稻纵卷叶螟幼虫对不同含氮糖人工饲料的取食选择行为

Feeding preference of Cnaphalocrocis medinalis larvae on artificial diets with different nitrogen and sugar contents

稻纵卷叶螟是我国水稻上重要害虫,由于其难以在室内大规模饲养使得诸多研究受到限制。试验在已有可以完成世代的人工饲料的基础上分别配置了5种不同氮含量和糖含量的人工饲料,观察稻纵卷叶螟初孵、3龄和5龄幼虫对不同氮、糖含量的人工饲料取食选择性。结果表明,初孵幼虫较喜欢取食糖含量较高的人工饲料;氮含量饲料总体对初孵幼虫选择性的影响不显著,但接虫2 h后,饲料氮含量显著影响幼虫的选择性,其中0.92%氮含量饲料上的落虫数占总数的36%,接虫48 h后,氮含量为1.16%的饲料上落虫数明显高于其他饲料。糖含量对3龄幼虫落虫数取食选择有显著影响;对于不同氮含量的人工饲料,稻纵卷叶螟3龄幼虫选择性显著受饲料含氮量的影响(P<0.001),倾向于1.53%氮含量饲料。5龄幼虫对糖含量较高(27.22%)的人工饲料有稍强的趋向性,而不同含氮量对其选择性无明显影响。总体而言,糖含量对稻纵卷叶螟的取食选择有重要影响,氮含量仅对3龄幼虫的取食选择有显著影响。

Cnaphalocrocis medinalis is an important rice insect pest in China, whose mass rearing in laboratory is too difficult to limit its research. This study reported the feeding preference of C. medinalis larvae to various artificial di- ets containing different contents of nitrogen and soluble sugar. The results showed that newly-hatched larvae preferred artificial diet with higher sugar. Nitrogen content in diet showed no significant effect on the selectivity of newly- hatched larvae in total, but the selectivity was affected by nitrogen at 2 h after infestation and the proportion of newly- hatched larvae on the diet with 0. 92% nitrogen was 36% in total ; and after injection for 48 h the number of larvae on diet with 1.16% nitrogen was higher than others. Sugar content could affect the selectiyity of 3^rd instar larvae. Ni- trogen content also affected the numbers of 3^rd instar larvae on the different diets, and 3^rd instar larvae preferred dietwith 1.53% nitrogen. The 5^th instar larvae liked to choose diet with high sugar （27. 22% ）. The amount of nitrogen showed no obvious effect on choosing different nitrogen artificial diets of 5^th instar larvae. In total, soluble sugar plays an important role in the feeding preference of C. medinalis larvae, while nitrogen only affects the activity of 3^rd-instar larvae in feeding preference.