London Zoo: The wind’s tiny passengers

Wind dispersal is common in the world of plants, with seeds of many species sailing air currents to reach new places. Though less common, there are also animals who rely on the wind to take them further than they can travel under their own power. Most wind-dispersed animals are arthropods.

A lot of young spiders disperse using the wind. They climb up to a high point in their environment, raise their abdomens, and produce a long strand of silk. The wind carries the spider by this silk thread, and can take the spider hundreds of kilometers away from their launch point. Dispersing with silk threads on the wind is called ballooning, and it is such an effective dispersal method that spiders are often the first animals to reach new places. For example, all plant and animal life on the island of Krakatoa was obliterated by a series of forceful volcanic eruptions in 1883. When researchers first visited the island in 1884, the only life they found was a single spider who presumably arrived there by ballooning.