Karner Blue Butterfly (Lycaeides melissa samuelis)
By Delores Savignano US Fish and Wildlife Service
Karner blue butterflies (Lycaeides melissa samuelis) derive their common name from the location where they were first described near Albany, New York, in the 1800s. While the Karner blue’s habitat currently ranges from New Hampshire to Minnesota, their populations are limited to specialized habitats where wild blue lupine plants (Lupinus perennis), are found.
Karner blue caterpillars only feed on wild blue lupine leaves, leaving behind “windowpanes” or a leaf “skeleton”. Wild blue lupines are found in the sandy soils of pine barrens, oak savannas and lakeshore dune habitats. These habitats require fire or other disturbance to maintain the sunny open patches where wild blue lupine is found, and they often support other rare species such as the frosted elfin (Incisalia iris), phlox moth (Schinia indiana), persius dusky wing (Erynnis persius), prairie fameflower (Talinum rugospermum), and the western slender glass lizard (Ophisaurus attenuatus).
Like many members of the Lycaenid butterfly family (the blues and coppers), Karner blue butterfly caterpillars are “tended” by ants. The caterpillars secrete small quantities of a liquid from a gland on the top rear of the caterpillar. In other species that have been studied these secretions contain sugars and in some cases amino acids, that provide food to the ants. The caterpillar gets something in return from the ants: protection from some predators and parasites. Caterpillars with ants are more likely to survive than those that do not have ant attendants.
Adult Karner blue butterflies have a wing span of only one inch and typically live only a few days to a few weeks. Male and female butterflies can be distinguished by the coloring on the top side of their wings. The top side of the male’s wings is a violet blue with black margins and white fringed edges. The violet blue color is only seen on the central part of the top side of the female wings, with the remainder a dark gray-brown. In addition, marginal orange crescents are typically present on the hind wings of the female. The underside of the wings of both males and females is gray with black spots. Near the edges of the undersides of both wings are orange crescents and metallic spots. The orange crescents on the underside of the forewings may be very difficult to see on butterflies from the eastern part of the range, especially males.
Adult Karner blues feed on the nectar of many plants, some of their favorites are butterfly weed (Asclepious tubersoa) leafy spurge (Euphorbia podperae), blazing star (Liatris cylindracea), wild Virginia strawberry (Fragaria virginiana), and New Jersey tea (Ceanothus americanus). As they feed on nectar, some pollen sticks to the adult butterfly and is unintentionally transferred from flower to flower. This transfer of pollen is likely to result in some pollination.
Karner blue butterflies were federally listed as endangered in 1992, because of dramatic declines in populations due to habitat loss and modifications, such as fire suppression. Overall, during the last few years the population of the Karner blue range-wide appears stable. However, declines over the past several years have been noted in New York, where Karner blue butterfly sites and population levels are low compared to the rest of their range.
Wisconsin and Michigan support more and larger populations of the species than the remaining states in their range (NH, NY, IN, OH and MN). Karner blue butterfly reintroductions are underway in New Hampshire, Ohio, and Indiana, with the goal of reestablishing viable populations in those states. Research on habitat management, dispersal, ant tending, and female egg-laying preferences are helping with the management of the butterfly. Protection of the Karner blue butterfly, wild blue lupine, and the habitat where they live is likely to assist in the survival of many other plants and pollinators that also thrive in these rare habitats.