Giant Swallowtail: Essential Guide for Butterfly Enthusiasts

The Giant Swallowtail butterfly, scientifically known as Papilio cresphontes, is an impressive and captivating species of butterfly. With its striking appearance and large wingspan, which can reach up to 5.5 inches, it’s no wonder that these creatures have captured people’s attention and admiration.

Featuring dark brown wings adorned with yellow spots that form bands across the top, the Giant Swallowtail showcases unique and visually pleasing patterns. When resting with folded wings, light yellow colors can be seen along with blue and red dots on the undersides, giving observers a glimpse of their captivating beauty. These enchanting insects are known to lay their eggs on wild lime and citrus plants, making them a crucial part of their respective ecosystems source.

Giant Swallowtail Overview

Species and Distribution

The Giant Swallowtail (Papilio cresphontes) is the largest butterfly in North America, boasting a wingspan of up to 6 inches. Its primary habitats range across the United States, stretching from Florida to California, and even reaching states like Kansas and New England. Outside the US, this species can be found in countries such as Cuba and Jamaica.

Habitat and Range

The Giant Swallowtail prefers habitats with citrus plants, mainly using wild lime for egg-laying. These butterflies can be spotted in a variety of environments, including gardens and wooded areas. Here’s a quick summary of their characteristics:

• Distribution: Throughout the United States, as well as in Cuba and Jamaica
• Primary habitat: Citrus plants, such as wild lime
• Wingspan: Up to 6 inches

Wing Coloration:

• Upper side: Dark brown with yellow spots forming bands
• Underside: Light yellow with blue and red dots

When comparing the Giant Swallowtail with other related species, you can use the below table to spot differences.

Physical Characteristics

Wingspan and Size

• The Giant Swallowtail is the largest butterfly in the United States.
• Its average wingspan ranges between 4 to 5.5 inches which makes it easy to recognize.

Coloration and Mimicry

Camouflage

• One of the strategies Giant Swallowtail uses is mimicking bird droppings.
• This is evident in their early larval stage when their white and brown saddle patterns give off an appearance of bird feces, deterring predators.

Adult Coloration

• Giant Swallowtails exhibit bright yellow and black colors on their wings.
• The ventral part of the hind wing showcases a small brick-red patch just interior to the blue median band¹.

Comparison with other Swallowtails

Life Cycle and Development

Eggs

The life cycle of the Giant Swallowtail begins with the female butterfly laying her eggs. Eggs are typically laid on the leaves of host plants, such as citrus trees. These eggs are:

• Small and round
• Light yellow-green in color
• Laid singly or in small groups

Caterpillar Stage

Once the eggs hatch, the Giant Swallowtail caterpillars emerge and begin to feed on the leaves of the host plant. During this stage, they go through multiple larval instars, which are stages of development. Caterpillars possess a unique organ called the osmeterium that deters predators:

• The osmeterium is a fleshy, forked structure
• Found behind the head of the caterpillar
• Releases a foul-smelling odor when threatened

Chrysalis and Pupa Stage

After reaching their final larval instar, Giant Swallowtail caterpillars enter the chrysalis and pupa stage. Here’s what happens during this stage:

• The caterpillar forms a chrysalis, a hardened protective cover
• This stage lasts between 10 to 20 days
• Inside, the caterpillar undergoes metamorphosis, transforming into an adult butterfly

Adult Butterfly Stage

Upon emerging from the chrysalis, the fully developed Giant Swallowtail butterfly displays its beautiful and eye-catching features. Some of the defining characteristics of the adult butterfly include:

• Largest butterfly in North America
• Dark blackish-brown wings with yellow bands
• Red patch on the ventral hindwing

Comparison of Giant Swallowtail Life Stage Features

During their short adult life, Giant Swallowtails mate and lay eggs to continue the cycle. The entire butterfly life cycle typically takes around 6 to 8 weeks, but can vary depending on environmental factors and predation.

Behavior and Ecology

Feeding and Nectar Sources

Giant swallowtails feed on nectar from various plants. Some favorite nectar sources include:

• Zinnias
• Azaleas
• Solidago
• Lonicera japonica

In comparison, the Tiger Swallowtail and Spicebush Swallowtail prefer milkweed and tulip tree flowers.

Host Plants and Caterpillar Diet

Host plants of the Giant Swallowtail caterpillars are mainly in the Rutaceae family. Examples include:

• Citrus
• Prickly ash (Zanthoxylum americanum)
• Hercules club
• Common rue
• Hoptree

With a preference for citrus plants, this sets the Giant Swallowtail apart from the Spicebush Swallowtail, which feeds on spicebush and tulip tree leaves in deciduous forests.

Defense Strategies and Predators

Giant Swallowtail butterflies and caterpillars have developed various defense strategies against predators like birds and snakes. Caterpillars resemble bird droppings, providing camouflage. Additionally, they possess an osmeterium, an organ that releases a foul-smelling substance when disturbed.

In contrast, the Eastern Tiger Swallowtail, another swallowtail butterfly, displays mimetic coloration, with females resembling the poisonous Pipevine Swallowtail to deter predators.

Interaction with Humans and Environment

Giant Swallowtail as Pest

The Giant Swallowtail (Papilio cresphontes) is known for its interactions with citrus trees, especially in citrus orchards that produce sweet oranges (Citrus × sinensis). Its caterpillars can feed on the leaves of lime pricklyash (Zanthoxylum fagara) and Zanthoxylum americanum Mill.

Another host for their caterpillars is Amyris elemifera. They are commonly referred to as orange dogs, due to their pest-like nature when feeding on citrus trees.

Pros:

• Pollination of citrus flowers.

Cons:

• Damage to citrus leaves and trees.

Conservation and Threats

Giant Swallowtails are not currently listed as endangered or threatened species. However, they share a similar habitat with the Schaus’ Swallowtail, which is an endangered species. Some factors affecting both species include:

• Loss of habitat due to human development.
• Pesticide use in citrus farms and gardens.
• Climate change affecting the range and distribution of host plants.

Comparison: Giant Swallowtail vs Eastern Tiger Swallowtail

To promote Giant Swallowtail populations, people can plant host plants, such as Zanthoxylum fagara and Amyris elemifera, along with nectar-producing flowers. Examples of nectar-producing flowers include Bougainvilla and Lantana. Planting these in gardens can help attract and support the Giant Swallowtail population.

Photography and Identification

The Giant Swallowtail, scientifically known as Papilio cresphontes, is a large and beautiful butterfly worth capturing in photographs. Here are some tips for photography and identifying this unique species.

• To photograph giant swallowtails, look for them near their host plants, like the citrus trees they often inhabit.
• Using a macro lens will help you capture the intricate details of their wings and body.

Identifying giant swallowtails can be achieved by examining their color and markings:

• Wings are black with yellow markings near wing margins and spots forming a diagonal band across the forewings¹.
• Hindwings feature a yellow spot band, wide yellow basal band, small orange-capped black spot, and a spatulate tail with a yellow central teardrop².

Comparison table: Giant Swallowtail vs. Schaus’ Swallowtail

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 – Orange Dogs defoliate Satsuma

Subject: Caterpillar that ate my Satsuma
Location: Livingston, Louisiana
March 23, 2013 7:34 am
It has been a while since I took this picture (it took me a while to find the picture). Around this time last year, can’t remember the specific day, I found this caterpillar on my small Satsuma. I have never seen a caterpillar like this one in my life. So I took a picture of them so I could see what they were. I found them on your web site, the Giant Swallowtail, but what I am wanting to know is – Do they hang around this area much? I live in Livingston Louisiana. I have lived at this residence for 15 years and this was the first time I had seen them. The small Satsuma they ate was mostly thorns. The Satsuma had been in the back yard for two years before I saw the caterpillars. Are they in this area much? If so I will leave the tree for them to snack on. I did not get to see the Butterflies and the caterpillars were gone the next day. I would love to see them in my yard more often. How can I do to get them to come back? What really peaked my curiosi ty was when my son touched one of them it put out a nasty odor and these bright red feelers or antenna. What do I need to do to bring one indoors to watch it emerge from a cocoon?
Signature: Rebecca Lambert

Hi Rebecca,
This might be our favorite photo ever of Orange Dogs, the caterpillars of the Giant Swallowtail, Papilio cresphontes.  We generally tell home gardeners that despite the caterpillars feeding on the leaves, the trees will survive and butterflies will follow, but we never get reports of so many Orange Dogs on a single tree.  Perhaps there was no other nearby food source, and that is why so many eggs were laid in one place.  Swallowtails deposit eggs singly, not in a cluster like some other insects.  We also love that your photo shows so many individuals with the osmeterium exposed.  The red horns, as you indicate, are a defense mechanism that acts as a visual deterrent as well as an olfactory one.  You are within the natural range of the Giant Swallowtail, a native species that fed on common pricklyash and other native plants prior to the introduction of citrus.  Cultivation of citrus has allowed a range expansion to occur and now Giant Swallowtails are common in southern California, a portion of the country that they are not native to.  The coloration of the Orange Dog is thought to resemble droppings from a bird, which acts as an additional camouflage protection.  You should be able to raise a caterpillar in an old aquarium with a screen top if you want to observe the eclosion.  We would also suggest planting nectar plants including lantana and composites like echinacea if you want to attract additional adult Giant Swallowtail butterflies to your garden.  Your letter indicates you took the photo last year, so we are guessing the 2007 date stamp is incorrect.

Letter 2 – Orange Dog

Caterpiller??
Found this one on my grapefruit tree. There were actually two of them and they were moving. Seems that the larger end is the head. What is it? Thanks in advance,
Richard R. Gongora
Houston, TX

Hi Richard,
This is the caterpillar of the Giant Swallowtail, commonly known as an Orange Dog.

Letter 3 – Orange Dog

caterpillar
Greetings, My cousin in Florida found this little guy in her back yard. Any ideas? My son thinks it is a snake mimic of some sort. Thanks,
Jessica

Hi Jessica,
We typically think of caterpillars with large false eyespots, like the Spicebush Swallowtail Caterpillar, as snake mimics. The Caterpillar of the Giant Swallowtail, also known as the Orange Dog, which you sent in, seems to many people (and we include ourselves in that camp) to imitate bird droppings. The caterpillar feeds on the leaves of citrus trees.

Letter 4 – Orange Dog

Caterpillar?
This was located on our fruit tree. What is it? And is it harmful or helpful?
Mark

Hi Mark,
Harmful and helpful are so relative. Are Preying Mantids harmful or helpful? They probably eat more pollinating insects than they do insects that are injurious to plants, yet they are considered beneficial in the garden. Honey Bees and butterflies might tend to disagree with that classification. This is an Orange Dog, the caterpillar of the Giant Swallowtail. In the scheme of things, the caterpillars eat leaves from citrus trees, but they do not harm the fruit. The caterpillars are rarely so numerous as to do harm to the tree. Eventually, the Orange Dog will metamorphose into a lovely butterfly. Our vote is on the helpful side, but we have a long standing record of voting for political candidates who lose the election. The horns that are visible in your image are a retractable scent gland known as the osmeterium. This caterpillar uses that scent gland as well as mimicing bird droppings to avoid being eaten.

Letter 5 – Orange Dog and Chrysalis

I thought you might like this
I saw on your site that you were looking for a photo of an ‘orange dog’ and I believe this is it. I found these huge caterpillars in late June on my lemon tree in Arlington, Texas. Stretched along the branches, they were perfectly camouflaged as bird droppings. When disturbed, they display a red-orange star-shaped organ that smells like ‘caterpillars’. The scent is what clued me in to their presence. I smelled them while watering the little tree. These are very large, scary-looking caterpillars, and I wore gloves to pick them up; however, they didn’t harm anyone. We kept these in an aquarium on the back porch (with netting over the top) and I sacrificed a few more of my lemon leaves to allow them to reach maturity. We released six of the adults in early July. Unfortunately I was unable to photograph the adults.
Char
P.S. Love your site.

Hi Char,
Your letter is quite wonderful. Since that request was made, we have received several wonderful images of Orange Dogs, but yours is the first submission of a Chrysalis, which excites us to no end. Swallowtail Chrysalids can be distinguished by the girdle of silk that keeps the pupa in an upright position.

Letter 6 – Orange Dog and Giant Swallowtail Chrysalis

orange dog images
Hi, I found your site while googling to indentify another caterpillar. Great site! If you would like some orange dog shots, here they are. We have a pet key lime tree and some grapefruits that are for a client. I pick all the larvae off the grapefruits and transfer them to the key lime, and my four year old is an avid orange dog rescuer as well! I think you forgot to mention that in addition to giving off the odor when they produce the antennae(which smells kind of like really strong orange oil to me), they look like a blob of bird poop. Very truly yours,
Lynnae Dehoff in West Palm Beach, FL

Hi Lynnae,
Thanks ever so much for sending us your wonderful images of the Orange Dog and the next stage in the metamorphosis of the Giant Swallowtail, the Chrysalis.

Letter 7 – Orange Dog on Lemon Tree

Subject: Found on a lemon tree in FL
Location: Florida
April 11, 2017 7:55 pm
My Aunt found this fella on her lemon tree and there is debate as to whether it’s an Elephant Hawk Caterpillar or an Orange Dog. Please, help to clarify, she didn’t check to see if it had the scented appendages that an orange dog would display while threatened, unfortunately. Thank you for what you do!!
Signature: The Artist Formally Known as Starving

Dear Artist Formally Known as Starving,
This is definitely an Orange Dog, the larva of a Giant Swallowtail.  The Elephant Hawkmoth is NOT a North American species.  Interestingly, though its native range is Eastern North America, most of our Giant Swallowtail sightings now come from Southern California as the butterfly’s range has increased due to the cultivation of citrus.  The species has adapted to feeding on the leaves of citrus, which is not native to North America, but it now seems to be a preferred host plant.  We believe Giant Swallowtails were first reported in Los Angeles in the late 1990s, and now they are quite common (t)here.  According to the Los Angeles Times in 2007:  “The giant swallowtail butterfly, Heraclides (Papilio) cresphontes, is native to the Southeast. Since the 1960s, populations have spread west following a corridor of suburban development and the species’ favorite larval food source — citrus — through Arizona, into the Imperial Valley, then San Diego and north to Orange and Los Angeles counties. They’ve been sighted as far north as Santa Barbara and Bakersfield.  Numbers have surged since 2000, says Jess Morton, president of the Palos Verdes-South Bay chapter of the Audubon Society. Members have held a butterfly count at the same location, on the first Sunday in July, every year since 1991. According to their records, a single giant swallowtail was first seen in the South Bay in 2000. They counted 23 in 2007.”

THANK YOU SO MUCH. You broke it down for us and everything!

Letter 8 – Orange Dog mimics Bird Dropping

Giant Swallowtail caterpillar in Louisiana
Location: Louisiana
October 31, 2011 1:13 pm
Hello WTB! Love your site. Attached is a couple pictures of what I believe to be a Giant Swallowtail caterpillar. I hope you can find use for it.
Signature: Simon Mahan

Hi Simon,
The larvae of Giant Swallowtails are commonly called Orange Dogs because they feed on the leaves of citrus trees, including orange trees.  Your caterpillar is an early instar, meaning is still will undergo several molts before transforming into a chrysalis.  Giant Swallowtail Caterpillars are easily overlooked by predators because they resemble bird droppings.

Thank you! And yes, it was on an orange tree =-)
-Simon

Letter 9 – Orange Dog reveals Osmetrium

caterpiller
Location: augusta, Ga
May 5, 2011 7:04 am
came out the house this morning and at first thought it a bird had poo on my orange tree till i moved the leaf and it stuch its 1 in long tongues at me not sure if they were forked did see where they came together.
Signature: kristina

we wish your photos were in focus.  The Orange Dog is the caterpillar of the beautiful Giant Swallowtail butterfly.

i took more this morning of it this morning.

Ed. Note: Reshoot
As instructors of photography, it is imperative that we instruct our students how to properly focus their images.  Unless soft focus is used creatively and consciously, students who create blurry images cannot receive an excellent grade on their assignments, and we generally recommend a reshoot.  We were very impressed that Kristina made the effort to reshoot her images of an Orange Dog, prompting us to post both the original and the subsequent images.  When it comes to educating photographers, we reward attempts to make better images even if the reshoot is not entirely successful by adding a few points, but nothing is more rewarding than seeing a major improvement when a student reshoots an assignment.  With that in mind, we are now posting Kristina’s efforts as well as elaborating on our original very short response to her.

Hello again Kristina,
These new images are a vast improvement over your original attempts, and we applaud the initiative you took.  Your new and critically sharp images show a “content” Orange Dog as well as the very effective defense mechanism utilized when that Orange Dog is threatened.  The red forked organ is known as an Osmetrium and when the disturbed, the Orange Dog, like its many closely related Swallowtail Caterpillar relatives, obtrudes the Osmetrium which in turn emits a foul odor.  The Osmetrium is a defense organ and the foul odor that is released is believed to ward off birds and other predators that would otherwise find the caterpillar to be a tasty morsel.  The red or orange color of the Osmetrium is most likely also a visual deterrent.

Letter 10 – Orange Dog, we believe

Subject:  Creepy thing in garden
Geographic location of the bug:  on my citrus dwarf mandarin tree
Date: 10/17/2018
Time: 09:00 PM EDT
Your letter to the bugman:  I’m assuming it may be some kind of moth maybe? But it looks so reptilian it’s creeping me out. Do you know what this is? Is it a beneficial creature to the garden?
How you want your letter signed:  doesn’t matter

Dear doesn’t matter,
Please provide us with a “geographic location of the bug.”  According to Sciencing:  “Geographic location refers to a position on the Earth. ”  Other online sources give similar definitions.  While it is helpful to know that it was found on a “citrus dwarf mandarin tree,” we can’t say for certain that this is an Orange Dog, but that is our opinion provided your sighting was in North America.  The loss of leaves from a single caterpillar will not compromise the health of your tree.  The Orange Dog is the caterpillar of a Giant Swallowtail.

Letter 11 – Orange Dogs

Subject: Orange Dog Caterpillar?
Location: Southern Orange County, CA
July 23, 2016 10:56 am
I found two caterpillars on my navel orange tree on July 22, 2016. Are these Giant Swallowtail Butterfly caterpillars?
Signature: Julie Macy

Dear Julie,
You are absolutely correct.  These are Orange Dogs, the caterpillars of Giant Swallowtails.  Interestingly, though they are native to North America, Giant Swallowtails were first reported in Southern California in the 1990s.  Their range expanded as citrus cultivation moved across the country.  Even though citrus is not native to North America, once cultivation of oranges and other citrus fruits gained popularity in the southeast, the native Giant Swallowtails adapted to them as a host plant.

Thank you!  I found another yesterday.  I’ve never seen them before.  It will be fun to watch them as they change.
Julie

Letter 12 – Probably Giant Swallowtail Caterpillar

Subject: Swallowtail caterpillar?
Location: San Gabriel , california
April 26, 2016 9:12 pm
I bought a pepper tree bonsai and I found this caterpillar attached to it. I believe it is a swallowtail caterpillar but I don’t know what variety. I was hoping to find out what is was since I want to care for it. Can I feed it lemon leaves instead of my poor bonsai?
Signature: Thank you, Meena

Dear Meena,
This sure looks like an Orange Dog, the caterpillar of a Giant Swallowtail  According to BugGuide:  “Larvae feed on leaves of plants in the Citrus family (Rutaceae), including Citrus (Citrusspecies), Pricklyash(Zanthoxylum species), Hoptree (Ptelea trifoliata), Rue (Ruta graveolens), etc. Adults take flower nectar from a variety of herbaceous plants and shrubs.”  We do not recognize your particular Pepper Tree and we would be curious to learn if it is in the citrus family.  You can try to feed your caterpillar leaves of an orange tree, but if it rejects those leaves, you may need to return it back to your bonsaii.  Caterpillars are not like dogs or pet fish.  They do not immediately begin eating if food is placed in front of them.  You may need to transfer your caterpillar to a citrus tree to see if it will accept the leaves.  Though lemon is a citrus tree, we cannot recall getting any reports of Orange Dogs feeding on lemon trees, but we have gotten reports of them feeding on lime, tangerine, grapefruit and the always popular orange tree.

Letter 13 – Puddling Giant Swallowtail

Subject: Puddling Butterfly
Location: Coryell County, TX
September 4, 2015 1:10 pm
Hello! I think this beautiful butterfly may be another Giant Swallowtail (Papilio cresphontes). It was puddling in a drainage area. So gorgeous! The wind was buffeting it about somewhat; today is partly cloudy and quite warm, 90 degrees. No significant rain for over a month, so any moisture is appreciated by wildlife.
Best wishes!
Signature: Ellen

Hi Ellen,
How nice to hear from you again.  Your puddling Giant Swallowtail is an excellent addition to our archives.

Letter 14 – Puddling Giant Swallowtail

Subject:  Giant Swallowtail Puddling
Geographic location of the bug:  Hialeah Florida
Date: 03/15/2019
Time: 12:05 PM EDT
Your letter to the bugman:  I was cleaning out algae-muck from my pool on March 3 and this Giant Swallowtail spent a long time drinking the dampness from it, so I was able to get a few really nice photos of it that I thought you might like.
I don’t see them very often, but twice I found them puddling when I’d done yard work and left water on cement/tile. I’m guessing that being so large, they need more moisture than the average butterfly, and so sometimes nectar just isn’t enough.
How you want your letter signed:  Marian

Dear Marian,
Your images of a puddling Giant Swallowtail are beautiful.  It is our understanding that butterflies newly emerged from the Chrysalis drink from puddles to get important minerals as well as moisture.  The Swallowtails, the Blues and the Sulphur Butterflies are among the most frequent puddlers.  It is also our understanding that males are more frequently found at puddles than are female butterflies.

Letter 15 – Queens, Monarch and Giant Swallowtail

Subject: Urban Oasis for Butterflies
Location: Harker Heights, Texas
November 15, 2016 9:00 pm
Hello again!
Bad news: I had to have dental surgery. 🙁
Good news: My very-excellent-surgeon has built a new office building, complete with wildlife gardens that he and his wife planted. 🙂
Clouds of butterflies are enjoying their gardens. Eighty-three degrees today, with not a cloud in the skies.
I saw monarchs, queens (I think? some mating), American snouts, giant swallowtails, sulphurs, skippers, whites, emperors, maybe sleepy oranges, tiny blues… all so beautiful.
Hoping you’re both having a great week.
Signature: Ellen

Dear Ellen,
We are sorry to hear about your surgery, and we think it is amazing that you took your camera with you to the dentist.  We love your images of Queens, a Monarch and a Giant Swallowtail.

Thank you! I had to return to the dental surgeon’s office a second day, oh joy, and took my camera then. The surgeon and staff had invited me into the employees’ courtyard to take photos because I admired the gardens through the picture windows when I saw them on the first day. So very kind of them!

Letter 16 – Snowberry Clearwing Caterpillar and Giant Swallowtail Caterpillar

caterpillars I live in Fort Worth, TX and found this green, horned caterpillar on my coral honeysuckle. I think it’s a hummingbird clearwing, but am looking for clarification on that. I have not seen any of the moths flying around. I’m also sending a picture of a giant swallowtail caterpillar because I didn’t see any pictures of them on your site and thought you might be interested. It’s on the rue which is also greatly populated by black swallowtails. Love your website! Thanks,
Jeanne

Snowberry Clearwing Caterpillar	Giant Swallowtail Caterpillar

Hi Jeanne,
The Caterpillar you suspect is a Hummingbird Clearwing is another species in the same genus, the Snowberry Clearwing, Hemaris diffinis. Your other caterpillar is correctly identified as a Giant Swallowtail Caterpillar.