Data from: Dynamic Wolbachia prevalence in Acromyrmex leaf-cutting ants: potential for a nutritional symbiosis

Wolbachia are renowned as reproductive parasites, but their phenotypic effects in eusocial insects are not well understood. We used a combination of qrt-PCR, fluorescence in situ hybridisation, and laser scanning confocal microscopy to evaluate the dynamics of Wolbachia infections in the leaf-cutting ant Acromyrmex octospinosus across developmental stages of sterile workers. We confirm that workers are infected with one or two widespread wsp genotypes of Wolbachia, show that colony prevalences are always 100%, and characterize two rare recombinant genotypes. One dominant genotype is always present and most abundant while another only proliferates in adult workers of some colonies and is barely detectable in larvae and pupae. An explanation may be that Wolbachia genotypes compete for host resources in immature stages while adult tissues provide substantially more niche space. Tissue-specific prevalences of the two genotypes differ, with the rarer genotype being overrepresented in the adult foregut and thorax muscles. Both genotypes occur extra-cellularly in the foregut, suggesting an unknown mutualistic function in worker ant nutrition. Both genotypes are also abundant in the faecal fluid of the ants, suggesting that they may have extended functional phenotypes in the fungus garden that the ants manure with their own faeces.

沃尔巴克氏体（Wolbachia）素来被视为生殖寄生微生物，但其在真社会性昆虫中的表型效应尚未得到充分阐释。本研究结合实时定量PCR（qrt-PCR）、荧光原位杂交技术与激光扫描共聚焦显微镜，对切叶蚁Acromyrmex octospinosus的不育工蚁不同发育阶段的沃尔巴克氏体感染动态进行了评估。本研究证实，工蚁可感染1或2种广泛分布的沃尔巴克氏体wsp基因型；蚁群感染率始终为100%，并鉴定出2种罕见的重组基因型。其中1种优势基因型始终存在且丰度最高，而另一种基因型仅在部分蚁群的成年工蚁体内增殖，在幼虫和蛹中几乎无法被检测到。这一现象或可解释为：沃尔巴克氏体基因型在昆虫未成熟期会竞争宿主资源，而成虫组织可提供的生态位空间显著更多。两种基因型的组织感染率存在差异，罕见基因型在成虫前肠与胸部肌肉中的占比更高。两种基因型均存在于前肠的细胞外间隙中，提示其在工蚁营养过程中存在尚未被揭示的共生功能。两种基因型在蚂蚁的粪便液中也大量存在，这表明它们或许可在蚂蚁以自身粪便施肥的真菌花园中发挥延伸性功能表型。