Chemical ecology of native systems: lessons for a sustainable use of plant chemical defense

An increasing number of studies focusing on the understanding of plant-insect interactions in natural systems as well as an increasing understanding of the mechanisms underlying plant resistance trait expression nurture hopes for an efficient utilization of natural plant chemical defenses in agriculture. Such hopes are also rooted in an increasing worldwide demand for environmentally and economically more sustainable agricultural practices. What can we actually learn from a natural system to be applied in agricultural systems? I will approach this question by reviewing results from a study system that naturally grows in the agricultural niche, the tall goldenrod, Solidago altissima. More specifically we tested the hypothesis that induced plant responses to herbivory can affect spatial dynamics of herbivore populations. We used field and laboratory choice and preference bioassays to analyze the effects that S. altissima induced resistance to herbivores has on host choice and performance of its herbivores. Moreover, we analyzed the potential cues that herbivores use for host choice as well as the effects their choice had on the spatial distribution of herbivory within the plant population. Our data demonstrate that herbivore-induced plant responses can have dramatic effects on herbivore population dynamics, which likely has significant effects on community composition and productivity. I will discuss these herbivore-induced plant responses as optimized plant strategies that allow maximized performance of the individual plant in dense plant populations.