Etxebeste Iñaki, Lencina José L, Pajares Juan
Sustainable Forest Management Research Institute, University of Valladolid -CIFOR-INIA, Avd. Valladolid 44, 34004 Palencia, Spain.
Bull Entomol Res. 2013 Oct;103(5):497-510. doi: 10.1017/S0007485312000879. Epub 2013 Mar 1.
Some bark beetle species (Coleoptera: Scolytinae) produce aggregation pheromones that allow coordinated attack on their conifer hosts. As a new saproxylic habitat is founded, an assemblage of associated beetles kairomonally respond to bark beetle infochemicals. Ips sexdentatus is one of the major damaging insects of Pinus spp. in Southern Europe. Its response to varying ipsenol (Ie) percentages in relation to ipsdienol (Id) was studied in northwestern Spain, along with the entire saproxylic beetle assemblage captured at multiple-funnel traps. Response profile modeling was undertaken for I. sexdentatus sexes and sex-ratios, associated species and for selected trophic groups using a reference Gaussian model. In addition, the effects on the saproxylic assemblages were analyzed. I. sexdentatus response curve peaked at 22.7% Ie content, while remaining taxa that could be modeled, peaked above ca. 40% Ie. Predator guilds showed a linear relationship with Ie proportion, while competitors showed a delayed response peak. Consequently, species assemblages differed markedly between varying pheromone component mixtures. Given that the evaluated pheromonal proportions mimicked that of logs being colonized by I. sexdentatus, results suggested that the registered differential responses at different levels might provide I. sexdentatus with a temporal window that maximizes conspecific attraction while reducing interference with competitor and predatory guilds. Described responses might help improve the monitoring of the population status of target bark beetles and their associates, but also point toward the by-catch of many natural enemies, as well as rare saproxylic beetle species, interfering with the aims of sustainable forest management.
一些小蠹虫种类（鞘翅目：小蠹亚科）会产生聚集信息素，从而能够对其针叶树寄主发动协同攻击。随着一个新的蛀木虫栖息地的形成，一群相关甲虫会通过嗅觉对小蠹虫的信息化合物做出反应。六齿小蠹是南欧松树的主要害虫之一。在西班牙西北部，研究了它对不同比例的异松油醇（Ie）与异长叶烯（Id）的反应，同时还研究了在多漏斗诱捕器中捕获的整个蛀木虫群落。使用参考高斯模型对六齿小蠹的性别和性别比例、相关物种以及选定的营养类群进行了反应曲线建模。此外，还分析了对蛀木虫群落的影响。六齿小蠹的反应曲线在Ie含量为22.7%时达到峰值，而其他可建模的分类群在约40%Ie以上达到峰值。捕食者类群与Ie比例呈线性关系，而竞争者的反应峰值出现延迟。因此，不同信息素成分混合物之间的物种群落存在显著差异。鉴于所评估的信息素比例模拟了被六齿小蠹侵染的原木的比例，结果表明，在不同水平上记录到的差异反应可能为六齿小蠹提供了一个时间窗口，既能最大限度地吸引同种个体，又能减少对竞争者和捕食者类群的干扰。所描述的反应可能有助于改进对目标小蠹虫及其相关物种种群状况的监测，但也指出了许多天敌以及珍稀蛀木虫物种的附带捕获问题，这干扰了可持续森林管理的目标。
