Beetles (Coleoptera) in cones of cycads (Cycadales) of the northern hemisphere: diversity and evolution

摘要

Three groups of beetles inhabit cones of cycads (Cycadales) in the northern hemisphere and are believed to be involved in their pollination. The primitive weevil subtribe Allocorynina (Coleoptera: Belidae) is restricted to the New World cycad genera Dioon Lindl. and Zamia L. One group of weevils (Curculionidae), found only in Cycas L., appears to be a relatively recent colonizer of northern hemisphere cycads. Members of the beetle subfamily Pharaxonothinae (Erotylidae) occur in all Asian and New World cycad genera. Phylogenetic trees of these beetles, based on DNA analysis and supported with morphological studies, are compared to patterns of continental drift and cycad phylogenies. Laurasian origins are suggested for these beetle groups with high latitude dispersal for at least one of these groups during periods of global warm climates.