The Billion-Dollar Buzz: Why We Must Stop Swatting Our Second-Most Important Pollinators

Chocolate Crisis and the Fly’s PR Problem

Imagine waking up to a world without chocolate. No truffles, no cocoa powder, no dark chocolate bars. This isn't a plot for a dystopian novel; it is a very real possibility if we lose a tiny, often-maligned insect: the Cacao Midge.

While the honeybee is the undisputed poster child of the pollination world, the order Diptera (true flies) constitutes the second most important group of pollinators on Earth. From the high-altitude peaks of the Himalayas to the humidity of the rainforest, flies are the silent workhorses of our ecosystems.

Despite the critical role of pollinators, they face a major public relations problem, often being viewed solely as pests or disease carriers. We fail to recognise our second most important pollinators.

This article examines the remarkable economic value of these winged underdogs, their role as ecological insurance policies, and the silent threats that could bring our food systems to a standstill.

The Hidden Billion-Dollar Economy of Diptera

We often quantify the value of pollination through the lens of bees, but recent studies suggest that flies are responsible for a massive chunk of global agricultural productivity.

Quantifying the Unseen Work

The economic contribution of flies is diverse, ranging from luxury goods to staple vegetables. Because many fly species are all-weather workers, active in temperatures and light levels that keep bees grounded, they provide a level of consistency that is vital for commercial farming.

The $100 Billion Chocolate Industry

The cacao tree (Theobroma cacao) has complex, tiny flowers that honeybees cannot navigate. They are exclusively pollinated by midges in the family Ceratopogonidae. Without these "chocolate flies," the global cocoa market would vanish.

Seed Production

Flies, particularly Hoverflies (Syrphidae), are essential for the production of onion, carrot, and leek seeds. In many greenhouse settings, flies are preferred over bees because they are less aggressive and more efficient at pollination in confined spaces.

Tropical Fruit Yields

Mangoes, avocados, and cashews rely heavily on a mix of blowflies and houseflies. In some regions, farmers actually place organic matter in orchards specifically to attract these flies during bloom time.

Key Pollinating Fly Families

Bees are the most famous pollinators, but flies are also important. Some of the flies are good pollinators (For details, see the USDA report. A short description is provided below:

Hoverflies- The Gardener’s Friend (Eristalis tenax) 

The members of the Syrphidae family mimic bees and wasps to avoid predators while visiting flowers (Fig. 1). The hoverflies are easy to spot by their ability to remain stationary in mid-air. They are essential pollinators for many fruit crops and wildflowers. Their larvae provide a bonus: they are voracious predators of aphids, making them a natural form of pest control. By planting flat, open flowers like dill and fennel, you can attract these high-efficiency flyers to your garden.

Bee Flies- The Fuzzy Dart (Bombylius major) 

The bee flies belong to the Bombyliidae family. They possess extremely long proboscises to drink nectar while hovering; they look like fuzzy bumblebees (Fig. 1). The bee fly is a harmless pollinator with a distinctive, needle-like proboscis. This long mouthpart allows them to drink nectar from tubular flowers while hovering, without the need to land. Common in early spring, they are vital for pollinating wildflowers in arid regions. While they appear cuddly, they are actually parasitoids; the females lay their eggs into the nests of ground-nesting bees to feed on their larvae.

Fig. 1. A hoverfly and a bee fly are sucking nectar from daisy and dandelion flowers

 

Blow Flies- The Metallic Messenger (Calliphora vicina)

They are the members of the Calliphoridae family. Blow flies are attracted to carrion flowers that smell like rotting meat (e.g., Pawpaw or Dead Horse Arum). Often recognised by their metallic blue or green bodies, blow flies are specialised pollinators for flowers that mimic decaying organic matter (Fig. 2). While they have a dirty reputation, they are critical for the pollination of specific plants, such as the Pawpaw tree and various dead horse arums. In some mango orchards, farmers purposefully attract them to boost crop yields.

Houseflies- The Urban Workhorse (Musca domestica) 

The urban workhorse belongs to the Muscidae family. The common housefly is a generalist pollinator that picks up pollen as it moves between food sources. Using their sponging mouthparts, they lap up nectar from a wide variety of flat-faced flowers. While less efficient than specialised bees, their sheer abundance and willingness to fly in cooler, overcast weather make them a vital backup pollination system in both agricultural and urban environments, ensuring that plants reproduce even when other insects are inactive.

Fig. 2. A blow fly and a housefly are sucking nectar from blackberry and fennel flowers

 

Tangle-veined Flies- The Deep-Reach Specialist (Moegistorhynchus longirostris) 

The deep-reach specialist belongs to the Nemestrinidae family. They are famous in South Africa for having mouthparts up to 8 cm long to reach deep nectar tubes (Fig. 3). They have specifically evolved to pollinate deep, tubular flowers that other insects cannot reach. They are strong, fast flyers that often make a loud humming sound. Their specialised relationship with local flora makes them a keystone species for maintaining regional biodiversity.

Tachinid Flies-The "Bristly Protector (Tachina fera) 

Bristly flies belong to the Tachinidae family. Bristly and robust, Tachinid flies are dual-purpose insects in the garden (Fig. 3). While the adults feed on nectar and help pollinate various wildflowers and herbs, they are best known for their parasitic nature. The females lay eggs on or inside pest insects, such as caterpillars and beetles, acting as a powerful biological control agent. Because they visit many different flowers to maintain their energy, they are underrated but important contributors to overall ecosystem health.

Fig. 3. A Tangle-veined fly and a Tachinid fly are sucking nectar from wild dagga and sweet clover flowers

 

Chocolate Midges- The Treat Maker (Forcipomyia spp) 

Tiny flies of the Ceratopogonidae family pollinate specific plants like cacao (chocolate) (Fig. 4). These flowers are small, white, and face down; the reason for all this is that they attract tiny flies, known as midges, rather than bees or other better-known pollinators. The midges are ordinarily attracted to fungus; cocoa flowers smell somewhat mushroomy, too. In essence, for the cocoa tree to bear fruit, first it has to be pollinated by midges (See USDA report for details).

The midges, specifically those in the genus Forcipomyia, are small enough to crawl inside and complete the task. Without these tiny gnats, the global chocolate industry would vanish, as there is currently no mechanical or bee-led alternative for cacao pollination.

March Flies- The Seasonal Swarmer (Bibionidae)

Flower-feeding flies pollinate plants in families like Asteraceae (daisies) and Scrophulariaceae (snapdragons) (Fig. 4). Also known as lovebugs or St. Mark's flies, these insects often appear in massive, seasonal swarms. While they are viewed as a nuisance when they splatter on car windshields, they are harmless to humans and active pollinators. They feed on the nectar of fruit trees and wildflowers during their short adult life. Their larvae live in the soil, feeding on decaying organic matter and helping to recycle nutrients back into the earth.

Fig. 4. Chocolate Midges and March fly are sucking nectar from the cacao and snapdragon flowers

 

Mosquitoes- The Night Pollinator (Culicidae)

Male mosquitoes feed on nectar and pollinate flowers from several plant families, such as the daisy family (Asteraceae), the legume family (Fabaceae), and the rose family (Rosaceae) (Fig. 5). While mostly known for their itchy bites, only female mosquitoes drink blood to produce eggs. Both males and females primarily feed on nectar for energy. In doing so, they act as important pollinators for certain plants, most notably the Blunt-leaf Orchid. In some remote environments, mosquitoes are the primary visitors to specific wildflower species. While they are a health concern for humans, their role in the food web and pollination cycle is undeniable.

Syrphid fly- The Ecological Insurance (Sphaerophoria philanthus)

This group exhibits a characteristic flight pattern where they hover and can abruptly change their position. As a result, they are called hover flies in Great Britain. The Syrphidae family is divided into 3 subfamilies and 15 tribes, containing more than 6,000 identified species. The total number of species may be greater, with many undescribed species found in Costa Rica (USDA Forest Service).

They are considered the second most important group of pollinators after bees (Fig. 5). They are particularly vital because they are active in lower temperatures, providing a "safety net" for crops during cold springs. 

Fig. 5. A mosquito and a Syrphid fly are sucking nectar from Chamomile and Buttonbush flowers

 

You can find more information about pollination by Birds, beautiful Hawk moths, bumblebees, and Butterflies 

 

Economic contribution of key fly families
 

Ecological Diversity: The High-Altitude Heroes

Beyond the farm, flies are the primary drivers of biodiversity in the world’s most extreme environments.

Pollination Where Bees Fear to Tread

In the Arctic tundra and high Alpine meadows, bees are rare. The cold, wind, and short growing seasons are too much for most Hymenoptera. Here, the flies take the lead.

• The arctic engine: In the Far North, flies in the families Muscidae and Anthomyiidae perform up to 80% of all pollination visits. Without them, the Arctic flora and the animals that depend on them would fail to reproduce.
• Synergistic pollination: Flies often act as an insurance. When a late spring frost or a rainy week prevents bees from flying, flies continue to move between flowers, ensuring that a single bad weather event doesn't lead to a total crop or seed failure. This is known as ecosystem stability.

Why Flies are the Ultimate "Ecological Insurance"

• Thermal resilience: Flies can fly at lower body temperatures than bees, allowing them to pollinate at dawn and dusk.
• Generalist behaviour: Most flies are not "picky" eaters. This generalism means they support a wider variety of rare wildflowers that specialised bees might ignore.
• Dual roles: Many pollinating flies serve two purposes. For example, hoverfly larvae are voracious predators of aphids, providing biological pest control while the adults pollinate the crop.

How to differentiate flies from bees?

 

The Silent Crisis: Threats to Fly Populations

Despite their importance, fly populations are declining at an alarming rate. Because they aren't as "charismatic" as bees, their disappearance often goes unnoticed by the public and policymakers.

Why We Are Losing the "Other" Pollinators

The threats to Diptera are multifaceted and often intersect with our modern industrial and domestic habits.

• Habitat homogenization: Modern "clean" farming and manicured gardening are deadly for flies. Many fly species need "messy" habitats for their larvae, such as stagnant water, decaying wood, or leaf litter. When we "clean up" these areas, we eliminate the next generation of pollinators.
• The pesticide ripple effect: Neonicotinoids and other systemic pesticides are designed to kill insects. Unfortunately, they don't discriminate. Research shows that even sub-lethal doses can impair a fly’s ability to navigate and forage effectively (See buglife.org.uk for details).
• Climate change & phenological mismatch: As the planet warms, flies may emerge from dormancy earlier than the flowers they pollinate. This "mismatch" leads to a double tragedy: the flies starve, and the flowers go unpollinated.

Modern Agricultural Pressures

• Loss of hedgerows: Hedgerows provide the windbreaks and floral diversity that hoverflies need to survive the "food deserts" of monoculture farms.
• Pollution and scent masking: Many flies find flowers through specific, often musky, scents. Nitrogen pollution and ozone can break down these chemical signals, leaving the flies "blind" to their food sources.

Future-Proofing the Fly: Conservation and Awareness

How do we protect an insect that most people want to swat? It begins with a shift in perception and a change in landscape management.

How to Build a Fly-Friendly World

Conservation doesn't have to be expensive; in fact, it often involves doing less rather than more.

• Integrated pest management (IPM): Farmers must be encouraged to view hoverflies as allies. By reducing the use of broad-spectrum insecticides, they protect the "free labour" provided by these aphid-eating pollinators.
• The "messy garden" movement: Encouraging homeowners to leave a patch of fallen leaves or a small pond can provide the necessary breeding grounds for a dozen different fly families.
• Public awareness: Science communication must highlight the "Chocolate Midge" and the "Hoverfly" to humanise the order Diptera.

Simple Action Points for Readers

• Plant umbellifers: Grow plants with flat, open flowers like dill, parsley, fennel, and coriander (epicgardening.com). These provide easy access to nectar for short-tongued flies.
• Avoid "perfect" lawns: A lawn with a bit of clover and some damp corners is a sanctuary for beneficial flies.
• Support organic cocoa: Buying sustainably sourced chocolate supports farming practices that maintain the shade-grown forests where midges thrive.

Conclusion: A Call for Dipteran Dignity

The fly on your windowpane might be a nuisance, but its cousins are the reason your garden grows, your mountains remain green, and your chocolate bar exists. As we face a global biodiversity crisis, we cannot afford to be "taxonomic snobs."

It is time to recognise the non-bee pollination services that keep our world functioning. By protecting the habitat of the fly, we aren't just saving a "bug"; we are securing the synergistic pollination that sustains our global food security. It’s time to stop swatting and start supporting.

FAQs

If I attract flies to my garden for pollination, will I also attract disease-carrying houseflies?

Not necessarily. Pollinating flies and "filth flies" generally have different ecological requirements. While houseflies are attracted to decaying food waste and animal feces, the most effective pollinators, such as hoverflies and bee flies, are attracted to nectar-rich flowers and humid, "natural" decay (like leaf litter or rotting logs). You can grow dill, fennel, and coriander plants rather than leaving out household waste.

Why are flies often considered "better" than bees for greenhouse agriculture?

Flies are increasingly preferred in Controlled Environment Agriculture (CEA) for three reasons:

• Resilience to confinement: Bees often become stressed and fly against glass until they die; flies remain calm and focused on foraging.
• Temperature tolerance: As established in recent studies, flies can remain active in cooler, overcast conditions where bees become dormant.
• Safety: Most pollinating flies, such as hoverflies, do not possess stingers, making them safer for greenhouse workers to handle.

Can commercial farmers "hire" flies like they hire honeybee hives?

Yes. As of 2025, companies like Polyfly and Olombria have commercialised the use of "managed" fly populations. They provide farmers with larvae or pupae of specialised hoverflies that are native to the region. These "precision pollination" services are used extensively in berry production and seed farming to increase marketable fruit yields by up to 70%.

How does climate change threaten flies differently than it does bees?

Recent research indicates that flies are more heat-sensitive than bees. On average, bees can tolerate temperatures about 2.3°C higher than flies before losing motor function. Because flies evolved in cooler, more temperate or high-altitude environments, they are at higher risk of "thermal burnout" as global temperatures rise. Furthermore, they are more susceptible to phenological mismatch, where they emerge from dormancy before their host flowers have bloomed.

What is the specific role of "The Chocolate Midge" in the global economy?

The Forcipomyia midge is the only insect small enough and specialised enough to navigate the intricate, 1mm-wide openings of the cacao flower. Without this fly, the $100 billion chocolate industry would face a total collapse of supply. These midges do not breed in the flowers themselves; they require damp, shady environments with "messy" organic substrates like rotten cacao pods and leaf litter to complete their lifecycle.

How can I tell the difference between a hoverfly and a stinging bee?

You can distinguish them through a few simple visual cues:

• The eyes: Flies have massive eyes that often cover most of their head, whereas bees' eyes are smaller and positioned on the sides.
• The wings: Flies (Diptera) have only two wings, while bees have four.
• The "Hover": Hoverflies are named for their ability to remain perfectly stationary in mid-air before darting away, a flight pattern bees rarely replicate.