Ultraconserved element phylogenomics and biogeography of the agriculturally important mason bee subgenus Osmia (Osmia)

Authors: Branstetter, Michael; MULLER, ANDREAS - Eth Zurich; Griswold, Terry; ORR, MICHAEL - Chinese Academy Of Sciences; ZHU, CHAO-DONG - Chinese Academy Of Sciences

Submitted to: Systematic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/11/2021
Publication Date: 2/10/2021
Citation: Branstetter, M.G., Muller, A., Griswold, T.L., Orr, M.C., Zhu, C. 2021. Ultraconserved element phylogenomics and biogeography of the agriculturally important mason bee subgenus Osmia (Osmia). Systematic Entomology. 46(2):453-472. https://doi.org/10.1111/syen.12470.
DOI: https://doi.org/10.1111/syen.12470

Interpretive Summary: UCE phylogenomics and biogeography of the agriculturally important mason bee subgenus Osmia (Osmia): One of the most important groups of bees for managed pollination are the mason bees in the subgenus Osmia. Four of the 29 known species in this group are actively managed for pollination services in various orchard crops throughout the temperate zone, with the blue orchard bee (Osmia lignaria) being heavily used in the U.S.A. Despite the importance of this group, few studies have examined its diversity globally in a comprehensive way. Using molecular phylogenomic data from ultraconserved elements and a near complete sampling of species, a robust phylogeny of the mason bee subgenus Osmia was generated, resulting in new insights into relationships among the agricultural species and their close relatives. Complimentary biogeographic analyses revealed that the group originated about seven million years ago in eastern Asia and western North America and dispersed several times across the Bering land bridge during its history. The sequencing results also identified several taxonomic problems in the subgenus, indicating that a few species names need to be re-evaluated and possibly synonymized with other species. Overall this work provides a new and greatly improved evolutionary framework for the subgenus Osmia that will help researchers and managers make informed predictions about the biology and ecology of species within this important group.

Technical Abstract: One of the most important non-Apis groups of bees for agriculture is the mason bee subgenus Osmia (Osmia), or Osmia sensu stricto (s.s.). Out of the 29 known species, four have been developed as managed pollinators for orchards and several others have been considered for use. Additionally, the group is important as a source of non-native species, given that several species have been intentionally or accidentally introduced into new areas, with at least one becoming established. Osmia s.s. occurs naturally throughout the temperate zone but has most of its species diversity in Europe and Asia. Despite the group’s importance, few studies have examined its phylogeny or taxonomy comprehensively, and none have included a formal biogeographic analysis. Here, we integrate molecular phylogenomic data from Ultra-Conserved Elements (UCEs), near complete taxon sampling, and a diversity of analytical approaches to robustly infer the group’s phylogeny, divergence times, and biogeographic history. We also demonstrate how mitochondrial sequence data can be extracted from UCE data and combined with data from public repositories in order to test phylogeny, examine species boundaries, and identify specimen-associated, non-bee eDNA. We confidently resolve the phylogeny of Osmia s.s., finding little conflict across analyses, and confirm with strong support that the Nearctic species O. ribifloris is the sister group to all remaining species. Biogeographic analyses indicate that the group originated during the Miocene in the Eastern Palearctic (EP) plus Western Nearctic (WN) regions and dispersed several times from the EP into the WN across the Bering land bridge prior to its closure 5.5-4.8 Ma. The mtDNA results highlight several taxonomic problems in the subgenus, supporting the conclusion that several species most likely need to be synonymized. Overall, the new phylogeny provides a robust estimate of relationships among agriculturally important species and relatives and should prove to be a useful resource for future research efforts.