Tiger Swallowtail: Essential Facts and Tips for Enthusiasts

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The Tiger Swallowtail is a captivating butterfly that sparks interest in several regions, particularly in the United States. You might have noticed the Eastern Tiger Swallowtail (Papilio glaucus), which is one of the most common and stunning butterflies found east of the Mississippi River and in some areas farther west into the Great Plains states. These butterflies are known for their large size and bright colors, capturing the attention of nature enthusiasts and butterfly lovers alike.

As you observe the beauty of these magnificent insects, it’s important to understand their ecological impact. Adult Tiger Swallowtails play a vital role in pollination by sipping nectar from various flowering plants, while their larvae are known to be more specific in their feeding habits. In the case of the Western Tiger Swallowtail, they typically enrich wetter environments during their flight season from June to July, contributing to the overall health and diversity of ecosystems.

A deeper dive into the world of the Tiger Swallowtail reveals fascinating insights into their lifecycle, including the differences between the Eastern, Western, and Canadian Tiger Swallowtails, as well as their preferred habitats and food sources. Enjoy observing these brilliant butterflies and learning more about their crucial role in promoting biodiversity and the wellbeing of their surrounding habitats.

Basic Identification


The Tiger Swallowtail is a large butterfly with a wingspan range of 7.9 to 14.0 cm (approx. 3.12 to 5.5 inches). They are mostly observed during spring and summer. As you observe these butterflies, you’ll notice some distinct features that make them easy to identify.

Characteristic Color Patterns

Tiger Swallowtails are known for their striking color patterns. Here are some key features:

  • Yellow: The primary color on both the Eastern Tiger Swallowtail and their Western counterpart is yellow.
  • Black Stripes: They have four black bands on their front wings, resembling a tiger’s stripes.
  • Blue Markings: On the dorsal side of the hindwings, you’ll find blue scales. This feature is especially prominent in females.

Gender Differences

When identifying a Tiger Swallowtail, it’s essential also to recognize the gender differences. Male and female Swallowtails have some distinct markings that set them apart:

  • Males: Generally yellow with black stripes and minimal blue markings on their hindwings.
  • Females: There are two female forms: yellow and black.
    • Yellow form: Similar to males, females exhibit yellow with black stripes. However, they have more extensive blue markings on their hindwings.
    • Black form: This form can be easily distinguished, as they are black with darker black stripes. The blue markings on their hindwings remain, but they do not have two complete rows of orange spots on the lower side of the hindwing, unlike yellow-form females.

When you spot a Tiger Swallowtail, keep these identification tips in mind to help you determine its species and gender.

Life Cycle


The life cycle of the Tiger Swallowtail starts with the female butterfly laying green eggs on the leaves of host plants. These eggs are typically laid singly on the upper side of leaves. Examples of host plants include aspens, birches, and willows1.


After hatching, the caterpillars emerge and begin feeding on the host plant’s leaves. The younger caterpillars resemble bird droppings, while the older ones are green with blue and yellow markings2. These caterpillars go through several stages (called instars) as they grow before entering the pupal stage. Some features of the caterpillar stage include:

  • Camouflage to avoid predation
  • Feeding on host plant leaves for nourishment
  • Rapid growth and shedding of exoskeleton during molts


Once fully grown, the caterpillar prepares to transition into an adult butterfly. It forms a chrysalis3 (also called pupa) for this purpose. The caterpillar attaches itself to a suitable surface and encases itself within the protective chrysalis. It undergoes a process of metamorphosis during the pupal stage, transforming from a caterpillar into a butterfly.

Adult Butterfly

After completing its metamorphosis, the adult Tiger Swallowtail butterfly finally emerges from the chrysalis. Adult butterflies feature vibrant yellow wings with black bands and markings4. They have a wingspan that ranges from 3.12 to 5.5 inches5. As adults, they exhibit various behaviors, such as:

  • Feeding on nectar from flowers for sustenance
  • Mating and reproducing to continue the life cycle
  • Migrating to more favorable locations as needed

In summary, the life cycle of a Tiger Swallowtail consists of four main stages: egg, caterpillar, pupa, and adult butterfly. Each stage plays a crucial role in the development and continuation of the species.

Habitat and Distribution

The Tiger Swallowtail butterflies can be found in various parts of North America, with some differences in habitats between the Eastern Tiger Swallowtail and the Western Tiger Swallowtail.

Eastern Tiger Swallowtail

You’ll typically find the Eastern Tiger Swallowtail in the eastern parts of the United States and some parts of Canada. Their habitat primarily comprises woodlands, forests, fields, gardens, and roadsides. These butterflies love areas with a mix of deciduous trees, such as aspens and birches, that serve as host plants for their caterpillars.

Western Tiger Swallowtail

The Western Tiger Swallowtail, on the other hand, is found in the western parts of the United States, some parts of Canada, and even some Mexican states. Their habitats are similar to those of Eastern Tiger Swallowtail, but they also thrive in woodlands with a mix of willow trees and plants from the carrot family.

In summary, Tiger Swallowtails adapt well to various habitats across North America. Exploring forests, fields, and gardens, you may encounter these beautiful butterflies, adding a touch of color and elegance to the landscape.


Tiger Swallowtails, like most butterflies, primarily feed on the nectar of various flowers. In addition, their caterpillars have specific host plants that they feed on as they develop. Let’s explore some examples of their preferred nectar sources and host plants.

The adult Tiger Swallowtail enjoys nectar from a variety of flowers such as Milkweed, Wild Cherry, and Willow. These plants provide essential nutrients that keep these butterflies healthy and energetic.

As for the caterpillars, they usually feed on leaves of specific host plants. Some common examples are Ash, Willow, and Wild Cherry trees. Eating the leaves of these plants helps caterpillars grow and transform into a butterfly.

Tiger Swallowtails are quite adaptable, so they may also be found feeding on other plants too. Keep in mind that it’s important to provide a diverse selection of plants to support the needs of these butterflies.

Here are some key points to remember about the Tiger Swallowtail’s diet:

  • Nectar serves as the primary food source for adults
  • Caterpillars rely on specific host plants for their growth
  • Examples of nectar sources: Milkweed, Wild Cherry, Willow
  • Examples of host plants: Ash, Willow, Wild Cherry

By understanding their dietary preferences, you can help support the Tiger Swallowtail population in your area and enjoy the beauty they bring to your garden.

Defense Mechanism

The Eastern Tiger Swallowtail butterfly exhibits an interesting defense mechanism called mimicry. By mimicking the appearance of other butterflies, like the Pipevine Swallowtail, Black Swallowtail, and Spicebush Swallowtail, it protects itself from predators. Let’s dive deeper into this fascinating strategy.

Tiger Swallowtails have different forms and colors depending on their gender and age. Females of this species can display two color forms. The first form is yellow and black, while the second form, known as the dark form, is mostly black and blue. This dark form closely resembles the unpalatable Pipevine Swallowtail, an example of Batesian mimicry.

Here’s a comparison table to understand the similarities:

Butterfly Colors Features
Tiger Swallowtail Yellow and black or dark form Large size, distinctive pattern
Pipevine Swallowtail Black and blue Similar dark coloration, unpalatable to predators
Black Swallowtail Black and yellow Similar size and pattern, easily confused with Tiger Swallowtail
Spicebush Swallowtail Dark blue and black Resembles both Pipevine and Tiger Swallowtails

In the case of mimicry with the Black Swallowtail and Spicebush Swallowtail, predators might get confused and avoid Tiger Swallowtails due to shared visual characteristics. This defense mechanism ultimately ensures the survival of the Eastern Tiger Swallowtail in its natural habitat.


  • Mimicry is a key defense mechanism for the Eastern Tiger Swallowtail
  • Different forms and colors in females provide camouflage and protection
  • Resembling unpalatable or harmful butterflies increases their chances of survival

Threats and Predators

The Eastern Tiger Swallowtail butterfly faces several predators in its natural habitat. These colorful creatures can become prey to a variety of species, such as birds, ants, and wasps.

Birds are among the most common predators, as they are attracted to the bright colors and large size of the swallowtail. When you observe these butterflies in the wild, you might notice some with missing parts of their wings. This is often a sign of a bird attack that the butterfly managed to escape.

Ants and wasps, on the other hand, typically target the eggs and larvae of the Eastern Tiger Swallowtail. These insects will search for and consume the vulnerable early stages of the butterfly, which can heavily impact the population.

Here’s a brief overview of the main predators:

  • Birds

    • Most common predators
    • Attracted to vibrant colors and large size
    • Often target adult butterflies
  • Ants and Wasps

    • Mainly attack eggs and larvae
    • Can significantly impact butterfly population

Although Eastern Tiger Swallowtails face various challenges due to natural predators, they remain one of the most widespread and easily recognizable butterfly species in eastern North America. As you enjoy the beauty of these insects, remember that they are part of a delicate ecosystem where every organism plays a crucial role.

Special Features

The Eastern Tiger Swallowtail butterfly has some unique characteristics that make it stand out amongst other butterflies:

  • Eyespots: Caterpillars of this species exhibit large eyespots, which serve as a defense mechanism to scare away potential predators 1.

  • Fast: Known to be a fast flyer, the Tiger Swallowtail can efficiently evade its predators and navigate through its environment 2.

  • Blue spots: Female Tiger Swallowtails can have blue scales on the dorsal (top) side of their hindwings 3.

  • Thorax: Similar to other butterflies, their thorax contains muscles that help control the wings, providing the power and mobility 4.

  • Hind wing: The Eastern Tiger Swallowtail has distinct black bands and orange spots on its hind wings, adding to its striking appearance 5.

Given these features, it is no wonder that the Eastern Tiger Swallowtail is one of the most admired and easily recognizable butterflies in the United States 6.

Species of Tiger Swallowtail

The Tiger Swallowtail is a beautiful species of butterfly belonging to the Papilionidae family. There are several species and subspecies of Tiger Swallowtails such as the Eastern Tiger Swallowtail, Canadian Tiger Swallowtail, and Western Tiger Swallowtail.

The Eastern Tiger Swallowtail is one of the most common and well-known species found east of the Mississippi River and into the Great Plains states. In comparison, the Canadian Tiger Swallowtail is a northern species that used to be a subspecies of the Eastern one, but was declared a separate species about 20 years ago.

While the Eastern Tiger Swallowtail feeds mostly on plants like aspens, birches, and willows, the Canadian one has a more limited diet. Tiger Swallowtail caterpillars are known for their connection to plants in the carrot family. It’s also important to note that all species of Swallowtail butterflies, including the Black Swallowtail and other Tiger Swallowtail butterflies, have unique and vibrant color patterns on their wings.

Here are some features of the Tiger Swallowtail butterflies:

  • Large size and strong wings
  • Bold, colorful patterns on their wings
  • Long, swallow-like tails on their hind wings
  • Caterpillars with unique feeding habits

Comparing the Eastern and Canadian Tiger Swallowtails:

Feature Eastern Tiger Swallowtail Canadian Tiger Swallowtail
Range East of the Mississippi River Northern regions
Diet Aspens, birches, and willows Primarily plants in the carrot family
Separation Older species Separate from Eastern about 20 years ago

Remember that although each species of Tiger Swallowtail has its characteristics, they all share the captivating beauty and grace that makes them a favorite among butterfly enthusiasts. By learning about each and observing them in nature, you’ll appreciate the diversity of these stunning insects.

Importance in Art and Symbolism

The Eastern Tiger Swallowtail has played an important role in art and symbolism throughout history. For example, it was the first North American swallowtail ever to be depicted in an artwork. This representation dates back to 1587, when John White, commander of Sir Walter Raleigh’s third expedition, drew a male tiger swallowtail in his illustrated log.

In art, tiger swallowtails are often used as a symbol of transformation, representing the butterfly’s journey from caterpillar to magnificent winged insect. This beautiful creature is admired for its vibrant colors, tiger-like stripes on the wings, and elegant tail, making it a great subject for different forms of art, such as paintings, drawings, and even tattoos. In fact, many artists find inspiration from the tiger swallowtail’s grace and beauty, which add to the appeal of their works.

  • Key features of the Eastern Tiger Swallowtail:
    • Prominent black tiger-like stripes on the wings
    • Wide black borders and yellow marginal spots on the hindwings
    • Striking appearance and elegant movement

As symbols in literature and popular culture, tiger swallowtails often denote change, growth, and positivity. They serve as a reminder of nature’s cyclical patterns and the potential for rebirth that exists within all living things.

In conclusion, the Eastern Tiger Swallowtail is a living representation of transformation, beauty, and life’s natural cycles. Its significance in art and symbolism has transcended time and continues to inspire people today. So next time you encounter one of these captivating creatures, take a moment to marvel at its extraordinary beauty and the deeper meaning it conveys.


  1. Field Station 2

  2. Eny-61/IN218 2

  3. source 2

  4. source same as 3 2

  5. source same as 3 2

  6. EDIS – University of Florida

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 – Puddling Tiger Swallowtail


first swallowtail
Today I saw the first swallowtail of ’08 in my yard, and it was doing something strange. It appeared to be drinking moisture from the areas where my dog urinates. I’ve never seen a swallowtail doing this before. What gives? Maybe there are not enough flowers with nectar right now. The lilies are only in bud and all the spring flowers are done. Then I saw the same swallowtail with a fly on its wing! Very unusual, I think. I live in Glassboro, New Jersey, and we’ve had a very warm winter. All the bugs are out in full force, it seems.
Hedy Hadley

Hi Hedy,
This activity is known as Puddling. Many butterflies engage in this activity. Often tens or even hundreds of swallowtails and certain other butterflies will gather around a puddle and drink. Here is what the Wisconsin Natural Resources website has to say about puddling: “Why does puddling occur? No one knows for certain. Many butterfly species feed on flower nectar that provides ample sugar and energy, but is very limited in necessary minerals and ions. Research suggests that the moisture or urine on gravel roads contains dissolved minerals and salt ions, in particular sodium, which may stimulate reproductive development or activate a temperature regulating system to help the young butterflies heat up and keep their cool. Only newly hatched males puddle, hence the name “bachelor parties.” Older males and females do not participate. And only species like sulphurs and swallowtails, whose males patrol territories, engage in puddling. Species like hairstreaks and coppers, whose males perch waiting for females to approach, do not puddle. “

Letter 2 – Puddling Tiger Swallowtails


Eastern Tiger Swallowtails dining
Hi again Lisa Anne and Daniel,
I just wanted to add my favourite picture from my recent vacation, taken at Washington Island (Door County, Wisconsin). I met these beautiful Eastern Tiger Swallowtails when my memory card of the camera crashed. It took me 20 nervous trouble shooting minutes until I could finally take this shot. I hope you enjoy it.
Best regards,

Hi Thomas,
Thanks for sending the photo of the Tiger Swallowtails puddling. Some species of butterflies drink water from puddles, and often, the nastier the water, the more they like it. We noticed your photo is enormous. Perhaps you were having a problem because the image is 6.2 M and that is overkill unless you plan to make a billboard.

Letter 3 – Puddling Tiger Swallowtails


Swallowtail butterflies
Dear Bugman,
I live in Southeast Tennessee, and we’ve had an unusal number of butterflies around the house lately. After days of unsuccessfully trying to photograph them, I finally got one to hold still. . . and then it was joined by another. . . and then a third! It was almost as if they wanted to pose for me. They sat very still and didn’t move, and even though I was walking around them, they seemed totally unconcerned with my presence. I thought you might enjoy the photo of the three of them together. Sincerely,
Amanda McCain

Hi Amanda,
Newly metamorphosed male butterflies from some families, including swallowtails and blues, congregate at mud puddles and other sources of moisture, an event known as a Bachelor Party (since they are all males) and an activity known as Puddling. Dissolved in the moisture are critical salts and minerals needed by the young adult butterflies. Your photo is quite beautiful.

Letter 4 – Swallowtail Caterpillar: Two Tailed Swallowtail or Western Tiger Swallowtail???


Caterpillar found in Palo Alto, California
Location:  Palo Alto, California
October 12, 2010 5:55 pm
We found this caterpillar in Palo Alto, California.
Any idea what it is?
And any pictures of what it will look like when it becomes a moth or butterlfy?
He had false eyes and a retractable head– like a turtle.
Feel free to use my pic in your great site!
Signature:  Jen, Connor and Alicia

Western Tiger Swallowtail Caterpillar

Dear Jen, Connor and Alicia,
Your caterpillar is that of a Swallowtail, but we are not certain if it is that of a Two Tailed Swallowtail or a Western Tiger Swallowtail.  Both butterflies are large black and yellow striped butterflies that glide gracefully as they fly and they look quite similar.  We have images in our archive of Two Tailed Swallowtails and you may also see images and get more information on BugGuide.

Letter 5 – Swallowtail Chrysalis Exuvia found on Avocado in Mount Washington likely Western Tiger Swallowtail


Remains of a Swallowtail Exuvia on Avocado Tree
Location:  Mount Washington, Los Angeles, California
June 29, 2014 12:13 PM
We noticed this shell of a Swallowtail Chrysalis in the avocado tree, and we tried to research which species of local Swallowtail has a caterpillar that will feed on the leaves of Avocado.  We have Western Tiger Swallowtails, Giant Swallowtails and Anise Swallowtails in the garden, but none of them feeds on avocado, to the best of our knowledge.  The only Swallowtail listed as eating avocado on the Easy Butterfly Garden website is the Magnificent Swallowtail,
Papilio garamus.  Perhaps this will remain a mystery.  Can the Magnificent Swallowtail have ventured this far north?  Here are additional images of the Magnificent Swallowtail from Animal PHotos.

Shell of a Swallowtail Chrysalis
Shell of a Western Tiger Swallowtail Chrysalis

Julian Donahue provides some input.
Hi Daniel,
The Spicebush Swallowtail is recorded as feeding on another species of Persea, but Tietz’s Index to Described Life Histories…. lists the only swallowtail feeding on Persea americana as Papilio rutulus, the Western Tiger Swallowtail. The BAMONA website doesn’t mention avocado as a hostplant.
Hope this helps,

The Western Tiger Swallowtails have been seen flying near that avocado tree.

Letter 6 – Tattered Tiger Swallowtail


Subject: a tattered Tiger
Location: near Lurray, VA
August 31, 2012 8:48 am
Here is a shot from up on Skyline Drive in VA
Signature: mj

Tattered Tiger Swallowtail

Good evening mj,
We just realized two things.  We currently love posting photos of Tiger Swallowtails and you create really great subject lines because we believe this is the third submission of yours we have posted in 48 hours.  This Tiger Swallowtail is a survivor.

Letter 7 – Tiger Swallowtail


I was looking for the identity of the Pearly Wood Nymph on your website after my brother in Michigan sent me a picture. I was so impressed with the information you’ve made available to folks like me. I saw that you have been unsuccessful in photographing the tiger swallowtail so I thought I’d share some that I’ve taken here in Indiana.
Kathy Roesener

Hi Kathy,
Thanks for the compliment as well as your beautiful photographs.

Letter 8 – Tiger Swallowtail


nice pic
Just thought you would like this pic. Took it the other day in Belton, Texas
Alma Jo

Hi Alma Jo,
It really is a swell photo of a Tiger Swallowtail. We don’t seem to be able to get them to pose in our yard. They inevatably fly away the minute we appear with a camera.

Letter 9 – Tiger Swallowtail


Georgia State Butterfly
I am sending these pics for your enjoyment. I also have a bunch of pics of Tiger Swallowtails on Purple Coneflowers. The Tiger Swallowtail appears to be a somewhat picky eater. Until I took these pics, I had only seen these beauties on my coneflowers. They flew by all the rest of my flowers and I have hundreds of flowers in yard, more than 30 types.

Hi Jacqui,
Thanks so much for providing us with personal observations. We have Tiger Swallowtails in our own Mt. Washington garden in Los Angeles, but they never alight on blossoms. It appears your other photos are on lantana in addition to the sunflower we are posting. Growing up in Ohio, Swallowtails and many other butterflies as well as Hummingbird Moths were attracted to Mom’s summer phlox.

Wow!! Never did I dream that I would be posted on your website!! I am VERY HONORED. BTW, you have a great eye! You were correct in identifying the other flower besides the sunflower as a lantana. (After living in South Texas and SoCal I primarily xeriscape and lantana’s are very heat and draught tolerant. With the 2 year draught we have been having in South/Middle Georgia, it is a good thing!) I had considered naming the flowers in the pics but I wasn’t sure of the relevancy… It is interesting that my observation about Tiger Swallowtails’ food preferences is correct. I am sorry that none “visit” your flowers 🙁 I bet if you add some lantana and purple coneflower to your garden — both of which should do very well in your area — you will see much more of these gorgeous butterflies. Sunflowers are fun, too, but don’t always fit into a garden plan. FYI, hundreds of vine swallowtails pass through my garden but alight on NOTHING!! They must be VERY picky eaters indeed. Additionally, there is another big butterfly that passes through my yard which I have not yet been able to identify but is primarily orange and brown (not a monarch or viceroy, both of which frequent my yard, too) who is very conscious of — and concerned about — the ability of a flower to support its weight. If a flower bends in the least under its weight, the butterfly moves on. He flits here and there very rapidly and with apparent frustration at being unable to get the nectar out of sooo many flowers. Poor thing… I was thinking about about phlox to my garden next year. I think I definitely will now. Thanks for the tip!!
P.S. I have your fav spider in my yard, too. First, one was on the sage bush with Big Moma (the preying mantis who regenerated a big rear leg) for days — but on opposite side of the bush and for good reason. Then, I found another one on a sunflower. I had NEVER seen one of those spiders before. They ARE beautiful!! A couple of days later, I found him on your website 😉 Sadly, none of my first set of pics, where the spider was on the sage, turned out well. I only have a basic digital camera — no fancy zoom lens or high speed shutter. I NEED those bells and whistles!! I have not yet checked the shots of the spider on the sunflower. Cross your fingers!!

Letter 10 – Tiger Swallowtail


Eastern Tiger Swallowtail
Location:  Lexington NC
July 23, 2010 5:53 pm
He was a bit leery so I could not get a real good shot, but hope you enjoy this one.

Tiger Swallowtail

We know first hand how elusive Swallowtail Butterflies can be when there is a camera present, so we are happy to post your image of this Eastern Tiger Swallowtail to acknowledge your accomplishment.  It appears as though he may be puddling, an activity engaged in by many male butterflies that often congregate in great numbers near damp places so they can drink fluids that contain necessary salts and minerals.

Letter 11 – Tiger Swallowtail


Unknown Gorgeous Butterfly
Location:  Eastern Ohio
July 25, 2010 10:10 pm
Yet another beauty found out on the trails in Eastern Ohio. Its about 3-3.5 inches wide, and as you can see has amazing color! An ID would be superb!

Tiger Swallowtail

Ed. Note: The following email arrived about five minutes after the first.

Tiger Swallowtail?
Location:  Eastern Ohio
July 25, 2010 10:15 pm
Here are two excellent photos of what I believe is a Tiger Swallowtail, as identified by WTB. Verify for me, oh great bug identifiers!

Tiger Swallowail

Hi Knaet,
The butterfly images attached to both of your emails are Tiger Swallowtails.  The individual in the first email appears to be puddling at the site of some moist soil.  We are uncertain if the second set of images is of the same specimen, which you correctly identified in about five minutes, or if you thought there were two different species of butterflies.  We suspect the former, in which case you should be congratulated on the proper identification.

Letter 12 – Tiger Swallowtail


Tiger Swallowtail
Location:  Suburb North of Atlanta, GA
September 20, 2010 10:14 pm
I was going through old pictures on the camera and discovered my bug love has rubbed off on my man. He snapped this close shot of what I think is a Swallowtail Butterfly in July. I can’t believe the butterfly was so patient to pose. And kudos to my man who must’ve almost been lying down to grab this angle. Enjoy.
Signature:  Resa

Tiger Swallowtail

Hi again Resa,
It is nice to see that fine quality photographs run in the household.  The detail in this image of a Tiger Swallowtail is exceptional.

Letter 13 – Tiger Swallowtail


Eastern Tiger Swallowtail?
Location: Western Maine
January 24, 2011 12:20 pm
This little beauty fluttered into my van last summer. Is it an Eastern Swallowtail butterfly? Thank you!
Signature: Cheryl Mitchell

Tiger Swallowtail

Hi Cheryl,
There are several other species that look very similar to the Eastern Tiger Swallowtail,
Papilio glaucus, including the Canadian Tiger Swallowtail, Papilio canadensis.  To further complicate identifications, the ranges of the Eastern and Canadian Tiger Swallowtails overlap in places, including Maine.  We cannot say for certain which species you have, but the blue markings on the hind wing indicate that this is a female.

Letter 14 – Tiger Swallowtail and Ermine Moth


Ermine moth (tropical)
I just had my moth identified and was researching it when I came across one of your threads. They’re from the south, but someone in Long Island had seen them as well. Attached is a picture I had taken this morning, and only found it by accident; I was photographing a swallowtail on my dahlia.
Tracey Schiess
New Milford, NJ

Thanks for the awesome photo Tracey,
We have been trying to photograph a Tiger Swallowtail in our garden for an entire year so we could post the photo. They are very elusive, flying away whenever we approach with a camera. Perhaps the Western species is more camera-shy than your Eastern Tiger Swallowtail, Papilio glaucus. We suspect the range of the Ermine Moth, Atteva punctella, has been extended as the food source, Ailanthus Trees or Trees of Heaven, have spread like weeds throughout the country.

Letter 15 – Tiger Swallowtail Black Morph and Inchworm


Inchworm/Oak Besma? Butterfly?
Hello again What’s That Bug.
I noticed on the Caterpiller page you have the Inchworm/Oak Besma identification, but the picture is hard to see. I’d like to contribute my own. Again, these are found in my backyard in central Indiana. I have also included a picture of a butterfly I found at the Gatlinburg Ripley’s Believe It Or Not! Aquarium in Tennessee. I searched the site, but I’m unsure as the type of butterfly it is. Can you help?
Heather Burdette

Hi Heather,
Your unidentified butterfly is a Tiger Swallowtail, Papilio glaucus, but a black morph. According to BugGuide: “A dark phase occurs in females through much of range, esepcially in southern states. The stripes are still faintly visible from some angles. The black females may be distinguished from other swallowtails from below, by the absence of the band of orange spots on the hind wing seen on Black and Spicebush Swallowtails, and lack of iridescent blue of Pipevine Swallowtails. ” We are not entirely sure your Inchworm is an Oak Besma. It appears to be feeding on a maple leaf and there are other Geometrid Caterpillars that look very similar. Bugguide lists the food plants as: “Oak, elm, poplar, willows, and white spruce.” So our verdict is maybe yes and maybe no.


  • 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.

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  • 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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