Karner blue

Small blue butterfly of oak savannas and pine barrens whose larvae feed exclusively on wild lupine (Lupinus perennis) - the only plant the caterpillars can eat. Two broods are produced each year, both tied to lupine bloom and regrowth, and the larvae are tended by ants in a facultative mutualism. Adults nectar on a range of open-habitat wildflowers, but the obligate dependence on wild lupine makes the butterfly a textbook case for why a single native host plant can be load-bearing for an entire species.

Larval host plants · 1

Historically ranged across roughly a dozen northern states from Minnesota to the Atlantic coast plus Ontario. Now restricted to scattered populations in the Great Lakes region and Northeast - chiefly Wisconsin, Michigan, New York, and New Hampshire, with reintroductions in Ohio, Indiana, and elsewhere.