Figure 2.
Spider Ballooning Behavior
(A) A spider showing a typical tiptoe stance.
(B) Finite element model of the electric potential (left) and e-field (right) in the behavioral arena. The electric potential is the potential energy required to move a charge from one place to another without producing any acceleration: the amount of work per unit charge. It is a scalar quantity. The electric field is a vector quantity and a force that surrounds an electric charge. It exerts either an attractive or repelling force on other charges. The base is modeled as ground with 5,000 V applied to the top plate. A water moat surrounds the takeoff site to prevent spiders escaping over ground. The water was electrically floating, not connected to ground or a voltage. The scale bar shows electric potential (left) and e-field (right). Aside from small areas around the base of the arena, the e-field is fairly uniform with a strength of 6.25 kVm−1 (blue color indicated on the scale bar).
(C and D) Boxplots showing the (C) number of dragline drops in response to 1.25 kVm−1, 6.25 kVm−1, and zero-voltage control and (D) the number of tiptoes in response to 1.25 kVm−1, 6.25 kVm−1 and zero-voltage control (D). Significance levels: ∗∗∗p < 0.001, ∗∗p < 0.01.