The Swallowtail Butterfly Family

Adult Spicebush Swallowtail butterfly
Adult Spicebush Swallowtail butterfly. Photo by Donna L. Long.

The Swallowtail butterfly family includes large, attention-demanding butterflies. They are classified as members of the subfamily Papilionidae of the order Lepidoptera (butterflies, skippers and moths). The family also includes the Parnassian butterflies. There aren’t any Parnassian butterflies in the East Coast region of North America and I don’t discuss them here.

 

 

Population

There are between 475 and 563 species of Swallowtail butterflies worldwide. They’re found worldwide except in the Arctic. This butterfly family has many wonderful species in the tropical areas of the world. Of the subfamily Papilioninae, called “true swallowtails”, there are between 460 and 490 species worldwide with 28 of those species in North America; 12 species are in the East Coast region (Maine to Florida). Of the 12 species in the East Coast region, 9 are year around residents and 2 are strays.

 

Spicebush Swallowtail (Papilio troilus). Swallowtail Family (Papilionidae). Photo by Donna L. Long.
Spicebush Swallowtail (Papilio troilus). Swallowtail Family (Papilionidae). Photo by Donna L. Long.

How Swallowtails Differ from other Butterflies

What scientists call the “true swallowtails” have distinctive “tails” on their hind wings. The tails are projections which aid the butterfly during flight.

 

Adult Life Cycle Stage

The adults are large butterflies that can’t be missed. Many, if not most of the family, are black butterflies with other colors on their wings. The colors can be yellow, orange, red, green or blue. Many species have iridescent blue, black or green background wing color.

The males and females often have different markings, which need close inspection to see and distinguish. An excellent field guide on book on butterflies help to identify the species and explore the markings in more depth.

These big butterflies prefer to feed from tall plants. My Joe-Pye Weed stands about seven feet tall in my garden. When it is in bloom, I am always thrilled to see one with wings spread wide as it sips nectar from the tiny flowers. Adult butterflies sip nectar, caterpillars eat plants.

The males like to “puddle”. “Puddling” is gathering at a wet muddy or sandy spot and sipping minerals from the moisture. Puddling takes place at puddles, streamsides, and seeps, which are areas where water trickles up out of the ground and forms a pool.

Tiger Swallowtail (Papilio glaucus) on Ironweed
Tiger Swallowtail (Papilio glaucus) on Ironweed in my garden.

Mating

The males either patrol or perch to find females. Their behavior to perch or patrol depends on the specie.

 

The Swallowtail’s Flight Style

These butterflies are strong fliers with large wings. Many continuously flap their wings when sipping nectar from flowers.

The Swallowtail family members have a very distinctive extension on their hind wings look like a tail. This tail resembles the wings of a swallow in flight. This is where the “swallowtail” name comes from. Scientists think the hind wing tails help to divert airflow over the wings and enable the butterflies to glide at angles higher than butterflies without hind wing tails. Butterflies without hind wing tails would stall and not be able to glide at high altitudes.

 

Egg Life Cycle Stage

For such a large butterfly, you would expect them to come from large eggs and they do. The eggs are large, plain and round. One egg is laid on a newly emerged leaf.

 

Black Swallowtail osterium
Black Swallowtail Butterfly flashes its osmeterium. Photo by Donna L. Long.

Caterpillar Life Cycle Stage

Most Swallowtail larva look like bird droppings. Who wants to eat a bird dropping? That is precisely the point. The bird dropping appearance probably stops many animals who would eat a Swallowtail larva from trying.

The caterpillars have an organ that no other known butterflies have, called an osmeterium. This is orange-colored, Y-shaped organs, which are located behind the head and are raised and waved when the caterpillar feels threatened.  I poked at the Black Swallowtail caterpillar in the photo above and the orange osmeterium was waved at me. You can just see it in this photo. I must admit, it scared me, just a little.

Adult butterflies sip nectar, baby butterflies (caterpillars) eat plants.

 

flat flower heads Golden Alexanders (Zizia aurea)
Flat top, umbrella shaped flower clusters of Golden Alexanders in my garden.

Swallowtail Host Plants

Most of the larva (caterpillars) feed at night on specific food plants called host plants.

The body chemistry of the caterpillars can digest plants with chemicals (aristolchic acids, furnocoumarins, and acetogenins) which make the caterpillars taste bad. Some species are emetic, which means eating them makes birds and other vertebrates vomit.

Swallowtail host plants include:

Golden Alexanders

Paw Paw (Asimina triloba) – Zebra Swallowtail

Pipe Vines (Aristolochia)- Pipevine Swallowtail

Tulip Tree (Liriodendron tulipifera) – Easter Tiger Swallowtail

Spicebush (Lindera benzoin) – Spicebush Swallowtail

 

 

 

Tiger Swallowtail in Joe-Pye Weed
Tiger Swallowtail sipping nectar from Joe-Pye Weed.

Nectar Plants

These big butterflies prefer to feed from tall plants. My Joe-Pye Weed plants stands about seven feet tall in my garden. When it is in bloom, I am always thrilled to see a swallowtail with wings spread wide as it sips nectar from the tiny flowers.

Ironweed

See Golden Alexanders: Pollinator Magnet, Black Swallowtail Host Plant

 

spicebush swallowtail chrysalis
Spicebush Swallowtail chrysalis – Papilio troilu. Photo WikimediaJudy Gallagher, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0&gt;, via Wikimedia Commons.

Chrysalis Life Cycle Stage and How the Swallowtail Butterfly Spends the Winter

Most species spend the winter as a chrysalis. The caterpillar may wander several feet from its host plant to find a place to pupate or turn into a chrysalis. Chrysalis overwinter as pupae (chrysalis). In winter the caterpillar rests in a stage called diapause, not like hibernation but similar.

The chrysalis spends the winter under or attached to a stone or a piece of bark, in under leaf litter or other protected sites near the ground. Here is another example of the importance of leaf litter. The chrysalis is suspended from a surface by a silk thread acts as a sling or girdle. A hook bearing structure at the tail end of the chrysalis attaches the chrysalis to a little pad of silk, which is stuck to a surface from which the chrysalis hangs.

 

 

butterfly_tiger swallowtail
Tiger Swallowtail butterfly on Zinnias.

The Swallowtail Butterflies in the East Coast region of North America

  • Zebra Swallowtail (Eurytides marcellus)
  • Pipevine Swallowtail (Battus philenor)
  • Polydamas Swallowtail (Battus polydamas)
  • Eastern Tiger Swallowtail (Papilio glaucus)
  • Canadian Tiger Swallowtail (Papilio canadensis)
  • Spicebush Swallowtail (Papilio trolilus)
  • Black Swallowtail (Papilio polyxenes)
  • Giant Swallowtail (Papilio cresphontes)
  • Palamedes Swallowtail (Papilio palamedes)
  • Schaus’ Swallowtail (Papilio aristodemus) – extreme south Florida

 

The four Swallowtail Butterfly species I see regularly in Philadelphia are:

  1. Eastern Tiger Swallowtail (Papilio glaucus)
  2. Pipevine Swallowtail (Battus philenor)
  3. Black Swallowtail (Papilio polyxenes)
  4. Spicebush Swallowtail (Papilio troilus)

 

Links to other posts and websites

The 6 Butterfly Families

See Golden Alexanders: Pollinator Magnet, Black Swallowtail Host Plant

Butterflies and Moths Information and Links

Pollinator Syndromes: How to Predict Which Flowers Insects Will Like

The Butterfly Egg and Where to Find It

The Caterpillar (Butterfly Life Cycle)

Chrysalis Into Butterfly (The Butterfly Life Cycle)

The Adult Butterfly (The Butterfly Life Cycle)

Butterflies of Philadelphia: A Checklist

Observing Butterflies at Home 

Websites

North American Butterfly Association http://www.naba.org/

Butterflies and Moths of North America: Collecting and Sharing Data about Lepidoptera – link to photos http://www.butterfliesandmoths.org/taxonomy

Regional Checklist’s – for around the North and South America and the Caribbean http://www.butterfliesandmoths.org/checklists

Hosts: The Hostplant Database https://www.nhm.ac.uk/our-science/data/hostplants/search/index.dsml

References

Links lead to Amazon.com. I am an affiliate and receive a small fee that goes to support this blog. see FAQS: Buying from this Site.

Butterflies of the East Coast  by Rick Cech and Guy Tudor

Butterfly Photographer’s Handbook by William B. Folsom

Caterpillars in the Field and Garden: A Field Guide to the Butterfly Caterpillars of North America – covers western caterpillars

Caterpillars of Eastern North America by David L. Wagner

Caterpillars of Western North America – I couldn’t  find  book that covered caterpillars of the western part of North America

Peterson First Guide to Caterpillars of North America by Amy Barlett Wright (suitable for use with kids)

Peterson’s Guide to Eastern Butterflies by Paul A. Opler and Vichai Malikul

Peterson’s Guide to Western Butterflies

Peterson First Guide to Butterflies and Moths by Paul A. Opler (suitable for use with kids)

Please comment, share a resource or ask and question in the comments below.

2 comments

  1. My yard is a flutter with the 20 zebra swallowtails I’ve hatched in my home and.set free. This being the third litter, how do I know what will be the last generation before winter and how should I overwinter the chrysalis?

    • This is a very interesting question. I researched for an answer a found this one in, The Butterflies of North America James A. Scott.

      “Sometimes eggs, larvae, or pupae go into diapause in the laboratory and refuse to develop further. This can be prevented in many cases by shining a light on them constantly. Individuals in diapause can be overwintered using large clay planting pots purchased from garden centers ( the unglazed kind semipermeable to water); plug the hole in the bottom, place the individuals in small open containers in the pot (cheesecloths prevents their escape from the containers), bury the pots three-fourths of the way into the ground, and cover it with with a lid (the saucer for a larger pot). Avoid a sunny hot place where they will cook or dry out, and in drought water the lid occasionally. This pot will provide natural temperatures and moderate humidity. When the food plant is available in late winter or early spring, bring them indoors and they should develop normally.” pages 510-511, The Butterflies of North America: A Natural History and Field Guide by James A. Scott, Stanford University Press, 1986.

      So, making sure the butterflies do not have light shining on them constantly so they can naturally enter diapause. When the butterflies go into diapause (a kind of hibernation) then place them in the clay pots and following the instructions should keep them until next spring. The butterflies can tell the season just like we can. Good luck They will naturally know the time of year.

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