A sound strategy for pollination

A sound strategy for pollination. Plants gain an advantage in attracting pollinators if they stand out from the crowd. And so, many plants have evolved flowers with spectacular coloration or enticing scents. Ralph Simon (University of Ulm) and colleagues now report that the Cuban vine Marcgravia evenia uses a novel trick—based on acoustics rather than visual or olfactory effects—to attract its pollinating bats. Just above its purple flowers, M. evenia presents specialized concave leaves, shown here, to the foraging bat. The leaf’s spherical-cap geometry enables it to return a strong and consistent echolocation reflection over a wide angular range. Thus, as the bat flies around in the vicinity, the plant’s steady signal is prominent amongst the random din of echoes from surrounding foliage. To check the effectiveness of the specialized leaf, Simon and colleagues hid a sugar-water feeder in artificial foliage and, in various trials, accompanied it with a replica of M. evenia’s concave leaf, a replica of the vine’s nonspecialized leaf, or nothing at all. Bats consistently found the feeder more quickly when the concave leaf was present. It’s hard to imagine, write the authors, that the specialized leaves can have any evolutionary advantage other than attracting pollinators. (R. Simon et al., Science 333, 631, 2011 10.1126/science.1204210 0036-8075; image courtesy of Corinna U. Koch.)