Butterfly dispersal across Amazonia and its implication for biogeography

Abstract

Spatial movement is fundamental to ecological and evolutionary processes because of its role in habitat colonization and diversification. This study examines the dispersal potential of two Neotropical butterflies, Morpho achilles and Bia actorion, to estimate the time necessary to expand into their current geographical distribution in the Amazon Forest. To do so, we use life history data, dispersal rates estimated from mark–release–recapture experiments, and reaction‐diffusion or integro‐difference equations to calculate an annual speed for the wave of dispersal across suitable unoccupied habitat. We show that times required for these butterflies to disperse across Amazonia are orders of magnitude smaller than phylogenetic estimates of the species ages. We compare dispersal rates of Morpho and Bia to other Neotropical butterflies, including taxa that could have moved relatively rapidly through Central America and Mexico. Our findings demonstrate that butterflies (and possibly many other organisms) have tremendous potential for rapid colonization of suitable habitats. Our results also suggest that dispersal can easily increase local diversity in areas where speciation has been attributed mostly to vicariance (such as the eastern slope of the Andes).