Transformations: Which Caterpillar Becomes Which Butterfly?

Transformations: Which Caterpillar Becomes Which Butterfly?

Eastern Tiger Swallowtail caterpillar. Photos by Gerry Lemmo.

The United Nations has coined 2010 to be The International Year of Biodiversity, so it’s only fitting that insects play a starring role in the pages of our summer issue. Insects, after all, are the most abundant animals on earth. While some species can be overlooked, due to their small size or out-of-the-way lifestyles, butterflies and caterpillars cannot. These veritable pop stars of the insect world – dolled up in coiffed hair tufts and shimmering wing scales – simply demand attention.

As any third-grader will tell you, Lepidoptera – the order of insects that includes butterflies and caterpillars – represent peak evolution in the cool-animal department. Sure, dogs and cats are great, but to even compete for the crown, Fido would have to shed his skin five or six times, then void his bowels, fashion himself a cocoon, digest his larval tissues and organs, and reemerge from the cocoon a few weeks later as a giant bird.

While the image of literal mammalian metamorphosis is silly, a philosophical interpretation is not. The human concept of redemption – this idea that we can change for the better – can be read into the caterpillar-to-butterfly progression. It’s no coincidence, then, that humans are attracted to butterfly totems, to tattoos and bejeweled winged amulets that rest against caterpillar-silk blouses. It’s no coincidence, then, that Hollywood filmmakers make hay here in the light version of human metamorphosis – the streetwalker-gone-good motif – and the dark side – the soul of great beauty who, like a butterfly, just can’t bring him- or herself to fly straight.

The influence that butterflies/caterpillars have on humans goes far beyond art and philosophy. In the world of raw economics, butterfly collectors still pay hundreds, if not thousands, of dollars for rare specimens. Farmers and foresters engage in epic battles with tree- and plant-munching larvae. One degree separate, but no less influential, is our human dependence on the relationship between caterpillars and plants. The aspirin you take for headaches is derived from salicylic acid, a plant compound that’s produced to thwart caterpillars. The coffee you may be drinking as you read this takes its bitter flavor from the same.

Back to square one now, the basic question that confronts every amateur naturalist when they gaze upon a caterpillar is: what kind of butterfly or moth will this become? You may know what a woolly bear looks like, but how about an Isabella tiger moth – the woolly bear’s adult form? Secondary questions include, what kind of food do they eat? And are they harmful if I touch them?

To answer these questions, we enlisted the help of photographer Gerry Lemmo and compiled photos of some of the most common caterpillars, and their subsequent butterflies or moths, that you’ll find in the Northeast. For more advanced studies, we’d suggest David L. Wagner’s Caterpillars of Eastern North America – an exceptional field guide – and Butterflies of the East Coast; An Observer’s Guide, by Rick Cech and Guy Tudor.

American Lady, Vanessa virginiensis

Description: Caterpillars vary in color, but the red bases of the hair tufts are usually a giveaway. Butterfly wingspan: 1¾–25/8 inches.

Ecology: American lady caterpillars are solitary creatures that feed in nests made out of silktied leaves. Favored fare includes pussytoes, ironweed, burdock, and plants in the sunflower family. Butterflies inhabit open places and are especially fond of aster, goldenrod, milkweed, and vetch.

Random Cool Fact: Like other “brush-footed” butterflies in the family Nymphalidae, American ladies have taste receptors on their feet that let them sample the flavor of a plant just by walking on it.

Black Swallowtail, Papilio polyxenes

Description: Larvae change dramatically with each molt; they start off looking like bird droppings and end up looking like the caterpillar pictured here. Butterfly wingspan: 1¾–25/8 inches. The butterfly pictured here is a female – males have less of that shimmering blue coloration and a more extensive yellow band.

Ecology: Caterpillars eat plants in the carrot family – look for them in the garden on dill, parsley, and fennel; in the wild, check out Queen Anne’s lace and poison parsnip. Black swallowtail butterflies eat nectar and, in an aesthetic irony, are attracted to mud and manure piles. They flourish around humans and open spaces; they’re declining as Northeastern farmland reverts back to forest.

Random Cool Fact: Caterpillars have retractable horns that emerge from a slit just behind their head when they’re alarmed.

Cecropia Moth, Hyalophora cecropia

Description: Sci-fi-looking caterpillars are frosted green and covered in shiny yellow, orange, and blue knobs. Moths are giant, with wingspans of 4¾–6 inches.

Ecology: Caterpillars eat many woody plants, including ash, apple, and box elder. Moths fly from April to July and are attracted to lights or, perhaps more accurately, are attracted to the darkness around bright lights.

Random Cool Fact: To pupate, a cecropia caterpillar folds itself into a leaf and secures its hideout with about a mile of silk.

Random Sad Fact: Native silk moths are all in decline – collateral damage in our war against the gypsy moth. When well-meaning but misguided scientists released tachinid flies in 1906 to kill gypsy moths, they didn’t count on the parasite having indiscriminate taste. Cecropias seem especially hard hit – in one Massachusetts study, 81 percent of lab-raised caterpillars that were released into the wild were parasitized by this exotic fly.

Luna Moth, Actias luna

Description: While beauty is subjective, most entomologists would be hard pressed to name an insect more beautiful than the luna moth. Larvae are lime green with faint pink spots and a pale stripe along the abdomen. Moths are otherworldly green with fern-frond antennae and pink, burgundy, white, and black eyespots. Wingspan can be wider than 4½ inches.

Ecology: Caterpillars eat a variety of tree leaves, including those of paper birch, sweet gum, hickory, and sumac. Adults live for about a week and don’t eat – their only purpose is to reproduce.

Random Cool Fact: Moth and butterfly wings are covered in thousands of wing scales, essentially flattened versions of insect hair. (Lepidoptera means “scaly winged.”). Lower inset photograph shows a close-up of the wing scales in a Luna moth eyespot.

Monarch, Danaus plexippus

Description: Look for these tiger-striped caterpillars on milkweed; the orange butterfly features a classic black-vein and white-dot pattern. Wingspan: 3½–4½ inch.

Ecology: Each fall, Northeastern monarchs undertake an epic migration south, where the entire population winters in a relatively small patch of forest in south-central Mexico. In spring, they move north, laying eggs and dying as they go. The monarchs you see this summer in northern Maine could be the fourth generation offspring of the monarch that flew south to Mexico last fall. All of this suggests that there must be a genetic component to the migration, since no individual butterfly makes the journey twice.

Random Cool Fact: The migration story wasn’t cool enough for you? OK, how about the fact that caterpillars sequester cardiac glycosides (i.e., poison) from the milkweed leaves they eat, concentrate it, and carry it forward into their chrysalis and adult stages. This makes them unpalatable to most birds.

Mourning Cloak, Nymphalis antiopa

Description: This spiny, black-and-red caterpillar cannot be confused with any other. When you see it, don’t touch it; the hairs break and release noxious chemicals that can cause nasty rashes. Butterflies have a wingspan of around 3 inches and are almost always the first butterflies encountered each spring.

Ecology: Caterpillars stay together upon hatching and can defoliate whole branches of poplar or willow trees. Butterflies go through a period of dormancy in summer, then re-emerge briefly in fall before finding a comfortable spot and hibernating through winter. In spring, look for them sipping sap at sapsucker holes.

Random Cool Fact: Mourning cloaks are our longest-lived butterfly – some individuals survive a whole year.

Eastern Tiger Swallowtail, Papilio glaucus

Description: Newly hatched eastern tiger swallowtail caterpillars are bird-dropping mimics. The last larval stage, seen here, has smallish eyespots that make it look like a tiny, nearsighted snake. Butterflies have 4½ inch wingspans and vary in color. Females can be yellow, like the one pictured here, but there’s also a black color phase.

Ecology: Caterpillars feed on black cherry, birch, ash, willow, cottonwood, and tuliptree. Butterflies take nectar and are often found in edge habitat, especially swamp edges.

Random Cool Fact: Eastern tiger swallowtails butterflies, and many other butterfly species, are often seen congregating at puddles on dirt roads. What they’re doing is eating the salt and minerals that have dissolved in the water. If there are no puddles, they still may gather on open dirt to regurgitate into the soil and slurp up nutrients this way.

White-Marked Tussock Moth, Orygia leucostigma

Description: The caterpillar is 1–1½ inches long, with a bright red head and four white to yellowish brush-like tufts of hairs on the back. Female moths, like the one pictured here, are wingless and therefore flightless. Males are medium-sized brown moths with a single dot on the forewing.

Ecology: One of our most ubiquitous caterpillars, the white-marked tussock could turn up on virtually any plant in the Northeast. A member of the Arctiidae family.

Random Cool Fact: Some male Arctiid moths sequester pyrrolizidine alkaloids (PA) from plants and use them as a defense mechanism. They can then sexually transmit this protection to a female mate. One study showed that a PA-deficient female becomes unpalatable to spiders almost immediately after copulation and that this unpalatability endures throughout her life.

European Skipper, Thymelicus lineola

Description: Green caterpillar can be distinguished from other grass skippers by the whitish lines that run the length of the body. Tiny orange butterflies are found in orchards and unmowed hay fields.

Ecology: European skippers overwinter as eggs. Caterpillars are private, feeding at night and sleeping through the day in silken leaf shelters. Butterfly is one of the most common in the Northeast.

Isabella Tiger Moth, Pyrrharctia Isabella

Description: The woolly bear is a fuzzy, orange and black caterpillar that becomes a dull, yellow to orange moth with a fat, furry thorax and a small head.

Ecology: One of our most familiar caterpillars, woolly bears are renowned wanderers. They hatch from eggs in fall and are often seen crossing roads, a strange fact, considering they eat almost everything. Look for them overwintering in your wood pile. In spring, they gorge themselves, then molt into Isabella tiger moths.

Snowberry Clearwing, Hemaris diffinis

Description: Simple, run-of-the-mill caterpillar becomes one of the Northeast’s most striking moths. Moths have fat, furry bodies and wings with clear windows in them (wingspan equals 1½–2 inches). They’re fast-moving and hover at flowers; as such, they’re often mistaken for tiny hummingbirds or giant bumblebees.

Ecology: Caterpillars feed on hawthorn, honeysuckle, snowberry, and viburnum. Moths like phlox, buddleia, and deep-throated flowers.

Gerry Lemmo is a professional freelance photographer from Warren County, New York. As a teenager, he was a member of the entomological club at the American Museum of Natural History.

  1. Loviegentle
    Apr 28, 2015

    I liked the pictures.

  2. Samuel karengo → in kenya
    Jul 27, 2015

    I once saw a yellow and black caterpillar which pupates underground. I wonder which moth/butterfly it came from.

  3. GWIZCO → in Indiana
    Aug 21, 2015

    Great piece! Helped me identify the White-Marked Tussock. The caterpillar is crawling by us at our campsite right now…awesome! Thank you!!

  4. Lynn → in Chardon, Ohio
    Aug 23, 2015

    I just photographed a Snowberry Clearwing at my front porch.

  5. Mary → in Southern California Beach City
    Sep 01, 2015

    A Giant Swallow Tail butterfly hatched this morning. My puppy saw it and barked and growled his head off. It was fanning it’s beautiful wings, and then left. But I have a full nursery of them in the Basil plant. It’s growing directly next to parsley but the cocoons are in the basil.  One caterpillar is totally green, I thought it would be black and yellow! It’s awesome. I hope I see them all hatch and fly away.


  6. Bonita Mascola → in Toms River, NJ
    Sep 07, 2015

    We planted a butterfly garden with great success, also we have 5 caterpillars eating our parsley. :)

  7. Foxy Moxy → in Delavan, WI
    Oct 19, 2015

    I just identified a tiger moth caterpillar. Thanks for the informative website!

  8. Jaime Pearson → in Kimberling City, MO
    Oct 22, 2015

    My kids saw the Wooly Bear Caterpillar and wanted to know what it would turn into.  Thank you for your site.  I love that I don’t have to know everything but instead can share in the adventure of learning with the kids.  They are 6 and 8.

  9. Jennifer Short → in Savannah, GA
    Oct 26, 2015

    I found a wooly bear (?) today in my garage.  It appeared to be all black.  I saw on another site that popular belief is that the less orange/brown on this caterpillar means a harsher winter for that area.  I hope not, but I’m sure it still won’t compare to other parts north of us.

  10. Debra Kearney → in Yulee florida
    Nov 03, 2015

    I found a pale yellow large caterpillar with a dark brown head in my yard. Waxy looking….what is he????

  11. Susan → in East London
    Nov 07, 2015

    I saw hundreds of worms with yellow heads and tails weaving all over the show, with lots in one woven nest, they are not very big, about 2cm and fairly thin. I am wondering what they become.

  12. Sophy → in Cambodia
    Jan 26, 2016

    Wow! Never see these butterflies! I hope will see these butterflies in my country.

  13. Annette → in Chigwell Essex
    Jun 06, 2016

    I have noticed that two separate bushes in my garden have been left like skeletons, as I took a closer look they have hundreds of deep green and black caterpillars. I am looking forward to see them change.

    Can anyone tell me when this might happen as I don’t want to miss it. I’m sure it will be beautiful, I would like to film it.

  14. Natalia → in Toronto, Canada
    Jun 26, 2016

    Thank you for this page. I just identified a black swallowtail caterpillar happily munching on my dill plant this morning.  Hopefully I get to see it pupate.

  15. Donna → in Central West Indiana
    Aug 04, 2016

    We have luna moths all the time but I never knew what the caterpillar looks like. Now I know why we have so many of them and where they are coming from. Excellent site.

  16. Ruby Dee Hammett → in Virginia
    Sep 17, 2016

    I did not know any of the combinations and its such a blessing. I am afraid of creepy crawling things. But I saw the small green tiger swallow-tailed caterpillar and took pics of it and was so excited to find it was going to be a butterfly and was no longer afraid. In fact it is quite cute and looks more like a fish with big yellow eye. Thank you so much for sharing your gift. Enjoy your blessings.

  17. Kelley Bradley → in Arkansas
    Oct 10, 2016

    Debra Kearney, it may be a Luna moth caterpillar. I see light green ones. (?)

  18. Terri → in Florida
    Oct 14, 2016

    Will the milkweed plant leaves grow back after caterpillars eat them?

  19. Melissa → in Florida
    Mar 13, 2017

    My hubby has milkweed plant growing in his garden and I have noticed that there are monarch caterpillars all over them. I am so excited to watch the whole process!!!! Thank you for this site.

  20. Khlang Kim Ann → in Cambodia
    Apr 26, 2017

    I do love the descriptions and pictures so much.

  21. Sue → in England Upminster Essex
    Jun 04, 2017

    We live in the southeast and found a white marked tussock moth which lives in the north east.

  22. Sue → in England
    Jun 04, 2017

    Thanks so so so so so so so so so so so much.

  23. Karen A Thomas → in Springfield, MA
    Jul 25, 2017

    Found a Snowberry Clearwing in Springfield, MA July 23, 2017. It was very woolly and brilliantly green.

  24. Elissa S. Aks-Srabstein → in Potomac
    Aug 14, 2017

    Thank you Dave Mance III and Gerry Lemmo!!  I found 4 caterpillars on a milkweed today (first time) and was able to quickly identify them as future Monarchs!! I’ll be reading up on what to expect, photographing and making sure they are safe and well-protected. (Yes, I am a helicopter Mom, I guess.)  This is incredibly exciting, as the butterfly population in my area (Potomac, Maryland), has been greatly reduced. All the best!

  25. Jim Bostic → in Reading, PA
    Aug 20, 2017

    Yesterday, I saw a small, short all-yellow caterpillar with reddish antennae.  I am unable to identify the caterpillar or what it will become as a butterfly or moth.  Any ideas?

  26. Kristi → in Upstate NY
    Aug 21, 2017

    Hello-I saw a unique type of moth the other day and couldn’t figure out what it was! I found your page on Google and saw the same moth! I am excited to put a name to the little guy-he was a snowberry clearing! Ty!

  27. LKeane → in Milwaukee
    Nov 11, 2017

    Thank you for your site. It helped me identify the Isabella Tiger Moth, a common moth caterpillar, but all the same , exciting to identify and know it will emerge in the spring! Looking for others now in the first frost of the season!

  28. Peter Cantu → in Jacksonville, TX 75766
    Apr 15, 2018

    I was digging up the roots to a old shrub came back 10 minutes later and found a luna moth caterpillar neon green,feed back.

  29. Sydney → in Western Pennsylvania
    Jul 15, 2018

    HELP! I found what looks like a type of chrysalis today and I have absolutely no idea what it is! Its mainly brown and it looks like its in a sort of “S” shape. You can see its antenna and it has two bumps on its back. Someone please help!!!

  30. Kimberly Ann Orton → in Claremore
    Jul 19, 2018

    I have butterfly plants and I am getting all kinds of caterpillars.

  31. Julia → in Deltona, Fl
    Aug 11, 2018

    We are raising Monarch caterpillars. They kept disappearing from our milkweed so we decided to bring them in to be safe. So glad we did. One emerged and it was an amazing experience.  We currently have three chrsysalis and five about to j shape any moment. We also found the leaf rollers or European Skipper infesting our Canna Lillie’s. We are waiting to watch this turn as it’s in chrysalis now.  If that all wasn’t enough, we found four woolly bears and are raising them. We homeschool our kids and this has turned out to be the best summer science project.

  32. Danniell → in Bellevue, NE
    Aug 19, 2018

    My mother planted parsley and dill in pots on our back deck to find the parsley FULL of swallowtail caterpillars. We had seen the adults flitting in the butterfly garden and I was pleased as punch to give up the parsley for these little babes.

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