DISSERTATION RESEARCH: Effects of a Hybrid Host Plant on Diversity and Abundance of Insects

人类经常长距离运输生物体，并使曾经在地理上分开的物种接触。如果相似的物种在接触时可以杂交，就会产生杂交种。因此，杂交正在增加，但生态后果还没有得到很好的理解。植食性昆虫对杂交植物的反应通常不同于它们对原始植物物种的反应。 昆虫对杂交种的反应会影响到食草昆虫的数量和其他以昆虫为食的生物的成功。本研究调查了杂交抗性现象，即杂交植物上的食草昆虫比原始亲本物种少。在香蒲属物种（香蒲属）的杂交种上已经记录了杂交抗性。在杂交种上，白蛾的数量较少，但这种抗性的原因尚不清楚。这个项目的第一个目标是确定除蛾类以外的昆虫物种是否以类似的方式对杂交种作出反应。第二个目标是发现为什么杂交种上蛾的数量较少。有两种可能性：（1）雌蛾不识别杂交种，避免在其上产卵;（2）幼虫在杂交种上存活率很差。这项研究的结果将有助于预测和管理其他杂交事件的结果。人们也越来越担心杂交香蒲，因为它是一个积极的竞争对手，并排除了湿地中的其他植物。草食动物的抗性可能有助于杂交种的竞争力，降低杂交种占主导地位的沼泽作为其他生物栖息地的价值。

Humans often transport organisms over long distances and bring into contact species that were once geographically separated. If similar species can interbreed when in contact, hybrids will be created. Hybridization is therefore increasing, but the ecological consequences are not well understood. Herbivorous insects often respond to hybrid plants differently than they would to the original plant species. The response of insects to hybrids affects the abundance of insect herbivores and the success of other organisms that feed on the insects.This research investigates the phenomenon of hybrid resistance, in which fewer herbivores are found on hybrid plants than on the original parental species. Hybrid resistance has been documented on hybrids of cattail species (Typha). The moth Limnaecia phragmitella is less abundant on hybrids but the reasons for this resistance are not known. The first objective of this project is to determine whether insect species other than the moth respond in a similar way to hybrids. The second objective is to discover why moths are less abundant on hybrids. There are two possibilities: (1) Female moths do not recognize hybrids and avoid laying eggs on them, and (2) Larval survival on hybrids is poor. The results of this study will help predict and manage the outcomes of other hybridization events. There is also growing concern over the hybrid cattail, because it is an aggressive competitor and excludes other plants in wetlands. Herbivore resistance may contribute to the hybrids' competitiveness and lower the value of hybrid-dominated marshes as habitat for other organisms.