New insight in how insects deal with wind
In the first study, published in Journal of Animal Ecology, the researchers used entomological and ornithological radar data from north-western Europe to investigate how two different nocturnal migrant taxa, the noctuid moth Autographa gamma and songbirds, deal with wind. They found that moths and songbirds use contrasting but adaptive responses to migrating through a moving flow. Compared to the songbirds the moths exposed themselves to a significantly higher degree of drift in order to obtain strong wind assistance, surpassing the songbirds in mean ground speed, at the cost of a comparatively lower spatiotemporal migratory precision.
To the paper in Journal of Animal Ecology: ”Adaptive strategies in nocturnally migrating insects and songbirds: contrasting responses to wind.”
In a second study, the research team reports the first evidence that insects not only use internal compasses, but also rely on turbulence cues to keep themselves from drifting off course in the wind. “Insects cannot sense the mean airflow directly because they are carried along by it and as a result they do not feel the air flowing past them, just as a man at sea far from land cannot tell if the boat is drifting or not,” Andy Reynolds of Rothamsted Research, explains. “But they can sense turbulent fluctuations in the airstream because they get buffeted from side to side by them.” By comparison, the researchers found that nocturnally-migrating songbirds do not use turbulence to detect the flow; instead they rely on visual assessment of wind-induced drift to indirectly infer the flow direction.
To the paper in Current Biology: ”Detection of flow direction in high-flying insect and songbird migrants.”