Data for ant queen lifespan in the field

Demographic studies of ant populations usually monitor nest site occupancy if a colony is present it is assumed to be the same colony as previously.  Little is known about the extent to which nest site occupancy is equivalent to colony identity, yet this knowledge is important for interpreting demographic data.  We combined long-term colony monitoring with periodic genotyping in 95 colonies of the western harvester ant Pogonomyrmex occidentalis to assess the degree to which continuous occupancy predicts colony identity.  We identified a single unsuspected turnover event in more than 1300 queen-years of observation.  We also documented colony replacement in five nest sites that were continuously occupied, but which displayed abrupt size decreases and/or declines in external appearance.  Including additional data in monitoring studies may improve the accuracy of colony lifespan estimates.

Methods
Samples of workers, gynes and males were collected from field colonies that were part of a long-term study of reproductive allocation. DNA was extracted and samples were genotyped using four highly polymorphic microsatellite loci.  The genotype of the colony's sole queen was determined, and compared between samples taken at different time points. If sample genotypes were identical, the colony identity was assumed to be maintained.

蚁群种群的人口统计学研究通常会监测巢址占用情况，若某巢址存在蚁群，则默认其与此前监测到的为同一蚁群。目前学界对巢址占用与蚁群身份的匹配程度知之甚少，但该认知对解读人口统计学数据至关重要。本研究针对95群西方收获蚁（Pogonomyrmex occidentalis），结合长期蚁群监测与周期性基因分型，以评估巢址持续占用对蚁群身份的预测程度。在累计超过1300个蚁后年的观测中，我们发现了1起此前未被察觉的蚁群更替事件。此外，我们还记录了5处持续有蚁群占用，但出现种群规模骤降和/或外部活动特征衰减的巢址的蚁群更替情况。在监测研究中纳入额外的基因分型数据，可提升蚁群寿命估算的准确性。

研究方法
从一项长期繁殖分配研究的野外蚁群中采集工蚁、处女雌蚁与雄性成蚁样本。提取样本DNA后，利用4个高度多态性微卫星位点（microsatellite loci）进行基因分型。确定该蚁群唯一蚁后的基因型，并比对不同时间点采集的样本基因型。若样本基因型一致，则默认该蚁群身份未发生变更。