Phytochemicals Involved in Plant Resistance to Leporids and Cervids: a Systematic Review

Area of Science:

• Ecology
• Plant Science
• Zoology

Background:

• Non-nutritive phytochemicals (secondary metabolites and fibre) influence plant defense against herbivores.
• Ecological studies of phytochemicals are hindered by uncertainty in which compounds to measure, especially with limited resources.
• Understanding plant resistance to herbivores is crucial for predicting population dynamics and ecological interactions.

Purpose of the Study:

• To systematically review the effects of non-nutritive phytochemicals on consumption by leporids (rabbits, hares) and cervids (deer).
• To identify potential proxies of plant resistance to herbivores based on phytochemical profiles.
• To provide guidance on selecting appropriate chemical analyses for plant defense studies.

Main Methods:

• Systematic literature review of 1790 articles, selecting 133 relevant studies.
• Analysis of phytochemical effects on herbivory across 18 herbivore species on four continents.
• Categorization of phytochemicals, including phenolics, terpenes, and fibre.

Main Results:

• Phenolic concentration generally correlates with high plant resistance to both leporids and cervids.
• Terpene concentration is linked to increased plant resistance, driven by total content for cervids and specific compounds for leporids.
• Tannins and fibre showed inconsistent effects on plant resistance.

Conclusions:

• The effectiveness of plant defense compounds varies, necessitating tailored chemical analyses based on research objectives.
• Ecological and evolutionary studies may require broad phytochemical analysis, while applied studies can focus on specific compounds.
• Improved understanding of plant defense chemistry can enhance studies of plant resistance and predict plant-herbivore interactions.