Ballooning (spider)

Ballooning, sometimes called kiting, is a process by which spiders, and some other small invertebrates, move through the air by releasing one or more gossamer threads to catch the wind, causing them to become airborne at the mercy of air currents and electric fields. A 2018 study concluded that electric fields provide enough force to lift spiders in the air, and possibly elicit ballooning behavior.^[1][2] This is primarily used by spiderlings to disperse; however, larger individuals have been observed doing so as well. 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. Journeys achieved vary from a few metres to hundreds of kilometres. Even atmospheric samples collected from balloons at five kilometres altitude and ships mid-ocean have reported spider landings. Ballooning can be dangerous (due to predators, and due to the unpredictable nature of long-distance ballooning, which may bring individuals to an unfavorable environment).

It is observed in many species of spiders, such as Erigone atra, Cyclosa turbinata, as well as in spider mites (Tetranychidae) and in 31 species of lepidoptera, distributed in 8 suborders. Bell and his colleagues put forward the hypothesis that ballooning first appeared in the Cretaceous.^[3] A 5-year-long research study in the 1920s–1930s revealed that 1 in every 17 invertebrates caught mid-air is a spider. Out of 28,739 specimens, 1,401 turned out to be spiders.^[1]