When an ant tumbles into a river, will it sink or swim? It depends on the species, according to a new study. To learn about how swimming evolved in the insects, scientists dropped 35 types of tropical forest ants into water. Certain ones, like the Odontomachus bauri seen above, took to the liquid like an Olympian. In all, more than half of the tested species could swim. Some, like Gigantiops destructor, reached top speeds of 16 centimeters per second, whereas others lagged behind—but still made it to shore—at a snail’s pace of 1 centimeter per second. Those that weren’t able to keep afloat were more likely to be better gliders, meaning that if they were falling, they might be able to maneuver to a safe landing zone. With so many different kinds of tree- dwelling ants demonstrating the ability to paddle, the researchers think that the skill evolved independently among various groups in response to the danger of toppling off foliage. (Other ants build rafts on the backs of their young.) The study, published today in The Journal of Experimental Biology, suggests that for ants that can’t glide, learning to swim was essential to increase survival chances.
(Video credit: Stephen P. Yanoviak)