Hoverflies are amazing little insects and they do so much good, which is why they are the beneficial insect I will be talking about in this Beneficial Bugs article.
Hoverflies, a.k.a. Flower flies and syrphids (their scientific family name is Syrphidae) are—as you might have guessed—flies that are often seen hovering around flowers. There are roughly 6000 species found all over the globe, so it is no surprise that there is much variation in their appearance and their behavior. Like all other flies (well, those with wings anyway) hoverflies have two wings, one on either side of their body, and can be easily distinguished from other fly families by looking at wing venation — if you are into that sort of thing.
Many hoverflies are wasp and bee mimics, being brightly colored with stripes, and spots, and alternating bands of yellow and black or brown that cover their bodies. I can almost guarantee that you have run away from an insect you thought was an angry wasp when it was really a harmless hoverfly — me included. They have evolved to look the way they do for this very reason; predators don’t want to get stung either. Many predators learn not to catch yellow and black stripy things, thus flies that are black and yellow would be avoided.. As the flies are harmless to humans and other predators, this Is known as Batesian mimicry — mimicry that’s meant to make them look like they are dangerous, even though they are not.
Most have a standard life cycle for a fly — egg, larva, pupa, adult. Most eggs are laid on land but some (those of the rat-tailed maggots, for example) are laid in the water. The larvae feed on a variety of foods, with some preferring to scavenge for decaying animal and/or plant material, while others are predatory insectivores that feast on plant-sucking insects, such as aphids and thrips. This is one of the ways in which these flies can be very beneficial — they provide amazing biological control in your gardens.
The adults have a very different diet and are, in fact, some of the world’s most important pollinators — they are thought to be second only to native bees. Many hoverflies are generalists and will visit a broad range of flowers, including agricultural crops, while some appear to be specialists and visit only a very narrow range of plants. There are several companion plants that you can include in your own garden if you want to increase the number of hoverfly visitors you get: chamomile, yarrow, buckwheat, parsley, statice, and Alyssum species.
Overall, hoverflies prove to be beneficial insects in both their larval stage and their adult stage by performing pest control for us in our gardens as larvae before growing their wings and moving on to help pollinate your flowers. So, try to take a moment to observe the yellow and black stripy insects you see in your garden, it’s likely you have many hoverflies from multiple different species helping to pollinate your flowers all summer long.
Read more articles in the Summer 2024 CSWCD Newsletter.
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