Ulrike Bauer/Univ. of Bristol
N. gracilis, which is native to Asia, is specially equipped to trap its prey this way. Its lid is lined with slippery wax crystals and vibrates much more quickly than that of a related species of pitcher plant. Both features seem to be crucial to the plant’s prey-trapping strategy. When the researchers removed the slippery wax or attached a slick N. gracilis lid beneath that of another species of pitcher plant, few to no ants fell to their death during simulated rainfall, researchers report October 5 in the Proceedings of the National Academy of Sciences.