The great American biotic interchange and diversification history in Dynastes beetles (Scarabaeidae; Dynastinae).

Biotic interchange between geographic regions can promote rapid diversification. However, what are the important factors that determine the rate of diversification (e.g., trait-dependent diversification) vary between study systems. The evolutionary history of Dynastes beetles, which can be found in both North and South Americas and exhibit two different altitudinal preferences (highland and lowland) is tested for the effects of biotic interchange between continents and different ecological preferences on the rate of species diversification. Additionally, the hypotheses of geological time-dependent and lineage specific diversification rates are also tested. Results from this study indicate that in Dynastes beetles a pre-landbridge dispersal hypothesis from South to North America is preferred and that the speciation rates estimated using BAMM are similar between lineages of different geographic origins and different altitudinal preferences (i.e., diversification rate is not trait-dependent). On the other hand, my result from marcoevolutionary cohort analysis based on BAMM outputs suggests that the rate of speciation in Dynastes beetles is, instead of trait-dependent (geographic and ecological), lineage specific. Furthermore, a steadily increasing speciation rate can be found in Pliocene and Pleistocene, which implies that geological and climatic events, i.e., colonizing North America, habitat reformation in the Amazonia, and forest contraction in Pleistocene, may have together shaped the current biodiversity pattern in Dynastes beetles. [ABSTRACT FROM AUTHOR]