Ballooning (spider)

A 2018 study concluded that electric fields provide enough force to lift spiders in the air, and possibly elicit ballooning behavior.

The spider climbs to a high point and takes a stance with its abdomen to the sky, releasing fine silk threads from its spinneret until it becomes aloft.

[4][5] A spider (usually limited to individuals of a small species), or spiderling after hatching,[6] will climb as high as it can, stand on raised legs with its abdomen pointed upward ("tiptoeing"),[7] and then release several silk threads from its spinnerets into the air.

These automatically form a triangular shaped parachute[8] which carries the spider away on updrafts of winds where even the slightest of breezes will disperse the arachnid.

However, adult females of several social Stegodyphus species (S. dumicola and S. mimosarum) weighing more than 100 mg and with a body size of up to 14 millimeters (0.55 in) have been observed ballooning using rising thermals on hot days without wind.

[8] In Australia, in 2012 and in May 2015, millions of spiders were reported to have ballooned into the air, making the ground where they landed seem snow-covered with their silk.

The trajectory further depends on the convection air currents and the drag of the silk and parachute to float and travel high up into the upper atmosphere.

They have even been detected in atmospheric data balloons collecting air samples at slightly less than 5 kilometers (16,000 ft) above sea level.