Spiders may lack wings, but they aren’t confined to the ground. Under the right conditions, some spider species will climb to a high point, release silk strands to form a parachute, and float away on the breeze. Buoyed by air currents, they’ve been known to drift kilometers above Earth’s surface, and even to cross oceans to reach new habitats (SN: 2/4/17, p. 12).
Now, new research suggests air isn’t the only force behind this flight, called ballooning. Spiders can sense electrical charges in Earth’s atmosphere, and the forces exerted by these charges might be a cue for them to alight, researchers suggest July 5 in Current Biology. That invisible signal could help explain why spiders’ take-off timing seem a bit, well, flighty. Some days, arachnids balloon en masse; other days, they remain firmly grounded despite similar weather conditions.