爱玉子传粉榕小蜂幼虫龄数的划分

Determination of larval instars of Ficus pumila L.var.awkeotsang pollinating fig wasp,Wiebesia pumilae(Hymenoptera:Agaonidae:Agaoninae)

桑科榕属植物爱玉子既是亚热带植物生态系统的关键树种,也是驯化成功的特有果树,它依赖爱玉子传粉榕小蜂传粉才能结实,而榕小蜂幼虫生活在密闭的榕果内,虫体小、历期长,龄数划分困难。本文旨在确定爱玉子传粉榕小蜂的龄数及其划分标准,探讨其个体发育进度的最佳形态特征和指标。采用野外定期取样的方法,对662头爱玉子传粉榕小蜂幼虫的头壳宽、体长和第3体节宽等进行测量,利用频次分布分析、均差分析和回归分析等方法分析幼虫形态与龄数的关系。以头壳宽、体长和第3体节宽为分龄指标的频次分布分析表明,爱玉子传粉榕小蜂幼虫的龄数共有5个龄期;回归分析显示,幼虫头壳宽、体长和第3体节宽的测量值与龄数之间均呈极显著正相关关系(P<0.01),由于头壳宽与龄数回归曲线(y=23.49e^(0.49x))的判定系数(R^(2)=0.98)最高,头壳宽可作为分龄的最佳测量指标。冬季爱玉子传粉榕小蜂1~5龄幼虫的龄期分别为8.05,10.47,14.70,46.07和91.35 d,幼虫期约171 d,并对各龄幼虫的形态特征进行了描述和比较。头壳宽可作为划分榕小蜂幼虫龄数可靠的分龄指标,为进一步研究榕小蜂生物学特性及其保护榕小蜂资源奠定基础。

Ficus pumila L.var.awkeotsang is not only the key tree species of subtropical plant ecosystems,but also the successful domestication of special fruit trees.It depends on Wiebesia pumilae pollination to produce fruit,and the larvae of W.pumilae live in syconium for a long time,with special features of small body,long duration,larvae instars division is difficult.The research aimed to establish criteria for the larvae instars of fig wasp and to explore a reliable method for determining the larvae instars of recessive insect.Head capsule width,body lengthand third somite width of 662 W.pumilae were measured by means of field sampling at regular intervals.The relationship between larva morphology and larval instars was analyzed by frequency distribution analysis,mean difference analysis and regression analysis.The analysis of frequency distribution using thehead capsule width,body lengthand third somite widthas instar indicators showed that the instar of larval fig wasps,which larvae of W.pumilae were divided into 5 instars.Regression analysis showed that the head capsule width,body lengthand third somite width were significantly correlated with the larval instars(P<0.01).Because the coefficient of determination(R^(2)=0.98)of regression curve(y=23.49e^(0.49 x))for head capsule width measurement and larval instars was the highest,the head capsule width was the optimal measurement index for larval instars division.The duration of 1 st~5 th instar larva of W.pumilae in winter were 8.05,10.47,14.70,46.07 and 91.35 d,respectively,and the larval duration was about 171 d.The morphological characteristics of different instars of larvae were described and compared.The head capsule width can be used as a reliable index to larval instars divisionof fig wasp,which laid a foundation for further research on biological propertiesof fig wasp and protection of its resources.