Cicada

The exoskeleton of a cicada clings to a leaf.

NPS/ Kenneth Ingham

Emerging from eggs laid in tiny slits of a tree, newly developed cicada (Cicadidae) nymphs fall to the ground where they search through leaf litter to find tiny cracks in the underlying soil. Using their strong forelegs they tunnel down up to twenty-four inches where they will spend the majority of their 2-3 year life. During this span of time the nymph uses sap from the roots of trees for nourishment. When sap is depleted from one source the nymphs burrow to another root, molting several times as it grows.

It is currently unknown what cues the cicada to the surface of the ground but increased sap flow in trees and warmer soil temperatures may serve as an indication of prime conditions to complete their life cycle. Making its way out of a ½” hole, the cicada emerges from the ground in the dark hours of the night and finds its way to a nearby tree, plant, or other structure, to climb for safety. The delicate process of shedding the old exoskeleton leaves the cicadae as a white, soft bodied insect however this will quickly change. The cicada sits near the empty shell for a few hours until its wings dry and harden at which time it flies in search of a mate.

Usually resting on the trunk of a tree, male cicadas will create a shrill, buzzing call using their muscles to vibrate two drum-like membranes that cover hollow chambers on the abdomen. This act can be hazardous for cicadas as they not only advertise their presence to females but also to predators. Many birds, rodents and small mammals prey on cicadas, whose only defense is their camouflage or flying away from danger.

After mating, the female cicada lays several hundred eggs by depositing 10-12 eggs at a time into small slits she makes in the branch of a tree. The eggs mature in the bark for approximately 6 weeks until they hatch into cicada nymphs and the lifecycle continues for a new generation.

 

Cicada exoskeletons clinging to the branch of a ponderosa pine tree. These exoskeletons or 'exuviae' are left behind after the cicada molts.

NPS/ Kenneth Ingham

 

The holes that mature cicada emerge out of are usually seen close together in somewhat soft soil, and measure about a half inch in size.

NPS/ Kenneth Ingham