Migration of the Butterfly Panacea prola (Nymphalidae: Biblidinae) in the Southeastern Peruvian Amazon

ABSTRACT Insect migrations rival those of vertebrates in terms of numbers of migrating individuals and even biomass, although instances of the former are poorly documented relative to their share of global biodiversity. This is especially true in the world's tropics, which harbor most of Earth's insect species. Understanding these mass movements is of critical and increasing importance as global climate and land use change accelerate and interact to alter the environmental factors that underly migration, particularly in the tropics. In this study we tested whether Panacea prola , a butterfly species found throughout the western Amazon and adjacent Andean foothills, was migratory at a site in lowland southeastern Peru. We show, through direct observation of flight behavior, that P. prola migrated annually between 2021 and 2025 during the dry season at the study site. We further show that the flight path of migrating P. prola butterflies is nonrandom and roughly northeast, leading toward the central Amazon basin. The discovery of a previously undocumented migration in a widespread and conspicuous butterfly is an important contribution to our currently poor knowledge of insect migration in the Amazon, the world's largest and most biodiverse tropical forest.