Cicadidae is one of two families of cicadas (order Hemiptera) which includes an estimated 2500 described species in three subfamilies and many others yet to be described, found in temperate to tropical climates on every continent in the world except Antarctica.The other cicada family is the primitive Australian Tettigarctidae (hairy cicadas), which contains two extant species.
Most closely related to leaf, tree, and plant hoppers, cicadas are large singing insects, often colloquially called locusts.This is incorrect, as locusts are species of swarming grasshoppers, but because the periodical cicadas -see below- emerge in such enormous numbers they were interpreted as locusts by early American settlers, an error which has continued to the present).Males have structures called tymbals on their abdomens with which they produce species-specific "songs"; females do not sing, but can make clicking noises with their wings.
Cicadas spend most of their lives in larval form (called nymphs).Depending on the species the nymphs live up to 2.5 meters (8.2 feet) below ground, feeding on plant sap from roots, which they pierce with their long proboscis.In the nymphs' final developmental stage, they dig their way to the surface with powerful digging legs, pull themselves up to a plant stem, and molt into an adult with prominent eyes and clear wings.They leave behind a very recognizable larval casing, with the slit on the dorsal side from whence the adult emerged clearly visible. After molting, the adults mate and females lay hundreds of eggs in slits they cut into tree bark.When the eggs hatch, the nymphs drop to the ground and burrow.
Cidadas are quite diverse in looks and behaviors.Most adults are between 2 to 5 cm (0.79–2.0in) in length, although Asian species in the genera Pomponia, Megapomponia, and Tagua measure 4.7-7 cm (1.8-2.8 inches) in total length, with the largest species (the empress cicada) reaching a 20 cm (8 inch) wingspan.
Most cicada species live for 2-8 years as larvae with individuals erupting from the ground every year (annual cicadas).However the seven well-known species of periodical cicadas (Magicicada), found only in North America, precisely synchronize their development so that almost all individuals in the same geographic area emerge as “broods” in the same year, either as 13 or 17 year cycles.These prime-year, large-scale emergences are thought to be adaptations to overwhelm predators (a phenomenon termed “predator satiation”). Periodical cicadas can hatch in enormous numbers of up to 1.5 million individual per acre, over large areas along the eastern seaboard and west to Kansas.
Cicadas are eaten around the world by many cultures and different animals, used in traditional medicines in Asia, and surface in many stories and customs.While a cicada might mistake you for a food source and try to poke you with its proboscis, these insects do not sting or bite and pose no danger to humans.
For more information on periodical cicadas see the EOL Magicicada page and the website of Prof. Chris Simon and colleagues.
(Simon 2013; Ramel 2013; Wikipedia 2013)
