Phylogenomic dating and Bayesian biogeography illuminate an antitropical pattern for eucerine bees

Authors: FREITAS, FELIPE - Universidade De Sao Paulo; Branstetter, Michael; CASALI, DANIEL - Universidade Federal De Minas Gerais; AGUIAR, ANTONIA - University Of Brasilia; Griswold, Terry; ALMEIDA, EDUARDO - Universidade De Sao Paulo

Submitted to: Journal of Biogeography
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/4/2022
Publication Date: 4/5/2022
Citation: Freitas, F.V., Branstetter, M.G., Casali, D.M., Aguiar, A.J., Griswold, T.L., Almeida, E.A. 2022. Phylogenomic dating and Bayesian biogeography illuminate an antitropical pattern for eucerine bees. Journal of Biogeography. 49(6):1034-1047. https://doi.org/10.1111/jbi.14359.
DOI: https://doi.org/10.1111/jbi.14359

Interpretive Summary: Phylogenomic dating and Bayesian biogeography illuminate the history of eucerine bees (Hymenoptera: Apidae): Eucerinae is a diverse group of bees with over 1,200 species that belongs to the same family (Apidae) as the well-known honey bee and bumble bees. Eucerinae includes many bees that specialize on just one type of plants. While many kinds of plants and animals are most diverse in tropical parts of the world, Eucerinae is found primarily in open, temperate regions. Using a recently published family tree of the group combined with fossils of known age and novel methods of analysis, the age and movement of Eucerinae were inferred. The results show that the group originated in southern South America during the Paleocene and expanded its range northward and outward as global climate cooled and open vegetation habitats expanded. Times of lower sea level also contributed to expansion of the group. This study represents the first comprehensive analysis of biogeographic patterns for Eucerinae. It also discusses important methods to analyze large molecular data.

Technical Abstract: Aim. We estimate divergence times and biogeographic history for eucerine bees, a large taxon (>1200 spp.) that likely diversified in association with the formation of the modern neotropical flora. We investigate how geological changes in the New World as well as the paleovegetational setting of South America influenced the evolution of eucerine bees. Location. All continents except Antarctica and Australia. Taxon. Eucerine bees (Hymenoptera: Apidae: Eucerinae). Methods. Using a published UCE data set, multiple fossil calibration points, and the Bayesian program MCMCTree, we carried out phylogenomic dating under two different clock models and using multiple strategies to vary matrix composition. We then reconstructed the biogeographic history of eucerine bees using a Bayesian implementation of the Dispersal Extinction Cladogenesis (DEC) model. Results. Eucerinae is estimated to have started its diversification during the Paleogene, with all of its tribes originating during the Paleocene/Eocene transition. We found no evidence that varying the amount of molecular data in analyses influences diverge time estimation. Biogeographic reconstructions highlight the importance of southern South America in the history of eucerine bees. Our results also provide evidence for at least two range expansions into North America (Eocene and Early Miocene). Main conclusions. The early diversification of Eucerinae is intimately associated with southern South America, with periods of dry and cooler climates probably influencing the colonization of other regions by eucerine bees. The multiple instances of range expansion out of SA before the full closure of the Isthmus of Panama were probably associated with expansion of open vegetation habitats. Additionally, we show that most of the uncertainty in divergence time estimation is associated with fossil calibration and uncertainty in molecular data, instead of the amount of molecular data being used.