Gliding Antics

My Animal Sructure & Function assignment was to write an article for New Scientist magazine, based on a scientific journal. As you probably know, those stodgy old scientists tend to make their papers unbelievably long winded and boring, even when the study itself is incredibly facinating. Here's a little bit of the finished product. Really quite interesting stuff.

Many tree-dwelling creatures have mastered the ability of gliding, or what scientists call “directed aerial descent”. Gliding is used by” flying” squirrels, frogs, lizards and snakes to escape from predators, or to find resources. Now, ants can be added to the list.

Canopy ants have many adaptations to help them thrive in their lofty habitat, such as sticky “tarsi”, or toes, to help them cling to surfaces. Despite these adaptations, the ants are frequently dislodged by the wind or other tree-dwelling creatures. Intriguingly, workers of the canopy ant species Cephalotes atratus also drop off their perches voluntarily, to avoid the approach of predators. These ants are then able to skillfully glide back to their home tree trunk, with more than 80% success, during a fall.

Observations of this behavior show that the falling ants follow a J-shaped trajectory back to the tree trunk in three distinct stages. The initial vertical drop is followed by a spectacular mid-air turn to align the abdomen with the tree, winding up in a steep but directed glide to the trunk. One of the most fascinating aspects of gliding ants is that they consistently glide backwards, hind legs first, which was previously unheard of in any other macroorganism. Upon making contract with the trunk, the ants would adhere there, or sometimes tumble downwards for a short distance before latching on. They then proceed to march back up the tree, often returning to the very same branch they originally dropped off from, usually within ten minutes of the fall.

This fascinating discovery has been documented in an article entitled “Directed aerial descent in canopy ants”, published in the February 10, 2005 issue of Nature. It is the first documented study of wingless, gliding flight in the Earth’s most diverse lineage, the insects. It is also the first record of intentional backwards gliding in any macroscopic creature.