Cicadas

You’ve heard them, and they are loud. Cicadas are amazing insects that grace us with beautiful buzzing songs, made by buckling and unbuckling their drum-like tymbals, which are corrugated membranes in the abdomen. The cicadas’ body serves as a resonance chamber, greatly amplifying the sound. Some cicadas produce sounds lower than 106 dB, among the loudest of all insect-produced sounds and about as loud as a car horn. There are about 25 different species of cicada in Alabama, and over 190 species in the United States. Worldwide, there are over 3,390 species, and new species are found every year.

Besides the big noise they make, cicadas are fascinating because of their unusual lifecycle. The males make the noises to attract females. After mating, the females cut slits in the tree bark and lay their eggs in the slits. When the eggs hatch, they drop to the ground and burrow. They live underground as nymphs for most of their live at depths down to 8 feet. Nymphs have strong front legs for digging and excavating chambers next to the roots they feed on. Some cicadas have an annual lifestyle, and some stay as nymphs in the ground, emerging after 13 or 17 years. The nymph digs an exit tunnel, climbs onto the tree and molts, emerging as an adult. The exuviae or abandoned exoskeleton remains, still clinging to the bark of the tree. Most adults are 1 to 2 inches long.

Adult cicadas can fly rapidly. They can’t jump and aren’t the best at walking either, so they fly if they have to move more than an inch or so. Their songs vary by species, but also, an individual can have a starting call, a chorus, and a distress call. You can listen to various calls at the Cicada Mania Web site.