Flies: The Unsung Heroes of Pollination

When people think about pollinating insects they usually think of honey bees first and then other insects like butterflies and bumble bees after that. They don’t always consider lesser known pollinators like moths, beetles, and the focus of the blog today: flies. According to university research flies are actually the second most important group of pollinating insects behind the bees. As members of the order Diptera, all flies have only two membranous wings. This helps to separate them from other insects like bees, wasps, and beetles. Diptera is an ancient group and a very diverse one; there are over 160,000 species of flies across planet Earth and many of those species will visit flowers and help to transfer pollen.

Tachinid fly, Archytas sp., IMO405 (2).jpg
An adult tachinid fly drinking nectar. As maggots tachinids are parasitoids.

Most flies that visit flowers do so in order to obtain nectar for their high energy needs. Nectar is filled with sugar and can help to fuel flies as they zip around to find mates or egg-laying sites. Flies are coated in thick hair on their body and pollen often sticks to it. This is very similar to what happens with bees when they visit plants. When flies purposefully visit a plant to gain nutrition it is called myophily. Several groups can exhibit this behavior including bee flies (Bombylidae) and hover flies (Syrphidae). Other flies are tricked into becoming pollinators. In a system called sapromyophily, flies like house flies and bottle flies that are normally attracted to dung or decaying animals are duped by plants into visiting their flowers. These flowers are often red or brown in color and produce strong smells that mimic dead animals to lure flies to them. Once inside of the flower, the fly quickly realizes they have made a mistake and leaves, taking a load of sticky pollen with them.

Syrphid Fly, Syrphus ribesii, JAK104 (2).jpg
A hover fly visiting a flower

Some of the fruits of flies’ labor that we enjoy include chocolate, mangoes, parsley, carrots, paw paws, and pears! If you are creating a pollinator garden to help conserve bees, you will inadvertently be helping the flies as well. Flies and bees both enjoy open, bowl shaped flowers that are yellow, blue, violet, or white. We’re still learning about the complex relationship between flies and flowers, but please remember the forgotten fly when you think about all the other great pollinators that are out and about in your landscape.


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