Sudden Appearance and Population Outbreak of Eunica monima (Lepidoptera: Nymphalidae) on Desecheo Island, Puerto Rico

Summary We documented the appearance and elevated abundance of the uncommon dingy purplewing butterfly, Eunica monima (Stoll) (Lepidoptera: Nymphalidae), and pronounced herbivory on its host plant Bursera simaruba (L.) Sarg. (Burseraceae) shortly after island-wide rat (Rattus rattus [L.]; Muridae) removal from Desecheo Island, Puerto Rico. We confirmed the species as E. monima by using both molecular and morphological analyses of larvae and adults. This is a first-time record of E. monima for the island of Desecheo, one of relatively few documented appearances in Puerto Rico during the last 100 yr, and an uncommon documentation of an outbreak of this species in the Caribbean. Although experimental manipulation would be needed to identify the cause of the E. monima population outbreak, we discuss possible cause-and-effect scenarios.