Data from: Seasonal shifts in the insect gut microbiome are concurrent with changes in cold tolerance and immunity

1. Seasonal changes in the environment, such as varying temperature, have the potential to change the functional relationship between ectothermic animals, such as insects, and their microbiomes. Our objectives were to determine: a) whether seasonal changes in temperature shift the composition of the insect gut microbiome, and b) if changes in the microbiome are concomitant with changes in the physiology of the host, including the immune system and response to cold. 2. We exposed laboratory populations of the spring field cricket, Gryllus veletis (Orthoptera: Gryllidae), to simulated overwintering winter and spring, we extracted and sequenced 16S bacterial genomic DNA from cricket guts, to capture seasonal variation in the composition of the microbiome. 3. The composition of the gut microbiome was similar between microcosms, and overall me, where overwintering resulted in permanent changes to these microbial communities. In particular, the abundance of Pseudomonas spp. decreased, and that of Wolbachia spp. increased, during overwintering. 4. Concurrent with overwintering changes in the gut microbiome, G. veletis acquire freeze-tolerance and immune function shifts temporarily, returning to summer levels of activity in the spring. Specifically, haemocyte concentrations increase but survival of fungal infection decreases in the winter, whereas the ability to clear bacteria from the haemolymph remains unchanged. 5. Overall, we demonstrate that the gut microbiome does shift seasonally, and in concert with other physiological changes. We hypothesize that these changes may be linked, and suggest that it will next be important to determine if these changes in the microbiome contribute to host overwintering success.

1. 环境的季节变化（如温度波动）可改变变温动物（ectothermic animals，如昆虫）与其共生菌群之间的功能关系。本研究旨在明确两个核心问题：a) 温度的季节性变化是否会改变昆虫肠道菌群（gut microbiome）的组成？b) 菌群的变化是否与宿主生理（包括免疫系统及耐寒响应）的变化相伴发生？
2. 我们将春田野蟋蟀（Gryllus veletis，直翅目Orthoptera：蟋蟀科Gryllidae）的实验种群暴露于模拟的越冬冬季与春季环境中，随后从蟋蟀肠道中提取16S细菌基因组DNA（16S bacterial genomic DNA）并进行测序，以此捕捉菌群组成的季节性变异。
3. 不同实验微环境中的肠道菌群组成相似，且总体而言，越冬处理会对这些微生物群落造成永久性改变。具体而言，越冬期间假单胞菌属（Pseudomonas spp.）的丰度下降，而沃尔巴克氏体属（Wolbachia spp.）的丰度上升。
4. 与肠道菌群的越冬变化同步发生的是，春田野蟋蟀（G. veletis）会获得耐寒冻性，且免疫功能出现暂时性改变，在春季恢复至夏季的活性水平。具体表现为：冬季时血细胞（haemocyte）浓度升高，但真菌感染后的宿主存活率下降，而从血淋巴（haemolymph）中清除细菌的能力保持不变。
5. 综上，本研究证实肠道菌群确实会随季节发生变化，且与其他生理变化协同关联。我们推测这些变化可能存在内在联系，并提出未来研究的重点应明确菌群的此类变化是否有助于宿主成功越冬。