Elevational variation of quinolizidine alkaloid contents in a lupine (Lupinus argenteus) of the Rocky Mountains.

Quinolizidine alkaloid contents of leaves and seeds ofLupinus argenteus (Fabaceae) collected from seven different localities near Gothic, Colorado were determined by capillary GLC. Differences in alkaloid levels between sites are substantial and alkaloid quantity decreases as elevation increases. Leaves at the lowest elevation, for example, contain six times the alkaloid levels of leaves at the highest elevation. Seeds from plants of low-and high-elevation sites were grown under identical conditions in the green-house. Alkaloid levels of leaves of seedlings were significantly higher in those seedlings derived from populations of low elevations than those of high elevations, indicating that the observed differences in the field are at least partly genetic and not environmental. To determine whether predation rates were responsible for these genetic differences, data on seed predation rates and observations on herbivory were collected.