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

摘要: Theories of plant invasion based on enemy release in a new range assume that selection exerted by specialist herbivores defence traits should be reduced, absent, or even selected against the environment. Here, we measured phenotypic atropine and scopolamine concentration Datura stramonium eight native (Mexico) 14 non-native (Spain) populations. Native populations produced between 20 40 times more alkaloid than (atropine: 2.0171 vs. 0.0458 mg/g; scopolamine: 1.004 0.0488 mg/g, respectively). Selection alkaloids was negative for positive both ranges. However, effect sizes gradients were only significant range. Our results support assumption reduction absence plant's natural enemies invasive ranges is driven selection.