Niche shift: a tool for expanding range? The case of Ocladius (Coleoptera: Curculionoidea: Brachyceridae).

The distribution and ecology of the genus Ocladius (Coleoptera, Curculionoidea, Brachyceridae) are considered. The majority of the species live in tropical and subtropical Africa and Madagascar, with a few species in the Mediterranean region and in central and western Asia. The southern African species whose biology is known are associated with several plant families, both Dicotyledons and Monocotyledons; the Mediterranean and Asian species are monophagous on Chenopodiaceae. Also based on the available data on phylogeny and diversification of the Chenopodiaceae it is hypothesized that some taxa of Ocladius, possibly in eastern Africa during the Miocene, underwent a niche shift to the chenopods, and that this event triggered an adaptive radiation, resulting in the expansion of the genus to Mediterranean and Asian habitats.