Locomotion and flow speed preferences in natural habitats by large water striders, Ptilomera tigrina, with micro-morphological adaptations for rowing

Abstract Water strider (Gerridae) morphology and behavior have become the focus of interdisciplinary research in biological diversification bio-inspired technology. However, diversity behaviors large-sized Gerridae not been intensely studied. Here, we provide locomotory legs’ micro-morphology large South-East Asian water strider, Ptilomera tigrina . Using high-speed videography experiments natural habitats, as well scanning electron microscopy midlegs, determined that (1) P. individuals prefer relatively high flow speeds 0.15–0.30 m/s, compared to other striders previously studied, they are also observed very up 0.6 m/s; (2) avoid stagnant water, but when on still slow flowing perform constant back-and-forth rowing using their midlegs; (3) antipredatory reaction involves repetitive fast “protean” movements propelled by (4) midleg tarsi tibiae equipped with brushes ribbon-like hairs, which used paddles for rowing. As flow-speed preferences require use midlegs rowing, presence special paddle structures illustrates a hypothetical adaptive match between midlegs’ function micro-morphology.