Some spiders crawl around your house, some jump across the lawn — others take transoceanic flights. With aircraft fashioned from strands of silk, certain species of tiny spiders can take to the air in a process that scientists call “ballooning.”
Ballooning spiders were first documented in the 17th century, Science magazine reported in April. But scientists didn’t know until now exactly how these spiders take to the air.
In a new study, published yesterday (June 14) in the journal PLOS Biology, a group of scientists from the Technical University of Berlin placed 14 crab spiders (the Xysticus genus) on a dome structure in a Berlin park to observe the tiny aviators’ behaviors in natural winds. The researchers then repeated their experiments in a wind tunnel in a lab.
The scientists found that these spiders were very careful about flying; the conditions had to be just right for the arachnids to decide to take off, according to the study.
The spiders first sensed the wind through hairs on their legs. Then, they further tested the wind conditions by lifting one, or sometimes both, of their front legs into the air for 5 to 8 seconds. Until the arachnids were satisfied with the wind conditions, they’d repeat the process, each time rotating their bodies in the direction of the wind.
When the spiders were finally ready to take flight, they raised their abdomens and spun their silk — each strand around 2 to 4 meters long (6.6 to 13 feet) — eventually forming a triangular sheet. With enough drag from the silk against the wind, the spiders could use these thin, silky kites to take off. During takeoff and throughout the flight, the spiders kept their legs stretched out, the scientists reported.
It seems these tiny gliders have figured out how to float past the chaos of the ground.
