【目的】油茶象Curculio chinensis Chevrolat是我国特有木本油料树种——油茶Camellia meiocarpa的专性蛀果害虫,常导致大量落果。幼虫准确分龄是其生物学、生态学及防控研究的基础,但对钻蛀性昆虫来说,这非常困难。本研究旨在明确研究样地油茶象幼虫龄数及各龄形态指标极差,试图探讨确定钻蛀性昆虫龄数及合理划分虫龄的可靠方法。【方法】收集了1 253头不同发育阶段的幼虫,测量头壳宽、头壳长和上颚宽3个形态指标,用多峰拟合分析频次分布资料,结合戴氏法则判断幼虫龄数。以正态曲线交点作为相邻虫龄分界点,计算各龄幼虫测量指标的平均值、极差、增长率及误判率。【结果】头壳宽、头壳长和上颚宽频次分布多峰拟合均呈显著的5个正态峰(P<0.01),对应5个虫龄;头壳宽、头壳长和上颚宽3个形态指标均以对3龄幼虫的误判率最大,分别为6.04%,7.03%和6.51%,而对其他虫龄误判率均小于5%,提示3个形态指标均可作为油茶象虫龄划分的可靠依据,以头壳宽最佳。各龄幼虫头壳宽、头壳长及上颚宽增长率依次为1.41~1.54,1.43~1.61及1.44~1.64,基本恒定,其平均值的自然对数与虫龄均呈极显著线性正相关(P<0.01),油茶象幼虫头壳生长呈间断性几何级数增长,符合戴氏法则。【结论】油茶象幼虫具5个虫龄,不同于前人报道的仅4个虫龄;多峰拟合可用于确定钻蛀性昆虫或野外种群的龄数,特别是为相邻虫龄形态指标重叠区虫龄划分提供有效方法。 【Objective】 Curculio chinensis Chevrolat is a peculiar boring pest of Camellia meiocarpa, a tree species endemic to China. It often causes a lot of fruit drop. The exact age of larvae is the basis of its biology, ecology and prevention and control, but it is very difficult for borers. The purpose of this study is to clearly study the age of larvae of Camellia oleifera and their extremely poor morphological indexes in sample plots, and try to find out a reliable method to determine the number of insect boring insects and to reasonably divide them. 【Method】 A total of 1 253 larvae of different developmental stages were collected. Three morphological indexes such as head shell width, head shell length and maxillary width were measured. The frequency distribution data were analyzed by multi-peak fitting, and the larvae age were determined by using the Dyer’s method. Taking the intersection of normal curves as the cut-off point of adjacent instar larvae, the mean value, range, growth rate and false positive rate of the measurement indexes of each instar larvae were calculated. 【Result】 The results showed that there were 5 normal peaks (P <0.01) with 5 broadleaved head shell widths, The misclassification rate of the three morphological indexes was 6.04%, 7.03% and 6.51% for the 3rd instar larvae, while the false-positive rate of other insect larvae was less than 5%, suggesting that all three morphological indexes could be used as the Determine the reliable basis for insect age, the best head shell width. The growth rates of head shell width, head shell length and maxillary width were 1.41-1.54, 1.43-1.61 and 1.44-1.64, respectively. The natural logarithms of the average values ​​were extremely significantly positively correlated with the worm age P <0.01), Camellia larvae head shell growth intermittent geometric progression, in line with the Debye rule. 【Conclusion】 The larvae of Camellia asiatica have 5 insect instar larvae, different from the 4 insect larvae reported in the past. The multimodal fitting can be used to determine the number of larvae or wild populations, especially for the adjacent insect instar larvae Indicator overlap zone insects age division provides an effective method.