Datura wrightii and its Toxic Relationships: A phytochemical island effect

Chemical ecology is the study of how organisms interact with other organisms and their environment through chemical compounds. Poisonous plants such as Datura wrightii are an ideal model to study these interactions. Though D. wrightii contains tropane alkaloids such as atropine and scopolamine that are deadly poisonous to humans, some insect herbivores have evolved a tolerance for these poisons and form important symbiotic relationships as both pollinators and predators. Previous studies have yet to collect chemical analysis data from habitats that are relatively similar but geographically isolated such as islands, suggesting the possibility of a phytochemical “island effect.” In this study, tropane alkaloid concentrations in both leaves and seeds were collected from populations of D. wrightii on both Santa Cruz Island and the mainland Santa Barbara area. This study uses the common garden method and UHPLC chemical analysis to determine whether island and mainland populations have evolved differing concentrations of atropine and scopolamine. The data collected could provide insights into the evolutionary arms-race between D. wrightii and its predators in isolated habitats, as well as the nuances of local environments that determine if high poison concentrations are adaptive or maladaptive.