为了确定自然条件下小线角木蠹蛾Streltzoviella insularis幼虫的龄数,从野外定时采集小线角木蠹蛾幼虫,测量其头壳宽、体长、体宽、前胸背板宽、上颚长、上颚宽6项指标,利用变异系数、Brooks指数、Grosby指数、频次分布图进行统计分析,并建立6项指标的回归方程.结果表明,小线角木蠹蛾幼虫13龄,头壳宽是判定小线角木蠹蛾幼虫龄数的最佳指标;并确定了各龄幼虫的龄期.结果可为小线角木蠹蛾发生规律的研究和防控方案的准确制定提供理论参考.
In order to determine the instar number of Streltzoviella insularis larvae under natural conditions,the larvae of S.insularis were collected in field at regular intervals,and the six indexes including head capsule width,body length,body width,pronotum width,mandible length and mandible width were measured,the regression equations of the six indexes were established by using the variance coefficient,Brooks index,Grosby index and frequency distribution graph.The results showed that S.insularis larvae had 13 instars and the head capsule width was the best index to determine the instar number of S.insularis larvae,the stadia of the larvae were determined.These results can provide a theoretical reference for the study of the occurrence regularity of S.insularis and the accurate formulation of prevention and control programs.