Evolutionary Tree for All Bumblebee Species World-Wide Estimated by Combining Information from Fast-Evolving Genes, Slow-Evolving Genes, and Genomic Data (Apidae, Bombus)

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Evolutionary Tree for All Bumblebee Species Worldwide Estimated by Combining Information from Fast-Evolving Genes, Slow-Evolving Genes, and Genomic Data (Apidae, Bombus)

Simple Summary

To estimate the evolutionary tree for all of the world's bumblebee species, we combine one earlier data for mostly slow-evolving nuclear genes, with two new data for a fast-evolving mitochondrial gene, and three results from a study of genomic data. The resulting tree provides an up-to-date starting point for comparative studies of all bumblebees.

Abstract

Evolutionary trees are of central importance in biology to develop explanatory frameworks for many kinds of studies, including studies of behaviour, ecology, and conservation. Since the last major estimate of evolutionary relationships among many bumblebee species two decades ago, there have been revisions to their taxonomy, descriptions of new species, and sequencing of many rarer species. By combining: one earlier data mostly from slow-evolving nuclear genes as a backbone tree; with two new data from fast-evolving mitochondrial COI barcodes to resolve more of the twigs on the tree, including sequences obtained from rare old specimens with ancient DNA techniques; as well as three the results from broader genomic data for resolving deep relationships, we make a Bayesian estimate of evolutionary relationships with BEAST two among all two hundred eighty-nine published and accepted extant bumblebee species, an increase of more than twenty-nine percent of the species on the previous largest tree. The new tree will serve as a framework for future comparative studies that should enable broader insights into the evolution and ecology of all bumblebees. We illustrate this with an analysis of the evolution of some male morphological characters related to male mate-searching behaviour. We also present a novel map of spatial variation in net diversification rates among bumblebee species worldwide, which indicates an especially rapid net diversification within the more recent Mesoamerican and South American faunas.