甾醇对斜纹夜蛾及其天敌斑痣悬茧蜂生长发育的影响OA

[Aim]This study aims to clarify the effects of dietary sterols on Spodoptera litura and its natural enemy Meteorus pulchricornis.[Methods]The sterol-depleted diet was oabtained from the normal diet by sterol stripping technology,and then supplemented with 1 mg/g stigmasterol,β-sitosterol or cholesterol to formulate different sterol diets,which were subsequently fed to the 1-day-old larvae of S.litura to determine the effects of feeding different types of dietary sterols on the survival,growth and development of S.litura.The development of M.pulchricornis adults emerged from the parasitized 3rd instar larvae of S.litura fed with different sterol diets was determined.In addition,the three sterols were seperately mixed with glucose solution to form homogeneous mixtures with the sterol content of 0.5％,and their effects on the feeding preference of adult M.pulchricornis were examined.[Results]S.litura larvae fed with the sterol-depleted diet could not develop to the 3rd instar.When S.litura larvae were fed with the stigmasterol diet,β-sitosterol diet or cholesterol diet,the total larval duration was significantly prolonged,and the body weight of the 10-and 20-day-old larvae was significantly reduced,as compared to those in the control fed with the normal diet.The pupal weight of S.litura fed with the cholesterol diet was significantly reduced,as compared to that in the control.While the cholesterol content in S.litura larvae at 12 d after being fed with stigmasterol and cholesterol diets significantly increased,and the cholesterol content in the hemolymph of S.litura larvae at 12 d after being fed with the cholesterol diet significantly decreased,as compared to those in the control.The longevity of M.pulchricornis adults emerged from the parasitized 3rd instar larvae of S.litura fed with different sterol diets was significantly shortened,but significantly prolonged when M.pulchricornis adults received sterol-supplemented food during the adult stage,as compared to that in the control.In feeding preference assays,M.pulchricornis exhibited the highest selection rate(40.5％)for stigmasterol food,whereas showed considerably lower preference for cholesterol food(selection rate:7.1％).No significant differences were observed in the feeding duration of M.pulchricornis on different sterol foods.[Conclusion]The existence and types of dietary sterols significantly affect the growth and development of S.litura.Stigmasterol and β-sitosterol exert greater adverse effects on the growth and development of S.litura than cholesterol.The impact of different sterols on M.pulchricornis via S.litura is primarily manifested during the adult stage.Sterol intake during the adult stage prolongs the longevity of M.pulchricornis,and this parasitoid exhibits a preference for specific sterol types.