10 Fun Fly Facts About These Tiny Creatures

The world of insects is vast and varied, but we often consider the fly a mere annoyance. Understanding fly facts gives us a more nuanced perspective of these creatures and their role in our ecosystem. 

Notably, flies undergo a complete metamorphosis, transitioning from egg to larva to pupa and emerging as adults. Despite their relatively simple brains, these tiny insects have a respectable sense of direction and can navigate proficiently. Looking into these facts about flies shows that they are far from ordinary. Read on for all sorts of things you likely didn't know about flies!

Related: Do you know more about flying insects? Check out these dragonfly facts and find out if flying spiders really do exist.

10 Fly Facts

1. There are hundreds of thousands of fly species.

Over 120,000 identified fly species exist worldwide, more than twice the number of bird species and mammals on Earth. Most flies have unique characteristics and behaviors². Hoverflies look like bees and hover in mid-air.

The Diptera order includes the housefly (Musca domestica), tsetse fly, fruit fly (Drosophila melanogaster), and robber fly. Flies buzz around homes, land on food, and transmit diseases. For instance, the tsetse fly spreads sleeping sickness, a potentially fatal disease. 

However, fruit flies are a valuable research subject in genetics due to the ease of identifying their traits. The robber fly is a predatory insect that captures other insects mid-flight. Flies can even walk upside down, thanks to suction pads. 

Finally, every fly species exhibits its diet preference. For example, some eat milk products or fruits, while some eat meat. 

2. Flies can fly in various ways.

One interesting fly fact is that, unlike most insects with four wings, flies have only one pair that beats approximately 200 times per second, enabling them to alter their angle in mid-air and perform sudden changes in direction and rapid escapes.

Additionally, flies can hover in one spot before abruptly darting backward or flipping upside down. Their built-in balance system, directly connected to their wings, enables them to maintain stability during these complex maneuvers.

Each fly wing has a rigid front edge and flexible rear. This design enables the fly to adjust the angle of wings, creating lift and thrust.

3. Flies are ancient.

The first true flies emerged In the Middle Triassic period when dinosaurs existed and life flourished in various forms. Fossil records indicate these insects existed over 240 million years ago.

During the Middle and Late Triassic periods, flies spread across the globe, adapting to various climates and environmental conditions.

People often overlook their role as early pollinators. Flies drink nectar and transfer pollen from one plant to another, contributing to the fertilization and growth of numerous plant species. Fossilized flowers from this era often reveal pollen transferred by flies, indicating their vital role in the life cycles of these plants.

4. Flies walk over food to "taste" it.

Have you ever wondered why house flies seem attracted to our food? It turns out that flies taste their food by walking all over it. Flies have taste receptors all over their feet and legs, which allow them to taste the world around them. By walking on food, flies sample the spread beneath their feet to determine whether they are standing on a potential meal.

These taste receptors can detect even the slightest hint of a substance. They help flies differentiate between what is tasty and what is toxic, much like a human food critic. Despite this, flies can still be picky eaters.

However, a fly does not eat based solely on its foot-tasting experience. Once a potential meal passes the 'foot test,' the fly will use the taste receptors in its mouthparts for a more precise flavor evaluation. Only after this secondary taste test will a fly decide to dine or decline.

5. Flies reproduce rapidly.

Although flies, like house flies, live short lives, their mating rituals are dramatic and fast. Male flies engage in aerial stunts and perform wing beats to attract female flies. They also offer a food source to help with the egg-laying process.

After mating, flies lay eggs in nutrient-rich spots such as meat scraps or carrion. Their larvae hatch quickly and begin to consume the food source, growing rapidly for up to a week. The larvae then transform into a pupa, which protects them as they undergo complete metamorphosis.

After a week or so, an adult fly emerges, ready to repeat the cycle. Under favorable conditions, the entire fly life cycle can occur in as little as a week.

If you're wondering why your household has a fly infestation that doesn't seem to go away, it's because of their incredibly rapid reproductive rate. 

6. Flies have no lungs and have 360-degree vision.

Next on our list of facts: Flies do not have lungs; instead, they rely on a network of tubes called tracheae to transport oxygen directly to their tissues. This respiratory system works through small openings called spiracles on the fly's sides. Flies can regulate their oxygen intake by controlling the opening and closing of these spiracles, which work like windows.

Moreover, flies have compound eyes consisting of thousands of tiny lenses called ommatidia, giving them a panoramic 360-degree view of their surroundings. These strategically placed and numbered ommatidia let flies see almost everything simultaneously.

In addition to their compound eyes, flies have three simpler eyes, known as ocelli, on top of their heads. These ocelli detect changes in light and do not provide detailed visual information.

7. Flies are invaluable to the ecosystem.

Flies are pollinators and decomposers¹. Hoverflies, for example, are incredibly proficient pollinators, surpassing even the various types of bees in their effectiveness with certain types of plants. They transport pollen from male to female flower parts, helping plants produce fruits and seeds and keep them from going extinct.

Moreover, flies are a much-needed meal for creatures from different food chains, like birds in the sky or spiders on the ground.

Additionally, young flies, or maggots, feed on dead organic material. With every meal, they break down this material, sending vital nutrients back to the soil. They are tiny cleanup crews that enrich the soil and boost plant growth.

Some flies, like the blowfly, even underwater, break down dead creatures. Moreover, the humble dung fly decomposes waste, keeping our environment clean and disease-free.

8. Flies have tiny hairs on their body.

Flies also have setae or fine hair-like projections on their bodies. These setae are not ordinary hairs but rather complex sensory apparatus that allow flies to perceive their surroundings in great detail³. Each seta acts as a finely tuned instrument of perception, enabling flies to sense the world exceptionally.

The setae on a fly's body function as its nerve center for environmental awareness. They work like a network of tiny antennas, transmitting a constant data stream to the fly's brain. The bristles have specific functions; some detect movement and vibration, alerting the fly to potential predators, while others act as chemosensory receptors, allowing the fly to 'taste' its surroundings. Additionally, certain setae give flies their remarkable climbing abilities.

9. Flies can bite, but they have no teeth.

While flies can bite, they do not do so with teeth. Instead, they use mandibles, sharp edges that serve as practical tools. When a fly lands on a person, they don't feel a bite but a swift jab from the precision-engineered mandibles.

However, not all flies possess the same type of mandibles. Some species have a sharp proboscis that functions more like a needle than traditional insect mouthparts. This proboscis is the key to their feeding process. For example, when house flies eat, they inject digestive juices onto solid foods that turn them into liquid, which they drink with their proboscis.

10. Fly populations are stable.

Flies can survive in various environments, from the Sahara desert's scorching sands to the Amazon rainforest's lush canopy. Despite being commonly shooed away from summer barbecues, flies can avoid swatters easily.

According to the International Union for Conservation of Nature data, no fly species are currently on the endangered or threatened list. Their impressive adaptability and tenacity have helped them master survival in the wild. 

In addition to maintaining the food chain, flies also play a part in pollination. While we believe bees are the only pollinators on Earth, flies contribute significantly to producing seeds and fruit for many plant species. Therefore, it is essential to recognize that flies–even the house fly–are a crucial part of a complex ecosystem.

However, the potential impact of flies on human health is a huge concern, as these insects can carry and transmit various pathogens and harmful bacteria. Flies have been known to spread diseases such as dysentery, typhoid, and cholera, posing severe risks to our well-being.

Tackling a fly problem on your own can be challenging and largely ineffective, so seeking professional help at the earliest signs of an infestation is advisable.

We hope you enjoyed this list of interesting facts about flies!

Related: To further explore the animal kingdom, check out some other animals that start with F.