Phylogenomics and biogeography of the small carpenter bees (Apidae: Xylocopinae: Ceratina)

Authors: SLESS, TREVOR - York University; Branstetter, Michael; MIKAT, MICHAEL - York University; ODANAKA, KATHERINE - York University; KERRIGAN, TOBIN - US Department Of Agriculture (USDA); REHAN, SANDRA - York University

Submitted to: Molecular Phylogenetics and Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/15/2024
Publication Date: 6/15/2024
Citation: Sless, T.J., Branstetter, M.G., Mikat, M., Odanaka, K.A., Kerrigan, T.B., Rehan, S.M. 2024. Phylogenomics and biogeography of the small carpenter bees (Apidae: Xylocopinae: Ceratina). Molecular Phylogenetics and Evolution. https://doi.org/10.1016/j.ympev.2024.108133.
DOI: https://doi.org/10.1016/j.ympev.2024.108133

Interpretive Summary: Bees are important pollinators of many food crops and many more diverse species in natural ecosystems and understanding their diversity and evolutionary history provides critical knowledge for studying them. The bee genus Ceratina includes over 370 species globally, with many species in the United States, and is behaviorally diverse, with many species showing varying levels of social behavior. To better understand the diversity of this genus, researchers used genomic data from ultraconserved elements and a sampling of 186 Ceratina species, to determine an evolutionary tree for the genus and to use the tree to improve the group's classification and to investigate where in the world the genus originated and how it changed its distribution over time. The study produced a highly resolved evolutionary tree and identified several taxonomic groups that need to be revised. The study also found that genus originated 42 million years ago in Africa and later dispersed outward multiple times to the other continents, with few dispersals back into Africa. The study provides a robust framework for studying the systematics and evolution of Ceratina and will aid future study of this important genus and pollinator research generally.

Technical Abstract: Small carpenter bees in the genus Ceratina are behaviourally diverse, species-rich, and cosmopolitan, with over 370 species and a range including all continents except Antarctica. Here, we present the first comprehensive phylogeny of the genus based on ultraconserved element (UCE) phylogenomic data, covering a total of 186 ingroup specimens representing 22 of the 25 current subgenera. Our results support most recognized subgenera as natural groups, but we also highlight several groups in need of taxonomic revision – particularly the nominate subgenus Ceratina sensu stricto – and several clades that likely need to be described as new subgenera. In addition to phylogeny, we explore the evolutionary history of Ceratina through divergence time estimation and biogeographic reconstruction. Our findings suggest that Ceratinini split from its sister tribe Allodapini about 72 million years ago. The common ancestor of Ceratina emerged in the Afrotropical realm approximately 42 million years ago, near the Middle Eocene Climatic Optimum. Multiple subsequent dispersal events led to the present cosmopolitan distribution of Ceratina, with the majority of transitions occurring between the Afrotropics, Indomalaya, and the Palearctic. Additional movements also led to the arrival of Ceratina in Madagascar, Australasia, and a single colonization of the Americas. Dispersal events were asymmetrical overall, with temperate regions primarily acting as destinations for migrations from tropical source regions.