草地贪夜蛾对三种寄主植物的取食选择性及其适应性研究

Feeding preference and adaptability of Spodoptera frugiperda on three host plant

为了解草地贪夜蛾对玉米、甘蔗和水稻的取食选择性及适应性,分别采用叶碟法和叶面积法在有选择和非选择条件下测定草地贪夜蛾各龄幼虫对3种寄主植物的取食偏好,并通过测定幼虫体重增长速率和蛹重,初步明确草地贪夜蛾对3种寄主植物的适应性。结果表明,草地贪夜蛾在有选择条件下和非选择条件下均表现出对玉米的偏好。但随着龄期的增长对玉米的取食偏好会逐渐减弱,在有选择条件下6龄幼虫在玉米和水稻上的选择取食率无显著差异,分别为32%和23%,在非选择条件下6龄幼虫取食3种寄主植物的叶面积无显著差异。取食3种寄主植物后幼虫体重增长均能与Logisitic生长模型较好拟合,取食玉米的幼虫体重增长速率最快,蛹重也最重。表明了当前新入侵广西地区的草地贪夜蛾种群对玉米的取食偏好要高于对甘蔗和水稻。

In order to understand the feeding selectivity and adaptability of Spodoptera frugiperda to maize,sugarcane and rice.The feeding preferences of different instars of S.frugiperda on three host plants were determined by leaf disc method and leaf area method under selective and non-selective conditions respectively.The adaptability of S.frugiperda to three host plants was preliminarily determined by measuring the growth rate of larvae weight and pupa weight.The results showed that S.frugiperda preferred to feed on maize under selective and non-selective conditions in three host plants.However,with the increase of insect age,the preference for feeding on maize would gradually weaken.Under selective conditions,the selective feeding rates of 6 th instar larvae on maize and rice were 32%and 23%,respectively.And there was no significant difference in leaf area of the 6 th instar larvae feeding on three host plants under non-selective conditions.After feeding on three host plants,the larvae weight gain could be well fitted with Logistic growth model.The larvae feeding on maize had the fastest growth rate and the heaviest pupae weight.Therefore,among the three host plants,they had obvious preference for maize,and there was no obvious preference between sugarcane and rice.The results showed that the feeding preference of the newly invaded population of S.frugiperda to maize was higher than that to sugarcane and rice.