Fly fact sheet | Field of Mars EEC

What are flies?

Flies are insects in the order Diptera. Diptera means ‘two wings’. Unlike most insects, true flies have one pair of wings and a second pair reduced to tiny balancing organs called halteres. Around Sydney and Field of Mars Reserve you may see house flies, blowflies, hover flies, soldier flies, crane flies and other true flies.

A fly.

Flies have one pair of wings, six legs and large compound eyes.

Where do flies live?

Flies live in almost every habitat. Adult flies may rest on bark, leaves, flowers, fences and other surfaces. Their larvae live in places that provide food, such as soil, leaf litter, compost, rotting fruit, animal dung, carrion or water. Some flies, such as crane flies, are often seen in damp or shady places. At Field of Mars Reserve, flies can be found in gardens, wetlands, eucalypt forest and around flowering plants.

A crane fly has a slender body and very long legs.

What do flies eat?

Different flies eat different foods. Many adult flies drink nectar or other liquids, and some feed on pollen. Others feed on decaying material, plant juices or animal fluids. Fly larvae, often called maggots, may feed on rotting organic matter, fungi, algae, dung, carrion, plants or even small insects such as aphids.

Some adult flies feed on nectar and pollen.

What is the life cycle of a fly?

Flies have complete metamorphosis. A female lays eggs on or near a food source. The eggs hatch into larvae called maggots. The larvae feed and grow, then change into a pupa. Inside the pupa the body changes into an adult fly. The adult emerges with wings, dries them, and begins the cycle again.

A hover fly egg on a leaf.

A hover fly larva, also called a maggot.

A hover fly pupa protected inside a puparium.

An adult hover fly.

What adaptations do flies have to help them survive?

Flies have several adaptations that help them survive. Halteres act like tiny balancing organs and help flies steer quickly in flight. Large compound eyes help them detect movement. Sticky pads and claws help many flies land on smooth surfaces. Their mouthparts are adapted for different foods, and many species can fly fast to escape danger. Crane flies have very long legs and slender bodies. These features help identify them. They are weak fliers and are harmless to people.

Crane flies have very long legs and slender bodies.

Why are flies important?

Flies are important members of ecosystems. Many species pollinate flowers. Others help break down dead plants, animal waste and other organic matter, which recycles nutrients back into the environment. Some fly larvae eat pests such as aphids, and flies are also food for birds, spiders, frogs, reptiles and other animals.

Flies can help pollinate flowers as they feed.

What are some common flies around Sydney?

Common flies that may be seen around Sydney and Field of Mars Reserve include house flies, blowflies, hover flies, soldier flies and crane flies. Different species live in different habitats and have different jobs in the ecosystem. Some visit flowers, some recycle nutrients, some live in damp places, and some help control pests.

House fly

Blow fly

Hover fly

Soldier fly

Crane fly

How can you help flies?

You can help flies by growing native flowering plants, avoiding unnecessary pesticides, protecting wetlands and leaving some natural habitat such as leaf litter and compost in your garden. Remember that not all flies are pests. Many species are helpful pollinators, decomposers and food for other animals.

Native flowering plants support many kinds of flies.

Related fact sheets

More invertebrate fact sheets

• Invertebrate fact sheets – overview
• Insects fact sheet  – flies are insects with the same basic insect body plan.
• Wasp fact sheet – another group of winged insects often seen on flowers.
• Beetle fact sheet – another insect group with complete metamorphosis.
• Moth fact sheet – another flying insect that can help pollinate plants.

Habitats and ecosystems

• Leaf litter fact sheet – leaf litter and soil can support fly larvae and the animals that eat flies.

• Mangrove forest fact sheet – damp habitats can support many insects, including some fly larvae.

• Eucalypt forest fact sheet– explains the local bushland context.

• Field of Mars Reserve fact sheet – explains the local reserve and habitat diversity.

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