Data from: Cryptic diversity, high host specificity and reproductive synchronization in army ant-associated Vatesus beetles

Army ants and their arthropod symbionts represent one of the most species-rich animal associations on Earth, and constitute a fascinating example of diverse host-symbiont interaction networks. However, despite decades of research, our knowledge of army ant symbionts remains fragmentary due to taxonomic ambiguity and the inability to study army ants in the lab. Here we present an integrative approach that allows us to reliably determine species boundaries, assess biodiversity, match different developmental stages and sexes, and to study the life cycles of army ant symbionts. This approach is based on a combination of community sampling, DNA barcoding, morphology and physiology. As a test case, we applied this approach to the staphylinid beetle genus Vatesus and its different Eciton army ant host species at La Selva Biological Station, Costa Rica. DNA barcoding led to the discovery of cryptic biodiversity and, in combination with extensive community sampling, revealed strict host partitioning with no overlap in host range. Using DNA barcoding, we were also able to match the larval stages of all focal Vatesus species. In combination with studies of female reproductive physiology, this allowed us to reconstruct almost the complete life cycles of the different beetle species. We show that Vatesus beetles are highly adapted to the symbiosis with army ants, in that their reproduction and larval development are synchronized with the stereotypical reproductive and behavioral cycles of their host colonies. Our approach can now be used to study army ant-symbiont communities more broadly, and to obtain novel insights into co-evolutionary and ecological dynamics in species-rich host-symbiont systems.

行军蚁及其节肢动物共生体代表了地球上物种丰度最高的动物关联类群之一，亦是宿主-共生体多样互作网络的极具吸引力的研究范例。尽管已有数十年研究积累，但受限于分类学歧义与实验室难以培养行军蚁的瓶颈，学界对行军蚁共生体的认知仍较为零散。本文提出一种整合性研究方法，可实现物种边界的可靠界定、生物多样性评估、不同发育阶段与性别个体的匹配，以及行军蚁共生体生活史的探究。该方法依托群落采样、DNA条形码（DNA barcoding）、形态学与生理学研究的联合应用。作为测试案例，我们将此方法应用于哥斯达黎加拉塞尔瓦生物站的隐翅虫科甲虫属Vatesus，及其不同的行军蚁属（Eciton）宿主蚁类群。DNA条形码分析揭示了隐秘生物多样性，结合大规模群落采样结果，证实了严格的宿主分隔现象，各共生体的宿主范围无重叠。借助DNA条形码技术，我们还成功匹配了所有目标Vatesus物种的幼虫阶段。结合雌性生殖生理学研究，我们得以重构出不同甲虫物种近乎完整的生活史。研究表明，Vatesus甲虫与行军蚁的共生关系高度特化：其繁殖与幼虫发育进程与宿主蚁群典型的生殖与行为周期完全同步。当前，该方法可被推广应用于更广泛的行军蚁-共生体群落研究，为物种丰富的宿主-共生体系统中的协同进化与生态动态研究提供全新的洞察视角。