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Flies are not a Curse

By Alan Hewett, Trust For Nature Covenanter

Flies! This year after all the wet weather they are peskier than normal. They drive us to distraction. They love to hang around humans because they feed on secretions from our eyes, mouth and nose and on our sweat. We consider them a threat to our health but they perform an important ecological function as nutrient recyclers and pest predators.

There are seven thousand native species of flies currently identified and many play an important role in attacking pest insects in our gardens. Robber flies eat bees, wasps, dragon flies, grasshoppers and spiders. Tachinid flies parasite the larvae of moths and butterflies. The Hover fly has black and yellow stripes and is often mistaken for a wasp or bee. They feed on nectar and pollen and their larvae eat aphids, scale insects and thrips.

Maggots get bad press too. But they should not be dismissed. They decompose any organic matter and recycle it into essential nutrients that are accessed by plants, animals and fungus.

However, it is as pollinators that flies play a more important role. While honey bees are the main pollinators of plants and flowers, they are under increasing pressure from disease and pollution. Therefore it will come as a surprise that pollination by flies contributes about $six billion to the Australian economy and a staggering $two hundred and fifty billion to the world economy.

A survey of Mango farms in North Queensland recorded that a honey bee transfers an average of 2.7 pollen grains, compared with the blue blowfly that transfers 6.8 grains. Not only are the flies more efficient but they visit the tree more often. Growers could achieve better yields by actively attracting more native species of fly.

Still not convinced about the value of flies? Consider this,without flies we wouldn’t have chocolate – really. Chocolate comes from the cacao tree. The flower of this tree, while small is complex in design and behaviour. Only a special kind of animal can pollinate it, and these are midges, tiny flies the size of a pinhead.

Pollinator conservation is important to ensure food security, maintain our native plants and trees and keep our gardens healthy. Despite their reputation, flies play an important part in this as well as biological control and waste decomposition. Great contributors to biodiversity.