Insect Herbivores and Plant Succession: Interactions and Mechanisms

本研究将探讨昆虫取食对沙丘原生植物演替过程中物种更替率和模式的影响。研究将集中在一种专门的甲虫Altica bimarginata和柳树Salix cordata上。一套综合的田间和温室试验将检查植物演替阶段对草食率的影响和草食动物对植物演替过程的影响，并提供潜在机制的关键测试。为了研究植食性丰度在植物演替阶段之间和内部的变化，野外实验将考察寄主植物和周围植物群落的属性如何影响植食性。植物间遗传差异对草食率的影响将通过互惠移植研究来解决。食草动物排除实验将检验食草动物在影响植物演替模式中的作用。本文将通过植物邻居去除实验来研究周围植物邻居影响演替的重要性以及食草动物如何影响演替。温室试验改变草食水平将检验寄主植物适应性的哪些方面受到草食的影响。虽然已知食草性强烈影响植物适应性和竞争相互作用，但食草性在影响植物演替中的作用在很大程度上被忽视了。通过植物对昆虫的影响和昆虫对植物的影响，阐明演替系统中昆虫-植物动态的相互作用性质。这些贡献对于昆虫和植物生态学，以及了解群落和控制物种多样性的因素具有重要意义。

The proposed research will investigate the effects of insect herbivory on rates and patterns of species replacement during primary plant succession on sand dunes. The research will focus on a specialist beetle, Altica bimarginata, and the willow, Salix cordata. An integrated set of field and greenhouse experiments will examine both the effects of plant successional stage on rates of herbivory and effects of herbivores on plant successional processess, as well as provide critical tests of the underlying mechanisms. To study how herbivore abundance varies between and within plant successional stages, field experiments will examine how attributes of host plants and the surrounding plant community influence herbivory. The role of genetic differences between plants in influencing rates of herbivory will be addressed with a reciprocal transplant study. Herbivore exclusion experiments will examine the role of herbivory in influencing plant successional patterns. The importance of surrounding plant neighbors in influencing succession and how herbivores affect succession will be studied with plant neighbor removal experiments. Greenhouse experiments varying the level of herbivory will examine what aspects of host plant fitness are affected by herbivory. Although herbivory is known to strongly affect plant fitness and competitive interactions, the role of herbivory in influencing plant succession has been largely ignored. By focusing on both the effects of plants on insects and the effects of insects on plants, the interactive nature of insect-plant dynamics in successional systems will be elucidated. These contributions are of central importance to insect and plant ecology, as well as understanding of communities and factors controlling species diversity.