This June, we are diving into the world of pollinators all month long to celebrate Pollinator Week (June 18 - 24). When we think of pollinators, the first creatures that come to mind are typically bees or butterflies, bustling among flowering plants to feed on pollen and nectar. This association is totally appropriate, but bees and butterflies don't capture the whole story of pollination. Our ecosystems rely on a variety of non-butterfly and non-bee pollinators, many of which are under appreciated or overlooked entirely. Among these other important pollinator groups are the often highly unpopular, even reviled, flies.

Yes, you heard that right! Flies may be widely associated with things we'd rather not think about - feces, rotting meat, and garbage to name a few - but they pollinate flowers and play a number of other vital roles in our environment. In fact, flies join bees as a group of insect species full of surprisingly effective pollinators. In this article, I will share some of the amazing things that flies do for our ecosystems, introduce us to a handful of fly pollinators, and make a case for why you should try to attract flies to your own yard.

 

So Wait, How Are Flies Pollinators?

Flies are much more than the nuisance insects we often dismiss them as: they are, in fact, crucial players in the world of pollination. Flies visit flowers more frequently than you may realize. But how exactly do these tiny creatures aid in pollination?

Flies are opportunistic feeders and can find sources of food in many different places. Like all animals, flies need sugars and proteins to get through their day. Just like their very distant cousins - the wild bees and other better-known pollinators, adult flies will regularly visit flowers to feed on nectar and carry pollen along as they zoom about their day. Most species of flies are extremely hairy and - just like many bee species - in the process of moving from flower to flower, these hairs trap and passively carry pollen grains. In this way, flies operate as very good pollinators in addition to the many other ecosystem services they provide. Flies pollinate many different kinds of flowers and even contribute to crop pollination and other agricultural systems, alongside managed pollinators like honey bees.

While they may not be as efficient in transferring pollen as bees on a per-visit basis, the sheer number of flies in many ecosystems often compensates for this, making fly pollination an essential part of our natural world’s pollination services. In fact, there are many species of solely fly-pollinated plants in the world! A striking example of these plants is the Corpse Flower (Amorphophallus titanum), which emits a stench akin to decaying meat to attract flies to visit its massive flower.

The Corpse Flower (Amorphophallus titanum) - a particularly large and striking example of our planet's many fly-pollinated flowers.

Do you like chocolate? Cocoa beans, which are the fruit of the Cocoa Tree (Theobroma cacao), are the essential ingredient in every chocolate product we enjoy. The Cocoa Tree is another exclusively fly-pollinated plant species. So the next time you take a bite of chocolate, you can thank pollinating flies for the effort!

Flies: Among Our Greatest Unsung Ecosystem Heroes

When it comes to the wider range of ecosystem contributions made by flies, carrying pollen from one flower to the next is just the tip of the iceberg. Flies handle many of the less savory "jobs" our ecosystems require to function well. As you'll see, despite their unpopular reputation, you would actually do well to encourage flies to come to your yard. Here are just a handful of the ecosystem services provided by flies in addition to pollinating flowers:

Decomposition and Nutrient Cycling: Many species of flies, particularly those in the families Calliphoridae (blow flies) and Sarcophagidae (flesh flies), are detritivores. Their larvae, commonly known as maggots, feed on feces, decaying plants, meat, and other dead or decomposing organic matter, breaking it down and returning essential nutrients to the soil. This decomposition process is vital for nutrient cycling in ecosystems.

Food Source: Flies themselves, and especially their larvae, serve as a significant food source for a wide variety of organisms, including birds, amphibians, reptiles, other insects, and spiders. This positions them as a crucial link in many food chains and is another way flies can help to cycle nutrients through their ecosystem.

Biological Pest Control Agents: Some types of flies, like the Tachinid flies, are parasitoids. Their larvae feed on other pests, often killing them. In this way, they serve as biological control agents, helping manage pest populations naturally.

Common Types of Pollinating Flies

Flies from several families are important in pollination. Here are four major types of pollinating flies:

Hoverflies (Family: Syrphidae): Also known as flower flies or syrphid flies, hoverflies are one of the most recognizable and common species groups of pollinating flies. Many species are brightly colored bee mimics, meaning they look very much like bees or wasps which lends them some protection from would-be predators (and humans). Hoverflies are frequent flower visitors and are important pollinators of a variety of plants. They are especially adept in pollinating small, shallow flowers.

Bee Flies (Family: Bombyliidae): Bee flies are - as the name already suggests - another group of flies that have evolved to mimic bees (it turns out it's highly adaptive to seem like you can sting!). Bee flies are usually quite hairy and are often seen hovering around flowers in sunny conditions. They have a long proboscis, or mouthpart, that they use to feed on nectar, making them important pollinators for flowers with long corollas.

Tangle-vein Flies (Family: Nemestrinidae): These long tongued flies are known for their extended proboscis which makes them the main pollinators of plants with long, tubular flowers. The long-tongued fly (Prosoeca ganglbaueri), a member of this family, is famous for its role in pollinating the very long flowers of certain species of the plant genus Zaluzianskya in South Africa.

Blowflies (Family: Calliphoridae): While perhaps best known for their role in decomposition, certain species of blowflies also visit flowers and can contribute to pollination. Some flowers emit odors that mimic rotting flesh to attract these flies, and their visits result in pollination.

These families represent just a fraction of the fly diversity involved in pollination. Flies from many different families can and do contribute to pollination, depending on the ecological context and the specific plant species involved.

How to Attract Flies to Your Yard (no trash required!)

If you're interested in creating a pollinator-friendly yard that supports a diverse range of pollinators, including flies, here are some homeowner-friendly methods to attract flies to visit your yard.

1) Plant Native Flowers: Native flowers are key to attracting a variety of pollinators, including flies. Some native plants that are particularly attractive to flies include wildflowers like goldenrod (Solidago spp.), yarrow (Achillea spp.), and coneflowers (Echinacea spp.).

2) Maintain Native Plant Diversity: Creating a diverse landscape with a variety of native plants ensures a continuous supply of nectar and pollen for wild pollinators throughout the growing season, attracting different fly species. Aim for a mix of plants with varying bloom times, flower shapes, and colors to cater to different fly preferences. This diversity of plant species will enhance the overall ecological capacity of your yard and will provide a more resilient habitat for flies and other pollinators.

3) Incorporate Decomposing Materials: Flies, especially certain species like carrion flies and dung flies, are attracted to decaying organic matter. Despite their unsavory names, these creatures play a vital role in our ecosystem. Incorporate decomposing materials such as compost piles or leaf litter in your yard to provide a suitable habitat for these flies. Not only will this attract flies, but it also helps in recycling organic waste and enriching your soil.

4) Avoid Pesticide Use: Minimize or eliminate the use of pesticides in your yard. Many insecticides are indiscriminate and can harm beneficial insects, including flies. By reducing pesticide use, you create a safer environment for flies and other pollinators to thrive and carry out their essential role in the ecosystem.

Remember, attracting flies to your yard is not about inviting pesky house flies but rather promoting and supporting the many beneficial native fly species that play a role in pollinating flowers. By incorporating these homeowner-friendly methods and embracing the ecological significance of flies, you can contribute to a healthier and more biodiverse environment while enjoying the beauty and charm of these often-underappreciated pollinators.

Final Thoughts

The world of pollination is full of surprises, and the fly is undoubtedly one of its most unexpected yet awesome contributors. Flies don’t have the charm of butterflies or the inspiring and industrious reputation of bees; but they still play a suite of unexpectedly awesome and critical roles in our ecosystems, including being incredible pollinators. So, the next time a fly buzzes past you, instead of shooing it away, take a moment to remember that this tiny creature is part of a vast and intricate web of life and will only improve the health of your yard and local ecosystem.