Caught in the Act: Bats Use the Sound of Copulating Flies as a Cue for Foraging

ScienceDaily (July 20, 2012) — Mating activities are a dangerous business because the attention to other important events in the surroundings is often reduced. Therefore the duration of copulation itself is usually very short. About 100 years ago researchers argued that copulating animals are at a higher risk of being discovered and, consequently, being eaten by a predator. Yet, surprisingly, there are only few observations that support this hypothesis. These examples comprise studies in water-living insects, such as amphipods and water striders, and also in land insects, as investigated in a recent study in Australian plague locusts that are at a higher risk of being eaten as mating pairs compared to single animals.

Apart from decreased attention, a reduced flight response as well as an enhanced conspicuousness induces a higher risk for these winged lovers to be easy prey. Stefan Greif from the Max Planck Institute for Ornithology, and colleagues, have now provided experimental proof for this phenomenon. In a community of house flies and Natterer's bats in a cowshed near Marburg, Germany, they analysed videotapes of the movements of almost 9000 flies. The researchers found that the flies rarely fly at night and mostly sit or run on the ceiling. Finding the flies by echolocation is nearly impossible for the bats as the faint insect echo is completely masked by the strong background echo which makes them virtually "invisible."

Continued:  http://www.sciencedaily.com/releases/2012/07/120723134525.htm