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Understanding Underrated Flies
Hoverfly. Myriam Zilles photo
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Understanding Underrated Flies
Nicole Köhler photo
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Understanding Underrated Flies
Virvoreanu Laurentiu Photo
Although life takes a seemingly endless variety of forms, the land lubbers of Earth share some basic experiences that bind us all together.
Among the most obvious, we tend to interact (and exchange gases with) the atmosphere, develop strategies to help weather seasonal temperature differences, and/or look to the sun for help with sustenance either directly or indirectly. We’ve also more than likely all come into contact with a fly. This is because flies are everywhere—in just about every biome, both indoors and out, flies are around to lend their characteristic drone to the air. Flies began their evolutionary journey over 200 million years ago, and so they’ve had plenty of time to specialize into the over 100,000 species catalogued today. Unlike bees, wasps, butterflies, and other flying insects relying on two sets of wings, the back wings of flies actually morphed into highly developed sensory organs that help them perform flips, barrel rolls, and other complex flight maneuvers. This gives these backyard mavericks the ability to perform a wide variety of dangerous jobs that would mean certain death for more clumsy fliers. In such a diverse group of animals, it’s unsurprising that some species will find themselves in close proximity to humans. This has allowed for a few bad apples to spoil the bunch when it comes to their reputation. Although a few species are known pests to plot and person, the vast majority of flies are indispensable members of the natural world.
The flies that tend to create the most human criticism are those of the carrion persuasion. These creatures lay their eggs in rotting flesh or animal droppings, where they can then pick up harmful pathogens. Although you definitely do not want large populations of these flies around your house or picnic, the benefits of carrion flies are nothing to sneeze at. These creatures play an important role in breaking down and recycling the dead animals and steaming piles on which they feast. Irritating as they can be, I would certainly rather share my space with a few of these flies than with an abundance of their favorite foods. Even though carrion flies aren’t readily drawn to most flowers, some plants have developed special blooms to help entice them for a helping hand in pollination. These fly magnets tend to mimic decaying meat through dark colors and even funky smells. Pawpaw trees are an excellent local example, which use specialized flowers to attract their favorite carrion fly and beetle pollinators.
“Ravenous corpse, trash, and poop eater” is the most readily distributed description of a fly, however most flies would probably be horrified to discover they’ve been tossed into that mold. There are many flies who do just the opposite in their young forms—instead of relying on inert food, large groups of flies instead feed on living prey in order to get the required nutrients they need to grow. Hoverflies, often adorned with black and yellow colorations that help them mimic bees and wasps in order to avoid predators, are common figures in a healthy landscape. Adult females are highly sensitive to scents, and are able to hone in on the smell of large congregations of aphids as they feed on plants. In some situations, the stressed plant also releases chemicals that serve to attract hoverflies as well. Upon finding a suitable aphid party, the fly will lay an egg or two nearby. Upon hatching, these young flies are estimated to consume over 100 aphids before transforming into their adult forms. In most cases aphid populations can be controlled by hoverflies alone. Their benefits to a garden are not lost there, however, as they then add to the multitude of adult flies constantly visiting flowers for a drink of nectar. Even though they usually aren’t covered in as many hairs as bees, flies visit so many flowers during the day that scientists believe them to be incredibly important pollinators, second only to bees in their pollination potential.
Flies normally don’t get the credit they deserve for their services to our environment. You can help—as you tour your landscape this growing season, turn the typically negative “shoo fly” into an encouraging “woohoo, fly!”
Plants for Flies
Some flies specialize in visiting specific flowers, like the chocolate midge, the only known pollinator of the cacao tree. Most flies are generalist floral visitors, though, which means they can usually make do with whatever’s in bloom at the moment. There are some general steps you can take to make sure your garden attracts as many flies as possible, in order to reap the benefits of their presence such as pest control, pollination, and nutrient recycling. Like other pollinator or wildlife gardens, design in a way that ensures a plant is in bloom at all times during the spring, summer, and early fall. Flies tend to have stubby mouthparts, and so they prefer shallow and easy to access flowers to feed on. Aster, sunflower, yarrow, carrot, and fennel are all examples of this type of bloom. Many of our small weedy flowers like bittercress and chickweed are also attractive to flies. Avoiding pesticide use is also important, especially for hoverflies and other predatory species which look for pest populations when deciding on whether to move into an area or not. Leaving populations of aphids and other pests untouched for a season or two is usually enough to attract hungry predators.