@article {143,
	title = {Genetic Diversity Increases Insect Herbivory on Oak Saplings},
	journal = {PLoS ONEPLoS ONE},
	volume = {7},
	number = {8},
	year = {2012},
	pages = {e44247},
	publisher = {Public Library of Science},
	abstract = {<p>A growing body of evidence from community genetics studies suggests that ecosystem functions supported by plant species richness can also be provided by genetic diversity within plant species. This is not yet true for the diversity-resistance relationship as it is still unclear whether damage by insect herbivores responds to genetic diversity in host plant populations. We developed a manipulative field experiment based on a synthetic community approach, with 15 mixtures of one to four oak (<italic>Quercus robur</italic>) half-sib families. We quantified genetic diversity at the plot level by genotyping all oak saplings and assessed overall damage caused by ectophagous and endophagous herbivores along a gradient of increasing genetic diversity. Damage due to ectophagous herbivores increased with the genetic diversity in oak sapling populations as a result of higher levels of damage in mixtures than in monocultures for all families (complementarity effect) rather than because of the presence of more susceptible oak genotypes in mixtures (selection effect). Assemblages of different oak genotypes would benefit polyphagous herbivores via improved host patch location, spill over among neighbouring saplings and diet mixing. By contrast, genetic diversity was a poor predictor of the abundance of endophagous herbivores, which increased with individual sapling apparency. Plant genetic diversity may not provide sufficient functional contrast to prevent tree sapling colonization by specialist herbivores while enhancing the foraging of generalist herbivores. Long term studies are nevertheless required to test whether the effect of genetic diversity on herbivory change with the ontogeny of trees and local adaptation of specialist herbivores.</p>},
	author = {Castagneyrol, Bastien and Lagache, L{\'e}lia and Giffard, Brice and Kremer, Antoine and Jactel, Herv{\'e}}
}
@article {147,
	title = {Fine-scale environmental control of hybridization in oaks},
	journal = {Molecular EcologyMolecular Ecology},
	year = {2012},
	pages = {n/a-n/a},
	abstract = {Natural hybridization is attracting much interest in modern speciation and conservation biology studies, but the underlying mechanisms remain poorly understood. In particular, it is unclear why environmental changes often increase hybridization rates. To study this question, we surveyed mating events in a mixed oak stand and developed a spatially explicit individual-based hybridization model. This model, where hybridization is frequency-dependent, pollen is nonlimiting and which allows immigrant pollen to compete with local pollen, takes into account species-specific pollen dispersal and sexual barriers to hybridization. The consequences of pollen limitation on hybridization were studied using another simple model. The results indicate that environmental changes could increase hybridization rates through two distinct mechanisms. First, by disrupting the spatial organization of communities, they should decrease the proportion of conspecific pollen available for mating, thus increasing hybridization rates. Second, by decreasing the density of conspecifics, they should increase pollen limitation and thus hybridization rates, as a consequence of chance pollination predominating over deterministic pollen competition. Altogether, our results point to a need for considering hybridization events at the appropriate level of organization and provide new insights into why hybridization rates generally increase in disturbed environments.},
	keywords = {disturbance, immigration, mass action model, paternity analysis, pollen limitation, Quercus petraea, Quercus robur},
	isbn = {1365-294X},
	author = {Lagache, L{\'e}lia and Klein, Etienne K. and Guichoux, Erwan and Petit, R{\'e}my J.}
}
