About the cover
The swirling lines in the cover image reveal the instantaneous direction of air flow induced by a mosquitos flapping wings. Richard Bomphrey and his colleagues show that the remarkably high wingbeat frequencies and shallow stroke amplitudes used by mosquitoes lead to novel aerodynamic mechanisms. Like most insects, the mosquito generates lift from leading-edge vortices, but this is augmented by trailing-edge vortices, which capture energy left over from previous wingbeats. This exquisitely timed rotational mechanism may explain the unusually high aspect ratio of mosquito wings, as it allows the insect to maximize the aerodynamic force along their wingspan. Cover image: Toshiyuki Nakata.