Why do plants make opioids? Testing the herbivore defense hypothesis for psychoactive alkaloids in kratom
Brent McNutt, Melissa R. L. Whitaker
The paper tests the herbivore defense hypothesis by showing kratom leaf and mitragynine affect insect growth and survival, but the effects are not mediated by mammalian opioid receptors.
bioRxiv · Jul 16, 2026 · PreprintEcology