The wriggling of some butterfly pupae, as shown in these sketches, produces twittering sounds. Researchers found that some swallowtail pupae (A) and brush-footed butterfly pupae (B) produce sounds when their wiggling pulls apart interlocked surfaces of tiny structures located at the membranes between their abdominal segments. (Originally published in Dolle et al 2018, Annals of the Entomological Society of America)