Peres Elen A, Sobral-Souza Thadeu, Perez Manolo F, Bonatelli Isabel A S, Silva Daniel P, Silva Márcio J, Solferini Vera N
Department of Genetics, Evolution and Bioagents, Institute of Biology, University of Campinas, Campinas, São Paulo, Brazil.
Department of Biology, Federal University of São Carlos, Sorocaba, São Paulo, Brazil.
PLoS One. 2015 Apr 9;10(4):e0121543. doi: 10.1371/journal.pone.0121543. eCollection 2015.
The influence of Quaternary climate oscillations on the diversification of the South American fauna is being increasingly explored. However, most of these studies have focused on taxa that are endemic to tropical environments, and relatively few have treated organisms restricted to subtropical biomes. Here we used an integrative phylogeographical framework to investigate the effects of these climate events on the ecological niche and genetic patterns of the subtropical orb-weaver spider Araneus omnicolor (Araneidae). We analyzed the mitochondrial (Cytochrome Oxidase I, COI) and nuclear (Internal Transcribed Subunit II, ITS2) DNA of 130 individuals throughout the species' range, and generated distribution models in three different climate scenarios [present, Last Glacial Maximum (LGM), and Last Interglacial Maximum (LIG)]. Additionally, we used an Approximate Bayesian Computation (ABC) approach to compare possible demographic scenarios and select the hypothesis that better explains the genetic patterns of A. omnicolor. We obtained high haplotype diversity but low nucleotide variation among sequences. The population structure and demographic analyses showed discrepancies between markers, suggesting male-biased dispersal in the species. The time-calibrated COI phylogenetic inference showed a recent diversification of lineages (Middle/Late Pleistocene), while the paleoclimate modeling indicated niche stability since ~120 Kya. The ABC results agreed with the niche models, supporting a panmictic population as the most likely historical scenario for the species. These results indicate that A. omnicolor experienced no niche or population reductions during the Late Pleistocene, despite the intense landscape modifications that occurred in the subtropical region, and that other factors beside LGM and LIG climate oscillations might have contributed to the demographic history of this species. This pattern may be related to the high dispersal ability and wide environmental tolerance of A. omnicolor, highlighting the need for more phylogeographical studies with invertebrates and other generalist taxa, in order to understand the effects of Quaternary climate changes on Neotropical biodiversity.
第四纪气候振荡对南美动物群多样化的影响正受到越来越多的探索。然而，这些研究大多集中在热带环境特有的分类群上，相对较少涉及局限于亚热带生物群落的生物。在此，我们运用综合系统地理学框架，研究这些气候事件对亚热带圆蛛蜘蛛Araneus omnicolor（园蛛科）的生态位和遗传模式的影响。我们分析了该物种分布范围内130个个体的线粒体（细胞色素氧化酶I，COI）和核（内转录间隔区II，ITS2）DNA，并在三种不同气候情景[当前、末次盛冰期（LGM）和末次间冰期盛期（LIG）]下生成了分布模型。此外，我们采用近似贝叶斯计算（ABC）方法比较可能的种群动态情景，并选择能更好解释A. omnicolor遗传模式的假设。我们获得了高单倍型多样性，但序列间核苷酸变异较低。种群结构和种群动态分析显示标记之间存在差异，表明该物种存在雄性偏向的扩散。经时间校准的COI系统发育推断显示谱系近期发生了多样化（更新世中期/晚期），而古气候建模表明自约120千年前以来生态位稳定。ABC结果与生态位模型一致，支持随机交配种群是该物种最可能的历史情景。这些结果表明，尽管亚热带地区发生了剧烈的景观变化，但A. omnicolor在晚更新世期间没有经历生态位或种群减少，并且除了LGM和LIG气候振荡之外的其他因素可能对该物种的种群历史有所贡献。这种模式可能与A. omnicolor的高扩散能力和广泛的环境耐受性有关，突出了需要对无脊椎动物和其他广适性分类群开展更多系统地理学研究，以了解第四纪气候变化对新热带生物多样性的影响。
