A cicada (family Cicadidae) on a twig. Cicadas are best known for their rhythmic mating calls, which fill the air in warm countries. The sound is produced by an oscillating membrane in an abdominal cavity. Cicadas spend most of their lives underground, where the nymph feeds on the sap of tree roots. The nymphs of each species emerge at the same time, after several years, then moult, dry-out, feed, mate and die within a month. Photographed in the Ecuadorian Amazon.