Carnivorous plant’s sound echoes draw bats in

Ch´ien C. Lee/

Carnivorous plant's sound echoes draw bats in

There is a plant in Borneo that literally has a built-in bat signal. Nepenthes hemslayana is a Paleotropic carnivorous pitcher plant that provides a safe place for bats to roost; it’s cool and free of parasites and other bats. The bat, in turn, helps the plant by providing extra nitrogen through its feces. But how do the bats find the plant in the first place? According to a new study, published online today in Current Biology, N. hemslayana’s tubalike shape features a long, reflective structure that extends back into the cylinder of the plant. As the bats search for a place to roost, the structure acts as an acoustic flag, bouncing back the ultrasonic calls the bats emit to navigate (a process known as echolocation) and waving the bats down to a comfortable home. The structure’s reverberations enable the bats to distinguish this roost-friendly pitcher plant from other closely related plants that lack the reflective piece. These structures are especially important in a crowded forest, allowing the pitcher plant to stand out among dense vegetation that otherwise masks the potential roost. Though it’s rare for plants to use sound as an attraction tactic, there are other species that employ this technique, like some bat-pollinated plants in the Neotropics; this, however, is the first example of a plant that doesn’t use the strategy for pollination.