Emperor Moth: Essential Facts & Insights For A Close Encounter

The Emperor Moth is a fascinating, large insect that captures the attention of many nature enthusiasts. These moths are best known for their vibrant, colorful wings and their impressive size. They are primarily nocturnal, which means you’ll most likely find them flying about at night.

Imperial Moth caterpillars come in a variety of colors and can grow to an astonishing 5.5 inches in length. As they develop, their appearance changes, making it an interesting process to observe. Not only are these caterpillars noteworthy for their size, but they also transform into stunning adult moths that are impossible to confuse with other species due to their unique patterns and colors.

An essential aspect to consider about the Emperor Moth is the selection of host plants on which they lay their eggs. These plants play a crucial role in the life cycle of these moths, and understanding their connection to specific host plants will offer valuable insights into their survival and reproduction.

Emperor Moth Overview

Saturnia Pavonia

The Emperor Moth, scientifically known as Saturnia pavonia, is a large and attractive moth species belonging to the Saturniidae family. Noted for their vibrant colors and bold patterns, these moths are especially fascinating for their unique appearance.

Distribution and Habitat

Emperor Moths are widely found across the British Isles, including England, Wales, Scotland, and Ireland, as well as in other parts of Europe. They inhabit various ecosystems such as heathland, moorland, and woodland, showing a preference for areas with birches and fens. Some typical habitats include:

  • Heathland
  • Moorland
  • Woodland (especially with birches)
  • Fens

Conservation Status

Thankfully, the Emperor Moth is not considered an endangered species. Their conservation status in most regions is stable, mainly due to their relatively wide distribution and adaptability to different habitats. However, it is essential to continue monitoring their populations and ensure the preservation of their habitats for their continued survival.

Appearance and Characteristics

Size and Wingspan

  • The Emperor Moth is a large and impressive moth
  • Wingspan ranges from 3 to 4 inches (7.5 – 10 cm)

The Emperor Moth is a large and visually appealing species. With a wingspan that ranges between 3 and 4 inches (7.5 – 10 cm), it is one of the most eye-catching moths native to the UK and Europe.

Colour and Markings

  • Males have mostly brownish-grey wings
  • Both have large eye spots on their wings
  • Eye spots are striking and resemble rings

The overall colour of the Emperor Moth varies slightly between males and females. Males typically have brownish-grey wings, while both sexes display large, striking eye spots on their wings, which resemble rings. These eye spots help ward off predators by acting as a defense mechanism to confuse or scare potential attackers.

Sexual Dimorphism

  • Females have more rounded wings
  • Males have more pointed wings
  • Males have feathery antennae
  • Females have less feathery antennae

Emperor Moths exhibit sexual dimorphism, with males and females having unique physical traits. Their wing shape is one such distinction, with females having more rounded wings, while males have slightly more pointed wings.

Feature Male Emperor Moth Female Emperor Moth
Shape of Wings Pointed Rounded
Antennae Feathery Less Feathery

Antennae are another sexually dimorphic feature in these moths. Males sport feathery antennae, while females possess less feathery antennae. This difference plays a role in the moth’s reproductive success, as the male’s feathery antennae help them sense and locate the pheromones released by females during mating season.

Life Cycle and Behaviour

Eggs and Caterpillars

Imperial moths lay their eggs on the foliage of host plants. The eggs hatch into caterpillars, which have a wide range of appearances and can grow up to 5.5 inches in length.

Some key features of imperial moth caterpillars include:

  • Large size
  • Variability in appearance
  • Feeding on host plant foliage

Pupa and Adult Moths

After the caterpillar stage, the imperial moth enters the pupa stage. The caterpillar forms a cocoon and becomes a pupa, eventually emerging as an adult moth.

Characteristics of pupa and adult moths:

  • Pupa development occurs within a cocoon
  • Adult moths have a beautiful and variable appearance
  • Adult males have more feathery antennae than females

Feeding and Predators

Imperial moth caterpillars feed on the foliage of a variety of host plants. They are considered generalists, as they will consume almost any type of plant material.

As for predators, some common ones include:

  • Birds
  • Small mammals
  • Carnivorous insects

Conservation Status

There is currently no specific conservation status for the imperial moth. However, their population, like other moths and butterflies, can be affected by habitat loss and pesticide use.

Comparison: Imperial Moth vs. Miller Moth
Feature Imperial Moth Miller Moth
Caterpillar Size Up to 5.5 inches (large) Smaller than imperial moth
Caterpillar Diet Foliage of various host plants Mostly grasses and grains
Adult Moth Size Large Smaller than imperial moth
Adult Moth Flight Mostly nocturnal Mostly nocturnal
Predators Birds, mammals, insects Birds, mammals, insects

Food Sources and Habitats

Woodland Rides and Heath

The Emperor Moth prefers living in woodland rides and heath areas, where they find ideal food sources. Some of the moth’s preferred food plants include:

  • Heather
  • Bramble
  • Blackthorn
  • Hawthorn

These plants provide an excellent source of nutrition while allowing the moth to camouflage itself with its surroundings.

Hedgerows and Field Margins

Hedgerows and field margins are another suitable habitat for the Emperor Moth. These areas usually contain a variety of woody plants, such as:

  • Sallow
  • Sallows
  • Other shrubs

These food plants are crucial for the growth and survival of the moth throughout its life cycle.

Sand Dunes and Moorland

Finally, sand dunes and moorland provide yet another ideal habitat for the Emperor Moth. Here, the moth can thrive among a variety of plant species while staying close to nature. The list of food plants found in this habitat includes:

  • Heather
  • Bramble
  • Other native plants
Habitat Food Plant Example 1 Food Plant Example 2
Woodland Rides Heather Bramble
Hedgerows Sallow Sallows
Sand Dunes Heather Bramble

By understanding the various habitats and food sources of the Emperor Moth, we gain a better insight into this beautiful butterfly’s behavior and preferences.

Miscellaneous Information

History and Classification

The Emperor Moth belongs to the Saturniidae family, and the species was first classified by Carl Linnaeus. They are considered large, showy insects that are known to fly at night. Caterpillars of this moth can grow up to 5.5 inches and display a variety of colors, from light to dark green and brown shades.

Some features of the Emperor Moth include:

  • Large size
  • Yellow wings with spots and speckles
  • Highly variable caterpillar coloration

Mating and Pheromones

For mating, Emperor Moths use pheromones to communicate. Male moths have more feathery antennae, which helps them to detect these pheromones in the air and locate females for mating. Mating usually occurs at night, aligning with their nocturnal nature.

Comparison of Male and Female Emperor Moths:

Feature Male Female
Antennae Feathery Less feathery
Flying Time Night Night

Although not a primary predator, owls may occasionally prey on Emperor Moths due to their nocturnal activity. As these moths fly and mate primarily at night, they can be difficult to observe and photograph, making pictures involving them a challenging but rewarding achievement in the world of science.

Authors

    by
  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

83 thoughts on “Emperor Moth: Essential Facts & Insights For A Close Encounter”

    • Thanks for the reply 50/50, after many months. I found this caterpillar on the grass in my garden in Johannesburg. When I discovered, after a week, that my whole Kiepersol tree was invaded, I was so shocked! They eat, but every single leaf on this tree! After they’ve eaten and fully grown, they bury themselves under the soil for the next stage, before becoming a giant moth. I also thought it was a Mopani worm, and googled it, but no, not a Mopani. Does anyone know a short name for this creature? Except for the African Emperor?

      Reply
  1. Happy Thanksgiving!

    You may want to take this up with Bill Oehlke, but the forewing on this specimen doesn’t seem quite dark enough to me to be H. dyops and looks more like Heniocha marnois. I am not certain about this so I would ask Bill.

    Reply
  2. Also Spotted in Pretoria South Africa in April 2013 beneath a Kiepersol tree. All of them fell off the tree and was moving to the West side of the stand.

    Reply
  3. Eyespots, wonderful!
    I also thought, “Bird Attack!” when I saw this butterfly. This red-tip hedge (of my neighbors) is patrolled by a mockingbird who was singing nearby while I took photos. I wonder…

    Reply
  4. Eyespots, wonderful!
    I also thought, “Bird Attack!” when I saw this butterfly. This red-tip hedge (of my neighbors) is patrolled by a mockingbird who was singing nearby while I took photos. I wonder…

    Reply
  5. My garden has just become invaded with these. There must be about 100 roaming around. The unfortunate part is because they wiggle like snakes, I am petrified 🙁

    Reply
  6. Dear WTB
    Thank you so much and for such a speedy response!
    The photographs you may of course use.
    I will direct my sister to the photos of the adult moth which is different in colouring from the ones commonly seen, which are pinkish in the eyes and the margin patterns and generally all over buff coloured. Where as the one shown in the related posts is yellow and brown and much lighter all over.
    I will let you know if she has any more information.
    Thank you again.

    Regards
    Anita

    Reply
    • Please send any photos of the adult moth you might have or might be able to take. It would be an excellent resource to be able to include photos of the caterpillar and moth on our site, especially as there is so much taxonomic revision being done regarding species and subspecies that are very local in distribution.

      Reply
  7. Dear WTB
    Thank you so much and for such a speedy response!
    The photographs you may of course use.
    I will direct my sister to the photos of the adult moth which is different in colouring from the ones commonly seen, which are pinkish in the eyes and the margin patterns and generally all over buff coloured. Where as the one shown in the related posts is yellow and brown and much lighter all over.
    I will let you know if she has any more information.
    Thank you again.

    Regards
    Anita

    Reply
  8. We are on holiday in Keurbooms and there are dozens of these caterpillars on a small tree in the garden, the neighbour says they are here every year ~ poor tree is denuded!! Got some amazing photos though 🙂

    Reply
  9. I have seen these caterpillars for the first time. The “water tree” in front of my house is invaded by them and has no leaves left. They are digging holes in the ground and I am worried that the tree is damaged. Obviously if these are moths I’m soon going to have an invasion plaque of giant moths. How can I get rid of them?

    Allison

    Reply
  10. I have seen these caterpillars for the first time. The “water tree” in front of my house is invaded by them and has no leaves left. They are digging holes in the ground and I am worried that the tree is damaged. Obviously if these are moths I’m soon going to have an invasion plaque of giant moths. How can I get rid of them?

    Allison

    Reply
  11. Hello,
    We found these interesting insects at the restaurant I work at in Port Elizabeth, there is a small garden area next to the function area and they came inside, was a mission to collect them but eventually managed to get them all we hope. We are all wondering if they are poisonousor not, a few of us handled them and a couple of guys managed to get themselves pricked by the spines.

    Sincerely
    Troyé

    Reply
  12. Hello,
    We found these interesting insects at the restaurant I work at in Port Elizabeth, there is a small garden area next to the function area and they came inside, was a mission to collect them but eventually managed to get them all we hope. We are all wondering if they are poisonousor not, a few of us handled them and a couple of guys managed to get themselves pricked by the spines.

    Sincerely
    Troyé

    Reply
  13. Hi, I just found about 50 in my neigbours fig tree. They are munching all the young leafs. Shame poor plant. If they burry themselves do they come back and eat on that tree again?

    Reply
  14. I have thesenasty looking catterpillars in my garden.
    They don’t bug, pardon the pun, me as much as scare me with their armour like body.
    I am scared they get into my roof and start feeding on the wood.
    Am I over-thinking this?

    Please let me know, as I would hate to exterminate something harmless.

    Thanks!!

    Reply
    • Emperor Moth Caterpillars feed on leaves, not on wood, so your roof is safe. According to Wikipedia: “Food plants Bauhinia spp, Croton spp, Harpephyllum caffrum, Cussonia spp, Celtis spp, and Ekebergia capensis. In DR Congo the larvae feed on Sarcocephalus latifolius, Crossopteryx febrifuga and Dacryodes edulis.”

      Reply
  15. I have thesenasty looking catterpillars in my garden.
    They don’t bug, pardon the pun, me as much as scare me with their armour like body.
    I am scared they get into my roof and start feeding on the wood.
    Am I over-thinking this?

    Please let me know, as I would hate to exterminate something harmless.

    Thanks!!

    Reply
  16. I live in Amanzimtoti in Kwa Zulu Natal, South Africa which is subtropical and last year we also had lots of these beautiful caterpillars in the garden and they too were on our Kiepersol (cabbage) tree, they had a wonderful feast and moved off. I thought they were stunning and picked a couple of them up for some photographs, (after I checked they were not poisonous.) Nature makes some amazing creatures.

    Reply
  17. I currently have a whole collection of the African Emperor worms eating my tree. I was totally shocked when I first saw them. Very happy they will turn into stunning moths. They are welcome to stay and graze 🙂

    Reply
    • The leaves will grow back after your caterpillars pupate. The caterpillars are also an important food source for birds and other insectivores.

      Reply
  18. Our cussonia trees are also invested with these ghastly emperor caterpillars. They are also creeping around on our patio and in the garden and we have to keep our little Jack Russel inside all the time. They are causing a massacre of the leaves of the cussonias and I really want to get rid of them. Am going to pour ant poison around the trunk of the tree. We have been living six years here and have never seen them before. Is it the drought that have brought them here? See you provide no eradication advice, but surely there is something which can be sprayed which is environment friendly?

    Reply
    • Insect populations change year to year depending upon weather conditions and food supplies. We are not sure why you are being so troubled this year and you have seen no evidence of Emperor Moth Caterpillars in previous years. You are correct that we do not provide extermination advice.

      Reply
  19. I found this caterpillar by my house,and it`s not eating or moving.It`s is night time at my house so it might sleeping,but I don`t know.I`m waiting for it to make a cocoon,then I`ll let it fly away.Can you tell me what it eats please.I would be sad if it did not eat. Thank you Bug Man ,Jake

    Reply
    • Chances are that if the caterpillar left its food plant, it was to search for a place to pupate. At that time, the caterpillar stops eating.

      Reply
  20. We are in Ballito and just noticed thousands of them eating away our tree there are big ones and smaller ones as well as some with eggs on them. Thought I wanted to exterminate them but after reading these comments we will leave these beauties to graze.

    Reply
  21. Thank you Bugman! Great website. We saw a lot of these African Emperor caterpillars purposely crawling along the grass and tarmac in our church carpark. We kept collecting them and putting them into the flower beds to keep them from being run over but they weren’t co-operating! It was obvious they were looking for a place to pupa. Our toddler group were fascinated by them! What beautiful creatures.

    Reply
  22. The caterpillars arrived virtually overnight again in the same kiepersol tree at the same time of the year in Northwold, Johannesburg. After about a week they disappeared again virtually ovennight. The tree is stripped bare in places ant the ground underneath thick with droppings—–but no caterpillars.

    Reply
  23. Very curious about this bug my dad found the exact same moth/butterfly in france is this normal ? Is this bug dangerous ?

    Reply
  24. Interesting to hear the news ab out the emperor moth caterpillars, I feel that they do the tree a favour as while they eat they also create fertiliser, and as most of these creatures depend on some sort of tree they seldom do that much harm to the tree as to destroy the tree altogether, they need to feed themselves again next year, you could say they are subsistence farmers of a sort.

    Reply
  25. HI There, We live in Pretoria South Africa, and have the same infestation of the gorgeous caterpillars in our kipersol tree. I have picked a few and put them in a box (with some kipersol leaves) to take to school. Do you think they would pupate if the don’t have soil? I would love to see them change to moths. My children are fascinated as are we.
    I would never spray these caterpillars or kill them. The trees will come back and shoot new leaves anyway. I am just so happy we still have interesting creatures to find in our garden in the city.
    They are so big at the moment they almost look like they are ready to change.
    So exciting!!

    Reply
  26. HI There, We live in Pretoria South Africa, and have the same infestation of the gorgeous caterpillars in our kipersol tree. I have picked a few and put them in a box (with some kipersol leaves) to take to school. Do you think they would pupate if the don’t have soil? I would love to see them change to moths. My children are fascinated as are we.
    I would never spray these caterpillars or kill them. The trees will come back and shoot new leaves anyway. I am just so happy we still have interesting creatures to find in our garden in the city.
    They are so big at the moment they almost look like they are ready to change.
    So exciting!!

    Reply
  27. I noticed one of these caterpillars yesterday. ( in Port Elizabeth) Today we saw more then realised they were coming down the tree trunk, lots of them! What we originally thought were little berries fallen on the ground must be caterpillar poop 🙂

    Reply
  28. We discovered dozens of these caterpillars on a milk wood tree in our garden in Grahamstown Eastern Cape South Africa. After a while they move onto the ground looking to bury themselves under the grass. How long do they take to chrysalis then emerge as moths? Very beautiful little creatures. Make sure to let everyone know they are totally harmless and a sign of healthy environment. Don’t kill them. They are a part of the ecosystem probably food for birds and bats

    Reply
  29. Good day! I just found a Emperor Catepillar and would love to keep it and show the cycle to my son but I am not to sure whats the best way to keep it save and feed it???
    Plse Help!!!

    Reply
  30. Good day! I just found a Emperor Catepillar and would love to keep it and show the cycle to my son but I am not to sure whats the best way to keep it save and feed it???
    Plse Help!!!

    Reply
  31. We have a whole stack of them in the neighbours tree. saw them yesterday feeding away and they get so fat they fall off onto the lawn. We live in Port Alfred, Eastern Cape. Glad to hear they are harmless. Scary looking for sure.

    Reply
  32. I collected a few fro my kids to watch change into moths, I collected soil and added some of the leaves fro them to eat, they unfortunately all shriveled up and died.

    Reply
  33. We visited near Bela-Bela and a nasty caterpillar got hold of me. Stung me in the neck. Havpie a severe rash.. Local told me it was a caterpillar, althtough I did not see it. Do you know more about it, and how long will rash last?

    Reply
  34. Why would the moths move into our ceiling and use the light fitting as a door? I’ve noticed the caterpillars for the first time this year in our Pretoria, South Africa, garden and now they hang around in our kitchen. Could the handful of indoor plants be the reason? We also have not used any poison in the garden since we’ve moved in 5 years ago.

    Reply
    • See that it’s warm has a bit of water/moisture and keep it away from the cat, a bit of cheese is also a good idea, some of them actually like candy floss.

      Reply
  35. Found one in our garden yesterday, (to my six year old sons delight) We are situated in Naboomspruit (Limpopo) I have never seen anything like it. Really a beautiful creature, but scary in a way.

    Reply
  36. I have had the same experience but all the caterpillars have had wasp eggs attached to them and will surely be devoured before they can pupate and become moths again

    Reply
  37. Found one of these caterpillars in my garden this morning under the peper tree. Took photos and then carefully relocated it to the reserve across the road.
    Nearest pine tree is about 800m away. Don’t know how it got to my garden.
    Lovely colours. Would love to see what it becomes.
    I’m located in Kleinmond, in the Overberg region

    Reply
  38. Found one of these caterpillars in my garden this morning under the peper tree. Took photos and then carefully relocated it to the reserve across the road.
    Nearest pine tree is about 800m away. Don’t know how it got to my garden.
    Lovely colours. Would love to see what it becomes.
    I’m located in Kleinmond, in the Overberg region

    Reply
  39. We are in Pretoria, Akasia. Our house is in a place called Chantelle. These worms scare my wife. They are looking fierce of course. Could you tell me what their common name is and any African name (any of the South African languages) if they have any?

    Reply
  40. Seeking information, defiantly a cabbage tree caterpillar. But no Kiepersol tree nearby? all making here way to somewhere? Where are they going? can they feed on other trees? how long till they become a moth?

    Reply
  41. Can you please tell me how long between starting the pupa stage to the orchard swallowtail butterfly emerging.
    The one on our curry leaf plant has been in pupa for two days.
    I was surprised it was on the curry leaf plant as we also have dwarf lime and kaffir lime nearby.

    Reply
  42. Can you please tell me how long between starting the pupa stage to the orchard swallowtail butterfly emerging.
    The one on our curry leaf plant has been in pupa for two days.
    I was surprised it was on the curry leaf plant as we also have dwarf lime and kaffir lime nearby.

    Reply
  43. We have hundreds of these which return to the same trees each year. Some of them have what look like white eggs all over them. Can anyone tell me what these are?

    Reply
    • Some species of large caterpillars, especially those in the families Saturdiidae and Sphingidae, fall prey to parasitoid Brachonid Wasps that lay eggs inside the developing caterpillar. The Braconid larvae feed on the non-vital internal organs, eventually emerging and forming pupae on the Caterpillar, which alas, will not survive the parasitization.

      Reply

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