Pupation Sites and Conservation of Frosted Elfins (Lycaenidae) in maryland, USA

Abstract

The frosted elfin (Callophrys irus Godart) is a globally rare butterfly that inhabits disturbance-dependent habitats often managed by prescribed fire. Natural history observations and published data are equivocal on whether frosted elfin caterpillars pupate below or above the soil surface, and some evidence suggests that pupation sites differ for caterpillars that feed on lupine (Lupinus spp.) versus wild indigo (Baptisia spp.). Pupation site has important implications for management because pupae located beneath the soil surface will likely be afforded greater protection from fire than those above the soil surface. Our study of both lupine- and indigo-feeding larvae at a single site in Worcester County, Maryland, found that pupation occurs above the soil surface in the leaf litter 92% of the time, and does not differ significantly with food plant preference. We recommend that land managers using prescribed fire as a habitat management tool for frosted elfin habitat assume some level of pupal mortality in burned areas and utilize a rotational burn schedule that maintains areas of unburned refugia in high-density elfin areas. We also recommend that managers try to establish a metapopulation structure for frosted elfin to address the possibility of natural occurring fires.