Reintroduction of imperiled species has become a popular conservation strategy. While most organism reintroductions focus on vertebrates, it has also become a prevalent strategy for endangered butterflies. Rigorous monitoring of reintroduced organism is vital to assessing the outcomes of these efforts and to learn strategies that may be applicable across multiple taxa. The Miami blue butterfly (Cyclargus thomasi bethunebakeri), a federally endangered lycaenid endemic to Florida, is the focus of an ongoing captive breeding and reintroduction project. In this study, we aimed to understand if life stage of the butterfly upon release influences the outcome of reintroduction activities. Captive-reared butterflies were released into large in-situ enclosures at two sites in the Florida Keys at either the pupal or adult stage. Released individuals were monitored in order to estimate pupal survival, adult butterfly survivorship, fecundity, and egg survival.
Results/Conclusions
Successful establishment of reintroduced butterflies occurred quickly at one site, where individuals went through multiple generations without further intervention by researchers. Establishment did not occur at the second reintroduction site. Although there were no significant differences in fecundity between butterflies released as pupae and those released as adults, fecundity was higher in field enclosures with greater cover of one larval host plant but not a second larval host plant. Nectar plant height and leaf litter were also positively associated with higher fecundity of reintroduced butterflies. These results indicate that Miami blue butterfly may experience higher survivorship on one larval host plant versus the other, though a lab experiment indicated that larval survival was not significantly different between the two host plants. These results indicate that future conservation efforts should incorporate habitat restoration and that it is critical to collect detailed natural history and ecological data in order to assess organism reintroductions.