Neither barriers nor refugia explain genetic structure in a major biogeographic break: phylogeography of praying mantises in the Brazilian Atlantic Forest

The Atlantic Forest is one of the world’s top biodiversity hotspots, but the diversification processes of its biota are still poorly known, with competing models attributing dominant roles to either Quaternary climatic changes or geographic barriers. Many studies identify the Doce river as a major phylogeographic break, but the reasons for this phenomenon are highly debated. Here we test the predictions of the refugial and barrier models for a common species of praying mantis, <i>Miobantia fuscata</i>, focusing in the areas immediately south and north of the Doce river. Our analyses show high intraspecific genetic diversity, deep coalescence times and no evidence for recent population expansion. Phylogeographic structure is inconsistent with a refugial hypothesis. Significant gene flow between northern and southern populations also conflicts with a strong role for geographic barriers. This study highlights the need for considering invertebrate taxa to infer recent landscape changes, and points towards a more complex picture of genetic diversification in the Atlantic Forest.

大西洋森林是全球顶级生物多样性热点地区之一，但其生物类群的多样化进程仍未得到充分认知。目前存在两种相互竞争的模型，分别将主导作用归因于第四纪气候变化或地理屏障。多项研究将多西河（Doce River）认定为一处重要的系统地理断裂（phylogeographic break），但该现象的成因仍存在广泛争议。本研究以一种常见螳螂<em>Miobantia fuscata</em>为研究对象，聚焦多西河南北紧邻区域，对避难所模型（refugial model）与地理屏障模型（barrier model）的预测假说开展检验。分析结果显示，该物种种内遗传多样性较高、溯祖时间（coalescence time）较深，且未发现近期种群扩张的相关证据。其系统地理结构与避难所假说并不相符；南北种群间存在显著的基因交流，这同样与“地理屏障发挥主导作用”的假说相悖。本研究强调，在推断近期景观变化时需纳入无脊椎动物类群的相关数据，同时也表明大西洋森林的遗传多样化进程可能远比此前认知更为复杂。