Survival of two species of adult butterflies that were free-ranging and allowed to feed on flowers from Mexican milkweed, <i>Asclepias curassavica</i>, (AC), that were untreated (C), treated with label rate (1X), or twice label rate (2X) of soil-applied imidacloprid (Marathon 1%G) or that were force-fed 30% syrup syrup (S) containing 0 ppb (C), 15 ppb (1X) and 30 ppb (2X) imidacloprid.

<p>Cox proportional hazards model with a random effect for cage, and stratified by replicate, α = 0.05.</p><p>Survival of two species of adult butterflies that were free-ranging and allowed to feed on flowers from Mexican milkweed, <i>Asclepias curassavica</i>, (AC), that were untreated (C), treated with label rate (1X), or twice label rate (2X) of soil-applied imidacloprid (Marathon 1%G) or that were force-fed 30% syrup syrup (S) containing 0 ppb (C), 15 ppb (1X) and 30 ppb (2X) imidacloprid.