Gliding ants use their legs as rudders

Tropical ants that nest in the forest canopy but launch themselves into the air when predators arrive can glide back to their trees using their back legs as rudders, scientists have found.

The arboreal ants, Cephalotes atratus, build elaborate nests in the trunks and branches of tall trees, but are sometimes dislodged by strong winds and tropical downpours, or jump to safety when lizards and birds approach.

Rather than fall directly to the ground, the ants flip their bodies in mid-air and glide backwards, usually to the tree from which they fell, while peering between their legs to see where they are going. Their elongated hind legs are used to adjust their trajectory and latch onto the tree when they land, scientists say.



Researchers used video to study the centimetre-long ants in flight after dropping them from treetops at a field station run by the US Smithsonian Tropical Research Institute on Barro Colorado Island in the Panama canal.

The ants' acrobatic behaviour was confirmed in the laboratory using a high-speed video camera to observe their mid-air manoeuvres.

"For these ants, to fall out of the forest canopy, either into leaf litter or water, would be a really big problem because they'd wind up being eaten," said Stephen Yanoviak at the University of Arkansas at Little Rock, who led the study. "By gliding, they can steer their way back to a tree, climb back up and go home."