Native supercolonies of unrelated individuals in the invasive Argentine ant
Native supercolonies of unrelated individuals in the invasive Argentine ant
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DOI：
10.1111/j.0014-3820.2006.tb01156.x
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发表时间：
2006-04-01
期刊：
影响因子：
3.3
通讯作者：
Keller, Laurent
中科院分区：
文献类型：
--
作者：
Pedersen, Jes S.;Krieger, Michael J. B.;Keller, Laurent
长期以来，群体成员之间的亲属关系一直被认为是促进社会性和生殖利他主义进化的主要因素，然而，一些蚂蚁有一种特殊的社会组织，称为单殖民地，即个体在物理上分开的巢穴中自由混合。这种类型的社会组织不仅是这些蚂蚁生态优势的关键属性，也是一个进化悖论，因为蚁群之间的亲缘关系实际上为零。最近，有人提出，在阿根廷蚂蚁中，单殖民地性是引入新栖息地后进化出来的一种衍生特性。在这里，我们通过对4个本地种群和6个引进种群进行详细的遗传分析来验证这一基本假设，这些种群有5到15个微卫星位点和一个线粒体基因。与本地种群由家庭为基础的种群组成的假设相反，我们发现本地种群也形成超级种群，并且是有效的单殖民地。此外，就像在引进种群中一样，在这些本土范围的超级种群中，配偶之间的亲缘关系几乎为零。原生超级群体之间的核标记和线粒体标记的遗传分化非常高，表明超级群体之间的基因流动非常有限。本地种群与引进种群之间的唯一重要区别是，在本地范围内（25-500米），超级种群要小几个数量级。这种大小差异对我们理解单群体结构的进化和稳定性有重要的影响，因为在本地范围内，超级群体的相对较小的规模意味着超级群体之间可能发生竞争，这可以通过消除庇护它们的超级群体来阻止自私突变体的传播。
Kinship among group members has long been recognized as a main factor promoting the evolution of sociality and reproductive altruism, yet some ants have an extraordinary social organization, called unicoloniality, whereby individuals mix freely among physically separated nests. This type of social organization is not only a key attribute responsible for the ecological dominance of these ants, but also an evolutionary paradox because relatedness between nestmates is effectively zero. Recently, it has been proposed that, in the Argentine ant, unicoloniality is a derived trait that evolved after its introduction into new habitats. Here we test this basic assumption by conducting a detailed genetic analysis of four native and six introduced populations with five to 15 microsatellite loci and one mitochondrial gene. In contrast to the assumption that native populations consist of family-based colonies with related individuals who are aggressive toward members of other colonies, we found that native populations also form supercolonies, and are effectively unicolonial. Moreover, just as in introduced populations, the relatedness between nestmates is not distinguishable from zero in these native range supercolonies. Genetic differentiation between native supercolonies was very high for both nuclear and mitochondrial markers, indicating extremely limited gene flow between supercolonies. The only important difference between the native and introduced populations was that supercolonies were several orders of magnitude smaller in the native range (25-500 m). This size difference has important consequences for our understanding of the evolution and stability of unicolonial structures because the relatively small size of supercolonies in the native range implies that competition can occur between supercolonies, which can act as a break on the spread of selfish mutants by eliminating supercolonies harboring them.