Sawfly fact sheet | Field of Mars EEC

What are sawflies?

Sawflies are insects related to wasps, bees and ants. Although their name includes ‘fly’, they are not true flies. Adult sawflies have six legs, antennae and two pairs of clear wings. Unlike many wasps, their bodies do not have a narrow waist.

The young stage, called a larva, often looks like a caterpillar. Most sawfly larvae have six or more pairs of short, fleshy legs along their abdomen. Most moth and butterfly caterpillars have five or fewer pairs.

Female sawflies use a saw-like ovipositor to make small cuts in leaves or stems and lay their eggs. This body part gives sawflies their name. The Australian Museum lists 176 sawfly species in Australia. Some larvae are called spitfires, but they do not spit fire and adult sawflies cannot sting.

An adult sawfly

This sawfly larva has a segmented body and many short, fleshy legs.

Where do sawflies live?

Australian sawflies live wherever the plants they need grow. Adults rest on leaves, stems and flowers. Larvae may feed on leaves, inside leaves or stems, or together along branches. Different species use different plants. Some feed on eucalypts, while others use paperbarks or bottlebrushes.

When they are fully grown, many larvae move into leaf litter, soil, soft bark or wood. They stay protected there while changing into adults.

Some sawfly larvae gather in groups on eucalypt branches.

What do sawflies eat?

Most Australian sawfly larvae eat plants. Their strong jaws help them chew leaves and other soft plant parts. Some eat only the soft tissue between the leaf veins. Others eat most of the leaf.

Most adult sawflies drink nectar from flowers. The larvae of a few unusual sawfly species feed on other insects.

Sawfly larvae chew leaves and may feed side by side.

What is the life cycle of a sawfly?

Sawflies have four life stages: egg, larva, pupa and adult. The female uses a saw-like egg-laying body part, called an ovipositor, to cut into a leaf or stem. She places an egg inside the cut. The larva hatches, eats and sheds its skin several times as it grows.

A fully grown larva stops eating and becomes a pupa. Some species make a cocoon around the pupa. This change may happen in leaf litter, soil, bark or wood. An adult later emerges. Some steel-blue sawflies can remain in the pupa stage for more than a year.

A female sawfly uses her ovipositor to cut into a plant before laying eggs.

What adaptations do sawflies have to help them survive?

Female sawflies have a saw-like egg-laying body part called an ovipositor. It cuts into plant tissue so eggs can be placed inside. Adults have two pairs of wings for flying and antennae that help them sense their surroundings. They do not have a sting.

Larvae have strong chewing mouthparts and fleshy legs that help them grip leaves. Some species gather in tight groups and move their bodies together when disturbed. They may also release a bad-tasting liquid that can irritate skin or eyes. Observe sawfly larvae without touching them.

Clustering is one defensive behaviour used by some sawfly larvae.

Why are sawflies important?

Sawflies are part of food webs. Larvae eat plants, and sawflies may be eaten by birds, spiders and other animals. Adult sawflies that drink nectar also visit flowers.

Large groups of larvae can sometimes remove many leaves from a plant. Predators, small parasitic wasps and diseases help control their numbers. These natural relationships help keep ecosystems balanced.

Some adult sawflies visit flowers to feed on nectar.

How can you help sawflies?

You can help sawflies and other insects by growing local native trees and shrubs. Leave some natural leaf litter in garden areas where it is safe to do so. Avoid using insect sprays unless they are needed because sprays can also kill helpful insects.

Look at sawfly larvae without touching them. Take photographs from the side and above and record the plant they are using. If they are badly damaging a garden plant, identify them and seek advice before using a control method.

Photographs can help identify sawflies without handling them.

Related fact sheets

More invertebrate fact sheets

• Invertebrate fact sheets⁠ – Explore more animals without backbones.
• Insects fact sheet⁠ – Learn about insect body features, life cycles and diversity.
• Wasp fact sheet⁠ – Compare sawflies with their narrow-waisted relatives.
• Moth fact sheet⁠ – Compare sawfly larvae with moth caterpillars.

Habitats and ecosystems

• Tree habitat fact sheet⁠ – Discover how trees provide food and shelter for insects.
• Leaf litter habitat fact sheet⁠ – Learn about the habitat where some sawflies pupate.
• Eucalypt forest ecosystems fact sheet⁠ – Explore ecosystems containing important host plants for Australian sawflies.

Food webs and ecological relationships

• Birds fact sheet⁠ – Learn about animals that can eat insects and their larvae.
• Spider fact sheet⁠ – Explore another group of invertebrate predators.

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