Role of Caribbean Islands in the diversification and biogeography of Neotropical Heraclides swallowtails
Résumé
Numerous hypotheses on the evolution of Neotropical biodiversity have stimulated research to provide a better understandingof diversity dynamics and distribution patterns of the region. However, few studies integrate molecular and morphological datawith complete sampling of a Neotropical group, and so there has been little synthesis of the multiple processes governing biodi-versity through space and time. Here, a total-evidence phylogenetic approach is used to reconstruct the evolutionary history ofthe butterfly subgenusHeraclides. We used DNA sequences for two mitochondrial genes and one nuclear gene and coded 133morphological characters of larvae and adults. A robust and well-resolved phylogeny was obtained using several analyticalapproaches, while molecular dating and biogeographical analyses indicated an early Miocene origin (22 Mya) in the CaribbeanIslands. We inferred six independent dispersal events from the Caribbean to the mainland, and three from the mainland to theCaribbean, and we suggest that cooling climates with decreasing sea levels may have contributed to these events. The time-cali-brated tree is best explained by a museum model of diversity in which both speciation and extinction rates remained constantthrough time. By assessing both continental and fine-scale biodiversity patterns, this study provides new findings, for instancethat islands may act as source of diversity rather than as a sink, to explain spatio-temporal macroevolutionary processes withinthe Neotropical region.