WEEVILS AND PLANTS: PHYLOGENETIC VERSUS ECOLOGICAL MEDIATION OF EVOLUTION OF HOST PLANT ASSOCIATIONS IN CURCULIONINAE (COLEOPTERA: CURCULIONIDAE)

Abstract

A great proportion of biodiversity is accounted for by organisms, particularly insects, intimately associated with plants. Knowing whether ecological or phylogenetic factors chiefly influence the evolution of host plant associations is essential to understanding speciation in, and therefore factors influencing diversity of, phytophagous insects. Through examination of known host plant associations in Curculioninae and comparison with available reconstructed phylogenetic relationships of certain taxa of Curculioninae, little, if any, evidence for cospeciation (parallel cladogenesis) is found. In curculionine taxa where sufficient host plant and/or phylogenetic data are available, weevil species are narrowly to broadly oligophagous; a number of related weevil species are associated with a single host plant species; many weevil genera have host plant ranges spanning distantly related plant taxa; and available weevil reconstructed phylogenies are not concordant with plant relationships. Rather, for at least some weevil taxa, evolution appears to be mediated by one or more of a variety of strictly ecological factors, particularly habitat associations. General applications of these results include biological control, pollination biology, conservation and restoration biology, and use of patterns in insect – host plant associations to resolve problems in plant classification.