At MNA, our Mission is to protect special natural areas and the rare species that live there. The goals of our blog are to cover the latest environmental issues affecting these areas and provide information about the efforts of our volunteers. Our weekly “ENDANGERED!” column serves to inform you about the endangered and threatened plant and animal species found in and around these special natural areas, and how you can contribute to conservation efforts before it is too late.
Karner Blue Butterfly
By Brandon Grenier
In late May and early June, as the first signs of summer appear, you may be lucky enough to glimpse the first wave of Karner blue butterflies (Lycaeides melissa samuelis). Difficult to spot, this nickel-sized butterfly can only be found in a few select states and lives in only one type of low-growing vegetation. Habitat is becoming scarce as suburban sprawl removes the pine barrens where the butterfly thrives. Beyond its aesthetic value, the Karner blue butterfly is an indicator of a healthy barren habitat and is part of an intricate food web in which other species depend on it to thrive.
The Karner blue is a small butterfly with an average wingspan of one inch. Males have vibrant blue wings with a black and white trim along the edges. Females have a dull-gray coloring on their outer wings and distinctive orange crescents along their wingtips. Both sexes have black dots along their undersides circled in white scattered throughout their wings and orange crescents running along their edges.
The Karner blues’ only food source is the wild blue lupine flower: caterpillars only eat the leaves and adults only drink the nectar of the flower, which restricts the butterfly’s habitat. The lupine flower grows only in pine and oak savannas and barren, thus choosing the only place Karner blues can be found. The butterfly once ranged from Maine to Minnesota, but now it has been restricted to small populations in Michigan, Wisconsin, Indiana, Minnesota, New Hampshire, New York and possibly Illinois.
Karner blue butterflies have two generations and hatch twice a year. The first hatch emerges in mid-May through early June and contains eggs laid in the previous winter. The second hatch emerges in mid-July through early August. Once hatched, the caterpillars are tended to by ants. Ants collect a sugary solution secreted by the caterpillar, and the ants protect the caterpillar from predators and parasites.
The Karner blue butterfly has been federally listed as an endangered species since 1992. Because the butterfly only eats one plant, if its food source is gone then it too will disappear. The pine barrens that the butterfly prefers are being split up by roads and urban development, resulting in the fragmentation of the Karner blue population. These secluded populations cannot interbreed and are gradually moving farther apart, making it harder for population growth.
The DNRE has adapted a Habitat Conservation Plan for the Karner blue butterfly that protects and restores the savannas and barrens where the species live. The plan asks that businesses manage their land in a way that is conscientious of the species’ needs and maintain environmentally friendly practices. Also, collection of the butterfly is illegal without a permit from the U.S. Fish and Wildlife Service.
MNA has a Karner blue sanctuary where stewards actively protect this species with projects such as prescribed burns, invasive species removal, and tree and brush removal to expand habitat.
How You Can Help:
To help save this butterfly before it is too late, you can plant butterfly-friendly and native plants in your home gardens to help support their populations. Exotic flowers may be beautiful to look at, but growing local flowers will help keep Michigan beautiful for generations.
MNA volunteers are currently working to protect this and other endangered and threatened species, and you can help too. Join our efforts as a volunteer removing invasive plants in the special natural areas where this species lives. Or, become a steward and take responsibility for planning efforts to maintain a specific MNA sanctuary. To find out how to get involved, visit our website.