Biogeography of Antillean Butterflies

Abstract

The Antilles support an impoverished butterfly fauna when compared with tropical continental America, but they host approximately the same number of species as southern Florida. The number of species, and especially the number of endemics, on each island depends on the size and diversity of the island. The Greater Antilles have developed a considerable number of endemics, but the smaller islands have few endemics and more than 60 percent are widespread continental species of great dispersal ability. For the Antilles as a whole, slightly more colonizations have come from Central than from South America, although including subsequent radiation, the butterfly fauna has come almost equally from Central and South America. The Greater Antilles have received more species from Central America, and the southern Lesser Antilles have received more species from South America. The poor representation of weak-flying taxonomic groups, the small number of endemic genera, the importance of the Lesser Antillean invasion route, the closer similarity of Antillean butterflies to those of Florida than to those of Mexico despite a continental connection from Florida to Mexico, the correlation of the number of restricted continental species per island with shortest distance to the mainland, and the similarity in origin of two groups of species with different ages of colonization, indicate that recent biological factors rather than possible past land connections have produced the modern fauna. THE PURPOSE OF this paper is to analyze the distribution and origin of the Greater and Lesser Antillean butterfly fauna, with special reference to the influence of dispersal across water versus dispersal over land, and to the influence of island habitat diversity on the development of the modern fauna. Butterflies consist of two closely related superfamilies of diurnal Lepidoptera, the Papilionoidea and Hesperioidea.