短梳角野螟的形态描述及幼虫虫龄判断

摘要

Meroctena tullalis is one of the most important pests which harm Homalium hainanense Gagnep and it is very important to determine the instars of the larva and morphological characters.Here we made a detailed study on the morphological characters,the habit of each developmental stage and the life history of M.tullalis.Through laboratory determination combined with field investigation,the three variables were head length,head width and body length,and the data were analyzed by SPSS 19.0 combined with the Dyar's rule and linear regression to design a reliable method for determining the instars of an individual larva.The results indicated that,as the larvae grew,the body color gradually changed from light green to deep green,and the head color progressively deepened and finally became redish-brown and deep color in the middle.Statistical analysis of the body measurements showed that the head capsule width was the most important indicator of larval instars,and the natural logarithm of the means of the head capsule width was significantly correlated with the instar number (y=0.181 6x-0.602 3,R2 =0.999 1).The head length and body length distribution fitted the Dyar's law.However,due to the lack of obvious peaks,they could only used as the auxiliary indices for determining larval instars.This study described the biological characteristics of this insect and identified the best way for determination of larval instars,which may provide crucial information for developing control and prevention strategies.%短梳角野螟Meroctena tullalis (Walker)是为害红花天料木Homalium hainanense Gagnep的重要食叶害虫,其形态描述和幼虫准确分龄是开展害虫生物生态学及林间防控研究的重要依据.本文采用林间采样与室内饲养相结合的方法,首次对短梳角野螟卵、幼虫、蛹和成虫的形态及生活习性和生活史进行调查和描述.并通过测定头宽、头长和体长3项分龄指标,利用SPSS Statistics19.0统计软件对数据进行频次分析,结合戴氏法则和线性回归等试图探究准确划分幼虫虫龄的可靠方法.结果表明:短梳角野螟幼虫随龄期增长,幼虫颜色由浅黄绿色逐渐变为深绿色,头部由肉色逐渐变深,最后形成外围红褐色中间深肉色.通过频次分析统计,测得短梳角野螟幼虫虫龄为5龄;头宽可作为最佳分龄指标,且头宽测量指标平均值自然对数与幼虫龄期呈线性关系(y=0.181 6x-0.602 3,R2=0.999 1).头长和体长统计检验,符合戴氏法则,但频次分析5个峰值不是很明显,且有部分区域重叠,只能作为划分虫龄的辅助指标.本研究确定了短梳角野螟各虫态的形态特征及划分幼虫龄期的最佳指标,以期为该虫林间防治提供生物学依据.