Summer of the Singing Cidada

As I write and draw this I’m sitting on my balcony in Sydney. It’s a warm summer evening, the sun just went down, friends are having a chat in the garden below and all seems peaceful. A cicada starts singing – it’s a pleasant sound, reminding me of warm holidays spent in France. The bug must have been a few gardens away. A closer one starts answering. And before I know it, the tree next to my ear explodes in a shrill cacophony of noise. Gone are the bird calls, gone are the voices from below, it is literally deafening. The summer of the cicada has come to my back garden.

A bit of artistic freedom: this one does not sing in my garden but in South America.
It's called the Giant Cicada (it's huge!) and is considered the loudest insect in the
Western hemisphere. 

It is a bumper year for cicadas, both in the USA and here in Australia. They haven’t emerged in large numbers like this for ten years (in Australia, seventeen years in the US). Species with names like shady underworld figures – masked devil, razor grinder, black prince – are prowling through the suburbs of Sydney and the Blue Mountains in swarms.

The typical lifecycle of a cicada

Why so many at the same time, you ask? Some of this can be explained by the life cycle of these noisy bugs. Eggs are laid in slits in the bark of trees. When they hatch a few weeks later the miniature cicada (called nymph) falls to the ground and buries itself up to 2m deep. It is here that they will spend most of their lifetime, feeding on the sap flowing through plant roots. They grow, occasionally shedding their skin, until they reach maturity. This underground stage can last any time from 9 months to 17 years(!), but most species will take 6 to 7 years. When they emerge, they shed their skin one last time and enter adulthood. This stage is quite short compared to the nymph stage, only a few days to a few months, typically 2 to 4 weeks.

It is not exactly clear why all cicadas decide to emerge at the exact same time – but they do. It most likely has something to do with environmental signs like increased sap flow in the tree roots indicating warmer weather and more rain. This would explain why the cicadas were particularly early this summer: Australia has had the mildest winter on record.

Studies of the only cicada I ever photographed -
a Singaporian fellow from the Pomponia genus

Emerging en masse does have its perks. The sole purpose of the adult cicada is finding a mate and produce eggs. Finding a mate becomes easier if there are millions of you buzzing around the same hectare. Cicadas also use an interesting survival technique called predator satiation. The idea is to overwhelm predators with such an overload they literally cannot eat them all. Mind you, the birds will do their best. This also has its advantages; it has been shown that in years like this birds produce stronger, healthier broods.

The perpetrator in my garden:
Cyclochila australasiae aka Green Grocer
(you can see why). It is one of the
only species adapted to living in urbanised
areas and incredibly loud.

Cicada swarms do very little damage. They are so single-mindedly focused on reproducing that they do not eat. They are not poisonous, they do not sting or bite. They don’t fly into your house and crawl under your bed. The only real damage they can do is to your ears. It’s only the male cicadas that sing, and when they do they can reach over 100 decibels. It’s like a high-pitched airplane coming over. While they have the peculiar ability to turn off their own hearing while singing, I do not. I think it’s time to get some headphones.

Made a new friend!

Me and my friend in the Simpson Desert
Pic by Shaun Doyle

I’d like to introduce you to one of my new friends here in Australia! He is a bit of a loner and somewhat prickly at the best of times, but bear with me and you’ll come to like him too!

His name? Thorny devil. Yes, really. In Latin it gets even worse, Moloch horridus. Moloch refers to an ancient god, revered around 2000BC by a people living on the Southern and Eastern Mediterranean shores (modern day Lebanon, Israel, Palestinian territories, Jordan and Syria). This god was associated with a particular kind of child sacrifice through fire. Not a great start. The last part ‘horridus’ means bristly or secondarily dreadful.

This reptile might look fearsome but it is not as dreadful as its name suggests. In a land filled with deadly dangerous animals, this one uses clever disguise and innovation to survive.

Poisonous? No

Fast? No

Ferocious? Eh.. no. When picked up it might looked slightly annoyed and then just close its eyes.

So how exactly does it survive?

Thorns. Lots of them. Not many animals enjoy swallowing something that looks worse than a cactus.

Holding at your own risk! Pic by Enyi Guo

Camouflage. You don’t see a thorny devil until your foot hovers right over one and you were happening to look where you were walking. Even when you know what you are looking for they are exceedingly tricky to find. Their body colouration is patchy, partly the red of the desert sand, partly the yellow/green (it varies per individual) of the vegetation. When the animal is undisturbed the colours are quite dull. However, when moving or picked up they brighten up considerably as a warning sign to potential predators: do not think about eating me, it’s going to be unpleasant!

Body colouration can rapidly change. Here, the colours are dark and distinct.
Pic by Shaun Doyle

Deception. On its neck, it grows a bump with thorns about the same size as its head. When threatened the thorny devil tends to tuck its real head between its front legs which manoeuvres this bump where the head usually is. Many predators will aim for the head first when attacking. When they get in contact with the spines some might decide they like their stomach without holes and dismiss the attack. The moloch survives without damage to its real head.

Notice the 'extra' head on top of its neck. Pic by Shaun Doyle

Innovation. The thorny devil is endemic to Australia, meaning it is only found there. It thrives in the dry, sandy interior of the continent. One thing is very hard to come by in this place: water. Luckily, the thorny devil has got a rather unique solution to this. In its skin it has a system of small grooves, all leading toward the corners of its mouth. These grooves collect and move water from the entire surface of its body towards its mouth by means of capillary action. The only thing he has to do is swallowing. If you put a moloch with its feet in a dish of water, within a matter of seconds its body will be glistening with moisture and without lowering its head it will start to swallow the water brought to its mouth from its feet. All tested by yours truly of course.

A thorny devil can drink via its feet

You won’t find these animals in captivity often; they are notoriously hard to keep. Outside Australia, only a zoo can get a permit to keep them as they are a protected species. And few zoos actually do keep them. The problem lies in the feeding behaviour of these animals. They are very picky eaters, only feeding on 2-3 species of tiny black ant. And even then, they will only eat those when they are moving in a line, picking them off one by one, consuming around 2000 every day. So keeping one in captivity requires keeping a few large ant colonies of a particular ant species as well, and training them to walk in a line through the enclosure of the thorny devil where most of them will be eaten. It is a daunting task.

In short, I am a lucky person to have such an elusive new friend!