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Plants have evolved various strategies to defend themselves against herbivores and pathogens. Although some of these strategies are constitutive, ie present at all times, others are induced only in response to herbivore feeding or pathogen infection. The induction of direct and indirect plant defenses in response to herbivory and other biotic stresses is well established (Karban and Baldwin, 1997), and a wide array of studies have documented such induced defenses (Schultz and Baldwin, 1982; Haruta et al., 2001; van Dam et al., 2004; Miranda et al., 2007). Induced defenses should be adaptive when:(1) defenses are costly to implement,(2) there is spatial or temporal variability in the distribution of herbivores or pathogens so that plants do not always experience attack, and (3) there are tradeoffs between defenses against different enemies (eg defenses against herbivores and pathogens or against different …