What Are Cicadas? Identification and Natural History
Cicadas are large, loud, plant-feeding insects known for their buzzing songs and, in some species, long underground life cycles. If you are asking what cicadas are, the short answer is that they are true bugs in the insect order Hemiptera, not beetles or flies. They spend most of their lives as immature nymphs underground, then emerge, shed their skins, and fill summer air with mating calls.
What Cicadas Are, in Plain Language
Cicadas are insects with piercing-sucking mouthparts, two pairs of wings, and stout bodies built for flight and sound production. When people ask for a cicadas definition or wonder what is cicadas bug, they are talking about a group of insects that feed on plant fluids from roots and stems. Adult cicadas do not bite people, sting, or eat leaves like grasshoppers.
They are part of the insect family Cicadidae, and they are famous for two things: the males sing, and some species wait years underground before emerging in huge numbers. That combination makes cicadas one of the most recognizable insects in North America.
How to Identify Cicadas
Body shape and size
Cicadas have broad heads, prominent eyes set wide apart, short antennae, and clear or partly colored wings held rooflike over the body. Many species are about 1 to 2 inches long, with sturdy legs and a chunky, armored look. Their bodies are built for clinging to bark and moving up tree trunks after emergence.
Signs you are looking at a cicada
The easiest clue is the sound. Male cicadas produce a strong buzzing, whining, or pulsing call from the abdomen. Another clear sign is the shed skin, called an exuvia, left behind on tree trunks, fences, or shrubs after the nymph molts into an adult. The empty shell has six legs, large eye sockets, and a split back where the adult came out.
If you are asking what are cicadas insects compared with other bugs, remember this rule: cicadas have clear wings, stout bodies, and piercing mouthparts, while beetles have hard wing covers and do not sing this way.
Life Cycle: Underground Nymphs to Singing Adults
Cicadas begin as eggs laid in slits on twigs. After hatching, the tiny nymphs drop to the ground and burrow into soil. There they feed on plant roots for years, growing through several molts. This underground stage is the longest part of the cicada life cycle and the reason these insects seem to appear out of nowhere.
When the nymphs are ready, they crawl out at night, climb upward, and split open their skin. The adult emerges soft, pale, and folded, then the wings expand and harden. Within hours to days, the insect darkens and begins calling. Adults live aboveground long enough to mate, lay eggs, and die.
Annual cicadas and periodical cicadas
Not all cicadas follow the same schedule. Annual cicadas appear every summer, but a new generation is maturing underground the whole time. Periodical cicadas follow a set cycle, with 13-year or 17-year broods that emerge in enormous numbers. That synchronized emergence answers the classic whats up with cicadas question, because their timing is the story.
Habitat, Diet, and Behavior
Where cicadas live
Cicadas live where there are trees, shrubs, and suitable soil for nymphs to burrow into. In yards and forests, they favor trunks, branches, and sunny areas where adults can warm up and call. The underground stage depends on healthy roots, while the adult stage depends on woody plants for egg laying.
What cicadas eat
Nymphs feed on root fluids, and adults feed on plant sap from twigs and stems. Their mouthparts pierce plant tissue and draw liquid food. They do not chew wood, and they do not feed on human food. In the garden, adult egg-laying can scar thin twigs, but that damage is usually limited to small branches and does not kill healthy trees.
Why cicadas are so loud
Only the males sing, using special sound-producing organs on the abdomen called tymbals. The call attracts females and helps males gather in chorus. Different species have different songs, which is why a summer evening can sound like a layered insect orchestra. Cicadas also use vibration and sound to recognize mates and species.
Why Cicadas Matter in Nature and Culture
Cicadas are important food for birds, mammals, reptiles, spiders, and other insects. Their emergence provides a sudden pulse of protein and nutrients to the food web. Underground nymphs also move nutrients through soil, and their empty shells return minerals to the ground after adults emerge.
In culture, cicadas have stood for rebirth, time, and seasonal change. Many traditions connect them with summer and renewal because of their dramatic emergence from the earth. In the United States, they are also a familiar symbol of hot weather, especially when their song starts before sunset and continues into the evening.
What Cicadas Mean for Homeowners and Gardeners
Cicadas are not a pest for most yards. Adults do not eat leaves, and the root feeding of nymphs does not damage established landscape plants in a way homeowners need to treat. The main garden issue is egg laying in young twigs, especially on small trees and newly planted ornamentals.
- Protect young trees with fine mesh netting before adults begin laying eggs.
- Use row cover or insect netting secured tightly around small saplings and fruit trees.
- Choose sturdy trees and shrubs for planting, and avoid exposing thin new branches during peak emergence.
- Prune only after emergence ends, so you do not remove healthy growth that can still support the plant.
For pollinator-friendly yards, cicadas are not a target for control with sprays or repellents. Focus protection on young plants, and leave mature trees alone. A healthy landscape can support cicadas as part of the seasonal insect community while still keeping tender plants safe.
Frequently Asked Questions
Are cicadas bugs or insects?
Cicadas are insects, and more specifically true bugs in the order Hemiptera. If someone says cicadas bugs, they are using the common word bug, not the strict scientific category. They are close relatives of aphids, leafhoppers, and other sap-feeding insects.
Do cicadas bite or sting people?
No. Cicadas do not sting people, and they do not bite in the way mosquitoes, bees, or assassin bugs do. Their mouthparts are for feeding on plant fluids, not human skin.
Why do cicadas emerge in such large numbers?
Periodical cicadas emerge in synchronized broods to overwhelm predators and improve mating success. When thousands or millions appear at once, many survive long enough to reproduce. That mass emergence is one of the most striking events in insect natural history.
What is left behind after cicadas emerge?
The hollow shell left on bark, siding, or outdoor furniture is the nymph exuvia. It is the split skin from the final molt. The adult cicada leaves that shell behind after climbing out and expanding its wings.