Like a fly on the wall
Let’s talk zygology; it’s the science of assembling and fastening products, or 'how to stick things together'. I reckon we can learn heaps from flies when it comes to just sitting on a wall. From post-it notes to rivets in a plane, zygology is pretty important to us.
We know that flies have two little “crampons” (toe-nail-claws) at the end of their tarsi, which hook into rough or soft surfaces. We also know they can deform their foot pads into miniature suction cups, but that still doesn’t tell us how they walk up-side-down in smooth surfaces like glass. Turns out they deposit a fatty material as they walk across glass. It's in minute quantities, and that assists them to effortlessly walk over glass.
I like flies – always look at their antics and capabilities. There are so many species, each one doing a different job on the planet:
The common old housefly breeds in rotting vegetable matter - fermenting and moist are key factors. This fly is indeed common and loves to come inside. It loves schools; small humans with sweaty palm-prints create a huge resource of acetic acid, which houseflies love to lick before reproducing.
At this time of the year you often find slightly smaller flies circling the room – often around a hanging light fitting. The go round and round a chandelier for hour after hour. Observant people will note that they actually fly in “squares”, suddenly changing direction in mid-flight. These are lesser houseflies (Fannia canicularis). Their larvae, aka maggots, are associated with bird dung: chickens, pigeons, you name it. They come inside to fly around the lampshade simply to meet a partner – they are “lek breeders”. Male stunt-flying! But all these flies can simply land on the ceiling upside-down with their great technology.
Even the cranefly – a large skinny “daddy long-legs” fly can move with great elegance and precision. You often see them sitting on a vertical wall, two wings stretched out and six long legs pointing in all directions of the compass. If you look really close you can see their “halters”: slender stalks with a terminal knob. These are actually the modified hind wings of flies; these knobbed stalks gyrate when the fly is flying. It provides stability in flight, allowing them to land on all sorts of surfaces, even up-side-down.
Blowflies are also common this time of year: maggots recycle dead meat/protein. Always good to see many of them when you have traps for Predator-Free-New-Zealand! A sign it’s working. Notice that when you are cooking with the kitchen windows open, how blowflies scream into the kitchen, looking for the cooking meat. If you raise your hand immediately, they’ll be able to find the open window and fly out. If you wait with waving more than – say – 5 seconds, the fly will have lost the ability to back-track. Is that indicative of their brain-attention-span? Or simply their spatial memory? If so, then it’s no use wanting to be “a fly on the wall”!
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