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"...a place called Karner, where in some pine barrens, on lupines, a little blue butterfly I have described and named ought to be out."
So wrote Vladimir Nabokov, who "discovered" the Karner blue, to his friend before setting out to look for his beloved butterflies in the wild. When first discovered - in 1862 - the Karner blue once covered its habitats in a sea of blue. Today people would find the butterfly too elusive with good reason. Since January 1992, the Karner blue has been listed as an endangered species due to dramatic declines in population.
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According to the U. S. Fish and Wildlife Service, over the past 100 years the Karner blue has declined by 99% with 90% having occurred in the past 15 years. The decrease in numbers is widely due to habitat loss from land development, fragmentation and fire suppression. Populations can still be found in Illinois, Indiana, Michigan, Minnesota, New Hampshire, New York, Ohio and Wisconsin; however, viable populations have yet been met in any of these states.
Karner blues prefer pine barren and black oak savanna habitats. In Indiana, populations have been found near dunes and swales near the lakeshore as well. Most importantly, their habitat must offer wild blue lupine.
The Karner Blue and Wild Blue Lupine
While adult Karner blues feed on the nectar of a variety of flowering plants, the larvae - or caterpillars - feed solely on the leaves of the wild blue lupine. Wild lupine is a perennial plant with beautiful pink to bluish purple blooms. It prefers dry, sandy soils found in natural communities like oak savannas and pine barrens. Like the Karner blue, wild blue lupine has also suffered habitat loss due to land development and forest encroachment due to fire suppression in its preferred habitats. Wildfire, prescribed burns, mowing and grazing are needed to maintain sites supporting wild lupines and Karner blue butterflies.
Wild blue lupine and the Karner blue's life cycles are curiously connected. Two generations of the butterflies are produced each year and correspond with the blooming of wild blue lupine. In April, the first generation of caterpillars hatch from eggs laid on lupine the year before. The caterpillars feed on the leaves until they are ready to form their chrysalis. A chrysalis is a cocoon-like shell where the caterpillar emerges as a beautiful butterfly towards the end of May, early June. The first generation will then mate and lay their eggs on or near the wild lupine. Within a week, the eggs will hatch, feed on the lupine leaves and build their chrysalis. In July, the second generation of Karner blues will emerge. These adults will also mate and lay their own eggs that will hatch the following year, continuing the cycle.
The Karner Blue in Indiana
Once present throughout northern Indiana, the Karner blue only occurs in a few northwest Indiana areas associated with the dune and swale complexes near the southern end of Lake Michigan. The dune and swale is a natural community consisting of black oak savanna ridges with patches of prairie surrounding the swales of wetlands, sedge meadows, and marshes - the perfect place for both wild blue lupine and the Karner blue to thrive. The Nature Conservancy's Ivanhoe Dune and Swale Preserve and the Indiana Dunes National Lakeshore are two of the areas in which the Karner blue has made their home.
The Nature Conservancy's Southern Lake Michigan Rim Project office in Indiana has played an important role in rebuilding Karner blue habitat and population. In 1996, TNC along with the U.S. Fish & Wildlife Services and the Environmental Protection Agency began work on thinning canopy cover and restoring fire to Ivanhoe Dune and Swale. Unfortunately before this could be done, wildfires wiped out the Karner blues habitat at Ivanhoe and, in addition to bad weather, the rare butterfly vanished from the preserve.
The Nature Conservancy, U.S. Fish & Wildlife Services and local partners began efforts to reintroduce the rare species. Successful projects restoring black oak savannas and planting of wild lupine gave way to TNC's 2001 release of captivity-raised Karner blues. So far more than 1,000 Karner blues have been released, dozens of acres have been restored and thousands of seedlings and seeds have been planted. Restoration and reintroduction projects are on-going and will be so until viable populations are met. As the loss of the Karner blue would mean the extinction of a distinct and irreplaceable species, TNC and its partners will continue to work diligently to make sure that the Karner blue will thrive in Indiana once again.
Was that a Karner Blue?
Interesting Facts About Karner Blues and All Butterflies
- Nabokov named the butterfly "Karner" for the hamlet of Karner in New York's Albany Pine Bush.
- Butterflies belong to the order Lepidoptera which means "scale-wing" in Latin. 'Scale-wing' refers to the scale cell structures found on the wings which gives off the vibrant colors we see. These scales have four functions although not every role is found on all species. The scales form bright patterns used as signals to: attract mates; to advertise its bad taste to predators; to help blend with their environment; and to soak up the sun when cool.
- Butterflies are diurnal; they are most active during the day.
- Butterflies are nearsighted; they are more attracted to large stands of flowers then they are to individual flower stems. However, they can see polarized light (where the sun shines) and ultraviolet light.
- The butterfly tastes with its feet and drink from its proboscis, a tube-like "tongue" used to sip nectar. The proboscis uncoils to sip and recoils into a spiral when not in use.
- The female butterfly releases pheromones that can be detected by the male as far as a mile away. Pheromones are chemicals that trigger a natural behavioral response in members of the same species.
- Butterflies rest with their wings closed as a way of protection from predators.
- Although fires have caused damage to Karner blue habitats, it is also a helpful tool in managing those same areas. Without fire, wild lupine is shaded out. Simply - no fire, no lupine, no Karner blues.
- The loss of Karner blue habitat not only affects the rare butterfly but many other species as well. The black tern, Blanding's turtle and the ottoe skipper are just a few examples.
For More Information
US Forest Service's Pollinator of the Month - Karner Blue