Five reasons flies are awesome (despite being really annoying)

By Nikki Galovic

2 January 2018

macro close up of a fly's head

It’s a warm summer afternoon and you have everything set-up for a lovely afternoon in the great outdoors. You’ve got a cold drink in hand and the smell of sausages sizzling away is making you hungry. You fold out the camp chair and dust of the cobwebs, ready to chill out. Just then, the all too familiar buzz of a fly echoes in your ear. And so the onslaught begins. You swat and they just come back, gluttons for the punishment of your lazily swiping hand.

Sure, they’re a nuisance. But flies get a bad rap and we’re here to try and convince you that they could in fact be seen as the true heroes of the Aussie summer.

Why flies swarm when it’s warm

It might seem that insects choose to annoy us over the summer but the real reason for their population boom is a complex interaction of winter rainfall, availability of food sources and increasing temperatures.

Insects are ectothermic, or “cold-blooded”, meaning their body temperature depends on the external environment. So in summer an increase in temperature typically correlates with an increase in insect activity.

Many insect species emerge from a winter resting phase in spring and summer to begin their winged adult life stages. These highly mobile, hungry, sex-obsessed young adults are the ones that interact with us over summer. Imagine schoolies’ week for insects, lasting an entire three months.

Check out this blog post for more info on why summer is the hot month for insects.

Now that we know why they bug us in summer more than other months, it’s time to ask: flies, huh, what are they good for?

Smooth pollinator

a fly on a yellow flower

Both biodiversity and food security depend on pollination of native plants and crops.

Most of the ingredients in that summer BBQ you were about to tuck into were probably grown thanks to insects. When you think of pollinating insects you probably think of bees or maybe even butterflies. But flies are actually the unsung heroes of pollination, pollinating plants at least as well as any honeybee might. Honeybees actually pack the pollen away in special baskets on their legs which mean the pollen grains are not available for pollinating the next flower. Flies don’t have the baskets, so all the pollen that gets stuck on the hairs on their body is available to pollinate the next flower.

“Horseflies are great pollinators because they’re so hairy,” says Bry the Fly Guy, also known as Dr Bryan Lessard of the Australian National Insect Collection.

“Recent research from University of New England shows the common blow fly can carry more pollen stuck to its body than a honey bee,” he says.

“It’s true that female horseflies will take a blood meal now and then because they need the proteins in blood to ripen their ovaries. Most of the time they feed on flowers, but exactly what they pollinate is a bit of a mystery,” he says.

And it’s not just the food on the table you have flies to thank for. Flies also help to pollinate hops in beer, apples in cider and grapes in wine. Cheers!

Flies for food

close up of hands folding fly larvae

Could this be the livestock feedstock of the future?

While you might find flies maddening, lots of animals you love rely on flies for their food. Birds, lizards and frogs all enjoy chowing down on tasty flies (as does my dog). So we know insects already play an essential role in the web of life, but new research shows they could be doing even more. While you might not want them spewing on your snag, they could be the food that fed the pig to make the snag.

We might not be quite ready yet in Australia to be eating insects ourselves, but we could instead feed insects to our farmed animals to feed to our growing population instead. Researchers have demonstrated that black soldier fly feed could partially or completely replace conventional agricultural feed. Studies have shown that this feed is suitable for the diet of chickens, pigs, alligators and farmed seafood such as blue tilapia, Atlantic salmon and prawns with no adverse effects on the health of these animals.

Read more about feeding our growing population with flies.

Eat shit and fly

Flies quite literally eat poo but they also clean up other waste too, helping clean-up after us humans.

They can eat our household waste and divert it from going into landfill. The black soldier fly, for example, can have up to 600 larvae, with each of these quickly consuming half a gram of organic matter per day. This small family can eat an entire household green waste bin each year.

Flies act as scavengers consuming rotting organic matter so we don’t have to deal with it which is a very important role in the environment. If it wasn’t for flies, there would be rubbish and dead animal carcasses everywhere. A lovely thought to mull over while you’re grilling. Flies turn poo and rotting carcasses into stock feed, and live bird, frog and lizard food for free. Pretty cool if you think about it.

Medical maggots

close up of a green bottle fly

Green Bottle Fly, Lucilia sericata. Credit: Calibas, GNU Free documentation license.

Speaking of eating rotting stuff. Ok don’t freak out but maggots can be used to treat gangrenous wounds without using antibiotics. The first recorded use of maggots for wound cleaning was on soldiers in the American Civil War.

Sheep blowfly larvae can be used to treat diabetic ulcers, bedsores and other wounds by applying them to infected area. The larvae eat the infected tissue, cleansing the wound with their antibacterial saliva and speeding up new tissue growth.

Do not try this at home though. Patients that undergo maggot treatment are supervised by “maggot nurses” who monitor the progress of the insect wound cleaners. And after they’ve done their work, the larvae simply fall out.

Find out more about maggots and other animals that have medical uses.

They’re bootiful

Some flies are downright gorgeous. Take, for instance, the Lecomyia notha soldier fly from Queensland. Its exoskeleton is shining purple, and looks a bit like an opal galaxy.

A few years ago, our resident fly expert Bry the Fly Guy was studying in the Australian National Insect Collection in Canberra going through some of its 12 million insect specimens. One with a bright, golden rear end — which is actually its abdomen — caught his eye. He knew it was a new species right away and named it Plinthina beyonceae, after none other than Beyoncé.

beyonce and the Plinthina beyonceae fly

They fly with the golden booty named after Queen Bey

We know they’re frustrating when you’re trying to enjoy your time in the sun. But next time you go to pull out the swatter, spare a thought for the many awesome things flies and all insects bring to the ecosystem.

Australia’s biodiversity is a national strength. Our country is home to more than half a million species. Three quarters are found nowhere else on Earth. Our biodiversity gives us countless benefits like clean water, crops and tourism. These are benefits we need to monitor and conserve.

Plenty of flies on us

Our National Research Collections Australia contain 16 million specimens, from fish to insects to microalgae to birds. These collections are a valuable resource for research and contribute to protecting our biodiversity.