The incredible Exuvia of Cicadas
Snakes shed their skin several times every year, but did you know, some insects also shed their “skin”, or exoskeleton as it is also known?
Pictured above is a cicada exuvia, or shed exoskeleton found on the hillside of KFBG. Exuvia indicate a crucial life stage of cicadas, marking the exact moment a cicada becomes an adult. When they first hatch, cicada young, or nymphs, drop to the ground from trees in which their eggs were deposited. These nymphs then burrow into the soil, feeding on the root sap of plants until the age of maturity arrives, which in some species in North America may take up to 17 years! At this point, nymphs finally exit the ground and cling on to a nearby plant. Their exoskeletons split open along the back, and they emerge as a winged adult, leaving behind an exuvia as you can see in the photographs! Adults then emit their famous and incessant calls that can reach up to 120 dB. The calls are used to search for mates, starting the process all over again.
In Hong Kong, nymphs emerge from the ground in March every year and the resulting exuvia can be found readily in Hong Kong's countryside, including at KFBG. Perhaps you can spot some during the next mating season!
Did you know? The cicada exuvia have been used in Chinese herbal medicine for many centuries, as it is believed by some that they may relieve cataracts in the elderly.