Data from: A fungal endophyte alters poplar leaf chemistry, deters insect feeding, and shapes insect community assembly

The endophytic fungi of certain grasses and other herbaceous plants have
long been known to provide plants with anti-herbivore defense compounds,
but there is little information about whether the endophytes of trees also
engage in such mutualisms. We investigated the influence of the endophytic
fungus Cladosporium sp. on the chemical defenses of black poplar (Populus
nigra) trees and the consequences for feeding preference and fitness of
herbivorous insects and insect community assembly. Endophyte colonization
increased both constitutive- and induced poplar defenses. Generalist
Lymantria dispar larvae preferred and performed better on uninfected over
endophyte-infected poplar leaves, most likely due to higher concentrations
of salicinoids in endophytic leaves and the endophyte-produced alkaloid
stachydrine. Under field conditions, the endophytic fungus also shapes
insect community assembly in young black poplar trees. Our results show
that endophytic fungi can play a major role both in defending trees
against herbivorous insects and in structuring insect communities of
poplar endophytes.