A specimen of Argiope lobata was observed oscillating itself and its web in a regular way when disturbed. This behaviour made it invisible, and is interpreted as a reaction for avoiding being seen by predators. A combination of four factors is important; (I) The large body mass and the long legs of the spider allow it to move the centre of gravity quickly, and thereby to oscillate. (2) The great elasticity and strength of its web allow the spider to control the oscillations so that slow movements are reduced to a minimum. (3) When it is oscillating. the eyes of a predator cannot accommodate to keep it in focus, but will focus on the background. (4) The irregular shape and variegated coloration of its body reduce its contrast against the background when it is sitting still, but also during oscillation.
Newsletter of the British Arachnological Society, 2007, Vol 109, p. 10-11