Monarch Butterflies and Bt Corn: Replacing Hoopla with Science

A correspondence to Nature three years ago reported a preliminary laboratory study that suggested pollen from from Bacillus thuringiensis (Bt) com could be hazardous to the larvae of the monarch butterfly, Danaus plexippus. Losey et al. (1999) showed that young monarch larvae given no choice but to feed on milkweed, Asclepias curassavica, leaves dusted with pollen from Bt corn hybrid ate less, grew more slowly, and had a significantly higher mortality rate than larvae feeding on leaves dusted with nontransgenic pollen. Based on this study, the authors questioned the environmental safety of Bt com and called for scientific investigations