Baltimore Checkerspot: Essential Facts & Insights

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The Baltimore Checkerspot is a fascinating medium-sized butterfly species that boasts a unique combination of colors and patterns on its wings.

Belonging to the family Nymphalidae, also known as brushfooted butterflies, these creatures possess reduced front legs, giving the appearance of having only four legs instead of six.

Recognizable by their black wings adorned with white and orange markings, Baltimore Checkerspots are slow, deliberate fliers.

Both males and females can be observed perching on low vegetation with open wings, while males are known to congregate in puddle clubs.

The females deposit clusters of several hundred tiny yellow eggs on host leaves, which turn red as they age, eventually giving way to the next generation of this captivating butterfly.

Baltimore Checkerspot. Source: Andy Reago & Chrissy McClarrenCC BY 2.0, via Wikimedia Commons

Baltimore Checkerspot Overview

Euphydryas Phaeton

The Baltimore Checkerspot is a fascinating butterfly species scientifically known as Euphydryas phaeton.

It holds the honor of being Maryland’s State Insect since 1973, and though relatively common then, its population has since declined.

Appearance

This medium-sized butterfly sports a striking color palette featuring:

  • A black base color
  • Rows of white spots in the middle of its wings
  • Orange spots along the wing margins

These distinctive markings make the Baltimore Checkerspot easy to identify. Its appearance serves as a prime example of the eye-catching patterns found among butterfly species.

Size and Wingspan

The Baltimore Checkerspot belongs to the Nymphalidae family, which comprises brushfooted butterflies.

They possess reduced front legs, giving them the appearance of having only four legs instead of six. With a wingspan of around 2.5 inches, it falls within the range of medium-sized butterflies.

Flight Pattern

Distinct flight patterns characterize various butterfly species, including the Baltimore Checkerspot.

Unfortunately, limited information is available on its specific flight pattern.

However, observing these beautiful creatures in their natural habitat can provide insight into their graceful aerial movements.

Life Cycle and Habitats

Egg Stage

The Baltimore Checkerspot life cycle begins with the female butterfly laying eggs.

These eggs are usually laid in clusters on the leaves of host plants, mainly white turtlehead and English plantain (Plantago lanceolata).

Caterpillar and Communal Web Stage

Once hatched, the caterpillars feed on the host plants and create communal webs as they grow.
Key features of the caterpillars are:

  • Black with orange spots
  • Spiky hairs on their body

Caterpillar

Pupa Stage

After several molts, the caterpillars transform into pupae.
During the pupa stage:

  • They are immobile
  • Metamorphosis takes place, transforming them into butterfly

Baltimore Checkerspot Chrysalis

Adult Butterfly Stage

Finally, the adult Baltimore Checkerspot emerges. Characteristics of the adult butterfly include:

  • Wingspan of roughly 2.5 inches
  • Distinct black, white, and orange patterns on wings

File:Baltimore Checkerspot - Euphydryas phaeton, Big Meadows, Shenandoah National Park, Virginia - 27732575521.jpg
Adult Baltimore Checkerspot. Source: Judy GallagherCC BY 2.0, via Wikimedia Commons

Habitats and Host Plants:

The Baltimore Checkerspot inhabits wet meadows, prairies, and damp woodland clearings where their host plants are abundant. They rely on host plants for eggs, caterpillars, and obtaining nectar as adults.

Comparison of host plants:

Host PlantBenefitsDrawbacks
White TurtleheadPreferred by Baltimore Checkerspot for egg-layingNot as widely available as Plantago lanceolata
English Plantain (Plantago lanceolata)Widely available; can support other butterfly speciesMay not be native to some areas

Seasonal Timeline:

  • Spring: Eggs are laid on host plants and caterpillars hatch
  • June-July: Adult butterflies emerge and start the cycle again

Conservation and Habitat Management

Endangered Status

The Baltimore Checkerspot butterfly is classified as a rare, threatened, and endangered species.

Sensitive Habitats

  • Found in wetland habitats
  • Depend on specific host plants
  • Affected by habitat degradation

Baltimore Checkerspots are predominantly found in wetland habitats, relying on specific host plants, like the white turtlehead, for survival.

Unfortunately, these sensitive habitats are vulnerable to degradation, leading to a decline in the butterfly’s population.

Source: Alison HunterCC BY-SA 2.5, via Wikimedia Commons

Protection Efforts

  • Habitat conservation and enhancement
  • Experimental translocation project

There have been various protection efforts put in place to ensure the survival of the Baltimore Checkerspot in Maryland.

They include habitat conservation and enhancement, and an experimental translocation project to support the butterfly’s population.

Feeding and Host Plants

Primary Host Plants

The Baltimore Checkerspot butterfly primarily relies on White Turtlehead (Chelone glabra) as its main host plant.

This plant provides the necessary nutrients and habitat for the butterfly’s larvae to feed and grow. Some important features of White Turtlehead include:

  • Tolerates a variety of environments
  • Blooms between late summer and early fall
  • Attracts Baltimore Checkerspot through its tubular white flowers

Nectar Sources

Adult Baltimore Checkerspot butterflies require a diverse range of nectar sources to feed on to maintain their energy levels. Some common nectar sources for this species include:

  • Milkweeds
  • Dogbane
  • Penstemon
  • Honeysuckle
  • Wild rose

These plants provide essential nutrients to facilitate the butterflies’ reproductive process.

Source: Andy Reago & Chrissy McClarrenCC BY 2.0, via Wikimedia Commons

Additional Host Plants

Baltimore Checkerspot butterflies will sometimes lay their eggs on other host plants if White Turtlehead is scarce. Examples of additional host plants are:

  • English Plantain (Plantago lanceolata)
  • False Foxglove (Sophronitis virginiana)
Primary HostAdditional HostNectar Sources
White TurtleheadEnglish PlantainMilkweeds
(Chelone glabra)(Plantago lanceolata)Dogbane
 False FoxglovePenstemon
 (Sophronitis virginiana)Honeysuckle
  Wild rose

These secondary host plants enable the Baltimore Checkerspot butterfly to maintain its population even when their primary host plant is limited.

It is essential to ensure a diverse range of host and nectar plants in your garden or landscape to support the Baltimore Checkerspot’s population.

Geographical Range and Regional Populations

Distribution in North America

The Baltimore Checkerspot butterfly is primarily found in the eastern United States and southeastern Canada. Key regions include:

  • Great Lakes region
  • Appalachian Plateau
  • Blue Ridge
  • Ridge and Valley regions

These butterflies favor wet meadow habitats within these locations.

State and Regional Information

Baltimore Checkerspot populations vary across different regions:

  • USA: Small and isolated populations are spread across states within the butterfly’s range.
  • Canada: Eastern provinces like Ontario and Quebec host relatively larger populations.

Within Maryland, most colonies are small and apparently isolated. Some notable counties with sightings include:

  • Baltimore County
  • Harford County
  • Howard County

Comparing the urban population to Baltimore Checkerspot habitats:

AreaPopulationHabitat Suitability
Baltimore City585,708Limited
Baltimore County847,000Suitable

In summary, the Baltimore Checkerspot is primarily found in the eastern United States and parts of Canada, mainly in wet meadow habitats throughout the Appalachian region.

Populations tend to be smaller and isolated in certain areas, but some regional hotspots, such as in Maryland, are more favorable for this unique butterfly species.

Symbolism and History

George Calvert Connection

The name of the Baltimore Checkerspot Butterfly is closely linked to George Calvert, the 1st Lord Baltimore.

He is an English nobleman and founder of the Maryland colony and had a profound impact on Maryland’s history.

The black and gold colors of the butterfly resemble the Calvert family’s heraldic shield.

Behavior, Predators, and Defense Mechanisms

Mating

Baltimore Checkerspot butterflies engage in a relatively simple mating process.

The male butterflies find a suitable mate by tracking the females’ pheromones.

Once a pair is formed, they mate in the dense vegetation, which provides them with some shelter and protection from predators.

Communal Web Stage

During the early stages of their life, Baltimore Checkerspot caterpillars live in a communal web.

This web serves as a protective shelter for the caterpillars and aids the young insects in feeding on their host plants.

The communal living style minimizes exposure to predators and increases the chances of survival for the young caterpillars.

Coat of Arms of Cecil Calvert. Source: Baron Baltimore. (2023, April 1). In Wikipedia. https://en.wikipedia.org/wiki/Baron_Baltimore

Predators and Parasitic Wasps

Baltimore Checkerspot butterflies and their caterpillars face various natural predators, such as:

In addition to these predators, parasitic wasps are also a significant threat to Baltimore Checkerspot butterflies.

These wasps lay their eggs inside the caterpillars, ultimately killing them as the wasp larvae develop and consume their host.

Defense Mechanisms

To defend themselves against predators, Baltimore Checkerspot caterpillars and butterflies employ a few strategies:

  • Aposematic coloration: The bright and contrasting colors of the butterfly’s wings act as a warning signal to predators that they may be poisonous or bad-tasting.
  • Communal living: As mentioned earlier, the caterpillars live together in a protective web, which helps to deter predators.
  • Chemical defense: The caterpillars feed on specific host plants that contain toxic compounds, incorporating these toxins into their bodies to make them unappetizing to predators.

Conclusion

As we wrap up this comprehensive guide on the Baltimore Checkerspot, it’s evident that this butterfly is not just a visual marvel but also a symbol of Maryland’s history and biodiversity.

From its unique color patterns to its specific habitat needs, the Baltimore Checkerspot serves as a reminder of the delicate balance in our ecosystems.

While it faces challenges from habitat degradation and predators, efforts are underway to conserve this fascinating species.

Whether you’re an amateur lepidopterist or simply an admirer of nature’s beauty, understanding the Baltimore Checkerspot enriches our appreciation for the intricate web of life around us.

Footnotes

  1. Rare, Threatened and Endangered Animal Fact Sheets 
  2. Alabama Butterfly Atlas  2
  3. Baltimore Checkerspot | MDC Teacher Portal 

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 – Baltimore Checkerspot

butterfly, can’t find anywhere
I have a bunch of butterflies in the field (usually low in the weeds or near puddles) which I can’t seem to find on the internet. (Perhaps I’m not searching the correct keywords) Could you please identify this for me? Thanks a bunch!
Heather Johnson

Hi Heather,
This lovely little butterfly is a Baltimore Checkerspot, Euphydryas phaeton. It is found in the Northeast United States.

Letter 2 – Baltimore Checkerspot Caterpillar

Subject: Spiny Orange-banded Caterpillar
Location: Amherst, MA
June 28, 2017 8:48 pm
Found several of these of an unmowed field in Amherst, MA.
Signature: Randall Phillis

Baltimore Checkerspot Caterpillar

Dear Randall,
We were able to identify your Baltimore Checkerspot Caterpillar,
Euphydryas phaeton, thanks to images posted to BugGuide.  According to BugGuide

“The primary larval food source is turtlehead (Chelone glabra), although recent studies have shown that the caterpillars will eat a larger variety of plant species including English plantain (Plantago lanceolata), a common yard weed.”  The adult Baltimore Checkerspot is a very lovely butterfly.

Baltimore Checkerspot Caterpillar

Thank you so much.
This helps and clearly is the match.
Feel free to use the photos I sent if they could be helpful for you guys.
Randy Phillis

Letter 3 – Baltimore Checkerspot Caterpillar and Chrysalis

Subject: butterflies
Location: Middleville, Michigan
July 25, 2014 12:01 pm
These Beauties are new to my yard this year. I believe they belong to a checkerspot.
Signature: Teri

Baltimore Checkerspot Caterpillar
Baltimore Checkerspot Caterpillar

He Teri,
We agree that your caterpillar looks exactly like a Baltimore Checkerspot Caterpillar,
Euphydryas phaeton, posted to BugGuide, and the chrysalis also looks like a Baltimore Checkerspot Chrysalis posted to BugGuide

According to BugGuide:  “The primary larval food source is turtlehead (Chelone glabra), although recent studies have shown that the caterpillars will eat a larger variety of plant species including English plantain (Plantago lanceolata), a common yard weed.” 

The plant you have documented with the caterpillar appears to be plantain, based on the images on the USDA site. 

Baltimore Checkerspot Chrysalis
Baltimore Checkerspot Chrysalis

Letter 4 – Baltimore Checkerspot Chrysalis

Subject: Beautiful chrysalis
Location: Belleville, MI
May 24, 2015 4:17 pm
Dear Bugman: Wanted to share my son’s photo of a beautiful chrysalis he found. It was on a sign in an area park.

Never seen one so beautifully patterned. We looked it up and found similar pictures and believe this will become a Baltimore Checkerspot butterfly.
Signature: MI Bugmama

Baltimore Checkerspot Chrysalis
Baltimore Checkerspot Chrysalis

Dear MI Bugmama,
We are in total agreement with you that this is the chrysalis of the Baltimore Checkerspot,
Euphydryas phaeton, and you can see that it is a perfect match for this BugGuide image.

Letter 5 – Possibly Baltimore Checkerspot Chrysalis

Subject: What’s this
Location: Castle Hayne,N.C. USA
August 11, 2016 10:08 pm
This critter was found in my flower garden in May or June in Castle Hayne, N.C. I am unable to find any info to ID it even though I have seen pictures of it somewhere. Do you know what it is?
Signature: James

Possibly Baltimore Checkerspot Chrysalis
Possibly Baltimore Checkerspot Chrysalis

Dear James,
Can you possibly send another image with a different angle, like a lateral view?  Since it was in your flower garden, are you able to provide the name of the plant upon which it was found?  How large was it? 

To us, this appears to be a Baltimore Checkerspot Chrysalis, but something does not look right.  It appears to be either deformed, or damaged.  You can also see this BugGuide image of a Baltimore Checkerspot Chrysalis.

This was the only pic. It was on a cone flower or black-eyed susan. It was small. Less than 3/8 of an inch.
thanks,
James

Authors

  • 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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Tags: Baltimore Checkerspot

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2 Comments. Leave new

  • What a cool and unusual find – baltimore checkerspots are supposed to be quite rare in their namesake area of Maryland. I live in Maryland about an hour from Baltimore and have never seen one. Apparently they have experienced a steep decline partly because of a lack of native plants that the larvae need to feed on.

    Reply
  • This is the shed skin of a caterpillar, probably an eastern black swallowtail or anise swallowtail depending on it’s location. Somewhere right above is a chrysalis!

    Reply

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