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

• Published in: Insect science Vol. 23; no. 2; pp. 191 - 199
• Main Authors: Huang, Wei, Ding, Jianqing
• Format: Journal Article
• Language: English
• Published: Australia Blackwell Pub 01.04.2016; Blackwell Publishing Ltd; Wiley Subscription Services, Inc
• Subjects: Animals; China; evolution of increased competitive ability; generalist; Herbivores; Herbivory; Insecta - physiology; Introduced Species; Phytolacca americana; Phytolacca americana - growth & development; Phytolacca americana - physiology; Phytolacca americana L; Plant Leaves - growth & development; Plant Leaves - physiology; resistance; resource allocation; tolerance; United States; 共同进化; 外来入侵植物; 外来植物入侵; 种群繁殖; 美洲商陆; 耐药性; 草食动物; 资源分配; United States; China; Phytolacca americana L; resource allocation; resistance; tolerance; evolution of increased competitive ability; generalist
• ISSN: 1672-9609; 1744-7917
• DOI: 10.1111/1744-7917.12244

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.