Everything You Need to Know About Citrus Swallowtail Caterpillars

Citrus Swallowtail Caterpillar, also known as the Giant Swallowtail Caterpillar, is an intriguing species of caterpillar found primarily on citrus plants. They’re known for their unique appearance, resembling bird droppings in their larval stages to help them avoid predators.

Feeding mainly on citrus plants, these caterpillars are sometimes referred to as “orange dogs” due to their common presence in orange groves. As they grow, they transform into stunning Giant Swallowtail butterflies, with beautiful yellow-filled tails and brick-red patches on their ventral hind wings.

In this article, you’ll discover everything you need to know about this fascinating creature, from its life cycle and habitat preferences to its impact on citrus plants and how to manage them in your garden.

Citrus Swallowtail Caterpillar Basics

Scientific Classification

The Citrus Swallowtail Caterpillar belongs to the order Lepidoptera and the family Papilionidae. There are three main species that are closely associated with citrus plants:

  • Papilio demodocus: Commonly found in Africa.
  • Papilio cresphontes: Known as the Giant Swallowtail, native to North and Central America.
  • Papilio demoleus: Found in Asia and Australia.

Distribution

Citrus Swallowtail Caterpillars are widely distributed across various continents, depending on the species. For instance, Papilio demodocus is native to Africa, while Papilio cresphontes is found throughout North and Central America. On the other hand, Papilio demoleus inhabits Asia and Australia.

Life Cycle

The life cycle of a Citrus Swallowtail Caterpillar consists of 4 stages:

  1. Egg: Tiny, yellow, and spherical – laid on citrus leaves.
  2. Larva: The caterpillar stage, which has a bird-dropping appearance and a blotchy brown-and-white pattern. It feeds primarily on citrus leaves and is often called an “orange dog” due to its prevalence in orange groves.
  3. Pupa: The caterpillar forms a chrysalis to undergo metamorphosis, typically attaching itself to a twig or leaf stem.
  4. Adult: The fully developed butterfly emerges from the chrysalis, showcasing vibrant colors and patterns on its wings.
Species Native Range Key Characteristics
Papilio demodocus Africa Yellow spots near wing margins
Papilio cresphontes North and Central America Yellow-filled tails, brick-red patch on wings
Papilio demoleus Asia and Australia Black wings with white, red, and blue spots

In conclusion, understanding the basics of the Citrus Swallowtail Caterpillar, its scientific classification, distribution, and life cycle can be helpful for gardeners, citrus growers, and butterfly enthusiasts.

Appearance and Identification

Eggs and Larvae

Giant swallowtail caterpillar eggs are small and round, often laid singly on host plants. Larvae go through several growth stages, called instars. In their early stages, they have a blotchy brown-and-white color pattern that looks remarkably like bird droppings 1. This camouflage helps protect them from predators.

Mature Larvae

Mature larvae grow up to 1-1/2″ to 2″ long 2. At this stage, they still maintain the bird-dropping-like appearance, with the following key features:

  • Blotchy brown-and-white pattern
  • Fleshy setae (hairs) on their bodies

This clever camouflage strategy allows them to blend in with their surroundings and remain relatively safe from predators.

Pupa

The pupa forms from the final larvae stage and is usually attached to the host plant. The color and texture of the pupa imitate the plant material, providing additional camouflage.

Adult Butterfly

As an adult, the giant swallowtail butterfly displays stunning features:

  • Wingspan: 4″ to 5″ 3
  • Predominant black with yellow markings
  • Distinct yellow-filled tails

The adult butterfly can be distinguished from other similar species, such as the Schaus’ swallowtail, by the presence of the yellow-filled tails and the small, brick-red patch just interior to the blue median band on the ventral hind wing 4.

Comparison of Giant Swallowtail Butterfly to Schaus’ Swallowtail Butterfly

Feature Giant Swallowtail Schaus’ Swallowtail
Tails Yellow-filled All black
Red Patch Present Absent

Host Plants and Habitat

Citrus Trees

Citrus swallowtail caterpillars primarily feed on citrus trees. They are often found in:

  • Orange groves
  • Lemon trees
  • Grapefruit trees

These caterpillars are called “orange dogs” because they’re commonly found in orange groves.

Other Host Plants

Aside from citrus trees, the caterpillars also feed on other plants in the Rutaceae family, such as:

  • Hercules club
  • Prickly ash
  • Common rue

These plants provide an alternative food source, crucial for their survival and growth.

Gardens and Agriculture

Citrus swallowtail caterpillars can be found in various habitats, including:

  • Gardens with citrus trees
  • Agricultural areas cultivating citrus
  • Parks and reserves with host plants

Though they prefer citrus trees, they might feed on other plants in the citrus family when citrus trees aren’t available.

Habitat Benefits Drawbacks
Gardens – Close to host plants
– Sheltered environment
– May be subject to pesticide use
– Can cause damage to citrus trees
Agriculture – Abundant food supply
– Large areas to thrive
– High pesticide use
– Destructive to crops
Parks and Reserves – Natural environment
– Reduced chemical exposure
– May experience competition for resources
– Variable host plant availability

Overall, understanding the host plants and habitat preferences of citrus swallowtail caterpillars helps in implementing effective management strategies and promoting their conservation in various ecosystems.

Behavior and Adaptations

Camouflage and Defense

Swallowtail caterpillars, like the Giant Swallowtail Caterpillar, are masters of camouflage. These caterpillars showcase cryptic coloration, which makes them resemble bird droppings. This disguise helps protect them from predators.

Some features of their camouflage include:

  • Brown and white blotchy pattern
  • Bird dropping-like appearance throughout larval stages

Feeding Habits

Swallowtail caterpillars have specific feeding habits. They primarily feed on citrus plants and are often called “orange dogs” because they are commonly found in orange groves. These caterpillars tend to target young citrus leaves and shoots.

In addition to citrus plants, some swallowtail caterpillars consume nectar from various flowers during their adult butterfly stage. Such feeding habits play a vital role in their courtship and mating rituals.

Comparison Table: Giant Swallowtail Caterpillar vs. Other Caterpillars

Feature Giant Swallowtail Caterpillar Other Caterpillars
Camouflage Bird dropping-like Varies
Primary Food Source Citrus plants Various host plants
Adult Feeding Preference Nectar from flowers Depends on butterfly type
Common Name Orange Dogs Differs by species

Citrus Swallowtail as a Pest

Effects on Citrus Crops

The citrus swallowtail caterpillar, also known as orange dogs, is considered a pest due to its consumption of citrus foliage. A few of these caterpillars can rapidly defoliate small or young plants. These larvae chew on both fruit and leaves, a unique characteristic among citrus pests.

Control Methods

There are several ways to manage citrus swallowtail caterpillars:

  • Biological control: Some natural enemies, such as predators and parasitic wasps like Pteromalus, can control the caterpillar population.
  • Bacillus thuringiensis (Bt): This natural, environmentally-friendly pesticide is effective against caterpillars, as it targets a specific amino acid that is essential for their nutrition.
Control Method Pros Cons
Biological control Natural, environmentally safe May not always be effective
Bacillus thuringiensis Targets caterpillars only Requires multiple applications

In conclusion, the citrus swallowtail caterpillar can cause significant damage to citrus crops, but there are effective biological controls and pesticides available to manage them.

Attracting Butterflies to Your Garden

Creating a butterfly-friendly garden is simple and rewarding. With a few easy steps, you can bring these beautiful insects to your own space.

First, choose the right plants. Butterflies, including the Citrus Swallowtail Caterpillar, need larval host plants for their caterpillar stage and nectar-producing plants for their adult stage. Opt for native plants, as they are naturally suited to your local butterfly species. Examples of suitable plants are milkweed, asters, and goldenrod.

Another crucial factor is sunlight. Butterflies need 6-8 hours of direct sun to bask in and warm their bodies for flight. Choose a sunny spot for your butterfly garden, away from harsh winds.

Here are some features of an ideal butterfly garden:

  • Full sun exposure for at least 6-8 hours
  • Native plants that provide both nectar and larval host options
  • Sheltered location, protecting the insects from strong winds

In spring, make sure to provide host plants for caterpillars, as this is the time they are most active and busy transforming into butterflies.

Finally, avoid using broad-spectrum pesticides in your garden. These chemicals can harm not only pests but also the butterflies you are trying to attract.

By implementing these tips, you can create a lovely sanctuary for butterflies and enjoy their enchanting presence throughout the spring and summer months.

Conservation and Importance

The Citrus Swallowtail Caterpillar, also known as Papilio cresphontes Cramer, can be found in various regions such as South Africa, the Caribbean, Madagascar, and Oman. It is crucial to conserve this species as they play an essential role in the ecosystem. Here’s why they are essential:

  • They are a vital food source for various bird species.
  • They contribute to the pollination of citrus plants.

These caterpillars are commonly found in Florida and are known for their distinct characteristics:

  • Blotchy brown-and-white pattern, resembling bird droppings
  • Foul smell when disturbed, acting as a defense mechanism
  • Primarily feed on citrus plants, earning them the name “orange dogs”

When discussing the distribution of Citrus Swallowtail Caterpillars in different locations, we can draw a comparison table as follows:

Location Caterpillar Type Importance
South Africa Citrus Swallowtail Pollination of Citrus Plants
Caribbean Papilio cresphontes cramer Aiding in Moth Population
Florida Orange dogs Contribution to local biodiversity

In conclusion, the conservation of Citrus Swallowtail Caterpillars is crucial for maintaining ecological balance and ensuring the diversity of species in the regions they inhabit. By protecting these creatures, we are, in turn, helping maintain the health and well-being of the many other species that rely on them.

Footnotes

  1. https://sfyl.ifas.ufl.edu/wakulla/natural-resources/big-bend-bugs/caterpillars/
  2. https://sfyl.ifas.ufl.edu/wakulla/natural-resources/big-bend-bugs/caterpillars/
  3. https://entnemdept.ufl.edu/creatures/citrus/giantswallowtail.htm
  4. https://entnemdept.ufl.edu/creatures/citrus/giantswallowtail.htm

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 – Citrus Swallowtail Caterpillar

Subject: Brown and white insect
Location: Sydney, Australia
March 3, 2017 5:44 pm
Hi bugman,
8 of these have appeared on my mandarin tree this morning. Are they a danger to it?
We’ve just moved from summer to autumn, and I love right near the central city, if that helps?
Signature: Lee

Citrus Swallowtail Caterpillar

Dear Lee,
This looks like an early instar Citrus Swallowtail Caterpillar,
Papilio aegeus, based on an image posted to the Brisbane Insect site that states:  “The first and second instars larva closely resembles a fresh bird dropping. The larva feed singly on food plants. They usually feed during the day and rest by night on the upper side of leaves.”  The fifth or final instar larva is an impressive caterpillar that will produce a forked, red osmeterium, a defense organ that releases a foul odor that will dissuade predators.  If this is a mature tree, it can handle losing the number of leaves eaten by eight caterpillars, and you will benefit from having adult Citrus Swallowtails flying in your garden.

Letter 2 – Citrus Swallowtail Caterpillar and Citrus Swallowtail Butterfly

Australian bird shit caterpillar
Hi Bugman,
I am no entomologist but I like science and looking at it I was thinking: What is that? A bird shit caterpillar !!! Wow, how darwinian !? Searching on the net I discover you have the same in Kansas… I thought you’d be interested to know that we have the equivalent in Australia living on our lemon tree, it’s the citrus thing that triggered my interest. Two bugs adopting the same mimicry eating the same kind of leaves…? It’s more than just a case of co-evolution. And I suspect the butterfly associated to this caterpillar is this gorgeous one that goes up and down and up and down in the hot summer afternoon in our backyard. I have a pic somewhere I’ll try to find it if you are interested. On the pic the caterpillar is in a defensive position, normally the pointy bits are not erected and it looks just like a bird poo. New years greetings from Oz
Olivier Bruge & Peter Young
Canberra

Hi Olivier and Peter,
Your caterpillar is a Citrus Swallowtail or Orchard Swallowtail, Papilio aegeus. The Butterflies of Australia website has images of the caterpillars and the adults. Your caterpillar is an early instar, and the coloration will change with subsequent molts. We would love to get a photo of the adult butterfly if you are able to send one.

Down under Papilio Aegeus !
Hi Daniel,
Thank you so much for your answer. Here is the pic of the butterfly I was very happy to know that my huntch was right. I love the idea that this beautiful insect comes out of a big poo!! It’s a great evolutionary version of Andersen’s “hugly duckling”. … Have a g’day (as we say here)
Olivier Bruge,
Canberra, Australia.

Letter 3 – Citrus Swallowtail

Citrus or Orchard Swallowtail Butterfly
Hi Bugman,
Hope you like this pic of female Citrus Swallowtail Butterfly feeding on Bouganvillea flowers. Taken April 5 2007 Gold Coast Queensland Australia keep up the good work guys, really appreciate your site, its a great source of information.
Trevor Jinks
Australia

Hi again Trevor,
Thank you so much for your latest photo addition to our site.

Letter 4 – Citrus Swallowtail Caterpillar from South Africa

Subject: citrus caterpillar
Location: Cape Town. South Africa
February 2, 2015 10:44 am
Hi
I really love this website. It’s wonderful. I found this caterpillar on my grapefruit tree. Summer, mid January. Very beautiful creature. My question is whether this caterpillar is indigenous South Africa and if not, where is it from? Also, could you post an image of its butterfly Please.
Signature: Bonnie

Citrus Swallowtail Caterpillar
Citrus Swallowtail Caterpillar

Dear Bonnie,
This is indeed a Citrus Swallowtail Caterpillar,
Papilio demodocus, and the adult, according to Kirby Wolfe, is known as a Christmas Butterfly because they are most common in December.  The species is native to sub-Saharan Africa, and according to the Butterflies of Africa:  “Papilio demodocus is found across most of sub-Saharan Africa, including Madagascar, and is also found in s.w. Arabia. The butterfly bears a remarkable resemblance to P. demoleus, an Oriental species found from n.e. Arabia to the Philippines, and which also occurs in Australasia. The two species however are not as closely related as their appearance would seem to indicate.”  Here are some images of the adult Citrus Swallowtail from our archives.

Letter 5 – Citrus Swallowtail Caterpillar Metamorphosis in South Africa

Caterpillar identification

Citrus Swallowtail Caterpillar prepares to Pupate

Caterpillar identification
Location: Still Bay, Western Cape, South Africa
February 19, 2011 10:13 am
Hi. I have a caterpillar that has decided to attach itself to our carport. Would love to know what species it is and how long we need to watch till it emerges again.
Signature: Galye

Citrus Swallowtail Caterpillar prepares to pupate

Dear Galye,
This is the caterpillar of a Swallowtail Butterfly in the family Papilionidae.  We believe it is the caterpillar of a Citrus Swallowtail,
Papilio demodocus.  You can compare you individual to this image on FlickR or this image on WebShots.  We hare happy you sent us images of both the pre-pupa and the Chrysalis.  The Chrysalis of most Swallowtail Butterflies is unique in that it is supported in an upright position by a girdle of silk.

Keith Wolfe provides some information
Hi Galye,
Yes, if healthy, your chrysalis will metamorphose into a Citrus Swallowtail — aka Christmas Butterfly, because adults are often commonest in December, and Orange Dog, because its caterpillars can be pests of young orange trees and related plants — in about 10 days.  BTW, here is a better image for you to compare (the above Flickr link shows an unusually marked individual, while the Webshots photo is misidentified): http://photocamel.com/gallery/data/1138/Papilio_demodocus_final_instar_Gillitts_14_Mar_09.jpg.
Best wishes,
Keith

Update from Galye
February 28, 2011
Thank you so much for your quick reply. Loved the photo links you sent. Unfortunately we missed the butterfly coming out of the pupa stage. Have some photo’s of the pupa casing that was left. Would love it if you could send me a link for some photos that show the butterfly emerging.

Citrus Swallowtail Chrysalis Exuvia

Hi Galye,
Thanks for the update and new photo, and we are sorry you missed the actual transformation process.  Alas, we were unable to quickly locate an image of a Citrus Swallowtail Butterfly emerging from the chrysalis, but we did get documentation of a newly emerged individual in 2007.
We also located this image of a Giant Swallowtail emerging from the Chrysalis on the Science Photo Library website.

Letter 6 – Citrus Swallowtail Chrysalis and emerged adult

Apologies for not getting back to you sooner. I discovered it was the Citrus Swallowtail, my address is southern Queensland in Australia and it hatched out yesterday, see the photos i’m pleased to attach, i was so sure i’d miss the moment. How do they fit into the case, it IS a miracle./
dawn

Hi again Dawn,
Thank you so much for the followup images of the metamorphosis of the spectacular caterpillar you sent our way on January 19. Your photos are all wonderful.

Letter 7 – Citrus or Chinese Swallowtail Caterpillar

Cute mystery caterpillar
Aloha!
After reviewing your site, I think this might be either a swallowtail or a sphinx moth caterpillar, but I’m not sure. I found it on a lime tree in my yard. The white on its underside is coloration, not parasitic eggs. I went back outside to double check after looking at the picture. Speaking of the picture, sorry it isn’t great-I couldn’t get my camera to focus on the bug instead of its surroundings. I live on the windward (eastern) side of Oahu, in Hawaii. I love your site! Can you identify my bug?
Thank you!
Ginger

Hi Ginger,
Though your photo is blurry, it is unmistakenly a Swallowtail Caterpillar. We are almost certain it is the Citrus Swallowtail or Chinese Swallowtail, Papilio xuthus. It is an introduced species and supposedly the only swallowtail in Hawaii.

Letter 8 – Citrus Swallowtail Caterpillar from South Africa

Subject: Please help me identify
Location: North west province, south africa
October 25, 2013 11:00 am
Hi, I found this creature crawling across my kitchen floor in hartebeespoort South Africa. It had red ’tentacles’ that emitted a nasty odour that it retracted. I figure it is some kind of swallowtail. Can you help me identify the species.
Signature: Jo

Citrus Swallowtail Caterpillar
Citrus Swallowtail Caterpillar

Dear Jo,
This is the caterpillar of a Citrus Swallowtail,
Papilio demodocus, and we are guessing there was a citrus tree nearby.  Like the individual in the link we provided, your individual is most likely searching for a place to begin metamorphosis.  The adult Citrus Swallowtail is a lovely butterfly.  We wish you had been able to provide an image of the osmeterium, the forked scent gland that is characteristic of Swallowtail Caterpillars and other species in the family Papilionidae including this Fuscus Swallowtail Caterpillar from our archives.  This photo from Getty Images identifies the Citrus Swallowtail as being in a different genus, and the name Princeps demodocus may represent a recent taxonomic change.

Thank you for that response. It is great idea you guys have and it’s nice to know there is somewhere one can go to have one’s bug questions answered. Keep well.
Jo

Letter 9 – Citrus Swallowtail Caterpillar from South Africa

Subject: Big Green worm
Location: Pretoria, Gauteng, South Africa
April 13, 2014 10:29 pm
Hi
I found these guys on my lemon tree and they have now spread to most trees in my garden.
Scary looking things with a thorn on there backs, have 2 big eyes and a mouth that looks like something out of aliens.
Pics attached.
Signature: Regards,

Citrus Swallowtail Caterpillar
Citrus Swallowtail Caterpillar

This is the Caterpillar of a Citrus Swallowtail, Papilio demodocus, a lovely butterfly that feeds on the leaves of citrus trees while in the larval stage.  All the features you describe are used as defense mechanisms by the caterpillar, which has a forked organ known as an osmeterium that is revealed and accompanied by a scent some predators might find off-putting.  We believe that is the thorn you have mentioned.  The eyes and mouth you mentioned are markings that might cause a predator, like a bird, to believe this is a much larger predator, like a snake, instead of a delectable morsel.

Letter 10 – Citrus Swallowtail Caterpillar from Taiwan

Subject: Can you identify?
Location: Taiwan
November 18, 2013 10:08 pm
Dear Bug People:
Are you able to tell me who is voraciously eating my cute mini-orange tree? (pic enclosed)
Location: Taipei, Taiwan
Found on: Orange tree sapling
Size: about 4 cm
Color: green, with some uneven black spots/bands
Built: muscular, probably works out, nice abs, compact
Hairs: none
Behavior: protested against being picked up by sliming me and extending two orange-red tentacle-like appendages from its head, which it subsequently subtracted.
Current status: moping on a Taro leaf on other balcony. Not happy?
Signature: Luuk

Citrus Swallowtail Caterpillar
Citrus Swallowtail Caterpillar

Dear Luuk,
This appears to be an early instar caterpillar of a Citrus Swallowtail or Lime Swallowtail,
Papilio demoleus.  You can see comparable images as well as images of the entire life cycle on Featured Creatures.  If you can endure the loss of a some leaves on your tree, your will eventually metamorphose into a lovely Citrus Swallowtail.

Dear Daniel:
Thank you so much for your trouble! I really appreciate the prompt and detailed reply.
I have taken the pouting Citrus Swallowtail caterpillar from the Taro where I had put it to save my frail orange tree, and put him back. He’s now happily munching away again. I figured I can always buy a new orange tree sapling, but I would not know where to purchase a beautiful butterfly.
Thanks again!
Luuk

Letter 11 – Citrus Swallowtail Caterpillars from South Africa

Subject: Catipillar identification
Location: Cape Town
October 14, 2016 2:13 am
Hi there. I have found a few of these on my lime tree. I was wondering what they are and what type of moth/butterfly they will become.
I live in Sunningdale, Cape Town. It’s October now and it’s the first time I have ever seen them.
When touched they produce a forked shaped protrusion from their head and secrete a clear liquid. They are still quite small and I’ve only found three so far.
Signature: Tamlyn

Citrus Swallowtail Caterpillars
Citrus Swallowtail Caterpillars

Dear Tamlyn,
These are Citrus Swallowtail Caterpillars, and there are several species that go by that common name.  We found this matching image on Alamy, but it is not identified to the species level.  
Papilio demodocus is one species called a Citrus Swallowtail, and it is pictured on BioDiversity Explorer, but there are no early instar caterpillars pictured. We also located a matching image on iSpot.

Letter 12 – Citrus Swallowtail from Solomon Islands

Solomons swallowtail
December 17, 2009
This is another video frame. Unfortunately the butterfly never stopped moving. This frame is the closest to “sharp” as I could grab from the video. I’m guessing it is a swallowtail sp.
Bruce, Atlanta
Solomon Islands, Tenaru River, Guadalcanal

Citrus Swallowtail
Citrus Swallowtail

Hi Bruce,
This appears to be a male Citrus Swallowtail, Papilio aegeus.  The Lepidoptera Butterflyhouse website has nice images of the entire metamorphosis.  This species exhibits sexual dimorphism, where the two sexes look radically different from one another.  Additionally, there are many races and subspecies throughout Australia, Indonesia, the Solomons and New Guinea.

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.

    View all posts
  • 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.

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3 thoughts on “Everything You Need to Know About Citrus Swallowtail Caterpillars”

  1. I live in the Philippines at roughly 400 meters above sea level and have for the last week been following the growth of a Citrus Swallowtail Butterfly. yesterday it entered chrysalis.

    I noted the classic V shape but was unable to get a shot. Today I did get some good shots.

    I hope to follow it through the entire cycle and if really lucky I’ll get a video of it’s coming out.

    I have been calling it a moth but thanks to your work now know it is a caterpillar. Thanks

    Brian

    Reply
  2. I live in the Philippines at roughly 400 meters above sea level and have for the last week been following the growth of a Citrus Swallowtail Butterfly. yesterday it entered chrysalis.

    I noted the classic V shape but was unable to get a shot. Today I did get some good shots.

    I hope to follow it through the entire cycle and if really lucky I’ll get a video of it’s coming out.

    I have been calling it a moth but thanks to your work now know it is a caterpillar. Thanks

    Brian

    Reply

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