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