1. There Are Many, Many Species of Flies
Flies are members of the Diptera order which is one of the largest orders of insects in the world. There are around 125,000 different species which have been identified so far but there are estimated to be more than a massive one million species in total. Some of the species classified as flies include crane flies, horse flies, black flies, mosquitoes, and midges.
2. They Live in Virtually Every Habitat in the World
Flies are some of the most diverse animals in the world, which isn’t really surprising considering how many species there are. However, they are so well adapted that they live in virtually every single habitat around. Incredibly, there are actually flies on every continent in the world and there is even a single species which lives in Antarctica. The tiny Antarctica midge is a endemic to Antarctica and is uniquely adapted to survive in freezing temperatures.
3. Flies Are Important Polinators
Although flies can often be annoying when they’re buzzing around us, they’re actually really important to the ecosystem. This is because they are one of the top pollinators of plants, behind only bees and their relatives. Flies account for around 30% of the world’s pollination and studies have shown that hover flies and blowflies are two of the best pollinators. Flies are such good pollinators because there are so many species across so many habitats. They also have a wide range and tend to forage further than bees do. Additionally, larger species are able to carry huge amounts of pollen on them which means that they are able to pollinate more plants.
4. Flies Taste With Their Feet
Can you imagine tasting something with your feet? Even thought the thought of having to walk all over your food just to taste it doesn’t sound that appetising, that is exactly what most flies do! This is because they have their taste receptors on their legs and feet. Although they do also have taste receptors in their mouth part too, they first decide if something is edible (or appetising enough) by crawling over it and rubbing their feet in it. This is a more efficient way of tasting food than using their mouth part. However, they do then taste the food in their mouth again before actually eating it.
5. Flies Don’t Have Teeth
Moving on from their taste buds, it might come as a surprise to learn that flies don’t have teeth. In fact, you’re probably now wondering how they manage to bite us if they don’t have teeth, right? Well, the simple answer is that many of them have sharp cutting edges on the mandible of their mouth parts which allow them to slice open skin with. Some don’t even have a cutting edge as such but simply “bite” by using their sharp needle-like proboscis. As they lack typical teeth, flies can’t literally take a mouthful of food. Instead, they inject some of their saliva into the wound. This usually contains properties which cause tissue to liquefy which they can then suck up with their proboscis.
6. Flies Have Four Stages of Life
All flies which are members of the Diptera order go through four different life stages – egg, larva, pupa, and adult. This is holometabolism – also known as a complete metamorphosis. The larval stage of flies is usually longer than their adult life while their main function as adults is to mate and lay eggs. The immature stages of flies look vastly different to their adult form. The egg stage is short and usually only lasts for a few days. The larval form is often known as maggots and mainly concentrates on feeding. The larval form can survive either in or out of water, depending on the species. Some can be found on fruit, vegetables, or other plant matter, while others live inside a live host. In the latter case, the flies have usually been attracted by open wounds or faeces and lay their eggs on the host. Upon hatching the maggots can cause serious problems for their prey. The third stage is the pupa stage which usually lasts between a couple of days to one week, depending on the species. The pupa moves very little and is sometimes covered in small spines. In some cases, the adult features are encased in the pupal body, while in others they are visible on the outside of it.
7. They Only Have One Pair of Wings
Although Diptera comes from the Greek words which mean “two-winged”, all of the true flies only have a single pair of wings which they use for flying. Their second pair of wings – the hindwings – have evolved into club-shaped organs known as “halteres”. Halteres provide the fly with information about rotational movement when they are flying and allow them to make such high-speed manoeuvres. Although there are several other species which have “fly” in their name (such as dragonflies and damselflies), only those with a single pair of functional flying wings are members of Diptera and therefore true flies.
8. Most Flies Beat their Wings 200 Times Per Second
Flying can be pretty hard work for flies, especially when they’re flying at high speeds and making split-second turns in mid-air. Therefore, they have to beat their wings a lot just so that they can stay in the air. Most flies beat their wings 200 times every second. However, there are even some species of midge which beat their wings 1,000 times per second.
9. Flies Multiply Really Quickly
If you’ve ever wondered why there are so many flies buzzing around, particularly in hot weather, then it’s simply because they are able to reproduce really, really quickly. Although the actual number of eggs varies between species, flies can usually lay a lot of eggs. Most species can lay up to 500 eggs in their lifetime, split between batches of 100 to 150. However, some can lay many more – especially no-see-ums. No-see-ums can lay up to 450 eggs in each batch and up to 7 batches in their lifetime.
10. Flies Have Been Around for Millions of Years
One of the most surprising things about flies is that they have actually been around for a really long time, millions of years in fact. The first true flies known were from the Middle Triassic period which was approximately 240 million years ago. They then became widespread between the Middle and Late Triassic periods. The first flies were also likely some of the earliest pollinators of plants and flowers too.
