Emperor Gum Moth: All You Need to Know – Simple & Comprehensive Guide

The Emperor Gum Moth is a fascinating and beautiful insect, native to Australia and known for its striking appearance. As a large moth species, it boasts a vibrant mix of colors that catch the eye and has become a popular subject for collectors and enthusiasts alike.

During its life cycle, the Emperor Gum Moth goes through several stages including egg, larva, pupa, and adult. Each stage offers unique characteristics, making this moth an interesting study for those curious about the natural world. In addition, the caterpillars feed on Eucalyptus trees and other plants, displaying a strong connection with their environment.

As nocturnal creatures, these moths are primarily active during the evenings, flying and searching for suitable host plants to lay their eggs. With their beauty and intriguing life cycle, the Emperor Gum Moth is certainly a species worth learning more about.

Emperor Gum Moth Overview

species

The Emperor Gum Moth, scientifically known as Opodiphthera eucalypti, belongs to the order Lepidoptera, which includes all butterflies and moths. As a species under the family Saturniidae, it is commonly referred to as the Emperor Moth.

Classification

Emperor Gum Moths belong to the following taxonomic classification:

• Kingdom: Animalia
• Phylum: Arthropoda
• Class: Insecta
• Order: Lepidoptera
• Family: Saturniidae
• Genus: Opodiphthera
• Species: Opodiphthera eucalypti

Here is a brief comparison table of the two major types of Saturniidae:

Key features of Emperor Gum Moths include:

• Size: typically measure around 100-150mm in wing span
• Color: brown and grey patterned wings
• Habitat: primarily found on eucalyptus trees
• Range: native to Australia

In general, Emperor Gum Moths are large, beautiful moths that belong to the Saturniidae family, which is also sometimes referred to as the Emperor Moth family. Originating from Australia and mainly thriving on eucalyptus trees, this unique species boasts brown and grey patterned wings spanning 100-150mm.

Physical Characteristics and Appearances

Caterpillar Stage

• Body: In the caterpillar stage, the Emperor Gum Moth has a smooth body with tubercles.
• Diet: Primarily feeds on Silver Birch leaves.

The Emperor Gum Moth caterpillar is characterized by its smooth body with small tubercles. Its diet primarily consists of Silver Birch leaves.

Cocoon and Pupa Stage

• Cocoon: Spins a silk cocoon
• Pupa: Transforms inside the cocoon

During the cocoon and pupa stage, the Emperor Gum Moth caterpillar spins a silk cocoon to encase itself. Inside the cocoon, it transforms into its adult form.

Adult Moth Stage

• Eyespots: Both male and female moths have eyespots on their wings.
• Colors: Vary in shades of brown, grey, and rust.

In the adult moth stage, the Emperor Gum Moth has both male and female individuals. Males have more feathery antennae compared to females and a slightly smaller wingspan. They both have eyespots on their wings which come in various shades of brown, grey, and rust.

Life Cycle and Metamorphosis

Eggs and Early Development

The Emperor Gum Moth (Opodiphthera eucalypti) begins its life cycle as eggs laid on eucalyptus leaves. The eggs are small, round, and pale green, which helps them blend in with their surroundings. During the summer months, these eggs hatch into tiny caterpillars ready to start feeding.

Caterpillar Growth

As the caterpillars grow, they go through a series of molts called instars. The initial color is green but it eventually develops into a vibrant coloration. Some characteristics of the caterpillars include:

• Bright green color with white spots
• Large, fleshy body
• Orange head with black markings

Throughout the instars, the caterpillars consume eucalyptus leaves, rapidly growing in size. By the final instar, they can measure up to 12 cm in length.

Pupation

Once the caterpillars reach their full size, they spin a cocoon. Inside, they undergo a pupal life stage, transforming into adult moths. This stage can last several weeks to months, depending on environmental conditions.

Adult Emergence

When the metamorphosis is complete, an adult Emperor Gum Moth emerges with a wingspan of 10-16 cm. The moth’s coloration is a mix of earthy brown and grey tones, helping it to camouflage. A comparison table of the different life stages:

Adult moths do not feed but focus on finding a mate and reproducing, completing the life cycle.

Distribution and Habitat

Australia

The Emperor Gum Moth (Opodiphthera eucalypti) is native to Australia, primarily found in the eastern states such as:

• Queensland
• New South Wales
• Victoria

This moth species inhabits various habitats like:

• Forests
• Woodlands

Host Plants

Emperor Gum Moths rely on specific host plants, with eucalyptus being a key example.

New Zealand

The Emperor Gum Moth was introduced to New Zealand in the early 1930s. It has established populations in:

• North Island
• Nelson

Just like in Australia, these moths are found residing in:

• Forests
• Woodlands

Host Plants

In New Zealand, Emperor Gum Moths prefer eucalyptus and other Australian tree species.

Host Plants and Diet

Common Host Plants

Emperor Gum Moth caterpillars are known to feed on different types of host plants. Some common ones include:

• Eucalyptus: Various species of eucalypt trees.
• Pine: Pinus radiata is a common host.
• Apricot: Prunus armeniaca trees.
• Grapevines: Vitis vinifera and related species.
• Pepper trees: Schinus molle trees.
• Liquidambar styraciflua: Sweetgum trees.
• Betula pendula: Silver birch trees.

Feeding Patterns

Caterpillars of the Emperor Gum Moth follow a typical feeding pattern:

1. They start feeding on the foliage of their host plants.
2. As they grow, they consume more leaves.

Damage

Although Emperor Gum Moth caterpillars consume a variety of host plants, the damage they cause is generally minimal. Some effects include:

• Partial defoliation.
• Mild damage to fruits, such as apricots and grapes.

However, healthy plants can often recover quickly from this damage.

Significance and Conservation

Threats and Concerns

Emperor Gum Moth (Opodiphthera eucalypti) faces certain challenges that affect their population:

• Habitat loss: Deforestation and urbanization reduce available food sources and mating grounds.
• Pesticides: Chemicals used in forestry can harm these moths during their larval stage.

The decline of these moths can impact the ecosystem as they play a crucial role as pollinators and as a food source for wildlife.

Role in Ecosystem

• Pollination: Adult moths contribute to pollination, helping maintain plant diversity.
• Food source: Caterpillars serve as prey for various birds and mammals, maintaining a balance within the forest ecosystem.

Conservation Efforts

Organizations like iNaturalist work to monitor and document insect populations, including Emperor Gum Moths. CSIRO research further helps to understand these moths and implement conservation strategies.

Comparison of Conservation Methods:

Key features of Emperor Gum Moths:

• Large, striking appearance with a wingspan up to 150mm
• Found throughout most of Australia, particularly in eucalyptus forests
• Caterpillars feed on eucalyptus leaves

Characteristics of Emperor Gum Moths:

• Two large eyespots on their wings deter predators
• Bright green caterpillars with white stripes and short spines
• Pupate inside a dense, oval-shaped cocoon

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Gum Moth from Australia, but what species??? Opodiphtera astrophela

Yellow moth
Location: Kumbia Queensland Australia
February 27, 2011 6:37 am
Hi ’Bugman’
I have been searching the net for identification of a moth I found today. I found a moth that was very similar but the markings on the wings are different and I think, so is the shape of the wings. I found it resting on the stairs of the school. Thought it was a toy one at first as it was such a bright yellow and I have seen rubber toy moths/butterflies on display recently at the local kindergarten.
Regards
Signature: E.

Dear E.,
This is a Gum Moth in the genus Opodiphthera, but we are not certain how to distinguish the different species.  The Moths of Australian Saturniidae webpage lists seven species in the genus.  The thumbnail of the Emperor Gum Moth, Opodiphthera eucalypti, looks correct, but that image is not on the Emperor Gum Moth page where all specimens seem very tan or brown. Opodiphthera astrophela, which does not have a common name, is described as “The female and male adult moths differ: The males are yellow, and the females grey. Originally they were thought to be different species. Both sexes have a brown eyespot on each wing, as well as two dark lines across each fore wing, and a curved dark line across each hind wing. They have a wingspan of about 8 cms. The species is found in the eastern quarter of Australia.”  That would explain the yellow coloration, but your moth is much larger than 8 cms.  It might also be Opodiphthera loranthi.  The Csiro website shows some color variations.  Perhaps the best choice is Opodiphthera fervida which is described as  “yellow with a brown eyespot on each wing, and a brown line across each wing. The moths have a wingspan of about 8 cms.  The species is found in Queensland.”  We will contact Bill Oehlke to see if he can provide a species identification.  We are copying him on our response to you as well since he may request permission to include your photo on his website.

Bill Oehlke provides an Identification: Opodiphtera astrophela
Hi Daniel,
This moth is depicted on WLSS.  I am surprised you did not see it. Thanks for thinking of me.
This is email I just sent to E.

Hi E.,
The moth you sent to Daniel Marlos for identification is Opodiphtera astrophela. I will be sending Daniel a copy of this email.
I wish permission to post the image, credited to you, to one of my webpages. If you grant permission, please send complete name so I can credit you properly, or I can just use E.
if you wish to remain anonymous.
Very nice picture.
Bill Oehlke

Thanks so much Bill.  In my defense, I was multitasking, which is not an efficient way for me to work.  I was putting most of my attention into assembling a lasagna sin carne for an Academy Awards party in my neighborhood.  I like the quote:  “Opodiphthera astrophela, formerly Antheraea simplex, (wingspan: 16 cm) flies in the eastern quarter of Australia, Central Queensland to central New South Wales“ from your website with the larger wingspan that troubled me in other species descriptions.  Also in my defense, E’s lovely photo of a vitally living male specimen and the way the vivid chrome yellow colors contrast with the floral print blouse cannot be compared to the desaturated coloration of the mounted specimens.  This photograph is a stunning example of edgy composition in nature photography.  If we ever print another calendar, this image would be a strong contender.

P.S. Unnecessary Carnage: It saddens us to see this example of unnecessary carnage.  Scroll down to “Opodiphtera astrophela  Rare and endemic Australian species. Male A1, female close to perfect. Pair: €120 SOLD”.

Letter 2 – Emperor Gum Moth in New Zealand

Massive Moth
December 21, 2009
Found this massive moth inside under some flourescent lights, I am interested to know what it is, I have never seen such a big moth before!
?
Palmerston North, New Zealand

Dear ?,
The Emperor Gum Moth, Opodiphthera eucalypti (formerly Antheraea eucalypti) is native to Australia, but it has been introduced to New Zealand in the early 20th Century.  The Government of South Australia has a nice online PDF available on the species.

Letter 3 – White Stemmed Gum Moth Caterpillar: It Stings!!!!

caterpillar freakazoid
we found a caterpillar yesterday in our driveway that is just under 8 inches long about 18cm! we dont know what kind it is. its freaky looking and is furry and spiky. can u help us out. we live in an urban area in north west NSW of australia. we dont think its a native.
Angela Ritter NSW Australia

Hi Angela,
The White Stemmed Gum Moth Caterpillar, Chelepteryx collesi, is a native species that we located on the Australian Caterpillars website. It is in the family ANTHELIDAE that is confined to Australia and New Zealand. The website explains that: “This Caterpillar is a great hazard to people climbing Gum trees. Scattered over its skin are tufts of long stiff reddish hairs, which are strong enough to penetrate human skin. When they do, they are very painful, and difficult to remove because they are barbed and brittle.” It is also noted that: “It is also one of the largest Caterpillars in Australia, growing in length to about 12 cms. Some trees where they may be found most years in Leichhardt are known by local school-children as ‘sausage trees’ because the Caterpillars look from the ground like sausages growing in the trees.”

Letter 4 – Moth Caterpillar from Australia: Syntherata escarlata

Subject:  Guava (?) caterpillar
Geographic location of the bug:  North Queensland, Australia
Date: 04/06/2019
Time: 08:27 PM EDT
Your letter to the bugman:  We found this large, colourful caterpillar on a guava tree today (Autumn). It is about the size and thickness of my thumb. What is it? What will it become? Is it harmful?
How you want your letter signed:  Connie

Dear Connie,
This is a Giant Silkmoth Caterpillar in the family Saturniidae, and we believe we have correctly identified it as the Emperor Gum Moth Caterpillar, Opodiphthera eucalypti, which is pictured on Butterfly House.  According to Butterfly House:  “Cherry Guava ( Psidium cattleyanum )” is listed as a food plant.  The Emperor Gum Moth Caterpillar is also pictured on Jungle Dragon and on the Woodlands Historic Park site.  Another possibility is that this might be Syntherata leonae, a species with no common name whose caterpillars are described on Butterfly House as:  “Later the caterpillars become olive green with a yellow line along each side, and have pink-tipped tubercles each of which has a cluster of short stiff hairs.”  The latter species is also pictured on Aus-Lep.  Neither is considered harmful.  Perhaps someone with more expertise in Australian Saturniids will be able to provide more clarification.

Update:  Thanks to a comment from Matthew Connors, we are concluding that this is Syntherata escarlata.

Letter 5 – Emperor Gum Moth from New Zealand

Largest Furry Moth I have ever seen!!
February 2, 2010
Hi bugman, we found this very large moth on our house this morning – Near Wellington, New Zealand.
He was approx 15cm wing span with beautiful colourful brown/green and even pink markings but a little too furry for my likings. Sorry its not the best photo, I did not like to get too close to it 🙂
We have some swan plants in our back garden with Monarch Butterfly eggs and caterpillars, so we are very proud of our bugs!!
Shona (mum), Charlie & Teddy
Paremata, Wellington, New Zealand

Hi Shona, Charlie and Teddy,
This gorgeous moth is an Emperor Gum Moth, Opodiphthera eucalypti.  As you can see from the images on the Csiro Entomology site for Australia, there are many variations.  It is an introduced species in New Zealand.

Letter 6 – Gum Emperor Moth from New Zealand

Subject:  Empower Gun Moth
Geographic location of the bug:  Maramarua, TeAroha, Nz
Date: 10/26/2021
Time: 11:11 PM EDT
Your letter to the bugman:  I spotted this moth on the wall of Cafe 77 at Maramarua, near TeAroha, Tuesday 26th October 2021.
How you want your letter signed:  Jenny

Dear Jenny,
We are thrilled to post your image of a living Gum Emperor Moth.  A few days ago we posted an image of one that was found dead in New Zealand.

Letter 7 – Helena Gum Moth: Caterpillar and Adult

not an Emperor Gum Moth Caterpillar?
Hi,
I almost stepped on this one this morning, I had thought it was an Emperor Gum Moth Caterpillar, but after looking at other photo’s on the web, it doesn’t seem "tufty" enough. looking at the photo (and measuring my hand), it’s probably about 90mm long near Ballarat in Central/Western Victoria, Australia Also seen at same location, I was assuming that this … is an Emperor Gum Moth ? can you confirm any of my ramblings ? thanks,
Glenn

Hi Glenn,
In our opinion, both your caterpillar and moth are a close relateive of the Emperor Gum Moth, the Helena Gum Moth, Opodiphthera helena.