Data from: Pleistocene niche stability and lineage diversification in the subtropical spider Araneus omnicolor (Araneidae)

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类群分化的影响正日益受到学界关注。然而，此类研究大多聚焦于热带环境特有分类群，针对局限于亚热带生物群落的生物的探讨则相对匮乏。本研究采用整合系统发育地理学框架，探究此类气候事件对亚热带园蛛Araneus omnicolor（园蛛科Araneidae）的生态位与遗传模式的影响。我们对该物种分布范围内的130个个体的线粒体基因（细胞色素氧化酶亚基I，Cytochrome Oxidase I, COI）与核基因（内部转录间隔区2，Internal Transcribed Subunit II, ITS2）进行了测序分析，并基于当前、末次盛冰期（Last Glacial Maximum, LGM）及末次间冰期盛期（Last Interglacial Maximum, LIG）三种气候情景构建了物种分布模型。此外，本研究采用近似贝叶斯计算（Approximate Bayesian Computation, ABC）方法对比多种可能的种群历史情景，筛选出最能解释A. omnicolor遗传模式的假说。测序结果显示，该物种具有较高的单倍型多样性，但核苷酸变异水平较低。种群结构与种群历史分析显示不同分子标记的结果存在不一致，暗示该物种存在雄性偏向的扩散模式。基于COI基因的时间校准系统发育推断显示，该物种的支系分化发生在较近的时期（中/晚更新世）；而古气候模拟结果则表明，其生态位自约12万年前（120 Kya）以来保持稳定。近似贝叶斯计算结果与生态位模型结果一致，支持泛交种群是该物种最可能的历史种群情景。上述结果表明，尽管亚热带区域在晚更新世发生了剧烈的景观改造，A. omnicolor的生态位与种群规模并未出现缩减；且除末次盛冰期与末次间冰期盛期的气候振荡外，其他因素或许也对该物种的种群历史产生了影响。该模式或与A. omnicolor较强的扩散能力与广泛的环境耐受度相关，这也凸显出开展更多无脊椎动物与其他广布类群的系统地理学研究的必要性，以厘清第四纪气候变化对新热带界生物多样性的影响。