ABSTRACT The halictine bee genus Homalictus (Apoidea: Halictidae) is distributed broadly across south east Asia, Indonesia, Australia and the archipelagos of the Pacific. The group is well represented in the bee faunas of Australia and Papua New Guinea, but Homalictus is particularly important in the Pacific where it plays a keystone pollination role as the only endemic bee group in many islands. Understanding the origin and radiation of this genus is therefore important for understanding plant-bee co-evolution, not only in the Pacific, but the greater Oceania region. Previous studies have suggested that Homalictus has an Australian origin, and then dispersed northwards, but this is yet to be phylogenetically examined. Here we combine DNA sequences from the mitochondrial COI gene from Homalictus species from Papua New Guinea, the Pacific and Australia to infer the geographical and climatic origins of this group and subsequent dispersal events. Our results indicate a tropical origin for Homalictus in Australia, followed by multiple dispersals into the Pacific and subtropical, temperate and arid Australia. A tropical origin for Homalictus not only indicates the likely dispersal corridors for the ancestor of the group but has important implications for understanding social evolution in halictine bees.

中文翻译：

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Homalictus (Apoidea: Halictidae) 的起源和分布在澳大利亚、巴布亚新几内亚和太平洋

摘要 盐蜂属 Homalictus (Apoidea: Halictidae) 广泛分布于东南亚、印度尼西亚、澳大利亚和太平洋群岛。该群体在澳大利亚和巴布亚新几内亚的蜜蜂动物群中有很好的代表，但 Homalictus 在太平洋地区尤为重要，它作为许多岛屿上唯一的地方性蜜蜂群体，发挥着关键的授粉作用。因此，了解该属的起源和辐射对于了解植物与蜜蜂的共同进化非常重要，不仅在太平洋，而且在大洋洲地区。先前的研究表明，Homalictus 起源于澳大利亚，然后向北扩散，但这尚未进行系统发育检查。在这里，我们结合了来自巴布亚新几内亚 Homalictus 物种的线粒体 COI 基因的 DNA 序列，太平洋和澳大利亚推断该群体的地理和气候起源以及随后的扩散事件。我们的结果表明 Homalictus 起源于澳大利亚的热带地区，随后多次扩散到太平洋和亚热带、温带和干旱的澳大利亚。Homalictus 的热带起源不仅表明该群体祖先可能的传播走廊，而且对理解盐碱蜂的社会进化具有重要意义。