Stable carbon isotope evidence for tracing the diet of the host Hepialus larva of Cordyceps sinensis in the Tibetan Plateau

Two types of Hepialus larvae with different diets were distinguished in the Sejila Mountain, Tibetan Plateau based on the stable carbon isotope data of the host Hepialus larva of Cordyceps sinensis and its closely adjacent tender plant roots and humus fractions. Type I is the larva chiefly fed by soil humus, and characterized by the delta C-13 values of -22.6aEuro degrees to -23.4aEuro degrees, and more than -23.4aEuro degrees in its heads. Type II is the larva chiefly fed by tender plant roots, and characterized by the delta C-13 values of -24.6aEuro degrees to -27.6aEuro degrees, and less than -24.6aEuro degrees in its heads. Our result has exceeded the traditional understanding that their food sources only come from the tender plant roots, and may provide evidence for choosing cheap and high-quality foods and further establishing artificial habitats in their large-scale reproduction.