Southeast Florida is considered part of the Caribbean archipelago and a biodiversity hotspot for conservation priorities, with many endangered species precinctive to the Lower Peninsula. The tropical butterfly Eumaeus atala (Poey) (Lepidoptera: Lycaenidae) is currently found in Southeast Florida, the Caribbean, Cayman Islands, and Cuba, but was once considered probably extinct in Southeast Florida, where it has made a significant population increase during the past 30 yr. The State of Florida lists E. atala as imperiled, based on the species' ephemeral and cyclic abundance, isolated extant populations, reduced and highly fragmented habitat, and vulnerability to stochastic weather events. The objective of this captive-rearing intensive study was to fill gaps related to E. atala's overall biology and ecology in order to assist recovery efforts. Life history was studied under controlled environmental conditions to document the life span, reproduction, and development. Longevity proved to be much greater than previously recorded, reproductive behavior supports increased genetic cross-over, and conservation efforts point toward the need for continued monitoring of fragmented populations. Results may help in the design or improvement of management practices for E. atala and other imperiled pine rockland species.