Impact of habitat biotic factors on selective food hoarding in Brandt's voles

Food hoarding is a key strategy for many small mammals to cope with winter food scarcity and meet their energy demands. Brandt's voles ( Lasiopodomys brandtii ) are non-hibernating, gregarious, herbivorous rodents that exhibit distinct selectivity in their winter food hoarding behaviors, which are influenced by a variety of biotic factors both within and outside their burrow systems. In this study, food hoarding was investigated in Brandt's voles from the typical grasslands of Inner Mongolia, China. From 2019 to 2021, the winter burrow systems of Brandt's voles were excavated to identify the plant species within and measure their nutritional content. The number, sex, and age of voles within the burrow systems were recorded. Concurrently, continuous monitoring of population density and aboveground plant biomass outside the burrow systems was conducted. By integrating the characteristics of animals and plants both inside and outside the burrow systems to analyze factors influencing Brandt's voles' food hoarding selectivity. The results show that the population density of Brandt's voles and aboveground plant biomass outside the burrow systems were significantly positively correlated with hoarding quantity ( t = 3.897, P < 0.05; t = 5.186, P < 0.001). Brandt's voles tend to prefer the dominant plants in their habitat such as Neopallasia pectinata and Allium polyrhizum as the primary foods for winter storage. Within burrow systems, the number of sub-adults showed the strongest correlation with hoarding amount ( t = 6.345, P < 0.001). Among plant nutrients, crude fiber and tannin contents were positively associated with hoarding ( t = 4.750, P < 0.001; t = 4.161, P < 0.001), while crude fat content was negatively associated ( t = −4.520, P < 0.001). Our study provides insights into the winter food hoarding strategies of gregarious small mammals and highlights the potential feedback between rodent foraging behavior and grassland ecosystem dynamics. • Three-year field excavation of Brandt's vole burrows revealed natural food storage patterns. • Combined analysis of inside/outside burrow characteristics revealed factors influencing overwintering food storage selection. • Linear mixed models eliminated interannual variation and selected optimal models.