Trade-offs in the host selection by phloeophagous parasitic insects on conifers

昆虫和植物已经共存了数亿年，经常进化出密切的联系，甚至相互依赖。植物和昆虫之间最常见的相互作用涉及昆虫利用植物组织作为食物和/或繁殖资源，经常使昆虫与人类的利益直接冲突。为了应对昆虫在木材中觅食或繁殖所施加的选择压力，大多数木本植物进化出了一种强有力的防御性化学物质混合物。大多数种类的昆虫只能有限地忍受这些化学物质，因此只能在死去的寄主身上喂养和繁殖，但有少数种类的昆虫可以利用活组织，它们要么在寄主死亡时入侵它，杀死它，要么在少数情况下作为寄生虫生存。寄生昆虫对了解昆虫选择寄主的线索很感兴趣，这是我们仍然不太了解的。

Insects and plants have co-existed for hundreds of millions of years, often evolving close associations and even co-dependence. The most common interaction between plants and insects involve the utilization of plant tissue as a food and/or breeding resource by insects, often placing insects in direct conflict with human interests. In response to the selective pressures exerted by insects feeding or breeding in wood, most woody plants have evolved a potent cocktail of defensive chemicals. Most species of insects can tolerate only limited exposure to such chemicals, and hence feed and breed only in dead hosts, but a limited number of species can utilize live tissue, either invading it as the host is dying, killing it, or in a few cases living as a parasite. The parasitic insects are of interest in understanding the cues that insects use in selecting a host, something we still don't understand very well.