Data from: Diversity and stability of egg-bacterial assemblages: the role of paternal care in the glassfrog Hyalinobatrachium colymbiphyllum

Embryos of oviparous organisms must cope with harsh environments and are especially susceptible to disease, considering that many immune mechanisms do not develop until later in life. Parents may transmit symbiotic microflora to eggs, which can contribute to embryo immune defense. Despite the importance of symbiotic microbes for immune function and survival of adult amphibians, vertical transfer of symbionts in amphibians has received less attention than in other taxa. Here, we test the role of male-only parental care in establishing and maintaining the diversity of egg-bacterial assemblages in a Neotropical glassfrog (Centrolenidae). Previous research suggests that father Hyalinobatrachium colymbiphyllum may transfer bacterial symbionts to their eggs. We combined a male-removal experiment in situ with 16S rRNA gene amplicon sequencing to determine whether egg attendance by father H. colymbiphyllum influences the bacterial community and survival of eggs. We found that eggs harbor a diverse and stable bacterial assemblage. Despite different host environments, we found that adult skin and eggs supported very similar bacterial assemblages—even after removing fathers. While we found overlap in the bacteria present on eggs and their fathers, our experiment reveals that extended male care does not contribute to the maintenance of egg-bacterial communities, so there may be other potential routes of transfer. This study contributes to our understanding of the diversity and maintenance of egg microbiomes, and motivates further research on how initial bacteria are acquired and the ontogenetic development of host–symbiont communities.

卵生生物的胚胎必须应对严苛的生存环境，且格外易受病害侵袭——鉴于多数免疫机制需至生命后期才会发育完善。亲代可将共生微生物群落传递至卵中，这有助于胚胎的免疫防御。尽管共生微生物对于成年两栖动物的免疫功能与生存至关重要，但相较于其他类群，两栖动物共生体的垂直传播尚未得到足够关注。本研究以新热带界瞻星蛙科（Centrolenidae）的一种玻璃蛙为研究对象，探究仅由雄性亲代抚育在建立并维持卵生细菌群落多样性中的作用。既往研究表明，雄性格林胄蛙（Hyalinobatrachium colymbiphyllum）可将细菌共生体传递至其所产卵中。我们结合原位雄性移除实验与16S rRNA基因扩增子测序技术，以验证雄性H. colymbiphyllum的护卵行为是否会影响卵的细菌群落组成与存活率。研究结果显示，卵中存在多样且稳定的细菌群落。尽管宿主环境存在差异，但即便移除雄性亲代后，成体皮肤与卵所携带的细菌群落仍极为相似。尽管我们发现卵与其父本表面的细菌存在重叠，但本实验表明，延长雄性亲代抚育时间并不会对卵生细菌群落的维持产生贡献，因此可能存在其他潜在的细菌传播途径。本研究有助于增进我们对卵微生物组多样性及其维持机制的理解，并为后续探究初始细菌的获取途径以及宿主-共生体群落的个体发育过程提供了研究方向。