Meeting Abstract
Long-distance journeys can drive gene flow, influencing ecology and evolution. Though animals such as monarch butterflies shed light on the extremes of navigation, it is also important to study navigational generalists, whose journeys likely depend on a conserved and widespread neurobiological toolkit. Jerry Coyne and colleagues showed, nearly 30 years ago, that Drosophila species can fly many kilometers across open desert, likely in a single night. This prompts many new questions: we here examine whether fruit flies can maintain straight headings over long distances, and whether azimuthal heading is influenced by particular celestial cues. We also aim to uncover rules governing flies’ olfactory plume tracking in the field. To address these questions, we are performing releases of lab reared, wild type Drosophila melanogaster from the center of a dry lakebed in the Mojave Desert. We have developed baited fly traps equipped with machine-vision cameras, which provide estimates of flies’ arrival times. The transit times we record suggest that most flies must fly with relatively straight trajectories at speeds ranging from 1.2 to 1.8 meters per second, largely irrespective of wind direction. That these average speeds are achieved over the visually homogeneous lakebed suggests flies may use celestial cues to maintain straight headings. Our field data are also intriguingly inconsistent with the positive anemotaxis fruit flies generally exhibit in laboratory wind tunnels, yet arrival times at our crosswind traps suggest flies are not passively blown downwind. To help interpret these data, we have constructed an agent-based model to simulate flights across the dry lakebed.
