Sexual Dimorphism in Jump Kinematics and Choreography in Peacock Spiders

Jumping requires a rapid release of energy to propel an animal. Terrestrial animals achieve this by relying on the power generated by muscles, or by storing and rapidly releasing elastic energy. Jumping spiders rely on hydraulic pressure and muscular action to propel their jump. Though males and females of jumping spiders vary in size, sex-specific differences in jumping have never been studied. We investigated sexual dimorphism in the jump kinematics of an Australian Peacock spider, Maratus splendens. We recorded locomotory jumps in males and females using high-speed videography (5000 frames per second). We determined the centre of mass of the animals using {micro}CT and tracked its displacement during a jump. We found that although females weighed more than twice as much as males, both had similar accelerations and take-off velocities. Males had shorter jump take-off duration, steeper take-off angle and experienced higher g-force compared to the females. We examine the jump choreography of male and female spiders and explore the factors behind the differences in their jump kinematics.