Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, 199 Abb Khoushi Ave. Mt. Carmel, Haifa, 3498838, Israel.
Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, Derech Kiryat Amal, Tivon, 3600600, Israel.
FEMS Microbiol Lett. 2019 Dec 1;366(24). doi: 10.1093/femsle/fnaa008.
Chironomids (Diptera; Chironomidae) are the most abundant insects in freshwater environments and are considered natural reservoirs of Vibrio cholerae. We monitored the annual dynamics of chironomid populations along with their microbiota in order to better understand host-microbiota interactions. Chironomus transvaalensis populations peaked biannually in August and May-June. The composition of the endogenous bacterial communities of their egg masses clustered in two groups according to the sampling periods August-November and May-July. Nevertheless, a core bacterial community (43%) was present in all egg-mass samples. The most abundant phyla were: Proteobacteria, Firmicutes, Cyanobacteria and Bacteroidetes. The abundance of several genera (e.g. Rheinheimera and Pseudomonas) was positively correlated with C. transvaalensis population dynamics, while a predator-prey interaction was observed between the relative abundance of Vibrio OTUs and C. transvaalensis population size. Chironomids are known to tolerate toxic and stress conditions, and our results demonstrated that bacterial genera that may protect the insect under these conditions are present in the egg masses. After hatching, the first larval meal is the gelatinous matrix that surrounds the eggs. This meal contains a probiotic consortium that may protect the larva during its metamorphosis. The results provide important insights into the host-microbe interactions of chironomids.
摇蚊（双翅目；摇蚊科）是淡水环境中最丰富的昆虫，被认为是霍乱弧菌的天然宿主。我们监测了摇蚊种群及其微生物群的年度动态，以更好地了解宿主-微生物群的相互作用。摇蚊 Transvaalensis 的种群每年在 8 月和 5 月至 6 月两次达到高峰。卵块内生细菌群落的组成根据 8 月至 11 月和 5 月至 7 月的采样期聚类成两组。然而，在所有卵块样本中都存在一个核心细菌群落（43%）。最丰富的门是：变形菌门、厚壁菌门、蓝细菌门和拟杆菌门。几个属（如 Rheinheimera 和 Pseudomonas）的丰度与 C. transvaalensis 的种群动态呈正相关，而在相对丰度的 OTUs 和 C. transvaalensis 种群规模之间观察到了捕食者-猎物相互作用。摇蚊已知能耐受有毒和胁迫条件，我们的结果表明，在这些条件下可能保护昆虫的细菌属存在于卵块中。孵化后，第一餐幼虫是包围卵的凝胶状基质。这顿饭含有一个益生菌联合体，可能在幼虫变态过程中保护幼虫。研究结果为摇蚊的宿主-微生物相互作用提供了重要的见解。
