a blue butterfly stops upon a bright orange flower.
Karner Blue Butterfly Once threatened by loss of its lupine home among oak savannas and pine barrens, is now making a comeback. © Ann Elliott Cutting Photography

Animals We Protect

Karner Blue Butterfly

Get to know this beautiful, endangered, and short-lived butterfly and what we're doing to protect them.

A karner blue butterfly on a large, bright flower.
Dimorphic Both sexes have orange bands on the underside of their wings. Female karner blue butterflies can be identified by the bands of orange in the tops of their wings as well. © Ann Elliott Cutting Photography

Karner blue butterfly facts

Scientific name: Plebejus melissa samuelis

Federal status: Endangered

Habitat: Mix of open and closed canopy habitats, oak savannas, barren sandy areas

Diet: Variety of native flowers (beebalm, cinquefoil, blackbery, leadplant, milkweed); larvae only eat wild lupine

Meet the Karner Blue Butterfly

A subspecies of the Melissa blue butterfly, the Karner blue (Lycaeides melissa samuelis) is a relatively small butterfly, averaging around one inch in wingspan. Males’ wings across the top are silvery blue to dark blue with narrow black margins. Females are graying brown with bands of orange inside the blade border. 

Karner blues are found around the Great Lakes and the northeast United States, typically in semi-shaded areas with sandy soil. They are fairly sedentary for a butterfly, rarely venturing farther than 300-600 feet from their hatching place.

A karner blue butterfly upside down on a branch.
Close to home Karner blues are fairly sedentary for a butterfly, rarely venturing farther than 300-600 feet from their hatching place. © Ann Elliott Cutting Photography

Karner blue life cycle

There are two broods each year of the Karner blue butterfly. The first set of eggs hatch in April. Larvae feed for a few weeks before cocooning. Adults emerge from cocoons and fly during the first 10-15 days of June. 

Those adults lay new eggs, which hatch about a week later. These larvae also feed for a few weeks, and cocoon and fly as adults in mid-August. Their eggs don't hatch until the following spring.

Adult karner blue butterflies have a very short lifespan, usually only five days or so. Some females have been recorded living up to two weeks. Larvae feed only on the wild lupine plant. They have a symbiotic relationship with ants. Ants protect the larvae from predators and in return feed on a liquid it secretes.

Two people in a greenhouse at the Toledo Zoo study captive-raised karner blue butterflies.
Head Start Over 20 years ago, TNC began helping blue Karner populations reclaim areas where it was previously extirpated. At the Toledo Zoo, butterfly specialists study captive-raised Karner blue butterflies. © Ann Elliott Cutting Photography

How We Protect the Karner Blue Butterfly 

The Karner blue butterfly experienced drastic declines in the 1970s and 1980s. It is now believed to be extirpated in Illinois, Iowa, Pennsylvania, Maine and New Hampshire, and in the Canadian province Ontario. It is listed as endangered by the U.S. government. 

The main threat to the species has been habitat loss and degradation. Because the larvae feed only on wild lupine, habitats are also lost to succession, the lupine being eventually shaded out by pines, oak and shrubby vegetation.

Over twenty years ago, the Conservancy began helping blue Karner populations reclaim areas where it was previously extirpated. TNC is also taking proactive steps to protect Karner blue habitat. At the Wilton Wildlife Preserve in New York, for example, the Conservancy is restoring habitat by removing encroaching vegetation and planting wild blue lupine and nectar species that the Karner depends upon.

Discover TNC's other conservation efforts in the Great Lakes region.