Effect of Miniaturisation on Jump Kinematics and Take-off Strategies in Jumping Spiders

Size affects the design of morphological and physiological characteristics along with the information processing capacity of animals. A reduction in size or miniaturisation is a biological phenomenon where animals within a single lineage have evolved extremely small body size where tissues and organs reach limits imposed by the physical world. Jumps, a common mode of locomotion in animals can be used as a benchmark information processing task. Jumping spiders of the family Salticidae frequently jump to avoid predators, capture prey and for locomotion. They also exhibit dramatic variation in body size both between and within species. Here, we investigated the effects of miniaturisation on the jumping kinematics and energetics in Australian spiders. We filmed the take-off locomotory jumps of 8 species of spiders that exhibited more than 50-fold differences in body mass. We carried out a frame-by-frame analyses and quantified their jump kinematics and energetics. While heavier spiders had higher take-off acceleration, we found ‘species’ explained most of the variation in acceleration. Variation in the energetics and jumping forces was best explained by body mass. We discuss here the variation in morphologies between species and how this affects jump take-off strategies in spiders in the context of miniaturisation.