My brother the twitcher has taught me the secret of finding birds. Tune into sound: let your mind move out from the place where you are standing, into the space above you and all around you and listen.
All this summer, I’ve been listening out for the sparrowhawks. Even lying in bed or sitting on the sofa, we could hear them begging for food or squabbling with the local cockatoos.
But come mid December, white noise and static started interfering with Radio Sparrowhawk. The cicadas had arrived.
This year’s a biggie for cicadas in Australia. Over 350 species of cicada have been described here, though there could be many more – we’re a diversity hotspot for these charismatic insects. And this summer, some of the biggest and noisiest species – the cherrynoses, the double drummers and the razorgrinders – have appeared en masse around Sydney. After maybe five or six years of living metres underground sucking on the tree-sap, the cicada instars crawl out of the earth and shed their exoskeletons for a short and noisy month or so as adults. It doesn’t happen every year. 2013 was a big year for cicadas in Sydney, and before that 2010. And now it’s on again.
Black Prince on a casuarina tree by the edge of Berowra Creek
No-one knows quite what triggers the horde of insects. In fact, no-one knows much about cicadas at all, despite their presence on every continent except Antarctica and their impossible to ignore, earsplitting calls. That long and decidedly boring youth, and the uncertainty about when they’ll re-emerge, makes researching them tricky. Imagine deciding to study the periodic cicadas of North America and then realising your three years as a PhD student would be over long before the seventeen years the critters spend underground was up?
An ex cicada thanks to the local orb spiders
One theory is that by appearing so infrequently and irregularly cicadas could avoid the predators – bird, bats, all sorts of mammals – keen to feast on the insect bounty. Very weird recent work from the US suggests that numbers of predating bird species start to drop around twelve years after the last cicada boom. Could it be that these devious insects are manipulating the beasts far higher up the food chain?
Razor Grinder in our front yard
Double-drummer in Berowra Valley National Park
In some ways, despite its wealth of cicadas, Berowra is less interesting for researchers than bits of Sydney not surrounded by national parks. Australia cities are unusual, it seems, in that they still have cicada species in the heart of suburbia. Silver princesses and green grocers survive in quite urban areas on the east coast. A local researcher (plants by day, cicadas by night) Dr Nathan Emery has been trying to work out how these species have survived, and whether there are others that can cope with city life. He’s set up the Great Cicada Blitz, a citizen science project crowd-sourcing information about when and where various species of cicadas can be found.
I’ve had a great time over the last month wandering around recording the din in our neighbourhood and trying without a lot of success to spot the earbleedingly loud cicadas to add to the Blitz database. The male cicadas’ strategy to collectively produce a chorus so loud it hurts the ears of birds works on humans too, even those with the advantage of being partially deaf already. Apparently even the males cicadas “switch off” the equivalent of their ears (their tympana) to save their own hearing.
Thanks to helpful tips from the experts as they confirm my dodgy IDs, I’m slowly learning how to identify the common species around these parts. Nathan Emery’s nifty little book A Photo Guide to the Common Cicadas of the Sydney Region has been really handy too. It has a lovely introduction from (and is dedicated to) Dr Emery’s scientist dad who took him and his siblings out cicada spotting as kids – inspiration to continue tormenting my offspring with my nerdy passions. And who wouldn’t be nerdy about cicadas – an animal whose wings has in-built nanostructures that literally rip bacteria apart…
Graphical abstract for Aaron Elbourne, Russell Crawford and Elena Ivanova’s 2017 article “Nano-structured antimicrobial surfaces: From nature to synthetic
analogues” Journal of Colloid and Interface Science 508 603-616.
Shouldn’t EVERYTHING have a graphical abstract?
I should also thank the popularity of the big liquidambar in our front yard with the local insects for the chance to improve my cicada identification skills. Adult cicadas like to latch onto thin-barked natives, but if push comes to shove they will feed on introduced trees, and liquidambars seem to be a favourite, of our local population of redeyes at least, although I think I’ve also heard calls from local tibouchina and robinia trees, as well as the local Sydney red and blue gums.
Red eyes in the neighbour’s pittosporum undulatum
A razorgrinder (or a eucalypt) “leaking”
Loads of razorgrinders on a sydney red gum at the edge of Berowra Valley National Park
Though some cicadas don’t seem to be too fussy about the trees they sup from, you have to worry for the next generation. In the last year, 15,000 trees – 3% of the tree cover on private land in Hornsby Shire – disappeared, thanks to a rash of tower buildings replacing the old fibros with rambling jungly backyards that used to hug the railway line. Next gen cicadas popping out about 2023 may find nothing taller than a cordyline to sing from and property developers taking over their traditional role local bloodsucker.
An exoskeleton clinging to the bark of a tall tree in a local school
I’ve not seen any green grocers or yellow mondays or silver princesses around here. There are double-drummers in the national parks down the road – they don’t do so well in back gardens, needing an expanse of acreage or bushland to survive. And so far we’ve heard at least four species around our yard: razorgrinders, black princes, floury bakers and the locally ubiquitous redeyes.
One of a whole bunch of redeyes high up in a Sydney red gum raining down excess tree sap on me
How do I know the red eyes are one of the most common cicadas around these parts, even before I started collecting photos and audio? Well, that’s the gossip from the local kids.
Cicadas weren’t a feature of my childhood, growing up by the River Murray in South Australia. But they’re a big part of children’s lives around here. Even the common names of the local species are courtesy of kids, which explains why they are named after colours or days of the week and not dead white European men as per normal service!
A razorgrinder, with black and white patterns on its wings
A dead red eye, I think, judging from the heavier black lines at the end of the wing.
My younger daughter (Anonymous Bob as she wants to be known) gave me the low down on what Berowra kids know about cicadas:
“At school in the cicada season, when the teachers aren’t looking, people climb the trees to try to catch cicadas. They climb the big thick trees because that’s where you find them. The main cicada zone is the little mossy grove next to the library. We treat them like exotic pets and look after them, until they want to be free or they die.
Once, there was a little boy. An older boy gave him a cicada to look after – it was sort of like an adoption. But the little boy decided to let him go so he could be free.
Another time, a bunch of kindies robbed a guy of his cicada. It was freshly caught and it had one leg missing, so he was desperate to protect it. They wanted to call it Princess and he wanted to call it Jeffie. They threw a ball at it while it was clinging to his shirt. It nearly fell off and died. And then the kindies started chasing the guy saying “Princess! Princess!” and then they had an attempted robbery but then a teacher came.”
“It’s fun to look after the cicadas. They’re kinda cute. Most cicada collectors try to find other species because in our school the redeyes are the most common. We find what they eat and take care of them. The cicadas cling onto your clothes which makes them pretty portable pets.”
Red eye at our place
“A while ago we did a thing where we would prank the teacher with cicada shells. At first it was just a joke and then it became a whole fiesta. It became a game and a compulsory activity. Not that the teacher said it was a compulsory activity, we just made it one.
Originally it was just seven cicada shells a day but it ended up with many many many shells from each person. We gathered cicada shells, and every day we would leave cicada shells around the classroom and she would have to find them.”
A very popular grapefruit tree in my neighbour’s garden
“We found the cicada shells everywhere – on plants, on trees, on everything. A few boys were the main gatherers. They did it at school, home, everywhere. They came in with huge plastic bags full: they were the main source of our cicada shells. Sometimes we used white out and sharpies to paint war paint onto the cicada shell to make them unique.
Graphical abstract of cicada exoskeleton on teacher’s key ri
You know how cicada shells have a slit? We slipped that onto the teacher’s key ring and when she found it, she was like “Not again!”. We started making a joke that she was cursed by the demon of cicadas.
At the very end of the year a few of the boys laid the cicada shells in a big love heart on the carpet and put a huge pile of chocolates in the middle and wrote their names on a card with love to the teacher.”
The love for a teacher expressed in the language of cicadas
Maybe there’s another project to be done on cicadas – a children’s natural history of these rowdy, charismatic insects…
Do you have any stories of childhood exploits with cicadas, in Australia or further afield? I’d love to hear them!
