Increased microbial decomposition of hemicellulose in the food stored by a neotropical termite

The evolution of termites was marked by modifications on symbiont composition and acquisition of new feeding strategies that improved the digestion of lignocellulose resulting in the diversification of food sources. It has been suggested that food gathering may offer termites with a nutritional provision during low resources availability. Additionally, feces employed as construction material are an excellent environment for microorganisms and plant material deposited inside the nest could provide some advantage to the termites in terms of lignocellulose decomposition. Here we conduct for the first time a comprehensive study of the microbial communities associated to a food-gathering termite species using Illumina sequencing of the 16S and spacer ITS regions of rDNA genes, together with enzymatic assays and data collected in the field. We found that \textit{Cornitermes cumulans} stored grass litter in nodules made from feces. The amount of nodules increased with nest site and nest isolation. Enzymatic analyses showing that food nodules have a higher xylanolytic activity against the hemicellulosic substrates. Actinobacteria and Sordariales dominated microbial communities of food nodules and nest walls, whereas Spirochetes and Pleosporales dominated worker and soldier gut samples. Our results indicate that the role of nodules seems to be related with food gathering; however, the higher xylanolytic activity in food nodules and their associated microbiota could provide \textit{C. cumulans} with an external source of predigested polysaccharides, which might be advantageous in comparison with litter-feeding termites that do not storage food. Funding: FAPESP # 2015/21497-6 and FAPEMIG # CRA-APQ-00878-12.