Aerodynamic trapping effect and its implications for capture of flying insects by carnivorous pitcher plants

This experimental study tests the hypothesis that carnivorous pitcher plants may have developed passive aerodynamic means to trap a flying prey. Using a miniature propeller, it is shown that hovering inside a pitcher-like container induces a re-circulating flow that pulls the propeller down, towards the bottom, and that the magnitude of this effect depends on the shape of the container and the location of the propeller. Analogously, re-circulating flow induced by a hovering insect inside the trap of a carnivorous pitcher plant should pull it towards the bottom of the trap, possibly preventing its escape.