Sex-Based Dietary Divergence in Plateau Pikas (Ochotona curzoniae) but Not Plateau Zokors (Eospalax baileyi)

Quantifying sex-specific dietary differences in small mammals reveals the internal resource allocation mechanisms within a species and provides new insights for ecosystem management and conservation practices. The plateau pika (Ochotona curzoniae) and plateau zokor (Eospalax baileyi) are dominant small mammals that exhibit distinct lifestyles and social structures on the Qinghai-Tibetan Plateau. Despite the fact that the diets of both species have been extensively studied, sex-specific dietary differences have rarely been investigated. This study employed DNA metabarcoding combined with a self-constructed plant DNA barcode database to analyze the diet composition and trophic niche of male and female plateau pika and plateau zokor during the growing season. The results showed that male and female plateau pika consumed 39 and 37 plant species, respectively, and male and female plateau zokor consumed 38 and 39 plant species, respectively. With respect to the plateau pika, males showed a significantly higher intake of Phlomoides umbrosa than females (p < 0.05), whereas females consumed a significantly greater proportion of tuberous plants (p < 0.05). Females also exhibited a significantly greater dietary diversity and trophic niche breadth than males. But there was no significant difference in dietary diversity and trophic niche breadth between the sexes in the plateau zokor. In conclusion, our results show that dietary differences between males and females depend on each species’ lifestyle. Social, surface-living pikas show apparent sex-based differences, while solitary, underground-living zokors do not.