Why Induced Defenses May Be Favored Over Constitutive Strategies in Plants

By A. Agrawal, R. Karban. 2000

209 citations recorded by the source corpus.

Although induced resistance has been documented in over 100 species of plants, why plants employ facultative defense strategies is not well understood. Although it has been widely accepted that induction may be a means of reducing resource allocations to defense when not needed, this explanation is not exclusive of a wide array of hypotheses for the advantages of induced defenses. In an attempt to shift attention away from the “allocation cost” model, here we focus on several alternative hypotheses for the benefits of induction. Given that most plants interact with multiple specialist and generalist herbivores, various pathogens, microbes, and mutualists, a host of constraints on maintaining constantly high levels of resistance arise. The temporal and spatial variability in food quality for phytophages created by induction may be especially important. Variability may hinder herbivore performance in ecological time as well as the evolutionary ability of herbivores to adapt to host plants. Research on the various benefits of induced defenses seems to be the obvious next step in understanding why so many plants employ induction.

Subfields: Ecology, Evolution, Behavior and Systematics, Nature and Landscape Conservation, Plant Science

View Paper: https://www.semanticscholar.org/paper/5b6fd613640123bafedd8bcab606f1e3fbeae027

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Citations in the corpus

Chemical information transfer between plants: back to the future (2001, background): “There is ample evidence for inducible defences in plants (Karban and Baldwin, 1997) and several theories describe why and when plants should employ inducible defences rather than constitutive defences (Agrawal and Karban, 1999).”
HOW TO BE SWEET? EXTRAFLORAL NECTAR ALLOCATION BY GOSSYPIUM HIRSUTUM FITS OPTIMAL DEFENSE THEORY PREDICTIONS (2004, background): “…resistance that are rarely inducible (Zangerl and Bazzaz 1992, Zangerl and Rutledge 1996, Karban and Baldwin 1997), whereas vegetative structures often show low constitutive levels that are frequently inducible (Zan- gerl and Rutledge 1996, Karban and Baldwin 1997, Agrawal and Karban 1999).”
Costs and benefits of induced resistance to herbivores and pathogens in plants (2010, background): “possessing induced resistance may have several other benefits over constitutive strategies [113–115].”
Future directions in the study of induced plant responses to herbivory (2005, background): “Even if considering both female and male fitness components, allocation to defense may not be easily detectable 100 Agrawal (Karban & Baldwin, 1997; Agrawal & Karban, 1999).”
Specificity of induced resistance in wild radish: causes and consequences for two specialist and two generalist caterpillars (2000, background): “In the current study I found no evidence that larvae of the specialist herbivores were stimulated by induced responses in wild radish (but see a review of the phenomena in Agrawal and Karban 1999).”
Specificity of induced plant responses to specialist herbivores of the common milkweed Asclepias syriaca (2004, background): “An intuitively appealing hypothesis predicts that specialist and generalist herbivores have divergent reactions to induced plant responses (Carroll and Hoffman 1980, Dussourd 1993, Karban and Baldwin 1997, Agrawal and Karban 1999).”
Recruitment of predators and parasitoids by herbivore-injured plants (2004, background): “, 1999) and reviews (Baldwin, 1994; Karban et al., 1997; Agrawal and Rutter, 1998; Agrawal and Karban, 1999; Baldwin and Preston, 1999; Dicke et al., 2003) have been devoted entirely to the subject of induced plant defenses.”