Data from: A test for a cost of opportunism in invasive species in the Commelinaceae

Many invasive species can respond opportunistically to favorable growing
conditions. In a previous work, we found that invasive species in the
family Commelinaceae were more opportunistic than their noninvasive
congeners and could therefore outperform noninvasive relatives in an
environment with abundant resources and no competition. Contrary to the
expectation that superior performance under favorable conditions comes at
the cost of reduced performance under stressful conditions, invasive
species did not perform more poorly relative to noninvasive congeners
under any conditions we examined. Here we expand our search for potential
costs of opportunism in invasive species to additional environmental
conditions in which invasive taxa have been shown or predicted to perform
poorly. We grew four invasive and four noninvasive species in environments
consisting of all possible combinations of high and low soil resources and
presence and absence of clipping (removal of aboveground biomass). We also
fed leaves of each species to a generalist herbivore to assess resistance
to herbivory. We found that the advantage of invasive species is reduced
but not eliminated by low soil resources and clipping. At low soil
resources, invasive species produced softer leaves than noninvasive
species and might therefore be less resistant to generalist herbivory than
noninvasive species, although a direct comparison of resistance in a
no-choice bioassay revealed no difference. The invasive species
outperformed noninvasive species only under the most favorable conditions,
and the noninvasive species did not outperform the invasive species in any
environment.