Larsson Stig, Björkman Christer, Gref Rolf
Division of Forest Entomology, Swedish University of Agricultural Sciences, P.O. Box 7044, S-750 07, Uppsala, Sweden.
Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 53, Umeå, Sweden.
Oecologia. 1986 Aug;70(1):77-84. doi: 10.1007/BF00377113.
We have studied how differences in needle resin acid concentrations between two clones of Scots pine influenced larval survival, larval developmental time, and cocoon weight in Neodiprion sertifer. Larvae were reared under controlled conditions in the laboratory on needles showing a three-fold difference, in resin acid concentration. Larval developmental time was significantly longer for larvae fed needles high in resin acids. No significant differences were found in cocoon weight. Larvae fed needles high in resin acids suffered significantly higher mortality, most of which occurred, in the first two instars. Data on relative growth rate for last-instar larvae, based on a traditional growth efficiency experiment, did not show any negative effects of resin acids, indicating that a possible induction takes place during early instars. Observations on the feeding behaviour of last-instar larvae, the high consumption of bark tissue (with high concentrations of resin acids) by larvae fed needles low in resin acids and preference for needle tissues high in resin acids, indicate that these larvae might actively search for tissues rich in resin acids. We conclude that the physiology and behaviour of N. sertifer has been shaped, in part, by the conflict between the negative effects of resin acids, primarily in early instars (longer developmental time with a corresponding increase in exposure to natural enemies and an increase in direct mortality), and the positive effect of resin acids in later instars (a need for resin acids for use in its own predator defence secretion).
我们研究了苏格兰松两个无性系针叶树脂酸浓度的差异如何影响欧洲松叶蜂幼虫的存活、幼虫发育时间和茧重。在实验室可控条件下，用树脂酸浓度相差三倍的针叶饲养幼虫。取食树脂酸含量高的针叶的幼虫，其发育时间显著更长。茧重未发现显著差异。取食树脂酸含量高的针叶的幼虫死亡率显著更高，大部分死亡发生在前两龄。基于传统生长效率实验得出的末龄幼虫相对生长率数据，未显示树脂酸有任何负面影响，这表明可能在幼虫早期发生了某种诱导作用。对末龄幼虫取食行为的观察发现，取食树脂酸含量低的针叶的幼虫大量取食树皮组织（树脂酸浓度高），且偏好树脂酸含量高的针叶组织，这表明这些幼虫可能会主动寻找富含树脂酸的组织。我们得出结论，欧洲松叶蜂的生理和行为部分是由树脂酸的负面影响（主要在幼虫早期，发育时间延长，相应增加了暴露于天敌的风险并导致直接死亡率上升）与树脂酸在后期幼虫阶段的积极作用（幼虫自身用于捕食者防御分泌需要树脂酸）之间的冲突所塑造的。
