Seasonal variation in gut microbial communities of the Eastern subterranean termite (Reticulitermes flavipes)

The relationship between a host and its gut microbiome has been reported to vary with season/temperature. Termite hindguts are inhabited by numerous gut symbionts that help with digestion, acetogenesis, nitrogen fixation, caste differentiation and immunity. Changes in gut environment if occurs due to seasonal change, it might impact the physiology of termite. Therefore, we studied the impact of seasonal changes on the composition and relative abundance of symbiotic bacteria in termite gut. Collections were made from cardboard-baited stations monthly from May-October and weather data was also recorded. The guts of ten termites were dissected and frozen within 1-d after collections. DNA was extracted from the above gut tissues in October, along with two older laboratory colonies (one from the same location and one from a different location) and used for 16S rRNA gene sequencing. After processing the sequences, we observed variations in the statistical significance of alpha diversity matrices, while based on Bray-Curtis (beta-diversity), samples from each month were significantly different from each other. At a taxa level, the bacteria Shuttleworthia, Candidatus Ancillula, Unidentified Paludibacteraceae, Uncultured Segniliparaceae, Sphingobium, Caproiciproducens, Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium and Phoenicibacter decreased over time with their lowest abundance in the October sample. Alternatively, bacterial species uncultured CR-115, Uncultured Microgenomates group bacterium, Fusobacterium, Alistipes and Uncultered COB P4-1 termite group increased over time with their highest abundance in the October sample. These results indicate that termite gut bacterial communities go through changes in relative abundance over time, possibly in response to seasonal temperature and moisture cycles.