Walking and Surface Film Locomotion in Terrestrial and Semi-Aquatic Spiders

摘要: SUMMARY The walking and surface film locomotion of a terrestrial spider, Lycosa rabida Walckenaer, semi-aquatic Dolomedes triton (Walckenaer), are compared. Stepping patterns during on solid substrate resemble an alternating tetrapod in both species. L. retains elements the gait when moving water: propulsive thrusts concentrated at tarsi intrasegmental legs step alternation. However, protraction/retraction (p/r) values generally greater phase adjacent ipsilateral lower compared to for animals. D. shows behavioural specialization aquatic locomotion: forces generated along length leg, move synchrony leg 4 (which is not used propulsion water) functions yaw correction. Changes p/r value accompanying transition from water similar those found rabida. fact that coordination within segment between segments can be altered independently proximate evolutionary time suggests interleg coupling spiders governed by two distinct mechanisms: intersegmental mechanisms. It suggested changes may effect sensory modulation motor control mechanisms certain specializations (such as corrective movements 4) derived primitive programme.