THE EVOLUTION OF CONVERGENT STRUCTURE IN CARIBBEAN ANOLIS COMMUNITIES

Just as the factors responsible for the origin of an adaptation may not be responsible for its maintenance, the processes currently operating in a community may not have been important in assembling the community. Consequently, historical and ecological studies must be integrated to understand why communities are structured as they are. Examples from Caribbean Anolis assemblages indicate the unique ecological insight a historical perspective can provide. In the Lesser Antilles, phylogenetic analysis indicates that character displacement probably has occurred, but perhaps only once, and that patterns of size dissimilarity across islands result from ecological size assortment subsequent to the evolutionary change in size. In the Greater Antilles, not only are communities composed of a suite of convergent ''ecomorphs,'' but the buildup of multispecies communities has followed a very similar trajectory, a finding not demonstrable by nonhistorical analyses. Further, phylogenetic analyses suggest the appropriate direction for ecological research concerning the occurrence of ''empty niches.''