Katydids Shift to Higher-Stability Gaits when Climbing Inclined Substrates

Synopsis When terrestrial organisms locomote in natural settings, they must navigate complex surfaces that vary in incline angles and substrate roughness. Variable surface structures are common in arboreal environments and can be challenging to traverse. This study examines the walking gait of katydids (Tettigoniidae) as they traverse a custom-built platform with varying incline angles(30^◦, 45^◦, 60^◦, 75^◦, 90^◦) and substrate roughness(40, 120, and 320 gritsandpaper). Ourresultsshow that katydids walk more slowly as the incline angle increases and as katydid mass increases, with a decrease of around 0.3 body lengths per second for every 1^◦ increase in incline.Atsteeperinclines and largersizes, katydids are also lesslikely to use an alternating tripod gait, opting instead to maintain more limbs in contact with the substrate during walking. Katydids also increased average duty factorwhen climbing steeperinclines andwith increasing body mass. However,substrate roughness did not affectwalking speed or gait preference in our trials. These findings provide insights into how environmental factors influence locomotor strategies in katydids and enhance our understanding of effective locomotor strategies in hexapods.