How Can Spiders Travel Through the Air on Silk?

The spider releases a fine silk thread

A spider preparing to balloon raises its abdomen and releases silk from its spinnerets. Air movement can pull on the thread and lift or carry the animal. Wind-tunnel and field research shows that thread length, spider mass, and local airflow affect whether a spider becomes airborne. [1]

Electric fields may play a role

Experiments have found that electric fields can elicit ballooning behavior, and charged silk has been measured. Researchers have proposed that atmospheric electric forces may help spiders take off or remain aloft, especially in low winds. The evidence does not mean every ballooning event is powered mainly by electricity; wind and turbulence remain important. [2]

Ballooning is dispersal, not steering

A ballooning spider cannot navigate like a flying insect. It is using air movement to disperse, sometimes over substantial distances. Landing depends on weather and chance, and the relative contributions of airflow, thread properties, and electric fields are still active research questions.

Ballooning is an uncertain ride

Wind and turbulence can carry a thread-bearing spider upward or sideways, and a change in air movement can end the trip quickly. The spider does not choose a destination or steer like an animal with wings.

Silk is also used for movement on surfaces, not only for aerial dispersal. Spider feet and silk help explain how they move across walls and ceilings, but ballooning depends on different forces and conditions.