Monarch butterflies have fascinated biologists for a long time. A 3,000-mile road trip in even the most comfortable car would prove daunting to many humans, but these beautiful insects can migrate that same distance every year from Canada to a specific grove of fir trees in Mexico each fall. The next generation of monarchs can then travel back to Canada in the spring. Scientists are investigating the tools that these tiny flying creatures use to achieve this feat. One leading monarch researcher has discovered an important reason why the butterflies’ antennae are vital for successful navigation...