Analysis of the cicada's growth process, the complete transformation from egg and nymph to adult

The cicada is a common agricultural and forestry insect, commonly known as the zhi liao, and in its lifetime it goes through three stages: egg, nymph and adult, making it a hemimetabolous insect. Unlike holometabolous insects such as butterflies, the nymph and adult of the cicada are fairly similar in form and do not go through the process of forming a pupa and emerging as a butterfly.

The female cicada uses her ovipositor to lay eggs beneath the epidermis of tender twigs. After the eggs hatch, the tiny nymphs drop from the branch to the ground and immediately burrow into the soil to live. Underground, the nymphs feed by piercing and sucking the sap from plant roots, growing larger through repeated molts. The number of years spent living underground varies greatly depending on the species; some need only a few years, while others can live more than ten years.

Once the nymphs have matured, they mostly emerge from the ground on summer evenings or at night, climb onto tree trunks, branches or grass stems, and complete their final molt, which is what people often call the golden cicada shedding its shell. After eclosion, the adult's body color changes from light to dark, and the wings gradually harden. The male cicada uses the sound-producing organ on its abdomen to call and attract females, and the adult stage usually lasts only about a few weeks.

The cicada's growth process has both value and harm. The cicada slough can be used as medicine, and in some regions the nymphs are also treated as a specialty food; however, egg-laying by adults can damage branches, and nymphs sucking sap from the roots may also weaken tree vigor, so fruit growers often need to pay attention and carry out control measures in orchard management.