Effects of generalist herbivory on resistance and resource allocation by the invasive plant, Phytolacca americana  

作　　者：Wei Huang Jianqing Ding 

机构地区：[1]Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei,China

出　　处：《Insect Science》2016年第2期191-199,共9页昆虫科学（英文版）

基　　金：We would like to thank Xue-Fang Yang and Shun-Liang Feng for plant harvests. We also thank English editing by Van Driesche Scientific Editing. This work was sup- ported by the National Natural Science Foundation of China （31470447 and 31200286 to W. Huang, 31370404 to J. Ding）.

摘　　要：Successful invasions by exotic plants are often attributed to a loss of co-evolved specialists and a re-allocation of resources from defense to growth and reproduction. However, invasive plants are rarely completely released from insect herbivory because they are frequently attacked by generalists in their introduced ranges. The novel generalist community may also affect the invasive plant＇s defensive strategies and resource allocation. Here, we tested this hypothesis using American pokeweed （Phytolacca americana L.）, a species that has become invasive in China, which is native to North America. We examined resistance, tolerance, growth and reproduction of plant populations from both China and the USA when plants were exposed to natural generalist herbivores in China. We found that leaf damage was greater for invasive populations than for native populations, indicating that plants from invasive ranges had lower resistance to herbivory than those from native ranges. A regression of the percentage of leaf damage against mass showed that there was no significant difference in tolerance between invasive and native populations, even though the shoot, root, fruit and total mass were larger for invasive populations than for native populations. These results suggest that generalist herbivores are important drivers mediating the defensive strategies and resource allocation of the invasive American pokeweed.Successful invasions by exotic plants are often attributed to a loss of co-evolved specialists and a re-allocation of resources from defense to growth and reproduction. However, invasive plants are rarely completely released from insect herbivory because they are frequently attacked by generalists in their introduced ranges. The novel generalist community may also affect the invasive plant＇s defensive strategies and resource allocation. Here, we tested this hypothesis using American pokeweed （Phytolacca americana L.）, a species that has become invasive in China, which is native to North America. We examined resistance, tolerance, growth and reproduction of plant populations from both China and the USA when plants were exposed to natural generalist herbivores in China. We found that leaf damage was greater for invasive populations than for native populations, indicating that plants from invasive ranges had lower resistance to herbivory than those from native ranges. A regression of the percentage of leaf damage against mass showed that there was no significant difference in tolerance between invasive and native populations, even though the shoot, root, fruit and total mass were larger for invasive populations than for native populations. These results suggest that generalist herbivores are important drivers mediating the defensive strategies and resource allocation of the invasive American pokeweed.

关 键 词：evolution of increased competitive ability GENERALIST Phytolacca americanaL. RESISTANCE TOLERANCE resource allocation 

分 类 号：X176[环境科学与工程—环境科学] S512[农业科学—作物学]