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New Jersey Endangered and Threatened Species Field Guide

Image of Baltimore checkerspot.Zoom+ Baltimore checkerspot. Photo courtesy of Eric C. Reuter.

Baltimore checkerspot

Euphydryas phaeton

Species Group: Invertebrate

Conservation Status

State: Special Concern



The Baltimore checkerspot (Euphydryas phaeton) is a medium-sized butterfly with a wingspan of approximately 1 ½ - 2 ½ inches. It has black wings with an orange border that are speckled with orange and white spots. Like other butterflies in the family Nymphalidae, also known as “brush footed” butterflies, the Baltimore checkerspot has reduced front legs. This makes it appear as if the insect has only four legs instead of six.

The Baltimore checkerspot larva exhibits a similar color pattern with black and orange stripes alternating horizontally down the body.

Image of Range of the Baltimore checkerspot in New Jersey.Zoom+ Range of the Baltimore checkerspot in New Jersey.


The range of the Baltimore checkerspot spans from Canada south to Virginia and North Carolina. They can be found in much of the Eastern United States west to the Great Lakes region. In New Jersey, Baltimore checkerspots are found mostly in the northern half of the state; however, its range is declining and reports are uncommon and on a local basis.

Its habitat consists of wet, stream fed meadows. Mostly early successional habitats, they contain of very few trees or shrubs and are primarily formed by waist-high herbaceous vegetation. White turtlehead (Chelone glabra), the host plant for maturing Baltimore checkerspots, is a staple of its habitat. Secondary host plants such as honeysuckle (Lonicera spp.) and arrowwood (Viburnum dentatum) are also common.


Young larvae of the Baltimore checkerspot feed on white turtlehead, a plant native to wetland habitats. As the larvae mature, their diet becomes more diverse, expanding to include honeysuckle, plantains (Plantago spp.), penstemon (Penstemon spp.), ash (Fraxinus spp.), and viburnums (Viburnum spp.).

Adult butterflies feed on a variety of nectar producing plants flowering during their flight period. Some of these plants include, wild blackberry (Rubus spp.), common milkweed (Asclepias syriaca), and dogbane (Apocynum spp.).


In early to mid-summer, female Baltimore checkerspots deposit eggs on the underside of white turtlehead leaves in clusters of approximately 100-600 eggs. The eggs develop for about 20 days, changing color from yellow, to tan, to red. Once hatching, the first instar larvae create a communal web at the end of the white turtlehead leaf and begin to feed. They continue to feed and develop into second and third instar larvae, becoming larger and more brightly colored at each stage.

The third instar larvae stop feeding around mid-August, when they thicken a part of their web. Here, they molt into fourth instar larvae, after which they cease to feed or grow and enter a state of diapause. At the end of October, the larvae aggregate into groups in the leaf litter and debris below their plant. The leaf litter and any snow insulate and protect the larvae from harsh winter temperatures.

Image of Baltimore checkerspot side profile.Zoom+ Baltimore checkerspot side profile. Photo courtesy of Eric C. Reuter.

When the weather warms again, about mid-April, the larvae begin feeding again, primarily on white turtlehead. They continue to grow until they reach their full size. Then, each larva forms a chrysalis or pupa. Development inside the chrysalis occurs for about two weeks, after which an adult butterfly emerges and the cycle repeats. It has a flight period that lasts from early June to early August.


The Baltimore checkerspot is recommended for listing as a “special concern” species in New Jersey. This means that they are especially vulnerable to habitat destruction or modification. A major threat to the species is the destruction of its native wetland habitats by development. Other human-caused impacts on the butterflies include inbreeding depression caused by habitat fragmentation and competition to host plants by introduced invasive species. These combine with natural threats and sources of habitat loss such as natural forest succession, loss of eggs and host plants to deer browse, and insect predators and parasites to suppress populations.

Conservation efforts nationwide have included monitoring habitat, protecting land, and educating the public about relevant conservation practices. Further movements to protect Baltimore checkerspots now aim to restore and enhance favorable habitat while working on captive rearing and release projects. Frontrunners in these projects include the Baltimore Checkerspot Recovery Team of Maryland and the Maryland Zoo as they aim to protect a state emblem in the Baltimore checkerspot.

In 2015, the New Jersey Endangered and Nongame Advisory Committee recommended a Special Concern status for this species within the state, but no formal rule proposal has been filed to date.

Text written by Kathleen Wadiak in 2015.


  • Maryland Department of Natural Resources
  • Maryland Department of Natural Resources
  • Michigan Department of Natural Resourses
  • North American Butterfly Association, New Jersey Chapter
Scientific Classification

Kingdom: Animalia
    Phylum: Arthropoda
       Class: Insecta
          Order: Lepidoptera
             Family: Nymphalidae
                Genus: Euphydryas
                   Species: E. phaeton

Find Related Info: Invertebrates, Special concern

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