Past climate shifts have led to major oscillations in species distributions. Hence historical contingencies and selective processes occurring during such phases may be determinants for understanding the forces that have shaped extant phenotypes. In the plant-ant Petalomyrmex phylax (Formicinae), we observed spatial variation in number of queens in mature colonies, from several queens (high polygyny) in the median part of its distribution to a moderate number of queens (weak polygyny) or even only a single queen (monogyny) in the southwesternmost populations. This variation did not correlate with indicators of variation in current nest site availability and colony turnover, the supposedly determinant selective forces acting on gyny in ants. We show here that the variation in social structure correlates with a historical process corresponding to a progressive colonization of coastal southern Cameroon by the ant. Using microsatellite markers, we observed a clear pattern of isolation by distance except for the southernmost populations. Measures of genetic variability that do not take into account allele size were at equilibrium in all except the southernmost populations, suggesting recent foundation of the latter. Measures of genetic diversity taking into account allele size showed a clinal north-south decrease in variance of allele size. We propose that southern populations have yet to regain allele size variance after bottlenecks associated with the foundation of new populations, and that this variance is regained over time. Hence variation in social structure mirrors an old but still active southward colonization process or metapopulation dynamics, possibly in association with an expansion of the rain forest habitat during the late Holocene. A low number of queens in ant colonies is typically associated with strong dispersal capacity. We therefore suggest that the initial founders of new populations belong to the monogynous to weakly polygynous phenotype, and that queen number progressively increases in older populations.

译文

:过去的气候变化导致物种分布出现重大波动。因此,在这些阶段中发生的历史偶然性和选择性过程可能是理解已形成现存表型的力的决定因素。在植物蚂蚁Petalomyrmex phylax(Formicinae)中,我们观察到成熟菌落中皇后数量的空间变化,从分布中位数的几个皇后(高多生)到中等数量的皇后(弱多生)甚至仅最西南人口中的一个女王(单身女)。这种变化与当前巢位可用性和菌落周转率的变化指标无关,所谓的决定因素是对蚂蚁的gyny作用的决定性选择力。我们在这里表明,社会结构的变化与一个历史过程相关,该历史过程对应于蚂蚁在喀麦隆南部沿海地区逐渐殖民。使用微卫星标记,除了最南端的种群外,我们观察到了清晰的距离隔离模式。除最南端的种群外,所有未考虑等位基因大小的遗传变异性指标均处于平衡状态,这表明后者是最近的基础。考虑等位基因大小的遗传多样性测度表明,等位基因大小方差在南北逐渐减少。我们提出,南方人群在与新人群的基础相关的瓶颈之后,尚未恢复等位基因大小的变异,并且随着时间的流逝,这种变异得以重新获得。因此,社会结构的变化反映了一个古老但仍然活跃的南方殖民化过程或种群迁移动态,这可能与全新世晚期雨林栖息地的扩张有关。蚁后蚁后数量少通常与强大的扩散能力有关。因此,我们建议新种群的最初建立者属于单性的到弱多性的表型,并且在较老的种群中女王的数量逐渐增加。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录