How are arthropod communities organized on an introduced plant Solidago altissima?

We have tried to understand mechanisms of organizing herbivore communities on introduced tall goldenrod, Solidago altissima. At first, to assess pattern on herbivore communities on S. altissima, we compared community composition, density, and species richness of herbivorous insects on S. altissima and on a related native species Solidago virgaurea at a same habitat in Japan. We found a large difference in community composition on the two plant species. In particular, exotic aphid greatly contributed to the difference in community composition. Next, to examine the aphid impacts on other herbivores, we conducted several experiments in Japan. We found strong impacts of the aphid on co-occurring herbivorous insects through the removal behavior of tending ants and on temporally separated herbivorous insects through changes in foliar quality and production of S. altissima. These two studies suggest that the exotic aphid plays an important role in organizing herbivore communities on S. altissima.