A touch of light: false moons over Mparntwe

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By MIKE GILLAM

Photo © Mike Gillam 

Following the drought-breaking December rains, swarms of insects tunnelled to the surface after months of subterranean bondage. Birds sang in praise and the pores of the saturated earth opened.

Ant and termite alates emerged on the first and second days of the event, trusting on significant rainfall, critical to the establishment of new colonies and the practical ease of digging new nests.

Those of us who routinely look to the skies would have noticed the aggregations of kites and crows circling above invisible vortices of flying insects. Competitive crows always make their presence felt when food is in the air.

Flying ants and termites hardly seem worthy of a raptor’s attention, yet predatory kites expend little effort as they ride the thermals, snatching up the queens in their talons and devouring them on the wing.

I’ve taken thousands of images of insects flying blindly around lights, captured in their irresistible thrall, expending energy in a pointless whirling, a spinning dance of death that consumes billions. In my imagination these lights are weapons of mass destruction, ice pipes for insects, no less.

For the detached viewer, the images are as beautiful, hypnotic and poetic as any mass suicide can be. They fail however, to show the immense scale of the carnage, the unimaginable waste of biological potential. Hawk-moths, the promise of future generations of Yeperenye caterpillars, are frequently among the victims.

This awakens the anarchist in me and I suppress the urge to smash these false moons: to free the legions, allowing them to fulfil their life’s true purpose; to break out of the ground after a lengthy period of stasis, to smell the fresh rain, to fly into a starlit sky, to drink the nectar of the native passion-fruit, to strive all night until sunrise, to search out a mate, be chased by bats and prevail or not, to lay eggs and finally, their life force spent, to succumb to exhaustion and scavenging ants.

An existence that is short and frenetic, that’s true, yet their triumphant stories, their egg sites and ceremonial grounds are the subject of time honoured legends vibrating on the air and beneath our feet.

I’ve tried various techniques to convey the sheer volume and energy of this spectacle and settled on mercury vapor lights for their photographic advantages and the invertebrate hell they often create. If you look closely you will see that many of the moth shapes are arranged in sequences, recording the arc of each flying moth and its wing-beats exposed by the light during the length of the exposure.  

Herein lies a clue to the lighting and shutter speed I selected for the image chosen for this week’s post. Mercury vapor lights flicker at a rate that ordinary mortals don’t notice. The shutter speed I selected was ¼ second and this has recorded the flight of individual moths at approximately 15-16 wing beats during the length of the exposure, the lighting provided not by a flash but by the rapidly flickering light source.

This suggests the mercury vapour light that proved so attractive to the cloud of flying insects swirling over an Alice Springs car yard was rated at 60 hertz. Conversely, if the viewer knew the hertz (cycles per second) of the light source I’d selected, they would be able to count the exposed wing beats and ascertain the shutter speed I’d used.

From street lights to car yards and suburban porches, we use bright night lighting with complete disregard for its destructive effects on urban wildlife. Do we really need to leave that verandah light on all and every night so that potential burglars can better see what they’re doing in the rare event they actually choose to intrude?

Town lighting sucks insects from the surrounding bush, from the river, the foothills and the mountains, in numbers so vast they can only be imagined in the tonnages.

Next morning, we spray the ant swarms and the prowling Irlperenye (stink or green tiger beetles) attracted to the dead and dying insects in the mall, the atriums of luxury hotels and shopping centres. Car yards must also believe it’s worth the effort to use high intensity lighting to illuminate their cars for perfect night viewing by prospective buyers.

They certainly pay a high price of collateral damage in the mass of dead and dying insects that cover their sparkling Duco, much to the chagrin of the long suffering car detailer.

While it may not be perfect for showing off products, yellow lighting is the friendliest option by far, the colour that interferes least of all with the behaviour of nocturnal insects and a time saver when it comes to managing the collateral damage or ‘pests.’

Yellow LEDs that fit bayonet or screw mounts must surely be available locally, at all good lighting suppliers.

 

Recently in this series:

A touch of light: waving at dragons

A touch of light: Gryllacridids in the Gidyea

The complete series is collected in our Features section – see the menu bar on the home page

6 COMMENTS

  1. “Do we really need to leave that verandah light on all and every night so that potential burglars can better see what they’re doing in the rare event they actually choose to intrude?”
    This remark brings back some memories – some three decades plus ago I lived at the (now former) CSIRO field station but worked next door at the Arid Zone Research Institute.
    Both places had security compounds for their respective vehicle fleets, pretty much the same distance away from the Stuart Highway (about a kilometre).
    Security lighting was installed at the AZRI compound while the CSIRO’s remained in darkness each night.
    No prizes for guessing which compound was plagued with break-ins, vehicle damage and thefts.

  2. The real problem is the growing numbers of young offenders who simply don’t care if the place they are going to vandalise or rob is lit up, or under surveillance or not.
    Not just in Alice but everywhere around Australia. Last weekend in Canberra a friend of mine who lives on the premises at his own panel beating business in Fyshwick was woken from sleep at 4am by thugs who broke in to a fully lit yard, tried to steal vehicles and tools then brazenly swaggered into the night.
    Yesterday a gang of young thugs bashed a 44 year old family bloke who went to the aid of a female they were bashing in Ron Andrews Park in Pakenham. It is a public park where there were plenty of witnesses in broad daylight. But they just kept beating and kicking him for several minutes before sauntering away.
    Young offenders simply do not care. It is a worrying youth behavioural cultural thing that is unprecedented and needs to be addressed as a cultural reality, not simply one-off criminal acts by youth from disadvantaged backgrounds.

  3. Yes, you are correct of course, young offenders do not care or even think about consequences. And what are the consequences?
    Nothing serious.
    Let out on bail. Ankle bracelets were supposed to be the answer.
    Well, if they are, why don’t they get applied?
    I don’t care if they are juveniles, if you do serious offending, bail should only be given providing ankle bracelet are fitted.
    Cut it off, extend the sentence more.
    Tired of hearing about offenders doing more crime while out on bail.
    Serious juvenile offending seems to be everywhere now.
    When did you ever see or hear of a 10 to 12 year hold up a shop keeper with a knife back in the day? Spit on people or call them white c’s … just so they can start something.
    Car theft is huge. Don’t come here on holiday unless you hide your keys.
    Government is a total joke. Will go down as worst the NT ever had.
    Figures will prove it.

  4. Oh crikey, I wasn’t intending to open the floodgates to diatribes about youth issues – such comments are completely off-topic for this latest contribution from Mike Gillam. My earlier comment was meant to be a bit whimsical.
    Returning to Mike’s theme about the fatal attraction of bright artificial lights to myriads of insects, I recall another memory from long ago – this time from the early 1970s when our family was resident at the AIB Farm (AZRI).
    When Radio 8HA commenced operation in 1971 – straight across the Stuart Highway opposite the main entrance to AZRI – a big bright sign was erected by the new station.
    My father was adamant this was a boon for us as all the local moths were drawn to the sign leading to less insect infestations of our gardens!
    Occasionally I’ve observed micro-bats take advantage of swarms of insects attracted to floodlights, it’s fascinating to watch these incredibly agile creatures plunging through smorgasbords on the wing.
    This happened at a new house 30km west of town when I lived there for awhile over two decades ago.
    The outdoor energy-saving fluoro lamps attracted hordes of insects, in turn enticing geckos, frogs, and sometimes micro-bats under the verandah eaves.
    That’s when I noticed the bats appeared not to rely on sonar for hunting insects if visible under lights, as I frequently observed them fly into poles and walls.
    On one occasion a bat flew through an open door into the laundry, struck the wall and dropped straight down into open top-loader washing machine!
    I immediately rescued the bat from the warm soapy water, rinsed it off, and hung it by its claws to dry out on a towel (this was in the days before anyone heard of lyssavirus).
    While incapacitated, another little bat kept vigil nearby and I could just hear them communicate in very high-pitched (to me) squeals. The second bat was not deterred by my presence at all.
    When the first bat dried out they both flew off together.

  5. Hi Mike. In Birdsville one morning I smelt before I saw mounds of something under street lights.
    Water beetles from the flooded Diamantina river had gathered under the lights overnight.
    They stunk like pigs and had piled up about half a metre high around the poles.
    The “collateral damage” was being scraped up and dumped into a tip truck by a council bobcat.

  6. Thanks Alex, for diverting the “crime wave” while I was out bush.
    And David for his observation that certainly enlarges the scale I’ve witnessed, wheel-barrows and gerni’s certainly but bobcats … that’s amazing. What a waste, both ecologically and fiscally.

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