食物氮含量改变对飞蝗取食、营养利用及生长速率的影响

Effects of changes in food nitrogen content on the feeding,nutritional utilization and growth rate of Locusta migratoria(Orthoptera:Acrididae)

【目的】食物氮含量改变对昆虫的影响是预测害虫种群变化趋势的重要内容。本研究旨在探究食物氮含量改变对飞蝗Locusta migratoria取食、营养利用及生长速率的影响。【方法】以氮含量为1.0%,2.5%,4.0%,5.5%和7.0%的食物分别饲喂飞蝗3龄雌、雄蝗蝻,每日收集剩余粪便和食物残渣并烘干后称重,计算取食量、生长速率及营养利用指标。【结果】1.0%氮含量食物组飞蝗3龄蝗蝻取食量最大,雌、雄虫取食量分别为0.2559和0.2326 g;7.0%氮含量食物组取食量最小,雌、雄3龄蝗蝻取食量分别为0.0944和0.0766 g。随着食物氮含量增加,飞蝗雌、雄蝗蝻取食量显著下降,但是近似消化率、食物利用率和食物转化率显著增加。雌蝗蝻生长速率在2.5%氮含量食物组最高。【结论】飞蝗蝗蝻取食低氮食物时可以通过增加取食量补偿氮。

【Aim】The effect of changes in food nitrogen content on insects is an important part of predicting the trend of pest population change.The aim of this study is to investigate the effect of changes in food nitrogen content on the feeding,nutritional utilization and growth rate of Locusta migratoria.【Methods】The 3rd instar female and male nymphs of L.migratoria were fed with the food with the nitrogen contents of 1.0%,2.5%,4.0%,5.5%and 7.0%,respectively.Feces and food residues were collected daily,dried and weighed,and the food intake,growth rate and nutritional utilization indexes were calculated.【Results】The food intake of the 3rd instar nymphs of L.migratoria in the food group with 1.0%nitrogen content was the most,being 0.2559 and 0.2326 g for females and males,respectively.The food intake of the 3rd instar female and male nymphs of L.migratoria was the least(0.0944 and 0.0766 g,respectively),when they were fed with the food with 7.0%nitrogen content.With the increase of food nitrogen content,the food intake of female and male nymphs decreased significantly,but the approximate digestibility,efficiency of conversion of ingested food and efficiency of conversion of digested food increased significantly.The growth rate of female nymphs was the highest in the food group with 2.5%nitrogen content.【Conclusion】L.migratoria nymphs can compensate for the nitrogen by increasing their intake of low-nitrogen food.