Department of Entomology, North Carolina State University, Raleigh, North Carolina, United States of America.
PLoS One. 2010 Feb 12;5(2):e9194. doi: 10.1371/journal.pone.0009194.
The most rapidly expanding habitat globally is the urban habitat, yet the origin and life histories of the populations of native species that inhabit this habitat remain poorly understood. We use DNA barcoding of the COI gene in the widespread native pest ant Tapinoma sessile to test two hypotheses regarding the origin of urban populations and traits associated with their success. First, we determine if urban samples of T. sessile have a single origin from natural populations by looking at patterns of haplotype clustering from across their range. Second, we examine whether polygynous colony structure--a trait associated with invasion success--is correlated with urban environments, by studying the lineage dependence of colony structure. Our phylogenetic analysis of 49 samples identified four well supported geographic clades. Within clades, Kimura-2 parameter pairwise genetic distances revealed <2.3% variation; however, between clade genetic distances were 7.5-10.0%, suggesting the possibility of the presence of cryptic species. Our results indicate that T. sessile has successfully colonized urban environments multiple times. Additionally, polygynous colony structure is a highly plastic trait across habitat, clade, and haplotype. In short, T. sessile has colonized urban habitats repeatedly and appears to do so using life history strategies already present in more natural populations. Whether similar results hold for other species found in urban habitats has scarcely begun to be considered.
全球增长最快的栖息地是城市栖息地，但栖息在这种栖息地的本地物种的种群起源和生活史仍然知之甚少。我们使用广泛分布的本地害虫——塔皮诺马 sessile 的 COI 基因 DNA 条码，来检验两个关于城市种群起源和与它们成功相关的特征的假设。首先，我们通过研究其分布范围内的单倍型聚类模式，来确定城市样本是否来自自然种群的单一起源。其次，我们通过研究群体结构的谱系依赖性，来检验多配偶制群体结构——与入侵成功相关的特征——是否与城市环境相关。我们对 49 个样本的系统发育分析确定了四个得到很好支持的地理分支。在分支内，Kimura-2 参数成对遗传距离显示 <2.3%的变异；然而，分支间的遗传距离为 7.5-10.0%，表明可能存在隐种。我们的研究结果表明，塔皮诺马 sessile 已经多次成功地殖民了城市环境。此外，多配偶制群体结构是一种在栖息地、分支和单倍型之间高度可塑性的特征。简而言之，塔皮诺马 sessile 已经反复殖民了城市栖息地，并且似乎使用了在更自然的种群中已经存在的生活史策略。在城市栖息地中发现的其他物种是否存在类似的结果，几乎还没有开始被考虑。
