Fly

Flies are busy bugs.

Most flies have only one pair of wings. This helps them fly very well. They have small parts that help them balance.

Flies have big eyes on their heads. They also have mouth parts for sucking. Some flies use these to drink blood.

Many flies help flowers grow. They move pollen from plant to plant. This is a big job.

Flies start as tiny eggs. They grow into maggots. Then they stay in a hard shell. Soon, a new fly comes out.

Some flies are very tiny. One fly is smaller than a grain of salt.

Flies are everywhere in our world.

Flies are very successful insects. There are more than 150,000 types of flies.

Most flies belong to a group called Diptera. This name means they only use one pair of wings to fly. Their back wings have changed into small parts called halteres. These halteres act like sensors. They help the fly balance during tricky flight moves.

Flies have many ways to eat. Some have mouthparts for piercing and sucking. Mosquitoes are a good example. Other flies use their mouths to lap up liquids.

They also have large compound eyes. These eyes are made of many small parts. This helps them see the world clearly.

Flies go through a big change called metamorphosis. They start as eggs. The eggs hatch into larvae, which many people call maggots. These larvae grow inside a hard shell called a pupa. Finally, an adult fly emerges. Flies help the Earth by moving pollen. They are the second largest group of pollinators after bees. Some flies are very small. One kind is even smaller than a grain of salt.

Flies are amazing insects that belong to a group called Diptera. This name means they use only one pair of wings to fly.

Their back wings have changed into special tools called halteres. These halteres act like tiny sensors to help them balance. They allow flies to perform very tricky moves in the air. This makes them some of the best flyers in the insect world.

Most flies go through a big change called complete metamorphosis. First, a fly lays eggs on a food source. These eggs hatch into larvae, which people often call maggots.

These larvae do not have true legs and often live in a safe spot. Next, the insect enters the pupa stage inside a tough shell. When it is ready, the adult fly finally emerges. This cycle helps them grow from tiny eggs into strong adults.

We can find fossils of early flies from a long time ago. The first true flies appeared during the Middle Triassic period. This was about 240 million years ago.

Since flowers did not exist then, they likely ate something else. Scientists think they might have eaten sweet liquid from sap-sucking bugs. Later, they became important helpers for the plants that eventually grew.

There are more than 150,000 different species of flies today. Some are huge, like the Gauromydas heros, which is the largest fly. Others are tiny, like Euryplatea nanaknihali, which is smaller than a grain of salt. Many flies live all over the world in almost every habitat. There are about 19,000 species in Europe and 23,000 in the Oriental region. This shows how many different kinds of flies exist on Earth.

Flies play many important roles in our world. They are the second largest group of pollinators after bees. They help many flowers grow by moving pollen around. However, some flies can be a problem for humans. Mosquitoes can spread diseases like malaria or yellow fever. Other flies, like houseflies, can spread germs to our food. Even so, some fly larvae are used in medicine to clean wounds.

Flies are highly diverse insects belonging to the order Diptera. The name Diptera refers to their unique flight mechanism. These insects use only a single pair of wings for aerial movement.

Their hindwings have evolved into specialized mechanosensory organs called halteres. These club-like structures sense rotation during flight. This sensory system allows flies to perform advanced and precise aerobatics. As a major insect order, Diptera includes more than 150,000 described species. This group includes familiar insects like mosquitoes, houseflies, and crane flies.

The anatomy of a fly is specialized for survival and movement. A fly's body consists of three main sections called tagmata. The first is the head, which contains the sensory organs. It features large compound eyes and often three small simple eyes called ocelli. The ocelli detect changes in light intensity to help the fly react to objects.

The second section is the thorax, which houses the flight muscles. The third section is the abdomen, which consists of 11 segments. The final three segments are often modified for reproduction.

Flies possess specialized mouthparts designed for specific feeding habits. Some groups, such as mosquitoes and robber flies, have mouthparts for piercing and sucking. Female horse-flies use knife-like mandibles and maxillae to make incisions in skin. They then lap up the resulting blood. Other flies have mouthparts meant for lapping and sucking liquids.

Their guts include large structures called diverticulae. These allow the insect to store liquid after a meal. To help them navigate, flies use motion-sensitive neurons to analyze visual information. These neurons allow them to estimate self-motion and separate objects from the background.

Most flies undergo a process called complete metamorphosis, or holometabolism. This involves radical changes through several distinct life stages. First, flies lay eggs, often on a specific food source. These eggs hatch into larvae, which are commonly called maggots.

These larvae lack true limbs and often develop in protected environments. Some species are ovoviviparous, meaning they deposit hatched larvae instead of eggs. After the larval stage, the insect becomes a pupa. The pupa is a tough capsule that protects the developing insect. Finally, the adult fly emerges from this capsule.

The evolutionary history of Diptera spans hundreds of millions of years. The first true dipterans appeared during the Middle Triassic, around 240 million years ago.

Because flowering plants did not exist until the Cretaceous, early flies likely ate different foods. Scientists suggest they may have fed on honeydew from sap-sucking bugs. The fossil record shows three major episodes of evolutionary radiation. The first occurred in the Triassic about 220 million years ago. A second radiation of lower Brachycera happened in the Jurassic, around 180 million years ago. A third radiation of Schizophora began 66 million years ago.

Flies are ecologically significant as both helpers and pests. They are the second largest group of pollinators, following only the Hymenoptera. In wet or cold environments, they are even more important than bees for pollination. However, some flies cause significant harm to humans and animals. Mosquitoes act as vectors for diseases like malaria, dengue, and yellow fever. Houseflies can spread foodborne illnesses globally. Larger flies, such as tsetse flies, cause economic damage to cattle. Conversely, some larvae are used in medicine for debridement to clean wounds.

Diversity within the order is immense and varies by region. There are approximately 19,000 species in Europe and 23,000 in the Oriental region. The size of flies varies wildly across the order. The Gauromydas heros is considered the largest fly in the world. In contrast, the Euryplatea nanaknihali is smaller than a grain of salt. Flies are found in nearly all terrestrial habitats. Some species even live in extreme environments like glaciers, hot springs, or even crude oil. This wide range of adaptations makes them one of the most successful insect groups on Earth.