Changes in mating system and social structure of the ant petalomyrmex phylax are associated with range expansion in Cameroon
Changes in mating system and social structure of the ant petalomyrmex phylax are associated with range expansion in Cameroon
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DOI：
10.1111/j.1558-5646.2007.00044.x
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发表时间：
2007-03-01
期刊：
影响因子：
3.3
通讯作者：
Kjellberg, Finn
中科院分区：
文献类型：
--
作者：
Dalecky, Ambroise;Debout, Gabriel;Kjellberg, Finn
过去的气候变化导致了物种分布的重大振荡。因此，在这些阶段发生的历史偶然性和选择性过程可能是理解形成现存表型的力量的决定因素。在植物蚂蚁Petalomyrmex phylax（蚁科），我们观察到的空间变化，在成熟的殖民地，从几个皇后（高一夫多妻制）在其分布的中间部分的皇后（弱一夫多妻制），甚至只有一个单一的皇后（一夫多妻制）在西南部最多的人口。这种变化并没有相关的指标变化，目前的巢址的可用性和殖民地营业额，据说决定性的选择力作用于雌蕊在蚂蚁。我们在这里表明，社会结构的变化与历史进程相对应的逐步殖民化的南部喀麦隆沿海的蚂蚁。使用微卫星标记，我们观察到一个明确的模式隔离的距离，除了最南端的人口。不考虑等位基因大小的遗传变异性的措施，在所有的平衡，除了最南端的人口，建议后者最近的基础。考虑到等位基因大小的遗传多样性的措施表现出倾斜的南北减少等位基因大小的方差。我们认为，南方人口尚未恢复等位基因大小的差异后，瓶颈与新的人口的基础，并随着时间的推移，这种变化是重新获得。因此，社会结构的变化反映了一个古老但仍然活跃的向南殖民过程或集合种群动态，可能与全新世晚期雨林栖息地的扩张有关。蚁群中蚁后数量少通常与强大的传播能力有关。因此，我们认为，新种群的最初创始人属于一夫多妻制弱一夫多妻制的表型，女王数量逐渐增加，在老年人口。
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 southwestern most 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.