A new paper published in Current Biology this month shows how one species of pitcher plant has evolved to attract a species of bat and use it as a source of fertiliser.

The Bornean pitch plant in question (Nepenthes hemsleyana) is part of a mutualistic relationship with the Common woolly bat (Kerivoula hardwickii), in which the pitcher offers the bat a safe place to roost, and in return the bat provides fertiliser in the form of guano (bat poop). Dr Michael Schöner and his team tested the pitcher with a sonar beam and found that it acts as a multidirectional ultrasound reflector. They then experimentally modified the shape of the pitcher, and found that one particular region, known as the orifice, helped bats locate the pitcher.

Plants signalling to animals is not unusual – many flowers have evolved characteristics such as colour, shape, smell, even pheromones, which attract a variety of insects and birds to provide services such as pollination. In each case, the type of signal is tailors to the animal’s biases – heavily visual species are given colour and shape queues, more smell-biased animals are given odours and pheromones. But acoustic adaptation has rarely been found before, and never to serve any purpose other than pollination. Bornean pitcher-plants have convergently evolved these traits along side bat-pollinated plants such as the vine (Mucuna holtonii) in the neotropics.

Want to Know More?

• Schöner et al (2015) Bats Are Acoustically Attracted to Mutualistic Carnivorous PlantsCurrent Biology
• Simon et al (2011) Floral Acoustics: Conspicuous Echoes of a Dish-Shaped Leaf Attract Bat Pollinators Science
• von Helversen & von Helversen (1999) Acoustic guide in bat-pollinated flower Nature
• Chittka et al (1994) Ultraviolet as a component of flower reflections, and the colour perception of hymenoptera Vision Research