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

Abstract

Two types of Hepialus larvae with different diets were distinguished in the Sejila Mountain, TibetanPlateau 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 δ 13 C values of −22.6‰ to −23.4‰, and more than −23.4‰ in its heads. Type II is the larva chiefly fed by tender plant roots, and characterized by the δ 13 C values of −24.6‰ to −27.6‰, and less than −24.6‰ 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.stable carbon isotopes, host Hepialus larva of Cordyceps sinensis, humus substances, Tibetan Plateau

Stable Carbon Isotope Composition of the Lipids in Natural <em>Cordyceps sinensis</em> from Major Habitats in China and Its Substitutes

“…It can be seen from Fig. 4 that there is an obvious variation of the δ 13 C values from plants to host larvae, and to C. sinensis on the basis of our previous [24] and newly-obtained data. Thitarodes larva, which generally lives in deeper soils and mainly feed on the tender roots of C3 plants [1], is the specific host of O. sinensis.…”

“…Thus, C18:2 in C. sinensis was originated both from the host larva and de novo synthesis. However, the host larva was unable to biosynthesize C18:2 [35,36], and had to assimilate C18:2 only from the tender roots of plants, especially Polygonum macrophyllum and Polygonum viviparnm, which were considered to be its favorite food with the δ 13 C value lower than that of the predator larva [24]. In the de novo synthesis of C18:2, the 13 C-depleted C18:1 in C. sinensis was preferred to be desaturated.…”

“…It can further be inferred that the δ 13 C value of C. sinensis should significantly correlate with environmental factors in diverse habitats if the host larva eats the same foods. However, the foods of the larvae are actually diverse and not limited to particular plants, even including humic substances in habitat soils in the period of food deprivations [24]. Consequently, the δ 13 C outliers of C. sinensis may be resulted from the omnivory of the host larvae and their complicated food web.…”

Fungus-larva relation in the formation of Cordyceps sinensis as revealed by stable carbon isotope analysis

“…They develop into infective conidia, which gradually infiltrate into deeper soils mainly due to rainfall. The host 3 , a healthy Thitarodes (Lepidoptera: Hepialidae) larva, will overwinter in the alpine grass lands in the Qinghai-Tibetan Plateau and its adjacent high-altitude areas 4 , 5 , go deep into the roots of Polygonum knotweed, Kobresia sedges or Astragalus milk-vetch, and safely nestle in the roots of its favorite foods 6 . It may be infected by the fungus in the soils through the mouth or the skin.…”

The Caterpillar Fungus Cordyceps Sinensis as a Natural Source of Bioactive Compounds

“…Thus, it is necessary to develop new methods and search for sensitive indicators to detect geographical origin. Cordyceps sinensis occurs on the Tibetan Plateau and its adjacent high-altitude areas characterized by low ambient temperatures [12], [13].And its lipid composition may be a sensitive marker reflective of its living environment. Lately, it has been found that the fatty acid composition in lipids may be used to access geographic origin.…”