Individual tracking reveals long-distance flight-path control in a nocturnally migrating moth

Each year, trillions of insects make long-range seasonal migrations. These movements are relatively well understood at a population level, but how individual insects achieve them remains elusive. Behavioral responses to conditions en route are little studied, primarily owing to the challenges of tracking individual insects. Using a light aircraft and individual radio tracking, we show that nocturnally migrating death’s-head hawkmoths maintain control of their flight trajectories over long distances. The moths did not just fly with favorable tailwinds; during a given night, they also adjusted for head and crosswinds to precisely hold course. This behavior indicates that the moths use a sophisticated internal compass to maintain seasonally beneficial migratory trajectories independent of wind conditions, illuminating how insects traverse long distances to take advantage of seasonal resources. We still know little about how many migrating species navigate across vast distances. This is especially true for invertebrates, which are challenging to monitor. However, new technologies leading to extremely light, animal-mounted tags are opening up new research avenues in this area. Menz et al . used such tags to track the flight of death’s-head hawkmoths that migrate between Europe and sub-Saharan Africa. They found that the moths were able to correct to their specific course even in the face of disruptive winds and high mountains. This work suggests that the moths are not merely passively moving in the right direction, but instead actively navigating based on an internal map or compass. —SNV Migrating hawkmoths continually adjust their flight headings in response to winds to maintain favorable migratory trajectories.