Water Surface Locomotion by Spiders: Distinct Gaits in Diverse Families

Pisaurids such as Dolomedes triton (Walckenaer 1837) are well known as inhabitants of ponds and streams and are adept at locomotion on the water surface. In a broad survey of water surface locomotion in spiders, we have found that most taxa do not use specialized gaits under these circumstances. However, some tetragnathids, araneids, and salticids (three families that are outside of the superfamily Lycosoidea to which the pisaurids belong) resemble D. triton to the extent that they do use specialized gaits when on the water surface. Of these, the tetragnathids are particularly accomplished at water surface locomotion, achieving velocities that exceed those of D. triton when it rows, but not when it gallops.