Data and R code used in: Plant geographic distribution influences chemical defenses in native and introduced Plantago lanceolata populations

Plants growing outside their native range may be confronted by new regimes
of herbivory, but how this affects plant chemical defense profiles has
rarely been studied. Using Plantago lanceolata as a model species, we
investigated whether introduced populations show significant differences
from native populations in several growth and chemical defense traits.
Plantago lanceolata (ribwort plantain) is an herbaceous plant species
native to Europe and Western Asia that has been introduced to numerous
countries worldwide. We sampled seeds from nine native and ten introduced
populations that covered a broad geographic and environmental range and
performed a common garden experiment in a greenhouse, in which we infested
half of the plants in each population with caterpillars of the generalist
herbivore Spodoptera littoralis. We then measured size-related and
resource-allocation traits as well as the levels of constitutive and
induced chemical defense compounds in roots and shoots of P. lanceolata.
When we considered the environmental characteristics of the site of
origin, our results revealed that populations from introduced ranges were
characterized by an increase of chemical defense compounds without
compromising plant biomass. The concentrations of iridoid glycosides and
verbascoside, the major anti-herbivore defense compounds of P. lanceolata,
were higher in introduced populations than in native populations. In
addition, introduced populations exhibited greater rates of
herbivore-induced volatile organic compound emission and diversity, and
similar chemical diversity based on untargeted analyses of leaf methanol
extracts. In general, the geographic origin of the populations had a
significant influence on morphological and chemical plant traits,
suggesting that P. lanceolata populations are not only adapted to
different environments in their native range but also in their introduced
range.