Cicadas are large, noisy insects known for their synchronized mass emergences. The direct answer is that cicadas do not bite people defensively or aggressively. They are not equipped with chewing mouthparts, nor do they seek out humans or animals as a food source. They are generally considered harmless to humans.
The Anatomy of a Cicada’s Mouth
Cicadas belong to the insect order Hemiptera, which includes all “true bugs” characterized by specialized piercing and sucking mouthparts. Instead of mandibles designed for biting and chewing, a cicada possesses a long, tube-like structure called a proboscis, also known as a rostrum or beak. This proboscis is kept tucked beneath the head and between the legs when the insect is not feeding.
The outer sheath of the proboscis holds four fine, needle-like components called stylets. These stylets are the true piercing tools, used to penetrate the tough outer layers of plants to access and feed exclusively on xylem fluid, the watery sap that transports nutrients.
Why Cicadas May Seem Threatening
The perception that a cicada can bite often stems from a misunderstanding of its feeding behavior when it lands on a person. If a cicada rests on human skin, it may attempt to “sample” the surface with its proboscis. This is not aggression, but a simple mistake in feeding location.
The insect confuses human skin for a plant surface and instinctively tries to insert its stylets to find the required xylem fluid. A person may feel a sharp prick or a brief, stinging jab as the stylets attempt to penetrate the skin. The cicada quickly realizes the error, as human tissue does not contain the necessary plant sap, and withdraws the proboscis.
Cicadas and Human Health
Cicadas pose no significant health risk to people, as they are not venomous and do not carry or transmit diseases to humans. Unlike mosquitoes, their saliva does not contain anticoagulants, so even if they attempt to pierce the skin, there is no resulting irritation, itching, or redness. The primary nuisance caused by cicadas is their mating song, which can reach high decibel levels during the day. While certain cicadas can be affected by a fungus that changes their behavior, this infection is not transmissible to people.