Spiders Use Atmospheric Electricity to Fly Hundreds of Miles

When one thinks of airborne organisms, spiders do not usually come to mind. However, these wingless creatures have been found 2.5 miles (4 km) up in the sky, dispersing hundreds of miles. To disperse, they ‘balloon,’ whereby they climb to the top of a prominence, let out silk, and float away.

Wind was considered to be the trigger and driving force for this behavior, but a duo of biologists at the University of Bristol, UK, shows that spiders can balloon without wind if there is a vertical electric field present.

“Many spiders balloon using multiple strands of silk that splay out in a fan-like shape, which suggests that there must be a repelling electrostatic force involved,” said lead author Dr. Erica Morley, an expert in sensory biophysics in the School of Biological Sciences at the University of Bristol.

“Current theories fail to predict patterns in spider ballooning using wind alone as the driver. Why is it that some days there are large numbers that take to the air, while other days no spiders will attempt to balloon at all?”

“We wanted to find out whether there were other external forces as well as aerodynamic drag that could trigger ballooning and what sensory system they might use to detect this stimulus.”

The solution to the mystery could lie in the Atmospheric Potential Gradient(APG), a global electric circuit that is always present in the atmosphere.

APGs and the electric fields surrounding all matter can be detected by insects. For example, bumblebees can detect electric fields arising between themselves and flowers, and honeybees can use their charge to communicate with the hive.

Spider silk has long been known as an effective electric insulator, but until now, it wasn’t known that spiders could detect and respond to electric fields in a similar way to bees.