Defense herbivore response

Two recent meta-analysis studies (Toth and Pavia 2007, and Chap. 3) have aided in clarifying patterns of induced defenses in macroalgae. These studies determined factors that do not play a role in inducing herbivore response (i.e., type of elicitor, artificial vs. natural food), highlighted factors that are important (i.e., size of the herbivore used and the timescale of the experiment), and illustrated distinct differences between algal groups in their ability to induce responses as observed through herbivore reactions (Toth and Pavia 2007, Chaps. 3 and 7). 

Cornell HV, Hawkins BA (2003) Herbivore responses to plant secondary compounds a test of phytochemical coevolution theory. Am Nat 161 507-522 Cronin G (2001) Resource allocation in seaweeds and marine invertebrates chemical defense patterns in relation to defense theories. In McClintock JB, Baker BJ (eds) Mar Chem Ecol. CRC, Boca Raton, FL, pp 325-354... 

Coevolution is defined as reciprocal stepwise adaptations between at least two species (Ehrlich and Raven, 1964). Coevolution without the criterion of reciprocity is indistinguishable from evolution and hence a useless concept (Lindroth, 1988). Consider the following scenario. A plant develops effective antiherbivore defenses. In response, a herbivore counteradapts to circumvent these defenses and is at a competitive advantage over other herbivores. The plant, in turn, responds to this breach of its defenses. In insects, such pairwise reciprocal evolution can take the form of a chemical arms race (Dawkins and Krebs, 1979). Coevolution differs from evolution by being narrower, with fewer participants, perhaps even only two species or two populations. In reality, in most ecosystems, many species prey on many other species. Therefore, we can at best speak of diffuse coevolution, with a number of participants that exert diluted selection pressures. 

T uomi J, Niemela P, Chapin FS, Bryant JP, Siren S (1988) Defensive responses of trees in relation to their carbon/nutrient balance. In Mattson JB (ed) Mechanisms of woody plant defense against insects search for patterns. Springer, New York, pp 57-72 Van Alstyne KL (1988) Herbivore grazing increases polyphenolic defenses in the intertidal brown alga Fucus distichus. Ecology 69 655-663... 

Plants respond to the mechanical or insect herbivore damage of their tissues." During herbivorous attacks, some plants emit a specific blend of volatiles, which may result in defense responses retarding development of the herbivores or attraction of herbivore enemies to feed upon them. In lima bean leaves, the spider mite-induced volatiles, as well as infestation and artificial wounding, activate the ethylene and JA signaling pathways. ... 

Other aspects of implementing indirect volatile defenses, as recently discussed in several excellent reviews [17, 94, 95], will include the assessment of timing and synergy of volatile emissions with direct defense responses of the herbivore-damaged plant, especially if indirect defense strategies will be integrated with toxin-based pest control strategies. 

Kollner TG, Held M, Lenk C, HUtpold I, Turlings TCJ, Gershenzon J, Degenhardt J (2008) A maize ( )-beta-caryophyUene synthase implicated in indirect defense responses against herbivores is not expressed in most American maize varieties. Plant Cell 20 482-494... 

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