas (here and here) so I thought I'd keep the theme going by posting some photos of a couple of local ones. For the benefit of those doing Google searches for Tasmanian cicadas I have also included a list below of all the species which can be found in this state.

(Click on Photos to Enlarge)

White Flash Cicada ( Cicadetta torrida )

Yellow-spot Cicada ( Diemeniana euronotiana )

In the three and a half years I've been back in Tassie these are the only two species I've seen although I must admit I haven't been actively searching for them. The White Flash Cicada came to the Mercury Vapour light at night and the Yellow-spot Cicada I just stumbled upon.

Two species is not much but it sounds better when you consider there are only eight species found in Tasmania.

Tasmanian Cicada Checklist

Cicadas belong to the order Hemiptera and the family Cicadidae.

Subfamily: Cicadinae

Psaltoda moerens

Subfamily: Tibicininae

Cicadetta abdominalis
Cicadetta spreta
Cicadetta torrida
Diemeniana euronotiana
Diemeniana hirsuta
Diemeniana tillyardi
Pauropsalta encaustica

References:

Semmens, T.D., McQuillan, P.B. & Hayhurst, G. (1982). Catalogue of the Insects of Tasmania - Department of Primary Industry, Hobart.
Moulds M.S. - (1990) - Australian Cicadas - New South Wales University Press
Daley. E - (2007) - Wings - An Introduction to Tasmanias Winged Insects - Riffles

Monday, 14 December 2009

Sibling Cannibalism

.....Common Spotted Ladybird (Harmonia conformis )

The macabre practice of cannibalism is rife in Tasmania. It's been occurring since long before the days of convict Alexander Pearce and right up to the present day. It takes place not only in the remote wilderness areas but even in some of the more affluent suburbs of our cities and towns. Read on if you dare.

A few weeks ago I posted a photo of some ladybird eggs on my nectarine tree. Well the tree is now covered in all stages of the ladybird life cycle.

(Click on photos to enlarge)

Newly hatched ladybirds - Harmonia conformis

After hatching, many insects feed on their own egg shells for their first meal. In the photo above you can see newly hatched larvae feeding on the eggs. I knew something was wrong with this photo but it took a few moments for it to dawn on me that the eggs in the photo have not hatched.

Note the empty (white) egg shells on the left

A few centimetres away you can see the empty eggs shells where the larvae have come from. They have then moved along to feed on their unhatched siblings.

Sibling cannibalism among ladybirds is not unusual. In fact it can be quite common, particularly if there is a shortage of food. It's a mechanism which appears to allow at least some of the ladybirds to get a good start in life as opposed to them all going hungry and dying off.

Larval Moult

This one is doing well. It has shed it's skin and entered another stage in it's development. You have to wonder how many siblings and cousins have helped it to get to this stage.