Genetic variation in anti-herbivore chemical defences in an invasive plant

Authors

  • Yi Wang,

    1. Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Institute/Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei 430074, China
    2. Graduate University of Chinese Academy of Sciences, Beijing 100049, China
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  • Evan Siemann,

    1. Department of Ecology and Evolutionary Biology, Rice University, Houston, TX 77005, USA
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  • Gregory S. Wheeler,

    1. Invasive Plant Research Laboratory, United States Department of Agriculture, Agricultural Research Service, 3225 College Avenue, Fort Lauderdale, FL 33314, USA
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  • Lin Zhu,

    1. Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Institute/Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei 430074, China
    2. Institute of Environmental Biology and Insect Resources, College of Plant Protection, Shandong Agriculture University, Taian, Shandong 271018, China
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  • Xue Gu,

    1. Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Institute/Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei 430074, China
    2. Graduate University of Chinese Academy of Sciences, Beijing 100049, China
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  • Jianqing Ding

    Corresponding author
    1. Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Institute/Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei 430074, China
      Correspondence author. E-mail: dingjianqing@yahoo.com
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Correspondence author. E-mail: dingjianqing@yahoo.com

Summary

1. Plants produce a variety of secondary metabolites such as flavonoids or tannins that vary in effectiveness against different herbivores. Because invasive plants experience different herbivore interactions in their introduced versus native ranges, they may vary in defence chemical profiles.

2. We subjected tallow tree (Triadica sebifera) seedlings from native (China) and introduced (US) populations to induction by leaf clipping or one of three Chinese caterpillars (two generalists and one specialist). We measured the concentrations of five flavonoids and four tannins in leaves produced before or after damage. We measured growth of caterpillars fed these leaves from plants of each induction treatment or undamaged controls.

3. Plants from introduced populations had higher flavonoids and lower tannins than plants from native populations, especially in new leaves following induction. Caterpillar responses to changing chemical concentrations varied in direction and strength, so overall performance varied from significantly lower (generalist Grammodes geometrica), unchanged (generalist Cnidocampa flavescens), to significantly higher (specialist Gadirtha inexacta) on introduced populations.

4.Synthesis. Together, such a trade-off in secondary metabolism in invasive plants and the effect on herbivores suggest divergent selection may favour different chemical defences in the introduced range where co-evolved natural enemies, especially specialists, are absent.

Ancillary