Processionary Caterpillar Fact File

Ochrogaster lunifer

Credit: Christopher Watson (, CC BY-SA 3.0 <>, via Wikimedia Commons









2 Months




Conservation Status


Not Evaluated

Following the leader...the leader!

The processionary caterpillar is named for their behavior of following one another using silken trails which they leave. These help large numbers to find their way to a food source.

Larvae feed on leaves from eucalypt and other similar trees. They may gather in such large numbers that they can defoliate a tree.

Females produce large groups of up to 600 eggs which are laid on a tree.

This species is covered by long hairs. If touched as an adult or a larvae they can cause irritation to the skin. If horses ingest these hairs it can cause them to abort a foal.

Read on to learn more about these incredible invertebrates.


What does the Processionary Caterpillar look like?

This species is best known from its juvenile or larval stage in which it looks like a hairy slug. Their body is covered by a minimum of 2 million fine hairs with small barbs.

Across most of their body they are colored grey with a brown head.

As an adult moth they have brown forewings and a white hindwing. In some individuals a white dot is seen on the forewings.

On the body they have an abdomen which is made up of yellow and orange bands. These are tipped with white hairs which can cause hives in people which touch them.

Adults have a wingspan of up to 5.5cm (2.2in) across. Males are slightly smaller than females.


How does the Processionary Caterpillar survive in its habitat?

The hairs covering the processionary caterpillar can cause hives or even worse effects in some animals.

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What does the Processionary Caterpillar eat?

Tree leaves make up the diet of the processionary caterpillar. Large groups gather at eucalypts, acacia and other similar trees and can remove the majority of the leaves.

Adults have no mouthparts and die a few days after pupation.

Learn more about the processionary caterpillar in this video from Native Australia on YouTube


Where do you find the Processionary Caterpillar?

Australia is the native home of the processionary caterpillar. Here they have been recorded from every state and territory on the mainland.


Where can the Processionary Caterpillar survive?

This species is found in a range of habitats . They require the trunk of a eucalypt or other similar food tree.

Processionary Caterpillar (Ochrogaster lunifer)

Credit: Public Domain


How does the Processionary Caterpillar produce its young?

A female will deposit her hundreds of eggs in a mass on a tree. Eggs hatch within three to four weeks of being laid.

As they grow the processionary caterpillar reaches a maximum size following which it will pupate in a cocoon located among ground debris. They reach 4cm (1.7in) long before undergoing pupation.

After two to four weeks they will emerge from their pupa as an adult moth.


What does the Processionary Caterpillar do during its day?

As processionary caterpillars move from one tree to another they will deposit silk in a trail. This is used to help them navigate their environment.

Their name is taken from the large groups, sometimes up to 200 individuals, which can be seen moving head to tail along these trails as they move between sources of leaves.

On occasion two caterpillars follow one another's silk trail and wind up going in a circle.

Caterpillars are active by night when they will feed.

These animals will rest in a large bag formed from silk. Inside of this shed skin and excretions will accumulate eventually leading to the sac bursting and the caterpillars inside falling to the ground.

Processionary Caterpillar (Ochrogaster lunifer)

Credit: Quartl, CC BY-SA 3.0 <>, via Wikimedia Commons

Predators and Threats

What stops the Processionary Caterpillar from surviving and thriving?

Due to the defence provided by their irritating hairs this species has few predators. They are parasitized by the Tachinid Fly.

If threatened the caterpillars will curl in to a ball showing off only their hairs.

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Quick facts

These animals may be accidentally ingested by animals grazing on grass. If this occurs they may burrow out of the stomach and cause bloodstream infections. In pregnant animals they may cause the pregnancy to abort.

Adults are known as the bag-shelter moth.

Processionary Caterpillar (Ochrogaster lunifer)

Credit: Christopher Watson (, CC BY-SA 3.0 <>, via Wikimedia Commons


Crew, B., 2021. Creatura. 1st ed. Terrey Hills, NSW: Australian Geographic. 2022. Bag shelter moth. [online] Available at: <> [Accessed 24 March 2022].

Chew, P., 2022. Bag-shelter Moth, Processionary Caterpillar - Ochrogaster lunifer. [online] Available at: <> [Accessed 24 March 2022]. 2022. Ochrogaster lunifer. [online] Available at: <> [Accessed 24 March 2022]. 2022. Ochrogaster lunifer. [online] Available at: <> [Accessed 24 March 2022].

Australian Insects Website | Common Household Bugs Australia. 2022. Ochrogaster lunifer | Australian Insects Website. [online] Available at: <> [Accessed 24 March 2022].

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