Flies: More than meets the eye
“Look deep into nature, and then you will understand everything better” (Albert Einstein)
It’s a warm summers day, the BBQ is sizzling, the salads look scrumptious, you’re relaxed sipping on a bevvy watching your mate fry up a feast. Then like clockwork, they arrive, the pesky flies buzz around your head land on your food and proceed to poop and vomit all over it. Great. But, is this all flies do, did they evolve with one purpose, to annoy us? What use are flies to the world?
These questions matter as we continue to lose biodiversity at an alarming rate and it makes me consider the value we place on animals that annoy us, or we find vulgar and unattractive. In the wise words of ecologist E.O. Wilson, he argues
that every scrap of biological diversity is priceless, to be learned and cherished, and never to be surrendered without a struggle.
So how do we accept and even appreciate the humble, often disgusting, fly? Perhaps by digging a little deeper into the life of flies we learn these little insects do us more good than harm.
The good, the bad and the ugly of flies
Let’s start with the harm. Flies are well known for their spread of germs as they feed on decomposing animal and plant matter then prance all over our food potentially transmitting pathogens that can make us sick. Flies aren’t equipped with teeth or a munching jaw, so they spit on their food helping them dissolve it for easy eating. You say yuck, I say fascinating (note to self however, definitely don’t leave food around to be pooped and spat on by flies).
But with every dark cloud there is a silver lining, right? Absolutely. Some flies are leading the way in cancer research while others are protecting our food crops. Yes, the pesky house fly is a nuisance and can transmit germs. However, there are many hundreds of species of fly in Australia doing remarkable jobs, some of which are of great benefit to us.
Cue the not so hideous ‘flower flies’
A case in point, is the hoverfly. I am quietly obsessed with these little, two-winged insects mimicking bees and flying like a helicopter, what little legends. In an amazing evolutionary phenomenon, hoverflies have taken on the black and yellow patterning we tend to see on the European Honeybee. A very neat trick to keep potential predators at bay.
Just as helicopters manoeuvre forwards and backwards so does the hoverfly, seeking out flowers through visual cues and their sense of smell.
Hoverflies work hard for a living
Hoverflies eat nectar and pollen just as butterflies and bees do. In doing so, they are important pollinators and perform a critical role in ecological communities spreading pollen between flowers enabling our native plants (and food plants) to replicate and flourish particularly when there are fewer bees around.
For the gardeners out there, you will know the dreaded plant-sucking destruction of the aphid. A small green bug that can wreak havoc in gardens and agricultural crops. As it happens, hoverflies really shine when they are in their larval stage (#maggots). As they are voracious and important aphid predators, they even have a special name for this: ‘aphidophagous’; try saying that ten times. A very handy and safe form of organic pest control.
Telling the difference between hoverflies (top) and European Honeybee (bottom): look for a single pair of wings on the hoverfly (two pairs for bees) short antenna (long on bees) and characteristic ‘flylike’ compound eyes – think Bono in sunnies. (Photos by Christina Renowden)
So next time you swipe at a fly, don’t put them all in the disgusting basket. Perhaps shift your perspective and spare a thought for the diversity of flies and their unique ecological roles in pollinating native plants and keeping our gardens and food crops and healthy.
Rodríguez-Gasol, N., Alins, G., Veronesi, E., & Wratten, S. (2020). The ecology of predatory hoverflies as ecosystem-service providers in agricultural systems. Biological Control, 104405.