Data from: Australian Lasioglossum + Homalictus Form a Monophyletic Group: Resolving the "Australian Enigma"

The bee genus Lasioglossum includes over 1000 species of bees distributed on all continents except Antarctica. Lasioglossum is a major component of the bee fauna in the Holarctic, Ethiopian, and Oriental regions, and is an important group for investigating the evolution of social behavior in bees. Given its cosmopolitan distribution, the historical biogeography of the genus is of considerable interest. We reconstructed phylogenetic relationships among the subgenera and species within Lasioglossum s.s. using DNA sequence data from a slowly evolving nuclear gene, EF-1α. The entire data set includes over 1604 aligned nucleotide sites (including three exons plus two introns) for 89 species (17 outgroups plus 72 ingroups). Parsimony and maximum likelihood analyses provide strong evidence that the primarily Indoaustralian subgenera (Homalictus, Chilalictus, Parasphecodes) form a monophyletic group. Bootstrap support for the Australian clade ranged from 73% to 77% (depending on the method of analysis). Monophyly of the Australian Lasioglossum suggests that a single colonization event (via Southeast Asia and New Guinea) gave rise to a lineage of over 350 native Indoaustralian bees. We discuss the implications of Australian monophyly for resolving the "Australian enigma" -- similarity in social behavior among the Australian halictine bees relative to Holarctic groups.

毛角隧蜂属（Lasioglossum）是一类蜂类，包含超过1000个物种，除南极洲外，在全球各大洲均有分布。该属是全北区、埃塞俄比亚区以及东洋区蜂类区系的重要组成类群，同时也是研究蜂类社会行为演化的关键类群。鉴于该属的广布分布特性，其历史生物地理学研究具有重要的学术价值。本研究利用缓慢进化的核基因EF-1α的DNA序列数据，重建了狭义毛角隧蜂属（Lasioglossum s.s.）内各亚属与物种的系统发育关系。本数据集共涵盖89个物种（17个外类群与72个内类群）的1604个比对后核苷酸位点，包含3个外显子与2个内含子。简约法与最大似然法分析均提供了强有力的证据，表明主要分布于印澳区的亚属（Homalictus、Chilalictus、Parasphecodes）构成一个单系群。澳大利亚支系的自展支持率介于73%至77%之间（依分析方法不同有所差异）。澳大利亚毛角隧蜂类群的单系性表明，仅通过一次殖民事件（经东南亚与新几内亚）便演化出了包含350余种本土印澳区蜂类的支系。本研究还探讨了澳大利亚类群单系性对于解析“澳大利亚之谜”的意义——即澳大利亚隧蜂科蜂类与全北区类群在社会行为上具有相似性这一问题。