小麦干旱胁迫对黏虫取食及食物利用效率的影响

Effects of Drought Stress in Wheat on Consumption and Utilization of Wheat as Food for the Oriental Armyworm Mythimna seperata(Lepidoptera:Noctuidae)

为了解小麦干旱对食叶害虫黏虫食物利用效率的影响,采用PEG-6000模拟干旱处理小麦植株,设置对照(0g·mL-1)、低(0.05g·mL-1)、中(0.1g·mL-1)和强(0.2g·mL-1)4个干旱胁迫水平,以盆栽小麦饲喂黏虫幼虫,观察黏虫取食及食物利用效率。协方差分析表明,干旱胁迫对黏虫幼虫的体质量、取食量有显著影响,但对食物利用量没有显著影响。与对照相比,强干旱胁迫下黏虫取食量减少10.4%,幼虫体质量增加量减少10.6%。经食物利用指数方法分析,干旱胁迫显著影响黏虫的近似消化率和食物转化率,强干旱胁迫下食物转化率较对照减小了8.0%,近似消化率增加10.5%;干旱胁迫对其他食物利用指数均无显著影响。以上结果说明,小麦中度和强度干旱胁迫可对黏虫营养利用效率造成不良影响。

Climate change is projected to increase temperature and cause greater variability in precipitation,leading to more frequent and heavy drought.The aim of this study is to examine the effects of drought stress in wheat seedlings on the food consumption and utilization efficiency of leaf-chewing Mythimna seperata caterpillars.Drought treatments were applied on potted wheat seedlings at 4levels of 0g·mL^-1（control）,0.05g·mL^-1（low）,0.1g·mL^-1（medium）and 0.2g·mL^-1（high）of Polyethylene Glycol（PEG）6000in water.The wheat plants from different treatments were used to feed M.seperatalarvae,then the food consumption and utilization efficiency of M.seperata larvae were calculated,The analysis of covariance（ANCOVA）and classical food utilization indices were used to evaluate the effects.The ANCOVA results showed that drought stress treatment in wheat decreased the food consumption amount and body weight gain of larvae,leading to a decrease by 10.4%in food consumption amount and 10.6%in body weight gain in the high drought treatment compared with the control.But the drought stress in wheat did not affect its food digestion by M.seperatalarvae.Analyses of classical food utilization indices showed that the high drought stress treatment reduced the efficiency of conversion of digested food by 8.0%,but increased the approximate digestibility by 10.5%compared with the control.The results of this study suggested that moderate and heavy drought stress in wheat plants can decrease the food use efficiency by M.seperatalarvae.