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Current Research (PhD Thesis):

Plants have a wide variety of defense responses against herbivorous insects. One of these mechanisms is indirect defense in which parasitoids or predators are guided towards their prey/host through volatiles emitted by the plant upon herbivory. Until now, with a few exceptions, volatile mediated indirect defenses have mostly been studied for agricultural crops with short life cycles and high genetic homogeneity, using simple linear food chains under controlled conditions. Little is known about indirect defense in a food web context, where more than one organism may attack a plant and where a plant that emits herbivore-induced volatiles is surrounded by other plants that emit odours that can mix with the herbivore-induced volatiles from the attacked plant. The existence of this mechanism in long lived trees is also unexplored territory.

Studying volatile mediated indirect defenses of Poplars (/Populus spp./) under natural conditions is challenging since the trees themselves posses a series of features that are not found in common crop species such as wood formation, perennial growth, seasonality, genetic diversity and gender division (dioecious). In addition, the recent completion of the genome sequence of the Black cottonwood /Populus trichocarpa/ has drawn a lot of attention to these species and provides important genetic tools to further elucidate the mechanisms of inducible indirect defense. On the other hand the gypsy moth/ Lymantria dispar /is a major pest of Poplars widely distributed in the northern hemisphere, its biology and ecology are well known and it has over 20 natural enemies (parasitoids and predators) occurring in its natural range, therefore this species is a suitable herbivore to evaluate the role of poplar volatiles in indirect defense.

Taking this information into account, the main objective of my research proposal is to determine if volatile mediated indirect defenses are functional mechanisms for poplar trees under natural conditions and to establish the factors that affect volatile emission and natural enemy recruitment using /Lymantria dispar/ as a model hervibore.
last updated on 2013-01-25