New York Status: Endangered
Federal Status: Endangered
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Description
The Karner blue is a small butterfly with a wingspan of approximately one inch. In the male, the upper surface of all four wings is a deep violet-blue fringed with white. In the female, the upper surface is a dusky brownish blue with orange spots on the edge of the hindwing. In both the lower surface is a pale silver with white-ringed black spots and rows of bright orange and blue markings near the edge of the hindwings. The protective coloration of the larva, which reaches half an inch in length before changing into a pupa, perfectly matches the green leaves of the vegetation. The larva is covered with very fine hairs.
Life History
Like all butterflies, the Karner blue has four stages in its life cycle - the egg, the larva (caterpillar), the pupa (chrysalis), and the adult (butterfly). There are two generations per year. The first-generation adults appear in late May to mid-June. Females lay eggs on the underside of a leaf or stem of the food plant, blue lupine (Lupinus perrennis). These eggs hatch in seven to eight days. Forty to fifty percent of the eggs survive to the adult stage. The resulting second brood adults, emerging in mid-July to early August, lay their eggs singly in dried lupine seed pods or near the ground on the stems. Eggs of the second brood overwinter, to hatch the next May.
Karner blue adults are nectar-feeders, aiding in the pollination of a variety of wildflowers. The larvae, however, are highly specialized, feeding exclusively on the wild blue lupine leaves. Without blue lupine, the Karner blue would not survive.
Distribution and Habitat
The Karner blue is found in scattered localities from Minnesota to New Hampshire. In New York, the butterfly is found in certain parts of the Hudson Valley sand belt which extends from the Albany Pine Bush north to the Glens Falls area.
Within its range, this species is restricted to dry sandy areas with open woods and clearings supporting wild blue lupine. This type of habitat is usually associated with pitch pine/scrub oak or oak savannah communities that are maintained by fire at an early stage of plant succession.
Status
The Karner blue is experiencing a decline primarily due to human activities such as agriculture, urbanization, and fire suppression. The sandy habitat essential to the blue lupine, and therefore the Karner blue, occurs mostly along river valleys and outwash plains. Because of the location and topography of such areas, they have been heavily favored as settlement sites. Extinctions of entire populations of the Karner blue have occurred around large urban centers such as Chicago and New York City. Other populations, such as those in the Albany Pine Bush, have been reduced both by habitat destruction from urbanization and by loss of lupine through natural succession resulting from fire suppression. The most intact populations remain in Saratoga County.
Management and Research Needs
Research is being conducted to develop methods of enhancing or creating habitat suitable for the Karner blue butterfly, in particular, the establishment and propagation of wild blue lupine. Methods used to establish or restore appropriate habitat conditions for blue lupine and the Karner blue include mowing and controlled burning. Protecting habitat from development is also important in preserving this species. Several of the largest populations of the Karner blue in New York are currently protected and managed by DEC under cooperative agreements with landowners.
A recovery strategy for the Karner blue is being developed by a cooperative working group of DEC; NYS Office of Parks, Recreation, and Historic Preservation; The Nature Conservancy; and the Albany Pine Bush Preserve Commission (leaves DEC website). The efforts of this partnership, involvement of local towns and counties, and the cooperation of private landowners offer the greatest hope for the recovery of this unique species in New York.
Watchable Wildlife
When looking for wildlife in New York, visit the Watchable Wildlife webpage for the best locations for finding your favorite mammal, bird, reptile, or insect. New York State has millions of acres of State Parks, forests and wildlife management areas that are home to hundreds of wildlife species, and all are open to the public. Choose from hundreds of trails and miles of rivers as well as marshes and wetlands.
Remember when viewing wildlife:
- Don't feed wildlife and leave wild baby animals where you find them.
- Keep quiet, move slowly and be patient. Allow time for animals to enter the area.
What to Watch for
- Size: A small butterfly - wingspan of about one inch. Three other butterflies might be mistaken for the karner blue: spring azure, silvery blue, and Eastern tailed-blue.
- Appearance:
- Males: Upper surface of all wings is a deep violet-blue fringed with white.
- Females: Upper surface of all wings is a dusky brownish-blue with orange spots near the edge of the hindwings.
- For males and females, the underside of the wing is pale silver with white-ringed black spots and rows of bright orange and blue markings near the edge of the hindwings.
- The larval stage (caterpillar) is pea green and covered with very fine hairs.
Where to Watch
The Karner blue is found only in dry, sandy areas with open woods and clearings that support the wild blue lupine. Pitch pine and scrub oak are the common tree species in this habitat. In New York State, populations are restricted to the Hudson Valley sand belt which extends from the Albany Pine Bush north to the Glens Falls area.
While the caterpillars feed only on wild blue lupine leaves, the adults feed on the nectar of several flowering plants.
Watch a clip about Karner Blue Butterfly and check out other clips on DEC's YouTube Channel (leaves DEC website).
Be Careful: Remember to stay on official trails when walking through Karner blue habitat to avoid crushing the lupine and caterpillars. Sometimes adults may land on people. Walk slowly, stop and take a good look around, and check your shoes and pant legs for visiting Karner blues.
When to Watch
In latemid-May or early June the adult butterflies emerge from the chrysalis. A second generation of adult butterflies appears in July.
