Selection on tropane alkaloids in native and non‐native populations of Datura stramonium

Theories of plant invasion based on enemy release in a new range assume that selection exerted by specialist herbivores on defence traits should be reduced, absent, or even selected against in the new environment. Here, we measured phenotypic selection on atropine and scopolamine concentration of Datura stramonium in eight native (Mexico) and 14 non-native (Spain) populations. Native populations produced between 20 and 40 times more alkaloid...