Avtzis Dimitrios N, Bertheau Coralie, Stauffer Christian
Forest Research Institute, N.AG.RE.F., Vassilika, Thessaloniki 57006, Greece.
Institute of Forest Entomology, Forest Pathology and Forest Protection, Boku, University of Natural Resources and Life Sciences, A-1190 Vienna, Austria.
Insects. 2012 May 7;3(2):453-72. doi: 10.3390/insects3020453.
Bark beetle species within the scolytid genera Dendroctonus, Ips, Pityogenes and Tomicus are known to cause extensive ecological and economical damage in spruce and pine forests during epidemic outbreaks all around the world. Dendroctonus ponderosae poses the most recent example having destroyed almost 100,000 km² of conifer forests in North America. The success and effectiveness of scolytid species lies mostly in strategies developed over the course of time. Among these, a complex system of semiochemicals promotes the communication and aggregation on the spot of infestation facilitating an en masse attack against a host tree's defenses; or an association with fungi that evolved either in the form of nutrition (ambrosia fungi) or even by reducing the resistance of host trees (blue-stain fungi). Although often specific to a tree genus or species, some bark beetles are polyphagous and have the ability to switch on to new hosts and extend their host range (i.e., between conifer genera such as Pityogenes chalcographus or even from conifer to deciduous trees as Polygraphus grandiclava). A combination of these capabilities in concert with life history or ecological traits explains why bark beetles are considered interesting subjects in evolutionary studies. Several bark beetle species appear in phylogeographic investigations, in an effort to improve our understanding of their ecology, epidemiology and evolution. In this paper investigations that unveil the phylogeographic history of bark beetles are reviewed. A close association between refugial areas and postglacial migration routes that insects and host trees have followed in the last 15,000 BP has been suggested in many studies. Finally, a future perspective of how next generation sequencing will influence the resolution of phylogeographic patterns in the coming years is presented. Utilization of such novel techniques will provide a more detailed insight into the genome of scolytids facilitating at the same time the application of neutral and non-neutral markers. The latter markers in particular promise to enhance the study of eco-physiological reaction types like the so-called pioneer beetles or obligate diapausing individuals.
小蠹科的齿小蠹属、 Ips属、 小蠹属和 松小蠹属中的树皮甲虫种类，在世界各地的流行病爆发期间，会对云杉和松树林造成广泛的生态和经济破坏。 西松大小蠹就是最近的一个例子，它已经摧毁了北美近10万平方公里的针叶林。 小蠹科物种的成功和有效性主要在于随着时间的推移而形成的策略。 其中，一个复杂的信息化合物系统促进了在侵染点的通讯和聚集，便于对寄主树的防御进行大规模攻击； 或者与真菌形成关联，这种关联以营养形式（共生真菌）进化，甚至通过降低寄主树的抗性（蓝变真菌）进化。 虽然有些树皮甲虫通常对某一树木属或种具有特异性，但有些是多食性的，能够转向新的寄主并扩大其寄主范围（例如，在小蠹属等针叶树属之间，甚至像 大瘤小蠹 那样从针叶树转向落叶树）。 这些能力与生活史或生态特征的结合，解释了为什么树皮甲虫被认为是进化研究中有趣的研究对象。 为了提高我们对它们的生态学、 流行病学和进化的理解，几种树皮甲虫物种出现在系统地理学研究中。 在本文中，对揭示树皮甲虫系统地理历史的研究进行了综述。 许多研究表明，在过去15,000年前末次盛冰期以来，昆虫和寄主树所遵循的避难区与冰期后迁徙路线之间存在密切关联。 最后，提出了关于下一代测序在未来几年将如何影响系统地理模式分辨率的未来展望。 利用这些新技术将更详细地了解小蠹科的基因组，同时促进中性和非中性标记的应用。 特别是后者有望加强对生态生理反应类型的研究，如所谓的先锋甲虫或专性滞育个体。
