SEASONAL CHANGES OF FATTY ACID COMPOSITION IN Thitarodes pui Larvae, A HOST OF Ophiocordyceps sinensis

BACKGROUND: Thitarodes larvae are the host of Ophiocordyceps sinensis and exist in the permafrost region of the Tibetan Plateau. OBJECTIVE: To understand the adaptation mechanism of Thitarodes larvae to seasonal fluctuations of ambient temperatures in the Tibetan Plateau by studying seasonal changes of the fatty acids composition in the larvae of T. pui. MATERIALS AND METHODS: The profile of fatty acids in the 6th instar T. pui larvae collected at the mid-month in a whole year were examined by GC-MS. RESULTS: There was a negative correlation between the total lipid and ambient (soil) temperature. Further study indicated that oleic, palmitic, linoliec, palmitoleic, stearic were the major fatty acids. The ratio of unsaturated fatty acids to saturated fatty acids (U/S) and the unsaturated index (UI) in triacylglycerols remain stable during the whole year, while the U/S and UI in phospholipids vary dramatically in response to soil temperature. CONCLUSION: The fluctuations in phospholipids were attributed to seasonal changes of oleic and linoleic. The changes of the fatty acid composition may result from their adaptation to the variation of temperature in different seasons.