Tag Archives: bladder cicada

Mystery of the clicks

The sounds of nature are always there, even in the city and suburbs, if you stop to hear.

Sometimes they are memorable, melodic noises. I remember lying in bed as a child in Brisbane in the dead of night listening to the cheerful call of a Willy Wagtail or the haunting, ‘mo-poke’ call of the Southern Boobook Owl. At other times the sounds are mysterious drones, clicks or whistles, all just part of the background of summer in the suburbs. Unless it’s a click that you’ve been trying to find the owner of for years.

The makers of many mysterious nocturnal noises lurk in a suburban backyard!

The makers of many mysterious nocturnal noises lurk in a suburban backyard! All photos R. Ashdown.

In our street on dusk after the first hot summer day, an all-enveloping, loud, continuous guttural rumbling fills the air. This is the call of the large, green Bladder Cicada (Cystosoma saundersii). These beautiful, large green insects are hard to find, given how loud and large they are.

Bladder cicada

Catching cicadas is a childhood pastime during an Australian summer. Some species sit warily high up on tall gum trees, taking flight at the slightest movement. Others, such as this Bladder Cicada, call on twilight and are well camouflaged. If detected, these cicadas will suddenly drop to the ground, hoping to avoid being caught.

Bladder Cicadas are found in closed forest and gardens on coastal Queensland and New South Wales. In males, the large, hollow abdomen acts as a resonant sound radiator, allowing the cicada’s song to carry long distances. In our suburb, the call of these insects on a summer evening can be deafening.

Most of the life of this cicada, like most species of this insect, is spent below ground as a nymph, feeding on the sap from the roots of trees. On  warm summer nights, nymphs leave the safe, dark earth, climb a tree or fence post and the adult cicada emerges from its brown skin, unfolding delicate wings that are pumped full of fluid as they unroll and harden. The shed skins, or ‘nymphal exuviae’ remain behind, clinging motionless and empty to a fence post, evidence of the adult cicada’s arrival above ground in the night.

Venation in a cicada wing.

Veins in a cicada’s wing.

The adult cicada usually only lives for two to three weeks. Males call to attract females, who fly to the male chorus and land within 50 cm of the male.The female produces a pheromone  which is distributed by wing-clicking. The male responds by changing to the courtship song, before moving towards the female and mating. The female cicadas lay eggs in the live branches of plants that are suitable for the larvae, which hatch and climb down below ground.

For many years, I’ve pondered a strange, intermittent clicking noise heard in summer in the suburbs of Brisbane and here in Toowoomba. The clicking was recently described by a naturalist mate, who had also heard them, as ‘like the sound made by two Aboriginal message or song sticks clacked together’. A perfect description. Advice from those who study insects and like stuff has pointed me towards another green cicada as the likely suspect — the  Bottle Cicada (Glaucopsaltria viridis). This cicada has a long, whistling sound on dusk, but is known to produce some intermittent clicking sounds during the day.

Bottle Cicadas are about 3 cm long. The male has an inflated hollow abdomen. They are found in south-eastern Queensland and northern New South Wales. Their main song is a continuous, monotonous whistle at dusk, between October and April.

It’s taken years, but I finally found one of these insects. While walking on dusk past a hedge from which I’d previously heard the mysterious clicking, I noticed a long whistling call emerging from all over the hedge. Closing in on one source of the sound, an insect flew down to the ground, where my faithful fellow-naturalist dog tried to eat it. I wrestled the insect from the dog’s mouth, and found that it was indeed one of these green cicadas. I had at last solved my personal mystery of the weird clicking sounds.

Bottle Cicada. Cicadas have two obvious, large, compound eyes, and three ocelli. Ocelli are three jewel-like eyes situated between the two main, compound eyes. It is thought that ocelli are used to detect levels of light and darkness.

Bottle Cicada. Cicadas have two obvious, large, compound eyes, and three ocelli. Ocelli are jewel-like eyes situated between the two main, compound eyes. It is thought that ocelli are used to detect levels of light and darkness.

Some naturalists are dedicated to investigating, and recording and analysing, the sounds of nature. Sid Curtis describes on the Nature Recordists forum his investigation into the clicking call of  Bottle Cicadas, using some specialist microphone and and recording gear:

Here in Brisbane the Bottle Cicada is common in our suburban gardens. Like many cicadas, the males all sing at the same time, thus making it difficult to locate any one individual. With just one’s ears, that is. Klas’s so excellent and highly directional Telinga mic and reflector make it easy. They sing at dusk: “Continuous and without apparent variation”, is how Dr Max Moulds author of the book Australian Cicadas, describes it. But that is not all.

During the day they have a very different and far-from-obvious call. Just a few (up to 5) short sharp ‘bips’ over a second or so. Then silence for several minutes. Also very effective in making it difficult to locate the insect by the sound. (And incidentally, using Peak LE software and a Mac computer, I have strung these bips together without spaces between them, and produced their continuous dusk song.)

To locate one during the day, play a recording of the continuous dusk song, and the cicada just has to join in. He won’t keep going for long after you stop the recording, but you can start him again. The dusk song of course is to attract females for mating. The song changes if a female arrives. I surmise that the intermittent day song is aimed at males — to enable each to maintain his personal space. I hoped to test this by concealing a small speaker fairly close to a male and playing a recording of the spaced-out day song. Unfortunately my garden is very small; I’d have to use the garden next door. This was a possibility but the house was sold and the new owners cleared the whole area — all trees and shrubs have gone, and there’ll be no cicadas.

But back to mechanical noise. At one stage someone used a motor-mower with
a whine of just the right pitch to match the cicadas dusk song. And they
joined in!

Now, I’ll need another mystery of the natural world to solve. Luckily, there are zillions more out there!

Aliens lurk in every hedge, cooking up bizarre sounds to intrigue us all.


Also see my earlier post on cicadas here.

Summer singers

A Cherrynose Cicada (Macrotristria angularis), a spectacular, large Australian cicada. I had to capture this one to photograph it so closely, as the males are exceptionally wary when on trees. Its call is a tinkling and reverberating song. The ‘nose’ is actually a postclypeus, which has nothing to do with breathing — it houses the muscles for the feeding system. Photograph R. Ashdown.

Cicadas are amazing creatures. A long life as an underground-dwelling nymph is followed by a wonderful transformation to adult winged treetop dweller. At the moment the air is alive with the sounds of cicadas. As I write this a Clanger (Psaltoda claripennis) is rattling and clanging away on a jacaranda tree on the footpath. Come twilight, the sound of traffic is completely drowned out by the rumbling drone of the Bladder Cicada (Cystosoma saundersii). In nearby eucalypt woodlands the roar of Razor Grinders, Cherrynoses and Double Drummers is truly overpowering.

These are the loudest insects on the planet. The Green Grocer, Yellow Monday and the Double Drummer produce noise intensity greater than 120dB at close range — a sound approaching the pain threshold of the human ear. A large Razor Grinder in full song can cause permanent hearing loss if held close to the human ear (great idea, eh?).

Entomologist Chris Burwell from the Queensland Museum explains cicada song in Wildlife of Greater Brisbane. Designed to attract females, the song of the male cicada unfortunately alerts predators, particularly birds,  to its presence. As a result calling male cicadas usually take flight as soon as you approach them (making them quite hard to photgraph). Calling males often form huge groups, and there is evidence that this ‘wall of noise’ actually repels birds, because it is so painful to their ears!

Their interesting songs, striking appearance and sudden summer arrival (including their mysterious abandoned nymph cases) has brought these harmless insects lots of fans. As a child I marveled over the images of emerging cicadas by the astonishing Densey Clyne, and as a photographer always enjoyed trying to capture them on film – which can be quite challenging. Photographing the emergence of adults from the nymph stage is always fun. This happens under cover of night (although some species will emerge during the day).

While walking at Ravensboune National Park recently we stumbled upon this emerging adult cicada. After watching it for a while we concluded that it was stuck, and had been so for a few hours. Putting aside my ‘don’t interfere with nature’ rule  for a moment, I moved the insect up so that it could grab the branch. Over the next 20 minutes we were transfixed by the entire process — with unfolding wings and the changing body colour, a fascinating transformation.

While walking at Ravensbourne National Park we came across this large emerging cicada. After watching it struggle without result for  a fair while we concluded that it was completely stuck, so we intervened, carefully tilting it up so that it could grab the trunk. Photograph R. Ashdown.

Within ten minutes the cicada’s wings were unfolding and its body colour was changing. This is the third and final stage of the cicada’s life. After emerging from an egg, the nymph climbs down to the soil and spends six or seven years underground. Cicada expert Dr Max Moulds has said that their underground sojourn can take anything from nine months to 17 years or more depending on the species. Photo R. Ashdown.

The cicada’s wings are unfolding as fluid is pumped through the veins. The delicate structures will need to harden before flight can be successful. It is usually several days before the cicada starts singing. Photo R. Ashdown.

The wings are moving with the breeze. By the next day I hope it was joining the raucous and joyful chorus with its mates — such an Australian bush sound. Photo R. Ashdown.

Ecologist Greg Ford has just sent me this wonderful image of an adult Double Drummer (Thopha saccata), photographed at Crows Nest National Park. I’d hazard a guess that our young cicada is one of these — the patterns certainly match, and its colour would have darkened during the day. Photograph courtesy Greg Ford.

Another place, another stunning cicada. This nymph has emerged during rain at Amity, on Stradbroke Island, using a verandah railing as the perfect emergence spot. I back-lit this one with a torch to bring out the delicate wing details. Photo R. Ashdown.

Shimmering new blue wings. Photo R. Ashdown.

For lots of information about cicadas, see the wonderful web work of Lindsay Popple.

Here are some other great links for information about cicadas:

First sounds of Spring

The first humid, warm night in Toowoomba, and a strange, throbbing, continual buzz fills the air.  Toowoomba’s first Bladder Cicadas (Cystosoma saundersii) have emerged.

This is such a common, loud, and ever-present summer song in Toowoomba that I am surprised more people do not comment on the deafening racket that surrounds them on dusk. The calls of the male cicada only continue for 30 minutes to an hour, and fade out as the air gets cooler.

The stunning, large green cicadas reponsible for the sound are hard to track down, as they are fabulously camouflaged, are ventriloquists, and will instantly drop to the ground if you get too close to them. They are 40-50mm in length, and the calling male has an enormously inflated, hollow abdomen. They are found from Fraser Island in Queensland to coastal New South Wales.

Cicada expert Max Moulds reports that there are three colour forms – green, turquoise or yellow, depending on the prescence or absence of two pigments – yellow and turquoise.

Their large hollow abdomen acts as resonant sound radiator, and the song has a remarkable ability to carry great distances with little apparent lack of volume. I have often been lured across paddocks believing all the while that my quarry was in a bush only a short distance ahead.

Max’s wonderful Australian Cicadas, is a must-have book for anyone interested in these fabulous creatures.

Bladder cicada

Closing in on the Bladder Cicada.

25 1 2007 028

Once they select a spot to call from, the male Bladder Cicada returns from daytime hiding to the same location each night. They live for about two weeks.