An experimental translocation of the imperiled frosted elfin (Callophrys irus)

Abstract

Here we present the first in-situ translocation of frosted elfin (Callophrys irus) caterpillars. The frosted elfin is rare and declining over much of its range with many extant populations separated by large expanses of unsuitable habitat. The development of translocation techniques will be necessary to facilitate dispersal to aid in future conservation practices. We translocated frosted elfin caterpillars (n = 20) among three patches within the Apalachicola National Forest that contained the host plant, sundial lupine (Lupinus perennis). Patches differed in their distances to other occupied sites: two translocations spanned 0.07 km and two spanned 2.71 km. Translocated caterpillars were marked with ultraviolet-fluorescent powder to aid in tracking individuals and their movements. Translocated caterpillars continued to feed and develop during six days of monitoring post-release. Although we did not observe any direct mortality, individuals were lost at a rate of two per day (β = − 1.82 ± 0.14 SE; p < 0.01). We believe the failure to detect marked caterpillars occurred when individuals molted, moved away to pupate, or were possibly predated. Of those remaining, three were observed pupated at their translocation site indicating developmental progress was not affected by translocation. Future efforts to develop successful translocation techniques for the frosted elfin should focus more on monitoring individuals post-release to assess the impact of caterpillar movement and predation. Here we outline a potential translocation method for use in recovering populations of imperiled frosted elfin butterflies. While some success was observed for translocated caterpillars, more focused monitoring post-release will verify the effectiveness of this method for future use.