Captive management and re-introduction of the Karner blue butterfly to the Oak Openings of Northwest Ohio, USA

Summary

The Karner blue butterfly (Lycaeides melissa samuelis), an endangered species dependent solely on wild lupine as a host plant, has vanished from most of its original 12-state range and was re-introduced to Ohio's Oak Openings region in 1998 by The Toledo Zoo after a benchmark habitat comparison against the founder population at Michigan's Allegan State Game Area. Zoo staff propagated over 5,000 lupine plants and developed rearing and transport protocols first tested on a closely related model species, the Melissa blue butterfly, before annually collecting first-generation adult females from Michigan source sites to breed at the zoo; larvae were separated to prevent cannibalism and reared to pupation under pine bark in isolated, disinfected rearing rooms before transport to the Kitty Todd Preserve release site. Post-release monitoring tracks first- and second-flight adults along fixed transects using paired spotters counting sightings by gender, condition, and weather, and Karner blues have since migrated and populated lupine patches throughout the preserve. Major setbacks included Endangered Species Act restrictions that initially blocked habitat management such as prescribed burning, later amended, and a severe May 2005 late freeze during eclosion that halted a previously steady population increase, from which numbers have not fully recovered; sourcing sufficient healthy lupine for captive rearing has also remained a persistent challenge. The project rated itself Partially Successful, noting the effort remains ongoing and a minimum viable population has not yet been achieved, though habitat management has benefited other state-endangered plants and butterflies sharing the site.